CN113818836B - An experimental device and method for simulating multi-node blockage and unblocking process of polymer injection wells - Google Patents
An experimental device and method for simulating multi-node blockage and unblocking process of polymer injection wells Download PDFInfo
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Abstract
The invention discloses an experimental device and a method for simulating multi-node blocking and unblocking technological processes of a polymer injection well, wherein the experimental device comprises a constant pressure air pump, N middle containers L for containing working fluid, and sand filling pipes which are connected in series and used for filling porous media; the constant pressure air pump is connected with the air inlet of the intermediate container, and the outlet of the intermediate container is connected with the inlet end of the sand filling pipe through the control valve; a constant temperature heating sleeve for controlling the temperature of the intermediate container is arranged outside the intermediate container; the outlet end of the sand filling pipe is connected with a liquid collecting device; the electronic balance is used for measuring the mass of the liquid collecting device; the automatic control and data acquisition system is also included, and the constant pressure air pump, the control valve and the electronic balance are all connected to the automatic control and data acquisition system; the invention can simulate the blocking condition of different positions of a reservoir and the blocking removal condition of blocking objects at different positions by the blocking removal working fluid under the porous medium seepage condition, can automatically acquire and control data, and has the advantages of simple operation, low cost and high experimental efficiency.
Description
Technical Field
The invention relates to the technical field of oil and gas field development, in particular to an experimental device and method for simulating multi-node blockage and blockage removal processes of a polymer injection well.
Background
With the continuous progress of oil field development, more and more oil fields enter a medium-high water content stage at present, the yield is obviously decreased, and therefore, chemical flooding is adopted for improving the recovery ratio of many oil fields. Polymer flooding is a main means for improving crude oil recovery efficiency and is widely applied, but along with the wide application of polymer flooding, polymer solution is used for wrapping inorganic scale, greasy dirt and the like due to the viscoelasticity of the polymer and the existence of insoluble residues, which are adsorbed and retained in near-wellbore zones. The well bore of the polymer injection well/production well and the near-wellbore zone are blocked, so that the problems of high injection pressure and serious underinjection of partial wells are caused, and some of the wells are stopped, so that the yield of the affected well is difficult to lift, the polymer flooding effect is seriously influenced, and the efficient and rapid development cannot be realized.
For plugging of polymer injection wells/production wells, one of the commonly used plugging removal measures at present is chemical plugging removal, and the principle of the chemical plugging removal is that a polymer degradation agent is utilized to degrade high-concentration polymers and insoluble matters thereof, an acid is utilized to erode inorganic scale, and a cleaning agent is utilized to dissolve and remove greasy dirt, so that the purpose of plugging removal is achieved. Thus, the preference of the chemical blocking remover formulation and process is particularly important.
And carrying out a long-time soaking experiment on the plugs by a large amount of plug removing agents, observing the shape change of the plugs, drying and weighing the solid residues, and calculating the final dissolution rate of the plugs to evaluate the plug removing effect of the plug removing agents. However, this method has the following disadvantages: 1) The dynamic condition of the plug changing along with time cannot be quantitatively evaluated, and the plug removing process can only be observed by naked eyes; 2) The evaluation method has relatively ideal conditions, and the contact surface, the contact time and the reaction concentration of the blocking remover and the blocking object are in sufficient states, and the experimental conditions are relatively ideal, so that the indoor evaluation effect of a plurality of blocking removers at present is very good, but the field construction effect is not ideal; 3) The method is not in line with the actual blocking removal construction process and the contact reaction scene of the blocking removal medicament and the blocking object, and the experimental result has poor guidance. In the actual blocking removal process, the blocking remover flows away through the surface of the blocking object, rather than the process of soaking the blocking remover in large doses for a long time. The blocking remover preferably obtained by this method is unsatisfactory in field construction due to the shortage of this evaluation method.
Another common method is to simulate a core blocking removal experiment, inject a high concentration polymer into the core, then inject a blocking remover, and test the permeability recovery of the core after the blocking remover reacts with the polymer. The method has the following defects: 1) The permeability and the micro-pore structure of different cores have larger difference, and the repeatability is poor, so that the experimental regularity is poor; 2) The plugging simulation is realized by directly injecting high-concentration polymer, and because the on-site plugging is performed through long-time accumulation and large-displacement injection, the indoor simulation method is greatly different from the actual situation, so that the simulated plugging degree is greatly different from the actual plugging degree of the injection well, and the on-site plugging situation cannot be simulated; 3) The experiment is more complicated, the preparation work is more, the experiment period is long, and the cost is high. 4) The blocking removal effect is evaluated by adopting the recovery condition of permeability/diversion capability, and is actually only the blocking removal effect of a main runner in a porous medium, but not the clearance rate of a blocking object. The blockage removing system obtained by the evaluation method has the problem of incomplete blockage removal, so that the blockage removing effective period is short, and repeated blockage of the main flow passage is fast generated.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides the experimental device and the method for simulating the multi-node plugging and unplugging process of the polymer injection well, which can simulate plugging of different positions of a reservoir and the situation that the plugging removing working solution removes plugs of different positions under the condition of porous medium seepage, and has the advantages of low cost, simplicity and easiness in operation and short experimental period.
The technical principle of the invention:
1) Blocking principle: the plugs are deposited/glued in the pores of the porous medium to form hypotonic lumps, so that the diversion capacity of the seepage channel of the reservoir is drastically reduced or lost;
2) The blocking removal principle: erosion/removal of deposited/cemented components in the pores of the porous media, restoration/enhancement of conductivity.
Aiming at the technical principle, the invention adopts the following technical ideas:
1) Multi-node occlusion simulation: simulating multi-node plugging downhole refers to simulating plugging conditions at different locations (nodes) downhole (e.g., gravel pack, different radius ranges near the wellbore). According to the permeability of different positions of the oil reservoir, quartz sand with corresponding mesh numbers is selected, different porous media are respectively and uniformly mixed with corresponding typical plug components, the mixture is respectively filled into a plurality of sand filling pipes for compaction, and the sand filling pipes are connected in series according to the underground plug change sequence so as to simulate underground multi-node plug. The plugs can be returned from the site, and plugs at different positions (such as polymer, polymer+inorganic scale, polymer+inorganic scale+dirty oil and the like) can be simulated and prepared according to the analysis result of components of the returned plugs. The method comprises the following specific steps: (1) determining typical plug composition for different nodes by performing composition analysis on plugs at different locations of the injection well; (2) determining the proportion of the volume of the blockage to the pore volume of the quartz sand according to the reduction condition of the on-site injection polymerization injection allocation volume so as to simulate blockage of different degrees; (3) filling quartz sand with the corresponding mesh numbers of different nodes and corresponding typical plugs into a plurality of sand filling pipes according to a certain order; (4) the lengths of sand filling pipes simulating different nodes are the same as or reduced in the same proportion with the actual different plugging radius ranges. Simulating multi-node continuous plugging at different positions in the well is a precondition for simulating and optimizing the on-site plugging removal process.
2) Simulation of a multi-node blocking removal process: heating the temperature of the unblocking working solution in the intermediate container through a constant-temperature heating sleeve, and simulating the temperature of on-site liquid water distribution; heating the sand filling pipe to the underground temperature of the target oil reservoir through a constant temperature tank; under the constant pressure condition, different blocking removing working fluid slugs are injected into a plurality of sand filling pipes connected in series, and the blocking removing working fluid is subjected to front porous medium adsorption and reaction with front plugs and then continuously reacts with middle and rear plugs under the simulated field porous medium seepage condition, so that the blocking removing working fluid is basically consistent with the field blocking removing process; the injection pressure of the blocking removal working fluid is adjusted to simulate the influence of the injection displacement of the on-site blocking removal working fluid on the blocking removal effect; different blocking removing working fluids are filled into a plurality of intermediate containers so as to simulate the field multi-fluid-mixing tank combined slug injection process, and slug combination (injection quantity and injection sequence) is optimized according to the change of blocking objects at different positions; and closing two ends of the sand filling pipe to simulate the construction process of the on-site well closing reaction.
3) Evaluation of blocking removal Effect
Under the conditions of the same pressure and the same mesh number of quartz sand, the blocking degree and the flow conductivity of the porous medium before and after blocking removal can be quantitatively evaluated by testing the flow velocity without blocking objects and the flow velocity before and after blocking removal; the removal rate of the plugs in the porous media of different nodes can be quantitatively evaluated by calculating the mass of the plugs added into the different nodes during filling and the mass of the residual plugs after the plugging removal. According to the evaluation index of the clearance of the plugs of different nodes, the technological parameters of plug combination and plug removal of the plug removal system can be further optimized, the plugs of different nodes can be thoroughly cleared, and the plug removal effect and the effective period are ensured.
In order to realize the technical principle and the technical thought, the invention adopts the technical scheme that: an experimental device for simulating multi-node blocking and unblocking processes of a polymer injection well comprises a constant pressure air pump, N intermediate containers for containing working fluid and L sand filling pipes which are connected in series and used for filling porous media, wherein N is more than or equal to 2, and L is more than or equal to 2; the constant pressure air pump is connected with the air inlet of the intermediate container, and the outlet of the intermediate container is connected with the inlet end of the sand filling pipe through the control valve; a constant temperature heating sleeve for controlling the temperature of the intermediate container is arranged outside the intermediate container; the outlet end of the sand filling pipe is connected with a liquid collecting device; the sand filling pipe is arranged in the constant temperature tank; the electronic balance is used for measuring the mass of the liquid collecting device; the automatic control and data acquisition system is further included, and the constant-pressure air pump, the control valve and the electronic balance are all connected to the automatic control and data acquisition system. The porous medium can be quartz sand, ceramsite and glass beads, and a mixture of the quartz sand, the ceramsite and the glass beads and the blockage respectively, preferably the mixture of the quartz sand and the blockage.
Further, a magnetic rotor is arranged in the intermediate container, and a magnetic stirrer matched with the magnetic rotor for use is arranged below the intermediate container.
Further, the intermediate container is arranged on the intermediate container fixing frame; the middle container fixing frame is arranged on the fixing bracket; still include unable adjustment base, fixed bolster, constant temperature tank and electronic scale all set up on unable adjustment base.
Furthermore, the automatic control and data acquisition system comprises system control, data acquisition software and a computer, so that the automatic control and data acquisition of the experimental process are realized.
An experimental method for simulating multi-node blocking and single-slug blocking removal processes of an injection well comprises the following steps:
step 1: the number of the intermediate containers is 2, namely a first intermediate container and a second intermediate container, wherein pure water is filled in the first intermediate container, and blocking removing working solution is added in the second intermediate container; the intermediate container is heated to the on-site liquid preparation temperature T through the constant-temperature heating sleeve 1 The method comprises the steps of carrying out a first treatment on the surface of the If the blocking removing working solution is a suspension or dispersion system, stirring is carried out by a magnetic rotor in the intermediate container and a magnetic stirrer below the intermediate container, so that the blocking removing working solution is ensured to be uniformly dispersed; filling quartz sand with preset mesh number into L sand filling pipes respectively, connecting the sand filling pipes in series, placing the sand filling pipes into a constant temperature tank, and setting the temperature of the constant temperature tank as the target downhole temperature T of an oil reservoir 2 Wherein L is more than or equal to 2; the mesh number of the quartz sand is selected according to the oil reservoir permeability; the outlet ends of the first intermediate container and the second intermediate container are respectively connected with a first control valve and a second control valve, and the first control valve and the second control valve are connected to the inlet end of the sand filling pipe in parallel; the outlet end of the sand filling pipe is connected to the liquid collecting device; the liquid collecting device is arranged on the electronic balance Applying;
the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 1 Setting when effluent liquid quality reaches M 1 Closing the first control valve and keeping the second control valve in a closed state; zero clearing the electronic balance and starting an experiment; calculating the flow velocity v of pure water in blank quartz sand according to the data of the effluent liquid quality collected by the automatic control and data collection system along with time 0 ；
Step 2: respectively filling the prepared mixture consisting of quartz sand and plugs at different nodes into L sand filling pipes, connecting the sand filling pipes with an intermediate container, and then placing the sand filling pipes in a constant temperature tank for preheating for 1h; the total mass of the mixture of quartz sand and plugs in each sand filling pipe is recorded as m 31 、m 32 、m 33 ……m 3L Calculating the mass m of quartz sand in each sand filling pipe 41 、m 42 、m 43 ……m 4L Calculating the total mass m of the mixture consisting of quartz sand and plugs in the L sand filling pipes 3 Calculating the total mass m of quartz sand in L sand filling pipes 4 ；
m 3 ＝m 31 +m 32 +m 33 +……+m 3L
m 4 ＝m 41 +m 42 +m 43 +……+m 4L
Wherein H is i I=1, 2 … L for the ratio of quartz sand to plug mass for different nodes;
step 3: the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 1 Setting when effluent liquid quality reaches M 1 Closing the first control valve and keeping the second control valve in a closed state; zero clearing the electronic balance and starting an experiment; after the experiment is completed, calculating the flow velocity v before unblocking according to the data of the effluent liquid quality which is acquired by the automatic control and data acquisition system and changes along with time 1 ；
Step 4: the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 2 The second control valve has an opening time t 2 Or is set to when the effluent mass reaches M 2 Closing the second control valve and keeping the first control valve in a closed state; starting an experiment, and injecting blocking removing working solution in a second intermediate container into the sand filling pipe; after the injection of the unblocking working solution in the second intermediate container is completed, setting the pressure of the constant-pressure air pump to be p on the automatic control and data acquisition system 1 The method comprises the steps of carrying out a first treatment on the surface of the When the effluent liquid quality reaches M 1 Closing the first control valve and keeping the second control valve in a closed state; starting an experiment, and calculating the flow velocity v after unblocking by utilizing the data of the effluent liquid quality collected by an automatic control and data collection system along with the time change 2 ；
Step 5: after the experiment is completed, taking out the sand filling pipes, respectively taking out quartz sand and the rest plugs in the L sand filling pipes, and respectively weighing the quartz sand and the rest plugs with the mass of m after drying 51 、m 52 、m 53 ……m 5L Respectively weighing the mass of m 31 、m 32 、m 33 ……m 3L Drying a mixture of quartz sand and plugs at different nodes, wherein the mass of the mixture is m 61 、m 62 、m 63 ……m 6L ；
Calculating the total mass m of quartz sand in L sand filling pipes and residual plugs after drying 5 Calculating the total mass as m 3 The total mass m of the mixture formed by quartz sand and plugs in L sand filling materials after drying 6 ；
m 5 ＝m 51 +m 52 +m 53 +……+m 5L
m 6 ＝m 61 +m 62 +m 63 +……+m 6L
Step 6: calculating the plugging degree D before plugging removal 1 Degree of clogging after unblocking D 2 Recovery rate eta of diversion capacity h Different node plug clearance η ji And overall clearance η of multinode plugs j ；
Wherein:
an experimental method for simulating multi-node plugging and multi-section plugging removal processes of an injection well comprises the following steps:
step 1: n intermediate containers, wherein N is more than or equal to 3; adding pure water into the first intermediate container; the rest intermediate containers are respectively filled with different blocking removing working fluids, and the intermediate containers are heated to the on-site liquid preparation temperature T through a constant-temperature heating sleeve 1 The method comprises the steps of carrying out a first treatment on the surface of the If the blocking removing working solution is a suspension or dispersion system, stirring is carried out by a magnetic rotor in the intermediate container and a magnetic stirrer below the intermediate container, so that the blocking removing working solution is ensured to be uniformly dispersed; filling quartz sand with preset mesh number into L sand filling pipes and connecting the L sand filling pipes in series, placing the sand filling pipes into a constant temperature tank, and setting the temperature of the constant temperature tank as the target downhole temperature T of an oil reservoir 2 Wherein L is more than or equal to 2; the mesh number of the quartz sand is selected according to the oil reservoir permeability; the outlet ends of the N intermediate containers are connected with control valves, and each control valve is connected to the inlet end of the sand filling pipe in parallel; the outlet end of the sand filling pipe is connected to the liquid collecting device; the liquid collecting device is arranged on the electronic balance;
The pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 1 Setting when effluent liquid quality reaches M 1 When the first intermediate container corresponding control valve is closed, the rest control valve is kept in a closed state; zero clearing the electronic balance and starting an experiment; calculating the flow velocity v of pure water in blank quartz sand according to the data of the effluent liquid quality collected by the automatic control and data collection system along with time 0 ；
Step 2: respectively filling the prepared mixture consisting of quartz sand and plugs at different nodes into L sand filling pipes, connecting the sand filling pipes with an intermediate container, and then placing the sand filling pipes in a constant temperature tank for preheating for 1h; record the total mass of the mixture of quartz sand and plugs in each sand filling pipe as m 31 、m 32 、m 33 ……m 3L Calculating the mass m of quartz sand in each sand filling pipe 41 、m 42 、m 43 ……m 4L Calculating the total mass m of the mixture consisting of quartz sand and plugs in the L sand filling pipes 3 Calculating the total mass m of quartz sand in L sand filling pipes 4 ；
m 3 ＝m 31 +m 32 +m 33 +……+m 3L
m 4 ＝m 41 +m 42 +m 43 +……+m 4L
Wherein H is i I=1, 2 … L for the ratio of quartz sand to plug mass for different nodes;
step 3: the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 1 Setting when effluent liquid quality reaches M 1 When the first intermediate container corresponding control valve is closed, the rest control valve is kept in a closed state; zero clearing the electronic balance and starting an experiment; after the experiment is completed, calculating the flow velocity v before unblocking according to the data of the effluent liquid quality which is acquired by the automatic control and data acquisition system and changes along with time 1 ；
Step 4: on an automatic control and data acquisition system, according to different designed injection sequences, injection time and alternate times of the deblocking working fluidThe pressure of the constant pressure air pump in the process of setting corresponding slugs in sequence is p respectively 2 、p 3 、…p N Setting the opening time of the control valve corresponding to different intermediate containers to be t respectively 2 、t 3 、…t N Or is arranged such that when the effluent mass reaches M 2 、M 3 …M N When one control valve is opened, the rest control valves are kept closed; starting an experiment, and injecting a blocking removal working solution;
step 5: after the injection of different blocking removing working fluids is completed, a constant pressure air pump is arranged on an automatic control and data acquisition system, wherein the pressure of the constant pressure air pump is p 1 When the effluent liquid quality reaches M 1 When the first intermediate container corresponding control valve is closed, the rest control valve is kept in a closed state; starting an experiment, and calculating the flow velocity v after unblocking by utilizing the data of the effluent liquid quality collected by an automatic control and data collection system along with the time change 2 ；
Step 6: after the experiment is completed, taking out the sand filling pipes, respectively taking out quartz sand and the rest plugs in the L sand filling pipes, and respectively weighing the quartz sand and the rest plugs with the mass of m after drying 51 、m 52 、m 53 ……m 5L Respectively weighing the mass of m 31 、m 32 、m 33 ……m 3L Drying a mixture of quartz sand and plugs at different nodes, wherein the mass of the mixture is m 61 、m 62 、m 63 ……m 6L ；
Calculating the total mass m of quartz sand in L sand filling pipes and residual plugs after drying 5 Calculating the total mass as m 3 The total mass m of the mixture formed by quartz sand and plugs in L sand filling materials after drying 6 ；
m 5 ＝m 51 +m 52 +m 53 +……+m 5L
m 6 ＝m 61 +m 62 +m 63 +……+m 6L
Step 7: calculating the plugging degree D before plugging removal 1 Degree of clogging after unblocking D 2 Recovery rate eta of diversion capacity h Different node plug clearance η jL And overall clearance η of multinode plugs j ；
Wherein:
further, the preparation method of the mixture composed of the quartz sand and the plug comprises the following steps:
s1: according to the permeability condition of the target oil reservoir, quartz sand with preset mesh number is selected, a shaft is used as a center of a circle, and corresponding plugs of different nodes are simulated and prepared according to the analysis results of the components of plugs with different radiuses;
s2: respectively filling preset mesh quartz sand into L sand filling pipes, and recording the volume V of quartz sand filled into each sand filling pipe 11 、V 12 、V 13 ……V 1L The method comprises the steps of carrying out a first treatment on the surface of the Weigh each sand filling pipe dry weight m 11 、m 12 、m 13 ……m 1L Injecting pure water into each sand filling pipe until the outflow end is discharged for 30min; weigh each sand filling pipe wet weight m 21 、m 22 、m 23 ……m 2L Calculating the pore volume PV of quartz sand in each sand filling pipe 1 、PV 2 、PV 3 ……PV L And porosity ofThe total pore volume PV of quartz sand in the L sand filling pipes;
PV＝PV 1 +PV 2 +PV 3 +……+PV L
wherein V is 1i The internal volume is calculated according to the corresponding sand filling pipe size parameter;
S3: selecting the ratio G of the volume of the blockage to the volume of the pore space according to the blockage degree of different nodes of the target well 1 、G 2 、G 3 ……G L Calculate and weigh the total volume of preparation V 1 、V 2 、V 3 ……V L Calculating the total mass and the content of each component of the plug, uniformly mixing and stirring each component of the plug, and calculating the mass ratio H of the quartz sand and the plug of different nodes 1 、H 2 、H 3 ……H L The calculation method is as follows:
2.5 is the true density of quartz sand, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the 1 is the density of the blockage, g/cm 3 。
S4: and (3) uniformly stirring and mixing the plugs of different nodes and quartz sand, sealing, and standing at the target well temperature for curing for A days for later use.
Further, the flow velocity v 0 、v 1 、v 2 The calculation method comprises the following steps:
and pure water is adopted to test the flow velocity of blank quartz sand, before and after unblocking, so that the influence on the calculated result of the clearance rate caused by the inorganic salt in the brine being adsorbed and retained in the sand filling pipe is avoided. And according to the time-varying data of the effluent quality acquired by the automatic control and data acquisition system, the flow rate at the stage of the stable increase of the effluent quality is the required flow rate.
The beneficial effects of the invention are as follows:
(1) According to the invention, the multi-node blockage with different nodes, different degrees and different blockage components can be simulated according to the actual condition of the site, and the continuous removal condition of the blockage removal working solution on the multi-node blockage under the porous medium seepage condition is more in line with the actual condition of the site, and the experimental result has greater guiding significance on the blockage removal process design;
(2) The multiple nodes are connected in series, the length of each node sand filling pipe corresponds to the blocking radius of a site node (the same or the same proportion is reduced), so that the blocking removing working fluid is simulated to pass through the front porous medium adsorption and react with the front end blocking object and then continuously act with the middle and rear end blocking object under the condition of site porous medium seepage, the influence of different nodes on the blocking removing effect under the condition of different blocking object components and blocking degrees is further guided to optimize the technological parameters such as the blocking removing agent injection concentration, injection speed, injection quantity, slug combination design, well closing reaction time and the like, the blocking removing working fluid is closer to the site comprehensive blocking removing condition, the guiding effect is stronger, and the optimal blocking removing effect is achieved;
(3) The blocking degree, the flow conductivity and the flow conductivity recovery rate of the porous medium before and after the blocking removal can be quantitatively evaluated by testing the flow velocity of pure water before and after the blocking removal in the porous medium; the mass of the plugs added into the quartz sand pores of different nodes and the mass of the plugs in the quartz sand pores of different nodes after the plugs are removed are calculated through testing, so that the clearance rate of the plugs in the quartz sand pores of different nodes is quantitatively evaluated, the formula of a plug removal system is further optimized, the plug removal system is ensured to thoroughly remove the plugs in the quartz sand pores of each node, and the plug removal effect and the effective period are ensured.
(4) The invention utilizes the automatic control and data acquisition system, can set experimental parameters and flow, carries out slug design, controls the start and the end of the experiment, automatically carries out data acquisition in the experimental process, has simple operation, low cost, reduces human error, and has short experimental period and high efficiency.
(5) The contact part of the experimental device and the working fluid is prepared from materials resistant to temperature, acid, alkali and oxidation, and is suitable for various types of working fluids.
Drawings
FIG. 1 is a schematic diagram of an experimental device for simulating a single-slug deblocking process.
Fig. 2 is a schematic structural diagram of an experimental device for simulating a multi-slug deblocking process.
Fig. 3 is a schematic structural view of the intermediate container according to the present invention.
In the figure: the device comprises a 1-constant pressure air pump, a 2-intermediate container, a 21-air inlet, a 22-constant temperature heating sleeve, 23-internal liquid, a 24-magnetic rotor, 25-outlet, a 26-magnetic stirrer, a 3-control valve, a 4-sand filling pipe, a 5-constant temperature tank, a 6-liquid collecting device, a 7-electronic balance, an 8-intermediate container fixing frame, a 9-fixing support, a 10-liquid discharge pipeline, a 11-air inlet pipeline, a 12-control line, a 13-automatic control and data acquisition system and a 14-fixing base.
Detailed Description
The invention will be further described with reference to the drawings and specific examples.
The materials (middle container, sand filling pipe, connecting pipeline, etc.) contacted with the working fluid are all prepared from materials with temperature resistance, acid and alkali resistance and oxidation resistance.
A closed experimental device for simulating a multi-node blocking removal process comprises a constant pressure air pump, N intermediate containers for containing working fluid and L sand filling pipes which are connected in series and used for filling porous media, wherein N is more than or equal to 2, L is more than or equal to 2, single-slug blocking removal process simulation can be performed when N is more than or equal to 2, and multi-slug blocking removal process simulation can be performed when N is more than or equal to 3; the porous medium can be quartz sand, ceramsite and glass beads, and a mixture of the quartz sand, the ceramsite and the glass beads and the blockage respectively, preferably the mixture of the quartz sand and the blockage. The constant pressure air pump is connected with the air inlet of the intermediate container, and the outlet of the intermediate container is connected with the inlet end of the sand filling pipe through the control valve; a constant-temperature heating sleeve for controlling the temperature of the intermediate container is arranged outside the intermediate container, and the temperature control range of the constant-temperature heating sleeve is between room temperature and 90 ℃, so that the temperature of the liquid distribution water of the target oil reservoir can be conveniently simulated; the outlet end of the sand filling pipe is connected with a liquid collecting device; the sand filling pipe is arranged in the constant temperature tank; the electronic balance is used for measuring the mass of the liquid collecting device; the system also comprises an automatic control and data acquisition system, a constant pressure air pump, a control valve and an electronic day average automatic control and data acquisition system. A magnetic rotor is arranged in the middle container, and a magnetic stirrer matched with the magnetic rotor is arranged below the middle container. The middle container is arranged on the middle container fixing frame; the middle container fixing frame is arranged on the fixing bracket; still include unable adjustment base, fixed bolster, constant temperature tank and electronic scale all set up on unable adjustment base.
The automatic control and data acquisition system comprises system control, data acquisition software and a computer, can control the running time and the revolution of the magnetic stirrer, can control and adjust the pressure and the running time of the constant pressure air pump, and simultaneously control the switch of different control valves, so as to realize the evaluation experimental flow of the blocking removal effect, the slug injection pressure, the slug switching sequence (the two modes of injection time and injection amount can be switched) and the slug injection amount/injection time control. And meanwhile, the constant-pressure air pump pressure and the mass data of the electronic balance are collected, the blocking removal effect of the blocking removal working solution is calculated and evaluated, the operation is simple, the human error is reduced, and the experimental repeatability is further improved.
The method of using the experimental set-up of the present invention will be described in the following by way of specific examples, which simulate the in-situ liquid water temperature T 1 Target reservoir downhole temperature T =50℃ 2 According to the plugging conditions (plug components and plugging degree) of the target oil reservoir, respectively simulating and preparing the mixture samples 1, 2, 3 and 4 composed of quartz sand and plugs at 4 nodes (the radius ranges are respectively 0.3-0.6 m, 0.6-0.9 m and 0.9-1.2 m) by taking the shaft as the center, wherein the total volume is 100mL. The number of sand filling pipes is 4, the blocking of 4 nodes is simulated respectively, the radius lengths of the 4 nodes are the same, and therefore 4 sand filling pipes with the length of 10cm are selected.
The method for preparing the mixture of quartz sand and plugs at the position with the shaft as the center and the node 1 and the radius of the node ranging from 0m to 0.3m comprises the following steps:
s1: according to the permeability condition near the target oil reservoir shaft, quartz sand (dried at 80 ℃) with the mesh number of 40-60 meshes and plugs to be tested are selected, and according to the analysis result of the components of the plugs, the plugs are as follows: polymer (75.4%) + inorganic scale (11.2%) + oil (13.4%), polymer (molecular weight 2000 ten thousand, degree of hydrolysis 25.5%) of polyacrylamide for target reservoir, inorganic scale calcium carbonate, oil of target reservoir crude oil;
s2: testing the porosity of 40-60 mesh quartz sandThe test method is as follows:
filling quartz sand into a sand filling pipe, and weighing the dry weight m of the sand filling pipe 11 Pure water was poured into the sand filling tube until the outflow end was discharged for 30min, = 256.7g, and the wet weight m of the sand filling tube was weighed 21 =266.6g, pore volume PV was calculated 1 Porosity of the porous body
Wherein V is 11 =25.2 mL is the internal volume calculated from the sand pack size parameter;
s3: selecting the ratio G of the volume of the blocking object to the volume of the pores according to the blocking degree of the target oil reservoir 1 =92% and the total volume V of the preparation is calculated and weighed 1 100mL of a mixture of quartz sand and plugs, the mass of quartz sand being 100× (100% -39.3%) ×2.5=151.8 g, the total mass of plugs being 100×39.3% ×92% ×1=36.1 g, including 75.4% of organic compound containing 0.5% 10000mg/L polymer 27.3g (polymer concentration is adjustable according to practical situation), 11.2% calcium carbonate inorganic scale 4.0g, 13.4% crude oil component 4.8g, mix each component in the plug evenly; calculating the mass ratio H of quartz sand to plug 1 =4.2, the calculation method is as follows:
2.5 is the true density of quartz sand, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the 1 is estimated density of the blockage, g/cm 3 。
S4: and mixing and stirring quartz sand and the plug uniformly, sealing, and curing for 7 days at the target well temperature.
In this embodiment, the number of sand filling pipes L is 4, the nodes 2, 3, 4, the radius ranges of 0.3-0.6 m, 0.6-0.9 m, 0.9-1.2 m quartz sand and the mixture preparation composed of plugs are repeated, the specific data and parameters are shown in the following table:
TABLE 1 data on porosity test of silica sand in different nodes
Total pore volume pv=38ml of quartz sand in 4-node 4-sand-filled tube
TABLE 2 parameters for the preparation of mixtures of silica sand and plugs at different nodes
TABLE 3 preparation of specific addition of 100mL of mixture of silica sand and plugs at different nodes
According to the prepared mixture formed by the quartz sand and the plugs of 4 nodes, the plugging and single-section plug plugging removal process of 4 nodes (taking a shaft as a center, with the radius ranging from 0 to 0.3m, from 0.3 to 0.6m, from 0.6 to 0.9m and from 0.9 to 1.2 m) of the injection well is simulated, and the device is shown in figure 1, and the experimental method is as follows:
Step 1: the intermediate container is a first intermediate container and a second intermediate container, the first intermediate container is filled with pure water, the second intermediate container is added with 3.0wt.% of unblocking working solution sodium percarbonate, and the liquid in the intermediate container is heated to the on-site liquid preparation temperature T through a constant-temperature heating sleeve 1 =50 ℃; quartz sand with 40-60 meshes, 80-100 meshes, 140-160 meshes and 140-160 meshes is respectively filled in 4 sand filling pipes, and the temperature of a constant temperature tank is set as the target downhole temperature T of an oil reservoir 2 =60 ℃, place 4 sand-filled tubes in a thermostatic bath; the outlet ends of the first intermediate container and the second intermediate container are respectively connected with a first control valve and a second control valve, and the first control valve and the second control valve are connected to the inlet end of the sand filling pipe in parallel; the outlet end of the sand filling pipe is connected to the liquid collecting device; placing the liquid collecting device on an electronic balance;
the pressure p of the constant-pressure air pump is set on the automatic control and data acquisition system 1 =0.15 MPa, set when the effluent mass reaches M 1 When the valve is in 600g, the first control valve is closed, and the second control valve is kept in a closed state; resetting the electronic scale, and starting an experiment; calculating the flow velocity v of pure water in blank quartz sand by utilizing time-varying data of effluent liquid quality acquired by an automatic control and data acquisition system 0 ＝203.4g/min；
Step 2: the mixture 1,2,3 and 4 composed of the prepared quartz sand with 4 nodes and the plugs are respectively filled in 4 sand filling pipes, and the sand filling pipes are placed in a constant temperature tank after being connected with an intermediate container, and preheated for 1h; the total mass of the mixture of quartz sand and plugs in the 4 sand filling pipes is recorded as m 31 ＝47.652g、m 32 ＝46.221g、m 33 ＝45.346g、m 34 = 42.554g, the mass m of quartz sand in 4 sand filling pipes was calculated respectively 41 ＝38.489g、m 42 ＝38.766g、m 43 ＝40.470g、m 44 = 40.314g; calculating the composition of quartz sand and plugs in 4 sand filling pipesTotal mass m of the mixture 3 Calculating the total mass m of quartz sand in 4 sand filling pipes 4 ；
m 3 ＝m 31 +m 32 +m 33 +m 34＝ 181.773g
m 4 ＝m 41 +m 42 +m 43 +m 44＝ 158.039g
Wherein H is i I=1, 2,3,4, which is the ratio of the quartz sand to the plug mass of different nodes;
step 3: the pressure p of the constant-pressure air pump is set on the automatic control and data acquisition system 1 =0.15 MPa, set when the effluent mass reaches M 1 When the valve is in 600g, the first control valve is closed, and the second control valve is kept in a closed state; zero clearing the electronic balance and starting an experiment; after the experiment is completed, calculating the flow velocity v before unblocking according to the data of the effluent liquid quality which is acquired by the automatic control and data acquisition system and changes along with time 1 ＝10.4g/min；
Step 4: the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 2 =0.1 MPa, set when the effluent mass reaches M 2 When the valve is in the condition of being 380g (10 PV), the second control valve is closed, and the first control valve is kept in a closed state; starting an experiment, and injecting blocking removing working solution in a second intermediate container into the sand filling pipe; after the injection of the unblocking working solution in the second intermediate container is completed, a constant-pressure air pump pressure p is arranged on an automatic control and data acquisition system 1 When the effluent mass reaches M =0.15 MPa 1 When the valve is in 600g, the first control valve is closed, and the second control valve is kept in a closed state; starting an experiment, and calculating the flow velocity v after unblocking by utilizing the data of the effluent liquid quality collected by an automatic control and data collection system along with the time change 2 ＝91.3g/min；
And 3-4, setting continuous experiments through an automatic control and data acquisition system.
Step 5: after the experiment is completed, take outThe sand filling pipes are respectively used for taking out quartz sand and the rest plugs in the L sand filling pipes, and the mass of the quartz sand and the rest plugs is respectively called m after the quartz sand and the rest plugs are dried (dried in an oven at 80℃) 51 ＝39.314g、m 52 ＝39.623g、m 53 ＝41.201g、m 54 41.067g, respectively weighing m 31 ＝47.652g、m 32 ＝46.221g、m 33 ＝45.346g、m 34 The mixture of quartz sand and plugs at different nodes (oven dried at 80 ℃) was dried = 42.554g, the mass was defined as m 61 ＝41.231g、m 62 ＝40.514g、m 63 ＝41.525g、m 64 ＝41.216g。
Calculating the total mass m of quartz sand in 4 sand filling pipes and residual plugs after drying 5 = 161.208g, calculated total mass as m 3 Total mass m after oven drying of mixture of quartz sand and plugs in 4 sand-filled tubes = 181.773g 6 ＝164.486g；
m 5 ＝m 51 +m 52 +m 53 +m 54
m 6 ＝m 61 +m 62 +m 63 +m 64
Step 6: calculating the plugging degree D before plugging removal 1 Degree of clogging after unblocking D 2 Recovery rate eta of diversion capacity h Different node plug clearance η ji And overall clearance η of multinode plugs j ；
Wherein:
flow velocity v 0 、v 1 、v 2 The calculation method comprises the following steps:
the automatic control and data acquisition system acquires signals of the electronic balance, and the flow rate at the stage of the stable increase of the effluent mass is the required flow rate.
According to the prepared mixture 1, 2, 3 and 4 composed of the quartz sand and the plugs with 4 nodes, the experimental method for simulating multi-node plugging and multi-section plugging removal processes of the injection well is shown in fig. 2, and the experimental method is specifically as follows:
step 1: the number of intermediate containers is N, where n=4; pure water is added into a first intermediate container, 3.0wt% of sodium percarbonate, 1.5 wt% of hydrochloric acid and 2.5 wt% of alkyl glycoside APG1214 are respectively filled into the remaining three intermediate containers, and the intermediate containers are heated to the on-site liquid preparation temperature T through a constant temperature heating sleeve 1 =50 ℃; the outlet ends of the intermediate containers are connected with control valves, the control valves are connected with the inlet ends of sand filling pipes in a parallel mode, and the outlet ends of the sand filling pipes are connected to a liquid collecting device; the liquid collecting device is arranged on the electronic balance; filling 40-60 mesh, 80-100 mesh, 140-160 mesh and 140-160 mesh quartz sand into 4 sand filling pipes respectively, connecting the sand filling pipes in series, placing the sand filling pipes into a constant temperature tank, and setting the temperature of the constant temperature tank as the target downhole temperature T of an oil reservoir 2 =60 ℃; the outlet ends of the 4 intermediate containers are connected with control valves, the 4 control valves are connected with the inlet ends of sand filling pipes in a parallel manner, and the outlet ends of the sand filling pipes are connected to a liquid collecting device; the liquid collecting device is arranged on the electronic balance;
the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 1 =0.15 MPa and start-up; setting when the effluent liquid quality reaches M 1 When=600g, closing the first intermediate container corresponding control valve; keeping other control valves in a closed state, resetting the electronic balance, and starting experiments; according to automatic control and numberCalculating the flow velocity v of pure water in quartz sand according to the time-dependent data of the effluent liquid quality collected by the collecting system 0 ＝202.6g/min。
Step 2: filling the prepared mixture consisting of 4 node quartz sand and the plugs into 4 sand filling pipes respectively, connecting the sand filling pipes with an intermediate container, and then placing the sand filling pipes in a constant temperature tank for preheating for 60 minutes; record the total mass of the mixture of quartz sand and plugs in each sand filling pipe as m 31 ＝47.633g、m 32 ＝46.225g、m 33 ＝45.344g、m 34 = 42.533g, calculate the mass m of quartz sand in each sand filling tube 41 ＝38.472g、m 42 ＝38.769g、m 43 ＝40.468g、m 44 = 40.294g, calculate the total mass m of the mixture of quartz sand and plugs in 4 sand-filled tubes 3 Calculating the total mass m of quartz sand in 4 sand filling pipes 4 ；
m 3 ＝m 31 +m 32 +m 33 +m 34＝ 181.735g
m 4 ＝m 41 +m 42 +m 43 +m 44 ＝158.009g
Wherein H is i I=1, 2,3,4, which is the ratio of quartz sand to plug mass for different nodes.
Step 3: the pressure of the constant-pressure air pump is set to be p on the automatic control and data acquisition system 1 =0.15 MPa; when the effluent liquid quality reaches M 1 When=600g, closing the first intermediate container corresponding control valve; keeping other control valves in a closed state, resetting the electronic balance, and starting experiments; after the experiment is finished, calculating the flow velocity v before blocking removal according to the time-dependent data of the effluent liquid quality collected by the automatic control and data collection system 1 ＝8.6g/min。
Step 4: on an automatic control and data acquisition system, constant pressure air corresponding to the slug process is respectively arranged according to the injection sequence agent alternating sequence of different designed deblocking working solutionsThe pump pressure is p 2 ＝0.12MPa、p 3 ＝0.08MPa、p 4 =0.12 MPa, according to the injection sequence of the deblocking working fluid (3.0% sodium percarbonate, 1.5% hydrochloric acid, 2.5% alkyl glycoside APG 1214) and the alternating sequence (2 times), the effluent mass was set to M 2 ＝114g(3PV)、M 3 ＝38g(1PV)、M 4 When=38g (1 PV), the corresponding control valve is closed; when a certain control valve is opened, the rest control valves are closed, experiments are started, and the blocking removing working fluid is injected into the intermediate container.
Step 5: after the injection of different blocking removing working fluids is completed, a constant pressure air pump is arranged on an automatic control and data acquisition system, wherein the pressure of the constant pressure air pump is p 1 =0.12 MPa; when the effluent liquid quality reaches M 1 When=600g, closing the first intermediate container corresponding control valve; keeping other control valves in a closed state, starting an experiment, and calculating the flow velocity v after unblocking according to the time-varying data of effluent liquid quality acquired by an automatic control and data acquisition system 2 ＝152.5g/min。
Step 6: after the experiment is completed, taking out the sand filling pipes, respectively taking out quartz sand and the rest plugs in the 4 sand filling pipes, and respectively weighing the quartz sand and the rest plugs with the mass of m after drying 51 ＝39.017g、m 52 ＝39.383g、m 53 ＝41.081g、m 54 40.917g, respectively weighing m 31 ＝47.633g、m 32 ＝46.225g、m 33 ＝45.344g、m 34 The mixture of 4 nodes quartz sand and plugs = 42.533, which is called m by mass 61 ＝41.221g、m 62 ＝40.504g、m 63 ＝41.515g、m 64 = 41.203g; calculating the total mass m of quartz sand in 4 sand filling pipes and residual plugs after drying 5 = 160.398g, calculated total mass as m 3 Total mass m after oven drying of mixture of quartz sand and plugs in 4 sand packs = 181.735g 6 ＝164.443g；
m 5 ＝m 51 +m 52 +m 53 +m 54
m 6 ＝m 61 +m 62 +m 63 +m 64
Step 7: calculation ofDegree of blockage D before unblocking 1 Degree of clogging after unblocking D 2 Recovery rate eta of diversion capacity h Plug clearance η for 4 different nodes jL And 4 node plug overall clearance η j ；
Wherein:
calculated blockage degree D before blockage removal 1 =95.8% degree of clogging after deblocking D 2 =24.7% of conductivity recovery η h =75.3% and plug clearance η j ＝62.8％。
Flow velocity v 0 、v 1 、v 2 The calculation method comprises the following steps:
and pure water is adopted to test the flow velocity of blank quartz sand, before and after unblocking, so that the influence on the calculated result of the clearance rate caused by the inorganic salt in the brine being adsorbed and retained in the sand filling pipe is avoided. The automatic control and data acquisition system acquires signals of the electronic balance, draws a curve of the effluent mass changing along with time, and the flow rate of the stage of the stable increase of the effluent mass is the required flow rate.
According to the invention, multi-node blockage with different nodes, different degrees and different blockage components can be simulated according to the actual conditions of the site, and the continuous removal condition of the blockage removing working solution on the multi-node blockage under the condition of porous medium seepage; the multiple nodes are connected in series, the length of each node sand filling pipe corresponds to the blocking radius of a site node (the same or the same proportion is reduced), so that the blocking removing working solution is simulated to pass through the front porous medium adsorption and react with the front end blocking material and then continuously react with the middle and rear end blocking material under the condition of site porous medium seepage, the influence of different nodes on the blocking removing effect under the condition of different blocking material components and blocking degrees is further guided to optimize the technological parameters such as the injection concentration of blocking removing agents, the injection speed, the injection quantity, the sectional plug combination design, the well closing reaction time and the like, the blocking removing working solution is closer to the site comprehensive blocking removing condition, the guiding effect is stronger, and the optimal blocking removing effect is achieved; the blocking degree, the flow conductivity and the flow conductivity recovery rate of the porous medium before and after the blocking removal can be quantitatively evaluated by testing the flow velocity of pure water before and after the blocking removal in the porous medium; the amount of the plugs added into the quartz sand pores of different nodes and the amount of the plugs in the quartz sand pores of different nodes after the plugs are removed are calculated through testing, so that the clearance rate of the plugs in the quartz sand pores of different nodes is quantitatively evaluated, the formula of a plug removal system is further optimized, the plug removal system is ensured to thoroughly remove the plugs in the quartz sand pores of each node, and the plug removal effect and the effective period are ensured. By utilizing an automatic control and data acquisition system, experimental parameters and flow can be set for slug design, the start and the end of an experiment are controlled, data acquisition is automatically carried out in the experimental process, the operation is simple, the cost is low, the human error is reduced, the experimental period is short, and the efficiency is high. The contact part of the experimental device and the working solution is prepared from materials with temperature resistance, acid and alkali resistance and oxidation resistance, and is suitable for various working solutions.
Claims (5)
1. The experimental device for simulating the multi-node blocking and unblocking process of the polymer injection well is characterized by comprising a constant pressure air pump (1), N intermediate containers (2) for containing working fluid and L sand filling pipes (4) which are connected in series and used for filling porous media, wherein N is more than or equal to 2, and L is more than or equal to 2; the constant pressure air pump (1) is connected with an air inlet (21) of the intermediate container (2), and an outlet (25) of the intermediate container (2) is connected with the inlet end of the sand filling pipe (4) through the control valve (3); the middle container (2) is externally provided with a constant temperature heating sleeve (22) for controlling the temperature of the middle container; the outlet end of the sand filling pipe (4) is connected with a liquid collecting device (6); the sand filling pipe (4) is arranged in the constant temperature tank (5); the device also comprises an electronic balance (7) for measuring the mass of the liquid collecting device (6); the automatic control and data acquisition system (13) is further included, and the constant pressure air pump (1), the control valve (3) and the electronic balance (7) are all connected to the automatic control and data acquisition system (13); a magnetic rotor (24) is arranged in the intermediate container (2), and a magnetic stirrer (26) matched with the magnetic rotor (24) for use is arranged below the intermediate container (2);
the experimental method based on the experimental device comprises the following steps:
step 1: the number of the intermediate containers (2) is 2, namely a first intermediate container and a second intermediate container, wherein pure water is filled in the first intermediate container, and blocking removing working solution is added in the second intermediate container; the intermediate container (2) is heated to the on-site liquid preparation temperature T through the constant temperature heating sleeve (22) 1 The method comprises the steps of carrying out a first treatment on the surface of the If the blocking removing working solution is a suspension or dispersion system, stirring is carried out by a magnetic rotor (24) in the intermediate container (2) and a magnetic stirrer (26) below the intermediate container (2), so that the blocking removing working solution is ensured to be uniformly dispersed; filling quartz sand with preset mesh number into L sand filling pipes (4) respectively and connecting the L sand filling pipes in series, placing the sand filling pipes (4) into a constant temperature tank (5), and setting the temperature of the constant temperature tank (5) as the target downhole temperature T of an oil reservoir 2 Wherein L is more than or equal to 2; the outlet ends of the first intermediate container and the second intermediate container are respectively connected with a first control valve and a second control valve, and the first control valve and the second control valve are connected to the inlet end of the sand filling pipe (4) in parallel; the outlet end of the sand filling pipe (4) is connected to the liquid collecting device (6); the liquid collecting device (6) is arranged on the electronic balance (7);
the automatic control and data acquisition system (13) is provided with a constant pressure air pump (1) with the pressure of p 1 Setting when effluent liquid quality reaches M 1 Closing the first control valve and keeping the second control valve in a closed state; zero clearing is carried out on the electronic balance (7), and experiments are started; calculating the flow velocity v of pure water in the blank quartz sand according to the time-dependent data of the effluent liquid quality collected by the automatic control and data collection system (13) 0 ；
Step 2: is divided into L sand filling pipes (4) Respectively filling the prepared mixture of quartz sand and plugs with different nodes, connecting a sand filling pipe (4) with an intermediate container (2), and then placing the sand filling pipe in a constant temperature tank (5) for preheating for 1h; the total mass of the mixture of quartz sand and plugs in each sand filling pipe is recorded as m 31 、m 32 、m 33 ……m 3L Calculating the mass m of quartz sand in each sand filling pipe (4) 41 、m 42 、m 43 ……m 4L Calculating the total mass m of the mixture consisting of quartz sand and plugs in the L sand filling pipes (4) 3 Calculating the total mass m of quartz sand in L sand filling pipes (4) 4 ；
m 3 ＝m 31 +m 32 +m 33 +……+m 3L
m 4 ＝m 41 +m 42 +m 43 +……+m 4L
Wherein H is i I=1, 2 … L for the ratio of quartz sand to plug mass for different nodes;
step 3: the automatic control and data acquisition system (13) is provided with a constant pressure air pump (1) with the pressure of p 1 Setting when effluent liquid quality reaches M 1 Closing the first control valve and keeping the second control valve in a closed state; zero clearing is carried out on the electronic balance (7), and experiments are started; after the experiment is completed, the flow velocity v before the blockage removal is calculated according to the time-varying data of the effluent liquid quality acquired by the automatic control and data acquisition system (13) 1 ；
Step 4: the automatic control and data acquisition system (13) is provided with a constant pressure air pump (1) with the pressure of p 2 The second control valve has an opening time t 2 Or is set to when the effluent mass reaches M 2 Closing the second control valve and keeping the first control valve in a closed state; starting an experiment, and injecting blocking removing working solution in a second intermediate container into a sand filling pipe (4); after the injection of the unblocking working solution in the second intermediate container is completed, the unblocking working solution is arranged on an automatic control and data acquisition system (13)The pressure of the constant pressure air pump (1) is set to be p 1 When the effluent liquid quality reaches M 1 Closing the first control valve and keeping the second control valve in a closed state; starting experiment, calculating flow velocity v after unblocking by utilizing time-varying data of effluent liquid quality collected by an automatic control and data collection system (13) 2 ；
Step 5: after the experiment is completed, taking out the sand filling pipes (4), respectively taking out quartz sand and residual plugs in the L sand filling pipes, and respectively weighing the quartz sand and the residual plugs with the mass of m after drying 51 、m 52 、m 53 ……m 5L Respectively weighing the mass of m 31 、m 32 、m 33 ……m 3L Drying a mixture of quartz sand and plugs at different nodes, wherein the mass of the mixture is m 61 、m 62 、m 63 ……m 6L ；
Calculating the total mass m of quartz sand in L sand filling pipes and residual plugs after drying 5 Calculating the total mass as m 3 The total mass m of the mixture formed by quartz sand and plugs in L sand filling materials after drying 6 ；
m 5 ＝m 51 +m 52 +m 53 +……+m 5L
m 6 ＝m 61 +m 62 +m 63 +……+m 6L
Step 6: calculating the plugging degree D before plugging removal 1 Degree of clogging after unblocking D 2 Recovery rate eta of diversion capacity h Different node plug clearance η ji And overall clearance η of multinode plugs j ；
Wherein:
the preparation method of the mixture of the quartz sand and the plug comprises the following steps:
s1: selecting quartz sand with preset mesh number, taking a shaft as a circle center, and simulating and preparing corresponding plugs of different nodes according to the analysis results of the plug components with different radiuses;
s2: respectively filling quartz sand with preset mesh number into L sand filling pipes (4), and recording the volume V of the quartz sand filled into each sand filling pipe (4) 11 、V 12 、V 13 ……V 1L The method comprises the steps of carrying out a first treatment on the surface of the Weigh dry weight m of each sand filling pipe (4) 11 、m 12 、m 13 ……m 1L Pure water is injected into each sand filling pipe (4) until the outflow end is discharged for 30min; weighing the wet weight m of each sand filling pipe (4) 21 、m 22 、m 23 ……m 2L Calculating the pore volume PV of the quartz sand of each sand filling pipe 1 、PV 2 、PV 3 ……PV L And porosity ofThe total pore volume PV of quartz sand in the L sand filling pipes;
PV＝PV 1 +PV 2 +PV 3 +……+PV L
wherein V is 1i The internal volume is calculated according to the corresponding sand filling pipe size parameter;
s3: selecting the ratio G of the volume of the blockage to the volume of the pore space according to the blockage degree of different nodes of the target well 1 、G 2 、G 3 ……G L Calculate and weigh the total volume of preparation V 1 、V 2 、V 3 ……V L Calculating the total mass and the content of each component of the plug, uniformly mixing and stirring each component of the plug, and calculating the mass ratio H of the quartz sand and the plug of different nodes 1 、H 2 、H 3 ……H L The calculation method is as follows:
2.5 is the true density of quartz sand, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the 1 is the density of the blockage, g/cm 3 。
2. The experimental device for simulating multi-node plugging and unplugging process of a polymer injection well according to claim 1, wherein the intermediate container (2) is arranged on an intermediate container fixing frame (8); the middle container fixing frame (8) is arranged on the fixing bracket (9); the constant temperature bath device further comprises a fixed base (14), and the fixed support (9), the constant temperature bath (5) and the electronic balance (7) are arranged on the fixed base (14).
3. The experimental device for simulating multi-node plugging and unplugging process of an injection well according to claim 1, wherein the automatic control and data acquisition system (13) comprises system control, data acquisition software and a computer, so as to realize automatic control and data acquisition of experimental procedures.
4. The experimental device for simulating multi-node plugging and unplugging process of an injection well according to claim 1, wherein the experimental method comprises the steps of:
step 1: the number of the intermediate containers (2) is N, wherein N is more than or equal to 3; adding pure water into the first intermediate container; the rest intermediate containers are respectively filled with different blocking removing working fluids, and the intermediate containers (2) are heated to the on-site liquid preparation temperature T through a constant-temperature heating sleeve (22) 1 The method comprises the steps of carrying out a first treatment on the surface of the If the blocking removing working solution is a suspension or dispersion system, stirring is carried out by a magnetic rotor (24) in the intermediate container (2) and a magnetic stirrer (26) below the intermediate container (2), so that the blocking removing working solution is ensured to be uniformly dispersed; filling quartz sand with preset mesh number into L sand filling pipes (4) and connecting the sand filling pipes in series, placing the sand filling pipes (4) into a constant temperature tank (5), and setting the temperature of the constant temperature tank (5) as the target downhole temperature T of an oil reservoir 2 Wherein L is more than or equal to 2; the outlet ends of the N intermediate containers are connected with control valves, and each control valve is connected to the inlet end of the sand filling pipe (4) in parallel; the outlet end of the sand filling pipe (4) is connected to the liquid collecting device (6); the liquid collecting device (6) is arranged on the electronic balance (7);
the automatic control and data acquisition system (13) is provided with a constant pressure air pump (1) with the pressure of p 1 Setting when effluent liquid quality reaches M 1 When the first intermediate container corresponding control valve is closed, the rest control valve is kept in a closed state; zero clearing is carried out on the electronic balance (7), and experiments are started; calculating the flow velocity v of pure water in the blank quartz sand according to the time-dependent data of the effluent liquid quality collected by the automatic control and data collection system (13) 0 ；
Step 2: the L sand filling pipes (4) are respectively filled with prepared mixtures of quartz sand and plugs with different nodes, and the sand filling pipes (4) are connected with the intermediate container (2) and then placed in the constant temperature tank (5) for preheating for 1h; record the total mass of the mixture of quartz sand and plugs in each sand filling pipe as m 31 、m 32 、m 33 ……m 3L Calculating the mass m of quartz sand in each sand filling pipe (4) 41 、m 42 、m 43 ……m 4L Calculating the total mass m of the mixture consisting of quartz sand and plugs in the L sand filling pipes (4) 3 Calculating the total mass m of quartz sand in L sand filling pipes (4) 4 ；
m 3 ＝m 31 +m 32 +m 33 +……+m 3L
m 4 ＝m 41 +m 42 +m 43 +……+m 4L
Wherein H is i I=1, 2 … L for the ratio of quartz sand to plug mass for different nodes;
step 3: the automatic control and data acquisition system (13) is provided with a constant pressure air pump (1) with the pressure of p 1 Setting when effluent liquid quality reaches M 1 When the first intermediate container corresponding control valve is closed, the rest control valve is kept in a closed state; zero clearing is carried out on the electronic balance (7), and experiments are started; after the experiment is completed, the flow velocity v before the blockage removal is calculated according to the time-varying data of the effluent liquid quality acquired by the automatic control and data acquisition system (13) 1 ；
Step 4: on an automatic control and data acquisition system (13), respectively setting the pressure of the constant pressure air pump (1) corresponding to the slug process to be p according to the injection sequence and the alternating sequence of different designed deblocking working solutions 2 、p 3 、…p N Setting the opening time of the control valve corresponding to different intermediate containers (2) to be t respectively 2 、t 3 、…t N Or is arranged such that when the effluent mass reaches M 2 、M 3 …M N When one control valve is opened, the rest control valves are kept closed; starting an experiment, and injecting a blocking removal working solution;
Step 5: after the injection of different blocking removing working fluids is completed, a constant pressure air pump (1) is arranged on an automatic control and data acquisition system (13) with the pressure of p 1 When the effluent liquid quality reaches M 1 When the first intermediate container corresponding control valve is closed, the rest control valve is kept in a closed state; starting experiment, calculating flow velocity v after unblocking by utilizing time-varying data of effluent liquid quality collected by an automatic control and data collection system (13) 2 ；
Step 6: after the experiment is completed, taking out the sand filling pipes (4), respectively taking out quartz sand and residual plugs in the L sand filling pipes, and respectively weighing the quartz sand and the residual plugs with the mass of m after drying 51 、m 52 、m 53 ……m 5L Respectively weighing the mass of m 31 、m 32 、m 33 ……m 3L Drying a mixture of quartz sand and plugs at different nodes, wherein the mass of the mixture is m 61 、m 62 、m 63 ……m 6L ；
Calculating the total mass m of quartz sand in L sand filling pipes and residual plugs after drying 5 Calculating the total mass as m 3 The total mass m of the mixture formed by quartz sand and plugs in L sand filling materials after drying 6 ；
m 5 ＝m 51 +m 52 +m 53 +……+m 5L
m 6 ＝m 61 +m 62 +m 63 +……+m 6L
Step 7: calculating the plugging degree D before plugging removal 1 Degree of clogging after unblocking D 2 Recovery rate eta of diversion capacity h Different node plug clearance η jL And overall clearance η of multinode plugs j ；
Wherein:
5. the experimental device for simulating multi-node plugging and unplugging process of a polymer injection well according to any one of claims 1 to 4, wherein the flow velocity v 0 、v 1 、v 2 The calculation method comprises the following steps:
and according to the time-varying data of the effluent quality acquired by the automatic control and data acquisition system (13), the flow rate at the stage of the stable increase of the effluent quality is the required flow rate.
Priority Applications (1)
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| DK201400318A (en) * | 2012-01-10 | 2014-06-18 | Altus Intervention As | Method and device for remowal of a hydrate plug |
| CN110359876A (en) * | 2019-07-16 | 2019-10-22 | 西南石油大学 | Simulating-estimating device integrated with acidification de-plugging and method are temporarily blocked up in crack |
| CN111912732A (en) * | 2020-08-12 | 2020-11-10 | 成都派倬石油科技有限公司 | Open type experimental device and method for simulating multi-slug plug removal process |
| CN111929402A (en) * | 2020-08-12 | 2020-11-13 | 西南石油大学 | Open type experimental device and method for simulating single-section plug unblocking technological process |
| CN112031761A (en) * | 2020-09-27 | 2020-12-04 | 西南石油大学 | Blockage removing device and method for simulating gas well hydrate blockage |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK201400318A (en) * | 2012-01-10 | 2014-06-18 | Altus Intervention As | Method and device for remowal of a hydrate plug |
| CN110359876A (en) * | 2019-07-16 | 2019-10-22 | 西南石油大学 | Simulating-estimating device integrated with acidification de-plugging and method are temporarily blocked up in crack |
| CN111912732A (en) * | 2020-08-12 | 2020-11-10 | 成都派倬石油科技有限公司 | Open type experimental device and method for simulating multi-slug plug removal process |
| CN111929402A (en) * | 2020-08-12 | 2020-11-13 | 西南石油大学 | Open type experimental device and method for simulating single-section plug unblocking technological process |
| CN112031761A (en) * | 2020-09-27 | 2020-12-04 | 西南石油大学 | Blockage removing device and method for simulating gas well hydrate blockage |
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