CN115166826A - A recovery method for multi-dimensional and multi-period formation paleopressure in unconventional reservoirs - Google Patents

Abstract

The invention discloses a method for recovering ancient pressure of a multi-dimensional and multi-period stratum of an unconventional reservoir, which comprises the steps of taking a typical pulse body of a rock core, carrying out inclusion temperature measurement and laser Raman testing, then recovering ancient pressure and corresponding time of the ancient pressure, carrying out time-depth conversion, structure trend surface continuation and other analyses on a backbone seismic section, reflecting the denudation amount, carrying out structure evolution section recovery and digital gridding, establishing key parameters required by simulation, gradually stripping back and restraining stratum morphology according to the recovered structure evolution section result, simulating the temperature pressure of each historical period of the stratum, recovering the ancient pressure measuring point time by using single-well buried history and temperature measurement results, finally carrying out correlation analysis and establishing a correction relational expression of each stratum pressure, and correcting the ancient pressure of each historical different depth section of each historical point on other points on the section. The method has the characteristic of more accurately recovering the paleo-pressure of the unconventional reservoir in the key geological historical period.

Description

A recovery method for multi-dimensional and multi-period formation paleopressure in unconventional reservoirs

technical field

The invention relates to the field of formation paleo-pressure recovery methods, in particular to a multi-dimensional and multi-period formation paleo-pressure recovery method for unconventional reservoirs.

Background technique

Formation pressure is the pressure acting on the fluid in the pore space of the rock formation, also known as pore fluid pressure. It is formed during the long-term evolution of the basin and plays an important role in the generation, migration and accumulation of oil and gas. Among them, abnormal high pressure is very beneficial to the preservation of shale gas and can indicate favorable shale gas enrichment areas. However, since paleo-pressure cannot be measured directly, the recovery of formation paleo-pressure is the key and difficult point in hydrocarbon accumulation mechanism and accumulation process.

However, at present, the reconstruction results of paleo-pressure in various geological historical periods are obtained under the constraints of the pressure calculation results of a single measurement point in each period and the current measured pressure. There is still a certain error between the simulation results obtained after constraints and the actual values. Paleo pressure is not corrected. In addition, the restoration on the profile (two-dimensional) only depends on the comparison with the test results of a single well, and the relative error between the simulated value and the measured value is used to illustrate its reliability. For the restoration of ancient pressure, the amount of data is small, the randomness is strong, and it is not convincing, and it is only a constraint on the present, and the ancient pressure in each historical period has not been corrected.

Therefore, it is necessary to design a more accurate restoration of palaeopressure in key geological historical periods of unconventional reservoirs.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for restoring multi-dimensional and multi-period formation paleo-pressure in unconventional reservoirs, which can more accurately restore the multi-dimensional and multi-period formation paleo-pressure in unconventional reservoirs.

In order to achieve the above object, the present invention provides a method for restoring multi-dimensional and multi-period formation paleopressure in unconventional reservoirs. The restoring method comprises the following steps:

S1: Fracture veins in different periods of different intervals of the target layer of key wells on the backbone seismic section are taken, and the periods include: Early-Middle Yanshan, Late Yanshan, Early Himalayan and Late Himalayan; Oil and gas-bearing development sublayers; then carry out fluid inclusion temperature measurement and laser Raman experimental test, and then carry out paleo-pressure time and pressure recovery. Neon laser Raman standard peaks Ne ₁ and standard peaks Ne ₃ are used to detect fluid inclusions. The Raman scattering peak correction of , using the pressure when the methane inclusions in the fracture veins are captured as the paleopressure, is calculated as follows:

v _d -v ₀ =211.3ρ ⁴ +73.328ρ ³ +24.477ρ ² -29.0632ρ

in

ρ is the density of methane inclusions, in g/cm ³ ; v _d is the corrected methane Raman scattering peak wave number; v ₀ is the methane Raman scattering peak wave number when the density is close to 0, v ₀ =2917.58cm ^{- 1} ; P is the pressure, the unit is MPa; T is the temperature, the unit is K; R is the gas constant, R=0.008314467MPa·dm ³ ·K ^-1 ·mol ^-1 ; V is the molar volume, the unit is dm ³ ·mol ^-1 , M is the molar mass of methane, M=16g/mol; Z is the compression factor; P _r is the relative pressure _{; Tr is the relative temperature, V r is} the relative volume, and the dimensions are all 1; P _c is the critical pressure, P _c =4.6MPa; T _c is the critical temperature, T _c =190.4K; V _c is the critical molar volume, in cm ³ /mol; a ₁ =0.08726; a ₂ =-0.75260; a ₃ =0.37542; a ₄ a5 = _0.00550 ; a6 = _-0.01848 ; _a7 = _0.00032 ; a8 = _0.00021 ; a9 = _0.00002 ; a10 = _-0.00002 ; a11 = 0.00012; a12 = _-0.00011 ; β=0.75397; γ=0.07717;

S2: Using the seismic profile data, 2Dmove is used to perform time-depth conversion, cross-section sliding splicing, de-folding, de-compaction correction, and the denudation amount reflected by the low-temperature thermochronology test to restore the two-dimensional profile structural evolution;

S3: Based on the present seismic section recovered in step S2, import it into PetroMod for digital gridding of the stratigraphic section, and establish the key parameters required for the simulation in combination with the regional stratigraphic depositional history, source rock geochemical data and boundary conditions; The parameters include: lithology, thickness and age; the source rock geochemical data include: TOC, hydrogen index and hydrocarbon generation kinetic model; the boundary conditions include: paleo-water depth, paleo-heat flow and water-rock interface temperature;

S4: according to the structural evolution profile result restored in step S2, increase the erosion amount to the profile formed in S3 and constrain the stratum shape layer by layer;

S5: Use PetroMod to simulate the formation temperature and pressure in each historical period of the profile, and use the single-well temperature burial history of the profile combined with the temperature measurement results of inclusions to restore the time of paleo-pressure measurement points;

S6: Use the paleo-pressure values of different interval points calculated in step S1 and the present measured formation pressure as the Y-axis and the paleo-stress value simulated by PetroMod at the corresponding time of the corresponding formation to perform a correlation analysis on the X-axis and establish a corresponding correction relation. This correction relation is used to correct the paleopressures of other points on the backbone profile at different depths in different historical periods.

Preferably, the fracture veins in the S1 are hydraulic fractured fractures and high-angle structural fractures.

The recovery method of formation paleo-pressure of the present invention has the following advantages: the present invention calculates paleo-pressure and software numerical simulation through fracture vein sampling experiments of stratified sections, stages, and causes (related to hydrocarbon generation and tectonic action). The correlation correction is performed on the value of the unconventional reservoir, and the multi-dimensional and multi-period formation paleopressure of the unconventional reservoir can be recovered more accurately by using the structural evolution profile to constrain the simulated profile.

Description of drawings

Fig. 1 is a flow chart of the multi-dimensional and multi-period formation paleo-pressure recovery method of the extraordinary reservoir of the present invention.

Fig. 2 is a sample diagram of some fractured veins of the present invention; A is the structural fracture in the late Yanshan period in the 12th sublayer of the Long 1 member; B is the hydrocarbon-generating hydraulic fracture in the early and middle Yanshan period, filled with fibrous calcite.

Fig. 3 is a diagram showing the morphology and production characteristics of methane inclusions in some fractured veins of the present invention; wherein A is the dispersed brine inclusions in the joint fractures; wherein B is the brine inclusions and methane inclusions with linear arrangement of natural micro-fractures .

FIG. 4 is a laser Raman spectrum of methane inclusions in some fractured veins of the present invention.

Fig. 5 is a histogram of the uniform temperature distribution of methane inclusions in some fractured veins of the present invention.

FIG. 6 is a structural evolution diagram of the backbone section in the Guodingshan area according to the present invention.

FIG. 7 is a diagram showing the distribution of well locations and the location of backbone sections in the Dingshan area of the present invention.

FIG. 8 is a simulation diagram of single-well burial history-temperature-pressure of Well A of the present invention.

FIG. 9 is a graph showing the relationship between the calculated paleo-pressure, the measured pressure and the simulated value according to the present invention.

FIG. 10 is a cross-sectional view of the paleo-pressure evolution after correction according to the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Referring to FIG. 1, the present embodiment provides a multi-dimensional and multi-period formation paleo-pressure recovery method for unconventional reservoirs, including the following steps:

S1: Take the fracture veins of different stages of the profile target layer to conduct experiments including body measurement and Raman spectroscopy, and count and calculate the experimental results. The relevant steps are as follows:

①Sampling the hydrocarbon-generating hydraulic fractures and high-angle fracture veins in different stages of the drilling target layer of the recovery profile, as shown in Figure 2 of the accompanying drawings;

②The temperature measurement of fluid inclusions: The temperature measurement of fluid inclusions in the vein body uses the AxioScope.AI dual-channel fluorescence-transmitted light microscope produced by Zeiss Company, and is equipped with THMSG600 cooling and heating stage and cooling and heating control system produced by Linkam Company. , the uniform temperature test error is ±1 °C; the heating rate is controlled at 0.1-5 °C/min, the inclusions with clear contour characteristics and uniform capture are selected, and the abnormal inclusions that are not uniformly captured are excluded, as shown in Figure 3 of the accompanying drawings. , observe and record the temperature when the inclusions are completely homogeneous and when the ice cubes are completely melted;

③ Laser Raman test: On the basis of the research on fluid inclusions, pure gas-phase methane inclusions with relatively complete and regular shapes were selected for microscopic laser Raman test, as shown in Figure 4 of the accompanying drawings. The laser Raman spectroscopic analysis and test used the LabRAM HR800 microscope laser Raman spectrometer produced by HORIBA JobinYvomS.AS. The experimental temperature was controlled at 22 °C, the light source was a YAG laser, and the time interval for a single data acquisition was 20-120 s. For the laser Raman spectrum data acquisition of inclusions, the signal peaks were firstly obtained with a 300 grating, which was used to determine the composition of the inclusions, and then the 1800 grating was used to collect and determine the peak displacement. Finally, the standard peak Ne1 (standard value of 2836.9888cm ^{- 1} ) and the standard peak Ne3 (standard value 3008.1274 cm ^-1 ) to correct the measured results.

④Analysis of experimental results: Statistics of the measured inclusion homogenization temperature are carried out, and the statistical results are shown in Figure 5 of the accompanying drawings. The paleo-pressure calculation method of the tested methane inclusions is calculated, and the test and calculation results are shown in Table 1. The Raman displacement and density calculation results of the methane inclusions in the target section of Table 1 are shown.

Table 1

S2: Import the seismic profile of the target layer into 2Dmove, digitize the seismic profile and perform time-depth conversion, cross-section sliding splicing, de-folding, de-compaction correction, and 2D profile structure combined with the denudation reflected by low-temperature thermochronology Evolution recovery, as shown in Figure 6 with reference to the accompanying drawings;

S3: Based on the present seismic section recovered in S2, import PetroMod to digitally grid the stratigraphic section, combine the regional stratigraphic depositional history (lithology, thickness, age), source rock geochemical data (TOC, hydrogen index, hydrocarbon generation dynamic model) and boundary conditions (paleo-water depth, paleo-heat flow, water-rock interface temperature) to establish the above key parameters required for simulation;

S4: According to the structural evolution profile results restored by S2, referring to Figure 6 of the accompanying drawings, increase the corresponding denudation amount for the profile formed in S3 at the geological time corresponding to formation uplift and denudation, and constrain the formation layer by layer.

S5: Use PetroMod to simulate the formation pressure in each historical period of the profile, in which the profile can intercept the temperature and pressure results of any vertical single well (one-dimensional) simulation, and intercept the single well temperature simulation results of sampling well A combined with the results of well S1A. The uniform temperature range of the inclusions determines the time corresponding to the paleopressure, as shown in Figure 7 of the accompanying drawings, and Well B and Well C are also based on this;

S6: Use the paleo-pressure values at different intervals calculated by S1 and the current measured formation pressures and their corresponding time simulation values to conduct correlation analysis and establish a relational formula. The simulated formation pressures at different depths in each historical period of the profile are changed and corrected according to the relational formula. , with reference to Figures 8 and 9 of the accompanying drawings.

While the content of the present invention has been described in detail by way of the above preferred embodiments, it should be appreciated that the above description should not be construed as limiting the present invention. Various modifications and alternatives to the present invention will be apparent to those skilled in the art upon reading the foregoing. Accordingly, the scope of protection of the present invention should be defined by the appended claims.

Claims (2)

1. a recovery method of multi-dimensional and multi-period formation paleo-pressure of unconventional reservoir, is characterized in that, this recovery method comprises the following steps: S1: Fracture veins in different periods of different intervals of the target layer of key wells on the backbone seismic section are taken, and the periods include: Early-Middle Yanshan, Late Yanshan, Early Himalayan and Late Himalayan; Oil and gas-bearing development sublayers; then carry out fluid inclusion temperature measurement and laser Raman experimental test, and then carry out paleo-pressure time and pressure recovery. Neon laser Raman standard peaks Ne ₁ and standard peaks Ne ₃ are used to detect fluid inclusions. The Raman scattering peak correction of , using the pressure when the methane inclusions in the fracture veins are captured as the paleopressure, is calculated as follows: v _d -v ₀ =211.3ρ ⁴ +73.328ρ ³ +24.477ρ ² -29.0632ρ

in

In the formula: ρ is the density of methane inclusions, in g/cm ³ ; v _d is the corrected methane Raman scattering peak wave number; v ₀ is the methane Raman scattering peak wave number when the density is close to 0, v ₀ = 2917.58cm ^-1 ; P is pressure, unit is MPa; T is temperature, unit is K; R is gas constant, R=0.008314467MPa·dm ³ ·K ^-1 ·mol ^-1 ; V is molar volume, unit is dm ³ mol ^-1 , M is the molar mass of methane, M=16g/mol; Z is the compression factor; P _r is the relative pressure _{; Tr is the relative temperature, V r is} the relative volume, and the dimension is 1; P _c is Critical pressure, P _c =4.6MPa; T _c is critical temperature, T _c =190.4K; V _c is critical molar volume, in cm ³ /mol; a ₁ =0.08726; a ₂ =-0.75260; a ₃ =0.37542 a ₄ =0.01073; a ₅ =0.00550; a ₆ =-0.01848; a ₇ =0.00032; a ₈ = _0.00021 ; a ₉ =0.00002; a ₁₀ = _-0.00002 ; = 0.04483; β = 0.75397; γ = 0.07717; S2: Using the seismic profile data, 2Dmove is used to perform time-depth conversion, cross-section sliding splicing, de-folding, de-compaction correction, and the denudation amount reflected by the low-temperature thermochronology test to restore the two-dimensional profile structural evolution; S3: Based on the present seismic section recovered in step S2, import it into PetroMod for digital gridding of the stratigraphic section, and establish the key parameters required for the simulation in combination with the regional stratigraphic depositional history, source rock geochemical data and boundary conditions; The parameters include: lithology, thickness and age; the source rock geochemical data include: TOC, hydrogen index and hydrocarbon generation kinetic model; the boundary conditions include: paleo-water depth, paleo-heat flow and water-rock interface temperature; S4: according to the structural evolution profile result restored in step S2, increase the erosion amount to the profile formed in S3 and constrain the stratum shape layer by layer; S5: Use PetroMod to simulate the formation temperature and pressure in each historical period of the profile, and use the single-well temperature burial history of the profile combined with the temperature measurement results of inclusions to restore the time of paleo-pressure measurement points; S6: Use the paleo-pressure values of different interval points calculated in step S1 and the present measured formation pressure as the Y-axis and the paleo-stress value simulated by PetroMod at the corresponding time of the corresponding formation to perform a correlation analysis on the X-axis and establish a corresponding correction relation. This correction relation is used to correct the paleopressures of other points on the backbone profile at different depths in different historical periods. 2 . The method for restoring multi-dimensional and multi-period formation paleopressure in an unconventional reservoir according to claim 1 , wherein the fracture veins in the S1 are hydraulic fracture veins and high-angle structural fracture veins. 3 .

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