CN102564900A - Simulation test method for seepage process of polymer solution at different positions of stratum - Google Patents

Abstract

The invention relates to a simulation test method for a seepage process of a polymer solution at different positions of a stratum. The method comprises the following steps of: preparing a sand filling tube model which accords with oil reservoir reality according to an oil reservoir mineral compositions, testing a porosity and a permeability parameter of a sand filling tube, and strictly simulating an oil reservoir corresponding parameter; selecting an injection flow value of a polymer system according to a researched stratum position; then performing a closed cyclic experimental test for simulating the original pressure and the temperature condition of the stratum, and simulating the seepage process of the polymer solution in the stratum; and closing, isolating oxygen, fetching a sample, testing the rheology of the sample, and comparing to calculate the change rule of the rheology. According to the simulation test method, the seepage process of the polymer system at different positions in the stratum can be reflected really; and a test and evaluation method is supplied to research on the rheology of the polymer solution during seepage at different positions and different seepage distances in the stratum.

Description

Simulation test method for seepage process of polymer solution at different positions in the formation

the

1. Technical field:

The invention relates to an indoor test and evaluation method of the rheological change rule of the polymer solution in the oil layer during the tertiary oil recovery process, in particular to a simulation test method of the seepage process of the polymer solution at different positions in the formation.

2. Background technology:

Polymer solution flooding technology is a relatively mature method of enhancing oil recovery in domestic and foreign oilfields, but there is no effective method for the study of rheological changes of polymer solution seeping to different positions in the formation, which leads to the The credibility of drug development effect evaluation lacks a strong basis. The rheological properties of polymer solution in porous media is an important field in polymer rheology, which is related to the physical process of polymer solution flowing in porous media. Accurate and scientific analysis has urgent practical significance for engineering design and process optimization. There has been no publication of relevant literature at home and abroad. The blankness of this research content has become a technical bottleneck restricting the research on the regular change of the rheological properties of polymer solutions in formation seepage, which further limits the evaluation of the effectiveness of polymer systems in oilfield development. , so it is of great significance to establish a method for simulating the rheological change of polymer solution seeping to different positions in the formation.

3. Contents of the invention:

The purpose of the present invention is to provide a simulation test method for the seepage process of polymer solution at different positions in the formation, which is used to solve the problem of lack of indoor testing and evaluation of the rheological change law of the polymer in the seepage process in the oil layer in the current oilfield development process.

The technical solution adopted by the present invention to solve the technical problem is: the simulation test method of the seepage process of the polymer solution at different positions in the formation, firstly prepare a sand-packing pipe model that is in line with the actual oil reservoir according to the mineral composition of the reservoir, and the size of the sand-filling pipe There are two designs: Φ25.4×400mm or Φ60×200mm. The mineral composition of the sand filling pipe is the same as that of the simulated formation, so that the minerals in the indoor simulation and the actual seepage of the formation have the same effect on the performance of the polymer solution. The porosity and permeability of the sand filling pipe are tested. rate parameters, which are strictly in line with the corresponding parameters of the simulated reservoir; the injection flow rate of the polymer system is selected according to the researched formation position; and then the closed cycle experiment test is carried out to simulate the original pressure and temperature conditions of the formation to simulate the seepage process of the polymer solution in the formation. Put the prepared sand filling pipe model into the experimental simulation environment, connect the closed oxygen-isolated circulation injection system, connect the injection system and the production device, start the injection system, turn on the pressure gauge, open the high temperature constant temperature control box, simulate the formation conditions, and set the injection parameters , the cyclic seepage experiment was carried out through the closed oxygen-isolated circulation injection system to simulate the seepage process of the polymer solution in the formation; the airtight oxygen-isolated sample was taken, the rheological properties of the samples were tested, and the rheological changes were compared and calculated.

In the above scheme, the method of preparing a sand-packing pipe model conforming to the actual reservoir is as follows:

(1) Select and prepare metal models according to the purpose of experimental simulation interpretation. For example, to test the relationship between the seepage distance and the rheological change of polymer solution, the Φ25.4×400mm model can be selected; Φ60×200mm metal model;

(2) Analyze the natural rock core obtained from the simulated stratum to obtain stratum pore structure parameters and mineral composition ratios;

(3) Select the mineral rock substrate according to the mineral composition ratio of the simulated formation in the experiment, then select the particle size ratio according to the particle size distribution, and mix the filling minerals evenly according to the mineral composition and particle size ratio. If there is no bonding mineral such as clay, an appropriate amount of clay can be added. admixture bonded minerals;

(4) Fill the model with mineral mixture, determine the compaction pressure according to the original pressure environment of the formation, and use the electric compactor to distribute the compaction model;

(5) Curing at constant temperature for 48 hours under reservoir temperature conditions;

(6) Determine whether the model has similar permeability properties to the simulated formation by measuring the permeability of the gas model under the reservoir temperature condition; measure the permeability of the model by simulating brine and water in the saturated formation, and then determine the similarity between the model and the simulated formation.

In the above scheme, the seepage process of the polymer solution in the formation is simulated:

(1) In the indoor airtight oxygen barrier cycle injection system, the similarity between the experimental environment and the simulated reservoir is realized through system pressure and temperature control;

(2) Open the injection system, inject the polymer solution according to the calculated flow rate, carry out the seepage simulation cycle, and determine the number of cycles according to the simulated formation distance;

(3) By filling nitrogen into the plunger type storage container of the extraction device, the isolation of the polymer solution from oxygen is realized; through the strict airtight connection of the entire airtight oxygen isolation cycle injection system, the airtight oxygen isolation of the injection system is realized to avoid contact with the solution Air to realize the closed cycle test process;

(4) At the outlet of the closed oxygen barrier cycle injection system, the outlet sample is preserved in oxygen barrier by the plunger type storage container;

(5) Rapidly measure the rheology of the polymer solution in the test system, and study its rheological change law;

      计算不同渗流速度对应的剪切速率，通过室内流变性测试结果对比分析不同渗流距离对聚合物溶液流变性的影响。 (6) by the formula

The shear rates corresponding to different seepage velocities were calculated, and the effects of different seepage distances on the rheology of polymer solutions were analyzed by comparing the results of indoor rheological tests.

The airtight oxygen barrier cycle injection system in the above scheme includes a plunger type intermediate container, an intermediate container, a sand filling pipe model, a four-way valve, a pressure gauge, a pump, and consists of the first plunger type intermediate container, the first plunger type intermediate container and the first plunger type intermediate container. The injection line between the first intermediate container, the sand filling pipe model, the second intermediate container, the injection line between the second intermediate container and the second plunger type intermediate container, and the second plunger type intermediate container form a polymer injection circuit; From the second plunger type intermediate container, the production line between the second plunger type intermediate container and the first intermediate container, the sand filling pipe model, the second intermediate container, and between the second intermediate container and the first plunger type intermediate container The production line and the first plunger-type intermediate container constitute the polymer production circuit; the pump is respectively connected to the lower chamber of the first plunger-type intermediate container and the lower chamber of the second plunger-type intermediate container through the first four-way valve ; Install a pressure gauge before and after the sand filling pipe model.

The size of the first plunger-type intermediate container and the second plunger-type intermediate container in the above scheme are equal; the size of the first intermediate container is equal to that of the second intermediate container.

In the above scheme, the second four-way valve is installed on the upper part of the first plunger-type intermediate container; the third four-way valve is installed on the lower part of the first intermediate container; the fourth four-way valve is installed on the upper part of the second intermediate container, and the second intermediate container The fifth four-way valve is installed on the lower part of the second plunger type intermediate container; the sixth four-way valve is installed on the upper part of the second plunger type intermediate container; the lower cavity of the first plunger type intermediate container and the lower cavity of the second plunger type intermediate container are respectively A discharge valve is installed, and the lower part of the second intermediate container is also provided with a discharge valve.

Beneficial effect:

The method for researching the rheological change of the polymer solution in the seepage process at different positions and different seepage distances in the formation provided by the present invention has a reliable principle, simple structure of the sand filling pipe model making and testing device, and can truly reflect the polymer system in the formation. The seepage process at different locations, and restore the underground pressure and temperature conditions to test the rheological changes of the conductive polymer system. The simulation method is practical and the test results have good adaptability. The invention provides a test and evaluation method for the research on the rheological change of the polymer solution in the seepage process at different positions and different seepage distances in the formation.

2. The present invention simulates a closed circulation injection system in which the polymer solution seeps in the formation.

3. The present invention establishes a method for preparing the mineral composition and pore structure characteristics of the simulated formation.

4. Description of drawings:

Fig. 1 is a flow chart of the present invention;

Fig. 2 is the layout block diagram of polymer solution seepage simulation circulation system in the present invention;

Fig. 3 is the structure schematic diagram of the airtight oxygen isolation cycle injection system in the present invention;

Fig. 4 is the structural representation of extraction device among the present invention;

Fig. 5 is a schematic diagram illustrating the difference in seepage velocity of fluid at different positions;

Fig. 6-Fig. 8 are schematic diagrams showing the differences of sand filling contact modes in the sand filling pipe model;

Fig. 9 is an explanatory diagram of distance simulation in the research method of rheological change during the percolation process of polymer solution.

1 Pump 2 First plunger type intermediate container 2′ Second plunger type intermediate container 3 First intermediate container 3′ Second intermediate container 4 Sand filling pipe model 5 Injection line 6 Production line 7 First four-way valve 8 Second Four-way valve 9 Third four-way valve 10 Fourth four-way valve 11 Fifth four-way valve 12 Discharge valve 13 Pressure gauge 14 Sixth four-way valve 15 Plunger type preservation container inlet 16 Distilled water outlet 17 High temperature constant temperature control box 18 Fan 19 Injection system 20 Sealed oxygen barrier cycle injection system 21 Extraction device 22 Test device.

5. Specific implementation methods:

Below in conjunction with accompanying drawing, the present invention will be further described:

The technical problem to be solved in the present invention mainly concentrates on two aspects:

(1) Prepare the original conditions of different formations for simulating polymer seepage, and the pressure environment that exists underground

and temperature environment to test the rheological changes of the polymer solution.

The original conditions of the formation for simulating polymer seepage: ① The mineral composition of the filling is the same as that of the simulated formation, so that the minerals in the indoor simulation and the actual seepage of the formation have the same effect on the performance of the polymer solution; The parameters of porosity, pore structure and seepage rate of the model are similar to those of the research formation, which ensures that the shear stress suffered during the seepage of the polymer is comparable to that of the actual formation, as shown in Fig. 6, Fig. 7 and Fig. 8.

(2) Simulate the seepage process of the polymer solution at different seepage positions in the formation and simulate the seepage process of the polymer solution at different seepage distances in the formation.

In conjunction with Fig. 1, Fig. 2, shown in Fig. 5, in order to solve above-mentioned two problems, the technical scheme that the present invention adopts is specifically:

First, according to the needs of the research question and the actual conditions of the formation, determine the preparation plan of the sand filling pipe, select the distribution and proportion of the quartz sand particle size, mineral composition and filling method, prepare the sand filling pipe, test the porosity and permeability parameters of the sand filling pipe, and strictly comply with the Corresponding parameters of simulated reservoir;

Select the injection flow rate of the polymer system according to the studied formation position (including: injection-production well bottom, the middle of the main stream of the well pattern and the low-velocity seepage area between wells);

Then carry out the closed cycle experimental test of simulating the original pressure, temperature and other conditions of the formation, put the prepared sand filling pipe model 4 into the experimental simulation environment, connect the closed oxygen barrier cycle injection system 20, connect the injection system 19 and the extraction device, and start Inject the system 19, turn on the pressure gauge, turn on the temperature control instrument, simulate the formation conditions, set the injection parameters, conduct the seepage experiment, take the sample with the outlet sealed and isolated from oxygen, test the rheology of the sample, and compare and calculate the change rule of the rheology.

Specifically:

Firstly, a seepage model that conforms to the rock pore structure and mineral composition of the simulated formation reservoir is prepared, and the making method is as follows:

If you only study the effect of shear stress on the rheology of the polymer solution in seepage, you only need to determine the particle size distribution of the quartz sand in the sand filling pipe; if you study the effect of adsorption on the rheology of the polymer solution, you need to fill the normal 2m sand pipe.

(1) Select and prepare metal models according to the purpose of experimental simulation interpretation. For example, to test the relationship between the seepage distance and the rheological change of polymer solution, the Φ25.4×400mm model can be selected; Φ60×200mm metal model.

(2) Analyze the natural cores obtained from the simulated strata to obtain stratum pore structure parameters and mineral composition ratios.

(3) Select the mineral rock substrate according to the mineral composition ratio of the simulated formation in the experiment, then select the particle size ratio according to the particle size distribution, and mix the filling minerals evenly according to the mineral composition and particle size ratio. If there is no bonding mineral such as clay, an appropriate amount of clay can be added. Mixtures bind minerals.

(4) Fill the model with mineral mixture, determine the compaction pressure according to the original pressure environment of the formation, and use the electric compactor to distribute the compaction model.

(5) Maintain at constant temperature for 48 hours under the reservoir temperature condition.

(6) Determine whether the model has similar permeability properties to the simulated formation by measuring the permeability of the gas model under the reservoir temperature condition; measure the permeability of the model by simulating brine and water in the saturated formation, and then determine the similarity between the model and the simulated formation.

Then, according to the calculation of the actual polymer solution injection speed and pressure limit calculation in the reservoir, the injection flow rate and pressure range of the indoor simulation experiment are determined:

(1)根据实验研究目的计算注入流量：根据实际地层不同渗流区域的渗流速度分别通过公式        计算室内模拟实验注入流量。不同区域渗流速度范围为：井底高速流动区：1.5-10.0米/天；井间稳定渗流区：0.5-1.0米/天；井间低速渗流区：0.05-0.5米/天。

(1) Calculate the injection flow rate according to the purpose of the experimental research: calculate the injection flow rate of the indoor simulation experiment according to the seepage velocity in different seepage areas of the actual formation through formulas. The range of seepage velocity in different areas is: the high-speed flow area at the bottom of the well: 1.5-10.0 m/day; the stable seepage area between wells: 0.5-1.0 m/day; the low-velocity seepage area between wells: 0.05-0.5 m/day.

(2) Determine the upper pressure limit of the injected polymer solution according to the actual pressure of the overlying strata and the original pressure of the formation.

Finally, the indoor simulated polymer solution seepage experiment was started to study the change law of the rheological properties of the polymer solution with the increase of seepage distance:

(1) In the indoor simulation system, the similarity between the experimental environment and the simulated reservoir is realized through system pressure and temperature control.

(2) Open the injection system, inject the polymer solution according to the calculated flow rate, and carry out the seepage simulation cycle, as shown in Figure 9, determine the number of cycles according to the simulated formation distance, for example: the rheology of the simulated polymer solution seepage to 100 meters from the bottom of the well Changes, such as the simulation model is 2 meters long, the number of cycles is 50, then 50 × 2 meters = 100 meters.

(3) By filling nitrogen into the plunger-type storage container of the production device, the isolation of the polymer solution from oxygen is realized; through the strict airtight connection of the entire injection system, the airtight oxygen isolation of the injection system is realized, and the solution is prevented from contacting the air, realizing Closed cycle test process.

(4) At the outlet of the closed oxygen barrier cycle injection system, the outlet sample is stored in an oxygen barrier through a plunger type preservation container.

(5) Rapidly measure the rheological properties of the polymer solution in the testing system 22, and study the changing rules of the rheological properties.

      计算不同渗流速度对应的剪切速率，通过室内流变性测试结果对比分析不同渗流距离对聚合物溶液流变性的影响。 (6) by the formula

The shear rates corresponding to different seepage velocities were calculated, and the effects of different seepage distances on the rheology of polymer solutions were analyzed by comparing the results of indoor rheological tests.

As shown in Figure 2, the polymer solution seepage simulation circulation system in the present invention is mainly composed of: temperature control system, pressure detection system, airtight oxygen barrier circulation injection system 20, extraction device 21, injection system 19, polymer solution preparation And rheological testing system.

Sand filling pipe model 4, closed oxygen barrier circulation injection system 20, pressure detection system, and sampling system.

The airtight oxygen isolation cycle injection system mainly includes: imported ISCO high-precision micro-pump, which can realize double-plunger cycle continuous injection, and the injection accuracy can reach 0.01ml/min. The injection flow rate is set according to the design flow rate, and the compressor provides 4 atmospheres Air pressure, open the pneumatic valve switch in real time for continuous injection. The pump is equipped with a high-precision pressure monitoring device, and can monitor the injection pressure and injection volume of the pump in real time.

The main device of the temperature control system is a high-temperature constant temperature control box 17, the controllable temperature range: 0-250 degrees, and the two-way fan 18 is provided in the box to ensure that the temperature in the box is evenly distributed.

The pressure monitoring system includes injection pump pressure monitoring, injection end, production end and precision pressure gauges with different ranges evenly distributed according to length,

The rheological testing system includes: electronic balance, imported rheometer, digital control agitator, constant temperature water bath, electronic computer, air compressor, etc.

Through the coordinated work of the above systems, the existing axial pressure, confining pressure and temperature environment can be simulated to test its conductivity.

As shown in Figure 4, the extraction device in the present invention is mainly a plunger type storage container, the plunger type storage container inlet 15 is at the upper end, and the distilled water outlet 16 is at the lower end.

As shown in Figure 3, the airtight oxygen barrier circulation injection system used in the cyclic seepage experiment in the present invention comprises a plunger type intermediate container, an intermediate container, a sand filling pipe model 4, a four-way valve, a pressure gauge, an ISOC pump 1, From the first plunger type intermediate container 2, the injection line 5 between the first plunger type intermediate container 2 and the first intermediate container 3, the sand filling pipe model 4, the second intermediate container 3', the second intermediate container 3' and The injection line 5 between the second plunger type intermediate container 2' and the second plunger type intermediate container 2' constitute a polymer injection circuit; the second plunger type intermediate container 2', the second plunger type intermediate container 2 ′ and the first intermediate container 3, the production line 6 between the sand filling pipe model 4, the second intermediate container 3 ′, the second intermediate container 3 ′ and the first plunger-type intermediate container 2, the production line 6, the first The plunger-type intermediate container 2 constitutes a polymer extraction circuit; the pump 1 is respectively connected to the lower cavity of the first plunger-type intermediate container 2 and the lower cavity of the second plunger-type intermediate container 2' through the first four-way valve 7 ; A pressure gauge 13 is respectively installed before and after the sand filling pipe model 4 . The first plunger-type intermediate container 2 is equal in size to the second plunger-type intermediate container 2'; the first intermediate container 3 is equal in size to the second intermediate container 3', and both are common intermediate containers.

A second four-way valve 8 is installed on the upper part of the first plunger-type intermediate container 2 of the airtight oxygen barrier cycle injection system; a third four-way valve 9 is installed on the lower part of the first intermediate container 3; the upper part of the second intermediate container 3' is installed The fifth four-way valve 11 is installed on the bottom of the fourth four-way valve 10 and the second intermediate container 3'; the sixth four-way valve 14 is installed on the top of the second plunger type intermediate container 2'; the first plunger type intermediate container 2 and the lower cavity of the second plunger type intermediate container 2' are each equipped with a discharge valve 12, and the bottom of the second intermediate container 3' is also equipped with a discharge valve.

In the present invention, the airtight oxygen barrier circulation injection system carries out the circulation experiment process and the realization steps are as follows:

Step 1: During the experiment, first clean and dry the plunger-type intermediate container chambers and the intermediate container chambers, inject nitrogen to replace the air in the above-mentioned intermediate containers, and then fill the polymer solution into the first intermediate container 3 cavities chamber and the upper chamber of the first plunger-type intermediate container 2; calculate the injection rate according to the position of the simulated formation;

Step 2: Turn on the ISCO pump 1 to start the experiment; open the first four-way valve 7, so that the distilled water in the ISCO pump 1 enters the bottom chamber of the first plunger-type intermediate container 2, and the first plunger-type intermediate container is injected under the action of pressure The plunger in 2 displaces the upper polymer solution from the bottom of the container, and the discharge valve at the bottom of the first plunger-type intermediate container 2 is closed at this time, so that the polymer solution passes through the second four-way valve 8 on the top of the first plunger-type intermediate container 2 , through the injection line 5 between the first plunger-type intermediate container and the first intermediate container, and then enter the first intermediate container 3 through the third four-way valve 9 at the lower part of the first intermediate container 3, and the polymer injection circuit is running at this time , the polymer solution is injected into the sand pack pipe model, while the polymer production loop is closed.

Step 3: After seeping through the sand filling pipe model 4, the polymer solution flows into the second intermediate container 3' through the outlet of the fifth four-way valve 11 at the lower part of the second intermediate container 3'; The discharge valve is closed (the discharge valve is opened when samples need to be collected for measurement); the polymer solution flows out from the fourth four-way valve 10 at the top of the second intermediate container 3', and passes through the second intermediate container 3 and the second plunger type intermediate container The injection line 5 between them flows into the upper chamber of the second plunger type intermediate container 2' through the sixth four-way valve 14, and under the action of the polymer solution, the distilled water in the bottom chamber of the second plunger type intermediate container 2' passes through The discharge valve 12 discharges; while the polymer production circuit is still closed.

After step 2 and step 3, the injection and airtight collection of the polymer solution are realized, and preparations are made for the cycle injection; the steps to enter the cycle are as follows:

Step 4: After the injection of polymer into the top chamber of the first plunger-type intermediate container 2 at the injection end connected to the ISCO pump 1 is completed, close the valve on the pipeline between the pump 1 and the lower chamber of the first plunger-type intermediate container 2 The first four-way valve 7 valve, simultaneously open the first four-way valve 7 valve on the pipeline between the pump 1 and the lower chamber of the second plunger-type intermediate container 2'; ISCO pump 1 injects distilled water into the second plunger-type intermediate The bottom chamber of the container 2'; the outlet polymer solution collected in the top chamber of the second plunger-type intermediate container 2' starts to be circulated and injected. At this time, the polymer extraction circuit is running, and the polymer injection circuit is closed. The extraction line 6 between the two plunger-type intermediate containers and the first intermediate container flows into the first intermediate container 3, and then injects the sand-filling pipe model 4 for circulation; the polymer solution injected into the sand-filling pipe model 4 exits through the second intermediate container 3 The outlet of the fifth four-way valve 11 at the lower part flows into the second intermediate container 3', and flows out from the fourth four-way valve 10 at the top of the second intermediate container 3', passing through the second intermediate container and the first plunger-type intermediate container The production line 6 between them flows into the top chamber of the first plunger-type intermediate container 2, and begins to collect the outlet polymer solution to prepare for the next cycle.

Step 5: After the injection of the polymer into the top chamber of the second plunger-type intermediate container 2' is completed, the polymer injection circuit is opened, and the polymer extraction circuit is closed at the same time, and the injection cycle starts again.

Through the above steps 2, 3, 4 and 5, the cyclic injection of the polymer solution is realized, and the number of cycles is determined according to the simulated seepage distance in the experiment and the length of the sand filling pipe model.

Claims (6)

1. A polymer solution simulation test method for the seepage process at different positions in the formation, characterized in that: this polymer solution simulates the test method for the seepage process at different positions in the formation. Sand filling pipe model (4), two types of sand filling pipe size design: Φ25.4×400mm or Φ60×200mm, the filling mineral composition in the sand filling pipe is the same as that of the simulated formation, so that the mineral to polymer solution in the indoor simulation and the actual seepage of the formation The performance impact is the same, the porosity and permeability parameters of the sand filling pipe are tested, which strictly conform to the corresponding parameters of the simulated reservoir; the injection flow rate of the polymer system is selected according to the researched formation position; and then the closed cycle experiment test is carried out to simulate the original pressure and temperature conditions of the formation , to simulate the seepage process of the polymer solution in the formation, put the prepared sand filling pipe model into the experimental simulation environment, connect the closed oxygen barrier circulation injection system, connect the injection system (19) and the extraction device (21), and start the injection system (19), turn on the pressure gauge, open the high-temperature constant temperature control box (17), simulate the formation conditions, set the injection parameters, and conduct a circulation seepage experiment through the closed oxygen-isolated circulation injection system (20) to simulate the seepage process of the polymer solution in the formation ; Take the samples in a closed oxygen barrier, test the rheological properties of the samples, and compare and calculate the changing rules of the rheological properties. 2. polymer solution according to claim 1 seepage process simulation test method at different positions in the formation, is characterized in that: the method for described preparation conforms to the actual sand-packing pipe model of the reservoir: (1) Select and prepare metal models according to the purpose of experimental simulation interpretation. For example, to test the relationship between the seepage distance and the rheological change of polymer solution, the Φ25.4×400mm model can be selected; Φ60×200mm metal model; (2) Analyze the natural rock core obtained from the simulated stratum to obtain stratum pore structure parameters and mineral composition ratios; (3) Select the mineral rock substrate according to the mineral composition ratio of the simulated formation in the experiment, then select the particle size ratio according to the particle size distribution, and mix the filling minerals evenly according to the mineral composition and particle size ratio. If there is no bonding mineral such as clay, an appropriate amount of clay can be added. admixture bonded minerals; (4) Fill the model with mineral mixture, determine the compaction pressure according to the original pressure environment of the formation, and use the electric compactor to distribute the compaction model; (5) Curing at constant temperature for 48 hours under reservoir temperature conditions; (6) Determine whether the model has similar permeability properties to the simulated formation by measuring the permeability of the gas model under the reservoir temperature condition; measure the permeability of the model by simulating brine and water in the saturated formation, and then determine the similarity between the model and the simulated formation. 3. polymer solution according to claim 2 seepage process simulation test method at different positions in formation, is characterized in that: described simulated polymer solution seepage process in formation: (1) In the indoor airtight oxygen barrier cycle injection system, the similarity between the experimental environment and the simulated reservoir is realized through system pressure and temperature control; (2) Open the injection system, inject the polymer solution according to the calculated flow rate, carry out the seepage simulation cycle, and determine the number of cycles according to the simulated formation distance; (3) By filling nitrogen into the plunger type storage container of the extraction device, the isolation of the polymer solution from oxygen is realized; the airtight oxygen isolation of the injection system is realized through the strict airtight connection of the entire airtight oxygen isolation cycle injection system, and the solution is avoided. Air to realize the closed cycle test process; (4) At the outlet of the closed oxygen barrier cycle injection system, store the export sample through the plunger type preservation container in oxygen barrier; (5) Rapidly measure the rheology of the polymer solution in the test system, and study its rheological change law; (6) by the formula

Calculate the shear rate corresponding to different seepage velocities, by The effect of different seepage distances on the rheology of the polymer solution was compared and analyzed by the rheological test results in the laboratory. 4. The method for simulating and testing the seepage process of polymer solution at different positions in the formation according to claim 3, characterized in that: the airtight oxygen barrier cycle injection system comprises a plunger type intermediate container, an intermediate container, and a sand filling pipe model (4), four-way valve, pressure gauge, pump (1), composed of the first plunger type intermediate container (2), the injection line between the first plunger type intermediate container and the first intermediate container (5), sand filling The tube model (4), the second intermediate vessel (3'), the injection line (5) between the second intermediate vessel and the second plunger intermediate vessel, the second plunger intermediate vessel (2') constitute the polymer Injection circuit: composed of the second plunger type intermediate container (2'), the production line (6) between the second plunger type intermediate container and the first intermediate container, the sand filling pipe model (4), the second intermediate container (3 ′), the extraction line (6) between the second intermediate container and the first plunger-type intermediate container, and the first plunger-type intermediate container (2) constitute the polymer extraction circuit; the pump (1) passes through the first four-way The valve (7) is respectively connected with the lower chamber of the first plunger-type intermediate container (2) and the lower chamber of the second plunger-type intermediate container (2′); a pressure gauge is installed at the front and back of the sand filling pipe model (4) (13). 5. The method for simulating the seepage process of polymer solution at different positions in the formation according to claim 4, characterized in that: the first plunger-type intermediate container (2) and the second plunger-type intermediate container (2 ') are equal in size; the first intermediate container (3) is equal in size to the second intermediate container (3'). 6. The method for simulating the seepage process of polymer solution at different positions in the formation according to claim 5, characterized in that: a second four-way valve ( 8); the third four-way valve (9) is installed on the lower part of the first intermediate container (3); the fourth four-way valve (10) is installed on the upper part of the second intermediate container (3'), and the second intermediate container (3') The fifth four-way valve (11) is installed on the lower part of the second plunger-type intermediate container (2′) and the sixth four-way valve (14) is installed on the upper part of the second plunger-type intermediate container (2′); the lower cavity of the first plunger-type intermediate container (2) A discharge valve (12) is respectively installed in the lower cavity of the second plunger-type intermediate container (2'), and a discharge valve is also installed in the lower part of the second intermediate container (3').

Images