Tight oil nano-agent cyclic flooding and subsequent development method and system

Abstract

This invention belongs to the field of reservoir development technology, and relates to a method and system for the continuous development of tight oil using nano-agents for cyclic displacement. The method includes: S1, determining the timing of the shift to displacement based on the dynamic fluid level of the production well; S2, calculating the cyclic displacement interval time under reservoir conditions based on the well shut-in time; S3, calculating the injection volume of the displacement agent based on the reservoir pore volume (PV) of the injection-production well group; S4, calculating the injection rate of the displacement agent based on the production rate and injection-production ratio of the injection-production well group; S5, implementing the continuous development of tight oil using nano-agents for cyclic displacement based on the selected nano-agent, the timing of the shift to displacement, the cyclic displacement interval time, the injection volume of the displacement agent, and the injection rate of the displacement agent. The system includes a decision module, a first calculation module, a second calculation module, a third calculation module, and an implementation module. This invention can adapt to the geological characteristics of tight oil reservoirs, effectively utilize the role of nano-agents in permeation and drainage, improve crude oil production and recovery rate, and achieve timely shift to displacement after energy storage volumetric fracturing production, realizing atmospheric pressure displacement.

Description

Technical Field

[0001] This invention belongs to the field of reservoir development technology, and specifically relates to a method and system for the periodic displacement and successive development of tight oil using nano-agents. Background Technology

[0002] Currently, research and practice on follow-up development methods after volumetric fracturing in tight oil storage mainly focus on three major categories and more than 20 methods, including repeated fracturing, secondary energy replenishment fracturing, synchronous fracturing, CO2 storage fracturing, rapid water injection and huff and puff, large volume water injection and huff and puff, dynamic permeation water injection and huff and puff, water injection and energy enhancement huff and puff, surfactant huff and puff, nano-agent huff and puff, directional well CO2 huff and puff, horizontal well CO2 huff and puff, direct injection and horizontal production area well network water drive, simultaneous injection and production in the same well, air foam drive, nano-agent drive, carbonized water drive, etc.

[0003] Even after high initial production following volumetric fracturing, the decline rate is significant, reaching 30%–40% in the first year for shale oil wells. Therefore, increasing shale oil production requires continuous well-to-well replacement, necessitating substantial new drilling and investment, and resulting in a low average production rate throughout the development period. High costs, rapid decline in single-well production, and low recovery rates necessitate sustained high investment. Water injection and injection-pump-and-pump methods are phased and unsustainable development approaches. Uneven gas injection effects and gas channeling are difficult to avoid and resolve. Repeated fracturing methods are diverse, highly targeted, but lack universality. Waterflooding and modified waterflooding with different displacement agents are widely used development methods for tight oil and shale oil, but for tight reservoirs, the low micro-sweep coefficient of continuous displacement leads to ineffective water injection, or water flooding when effective. Therefore, it is necessary to introduce nano-agents for cyclic displacement. Summary of the Invention

[0004] To address the above problems, the present invention adopts the following technical solution: a method for the continuous development of tight oil using nano-agents for cyclic displacement, the method comprising the following steps: S1, determining the timing of the switching to displacement based on the dynamic fluid level of the production well; S2, calculating the cyclic displacement interval time under reservoir conditions based on the well stagnation time; S3, calculating the amount of displacement agent injected based on the reservoir pore volume (PV) of the injection-production well group; S4, calculating the displacement agent injection rate based on the production rate and injection-production ratio of the injection-production well group; S5, implementing the continuous development of tight oil using nano-agents for cyclic displacement based on the selected nano-agent, the timing of the switching to displacement, the cyclic displacement interval time, the amount of displacement agent injected, and the displacement agent injection rate.

[0005] Furthermore, S1, determining the timing of switching the drive based on the dynamic fluid level of the oil well includes: calculating the corresponding minimum dynamic fluid level height of the oil well based on the saturation pressure, monitoring the dynamic fluid level height, and switching the drive before reaching the minimum dynamic fluid level height.

[0006] Furthermore, the minimum dynamic fluid level height corresponding to the oil well calculated based on the saturation pressure is: h lc =D w-85P ob / ρ l ; where h lc D is the minimum dynamic liquid level height. w P represents the depth of the oil well. ob ρ is the saturation pressure of crude oil. l ρ is the density of the liquid column.

[0007] Furthermore, S2, based on the well-closing time, calculate the periodic displacement interval under reservoir conditions, including:

[0008] Based on the experimental analysis of well stagnation time, the periodic displacement interval time under reservoir conditions was calculated using the similarity criterion formula.

[0009] Furthermore, the similarity criterion formula is as follows:

[0010]

[0011] Where σ and θ represent the oil-water interfacial tension and oil-water interfacial wetting angle under indoor experimental conditions and reservoir conditions, respectively; ΔP(t) lab ΔP(t) represents the pressure difference between the initial inlet pressure and the pressure during the steady-state phase under indoor experimental conditions. feild This represents the difference between the bottom hole pressure under reservoir conditions and the initial pressure during the pressurized seepage stage, i.e., the difference between the fracturing stabilization pressure and the bottom hole pressure at the end of the well shut-in period; (t) 焖井 ) lab 、(t 焖井 ) field These represent the well-sinking time under indoor experimental conditions and reservoir conditions, respectively; (L) c ) lab 、(L c ) field The characteristic lengths under indoor experimental conditions and reservoir conditions are respectively; r lab r field denoted as effective pore radii under indoor experimental conditions and reservoir conditions, respectively; r is the effective pore radius of the reservoir.

[0012] Furthermore, the formula for calculating the feature length is:

[0013]

[0014] Among them, V b A represents the volume of the core matrix. i Let l be the area of ​​the contact surface for absorption in the i-th direction; Ai is the distance from the front edge of the seepage to the closed boundary along the opening surface; n is the maximum number of contact surfaces.

[0015] Furthermore, the effective pore radius is calculated using the formula: r = 0.835 × exp(-P / 2.711) + 0.079

[0016] Where P is the net pressure under indoor experimental conditions or the net pressure under reservoir conditions.

[0017] Furthermore, under indoor experimental conditions, the net pressure is the difference between the confining pressure and the average inlet and outlet pressures; under reservoir conditions, the net pressure is the difference between the pressure of the overlying strata and the pore pressure.

[0018] Furthermore, the amount of displacing agent injected is less than 1.0 PV.

[0019] Furthermore, S4, calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group, including:

[0020] V nano =V l ×I R

[0021] Among them, V nano V is the injection rate of the displacing agent. l I represents the fluid production rate of the injection-production well group; R For injection ratio.

[0022] Furthermore, the injection-production ratio is determined based on the cumulative deficit, and the injection-production ratio is between 1.0 and 1.3.

[0023] Furthermore, S5, based on the selected nano-agent, the timing of the shift, the periodic displacement interval, the amount of displacer injected, and the rate of displacer injection, the tight oil nano-agent periodic displacement follow-up development is implemented, including: based on the selected nano-agent, the timing of the shift, the periodic displacement interval, the amount of displacer injected, and the rate of displacer injection, a nano-agent periodic displacement reservoir engineering development plan, an oil production process plan, a surface engineering plan, and a health, safety, and environmental management plan are formulated, and the tight oil nano-agent periodic displacement follow-up development is implemented.

[0024] This invention also proposes a system for the continuous development of dense oil nanoparticles through periodic displacement, the system comprising: a decision module, a first calculation module, a second calculation module, a third calculation module, and an implementation module;

[0025] The decision module is used to determine the timing of the drive based on the dynamic fluid level of the oil well.

[0026] The first calculation module is used to calculate the periodic displacement interval time under reservoir conditions based on the well simmering time;

[0027] The second calculation module is used to calculate the displacement agent injection amount based on the reservoir pore volume PV of the injection-production well group;

[0028] The third calculation module is used to calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group.

[0029] The implementation module is used to carry out the continuous development of tight oil nano-agent cycle displacement based on the preferred nano-agent, the timing of the displacement, the cycle displacement interval, the amount of displacement agent injected, and the displacement agent injection rate.

[0030] Furthermore, the decision module is used to determine the timing of the drive shift based on the dynamic fluid level of the oil well, including: the decision module is used to calculate the corresponding minimum dynamic fluid level height of the oil well based on the saturation pressure, monitor the dynamic fluid level height, and shift the drive before reaching the minimum dynamic fluid level height.

[0031] Furthermore, the first calculation module is used to calculate the periodic displacement interval time under reservoir conditions based on the well stagnation time, including: the first calculation module is used to calculate the periodic displacement interval time under reservoir conditions based on the experimental analysis of the well stagnation time and the similarity criterion formula.

[0032] Furthermore, the second calculation module is used to calculate the displacement agent injection amount based on the reservoir pore volume PV of the injection-production well group, including: the second calculation module is used to calculate the displacement agent injection amount as less than 1.0PV based on the reservoir pore volume PV of the injection-production well group.

[0033] Furthermore, the third calculation module is used to calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group: V nano =V l ×I R V nano V is the injection rate of the displacing agent. l I represents the fluid production rate of the injection-production well group; R The injection-production ratio is determined based on the accumulated deficit, and its value ranges from 1.0 to 1.3.

[0034] Furthermore, the implementation module is used to implement the continuous development of tight oil nano-agent cycle displacement based on the preferred nano-agent, displacement timing, cycle displacement interval, displacement agent injection amount, and displacement agent injection rate, including:

[0035] The implementation module is used to formulate a nano-agent periodic displacement reservoir engineering development plan, oil production process plan, surface engineering plan, and health, safety and environmental management plan based on the selected nano-agent, the timing of the shift, the periodic displacement interval, the amount of displacement agent injected and the displacement agent injection rate, and to implement the continuous development of tight oil nano-agent periodic displacement.

[0036] In addition, the present invention also relates to a computer-readable storage medium storing computer instructions for causing a processor to execute the above-described method for the periodic displacement and succession development of dense oil nanoparticles.

[0037] The present invention also relates to an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for the periodic displacement and succession development of dense oil nanoparticles.

[0038] Compared with existing technologies, the beneficial effects of this invention are as follows: it solves a series of problems in the development of unconventional oil reservoirs such as low-permeability, ultra-low-permeability tight oil and shale oil, such as rapid decline in crude oil production, continuous depletion of formation energy, rapid drop in formation pressure, crude oil degassing, fracture closure, and low crude oil recovery rate when relying on energy storage volumetric fracturing. It can adapt to the geological characteristics of tight oil reservoirs, effectively utilize the role of nano-agents in oil permeation and drainage, replenishing formation energy, and improving crude oil production and recovery rate. Moreover, it can promptly switch to displacement after energy storage volumetric fracturing production to achieve atmospheric pressure displacement, achieve stable production and improved recovery, and obtain higher economic benefits.

[0039] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention will be realized and obtained from the description and the drawings. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A flowchart illustrating a method for the continuous development of dense oil nanoparticles through cyclic displacement.

[0042] Figure 2 A schematic diagram showing the comparative data of oil displacement efficiency and injection pressure between periodic and continuous displacement experiments;

[0043] Figure 3 This is a schematic diagram of the displacement experiment results after infiltration;

[0044] Figure 4 This is a schematic diagram of a dense oil nanoparticle cycle displacement succession development system. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] This invention relates to a method for the continuous development of tight oil using nano-agents through cyclic displacement, the method comprising the following steps: S1, determining the timing of the displacement based on the dynamic fluid level of the production well; S2, calculating the cyclic displacement interval time under reservoir conditions based on the well simmering time; S3, calculating the amount of displacement agent injected based on the reservoir pore volume (PV) of the injection-production well group.

[0047] S4. Calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group; S5. Implement the continuous development of tight oil through the cyclic displacement of nano-agents based on the selected nano-agent, the timing of the shift, the cyclic displacement interval, the amount of displacement agent injected, and the displacement agent injection rate.

[0048] In the aforementioned method for continuous development of tight oil using nano-agents, the determination of reasonable well-keeping time and displacement cycle interval is based on the four-stage mechanism of tight oil permeation. Static permeation experiments under reservoir temperature and formation oil viscosity conditions show that permeation efficiency exhibits a phased pattern. The permeation curves of nano-agents and fracturing fluids can be divided into four stages: a permeation-discharge gap, a high-speed permeation-discharge period, a rapid permeation-discharge period, and a low-speed permeation-discharge period. The permeation-discharge gap is an objective reality in reservoir development that has been overlooked in previous observations. Theoretically, or through online low-field NMR measurements, crude oil is instantly permeated, replaced, and discharged after the core sample is immersed in permeation fluid. However, due to the small quantity, this discharged crude oil cannot reach the fluid surface or accumulate at the bottom of the well, and therefore is invisible during production. Only when crude oil discharged from medium and large pores and seeped from micro and nano pores accumulates from within the rock mass to the outside, forming small oil droplets, which then merge to form large oil droplets. When the buoyancy of these large droplets exceeds gravity and viscosity, they rise to the surface and can be observed; this period is the oil drainage window. As seepage continues, under the influence of confining pressure and internal pressure differences within the rock mass, the fluid in the medium and large pores undergoes Darcy seepage, resulting in high-speed seepage (stage 2). Simultaneously, the tight oil micro and nano pores, under the influence of capillary forces and the resulting capillary pressure, also drain oil, at a slower rate than the medium and large pores. As the internal and external pressure differences of the rock mass decrease and tend towards equilibrium, Darcy seepage weakens, and seepage transitions from high-speed to rapid seepage (stage 3). In this stage, the concentration of nanoparticles inside the rock mass increases, and the unique "wedge-shaped compression" effect at the nanoscale intensifies, stripping crude oil from the solid rock surface for drainage. Stage 4 is the low-speed seepage stage. As water saturation increases, capillary force and capillary potential energy decrease rapidly, and ion diffusion gradually becomes apparent. However, the oil discharge rate differs by orders of magnitude from the previous stage, indicating a slow percolation phase that is difficult to observe in experiments. When the percolation front contacts the pore wall containing salt ions, the salt ions dissolve and enter the water, inducing ion diffusion, resulting in extremely slow crude oil discharge.

[0049] In this embodiment of the invention, taking the tight oil core used in the experiment as an example, the seepage and drainage window period is 0.5-1 day, the high-speed seepage and drainage period is 1-2 days, the rapid seepage and drainage period is 8-9.5 days, after which the low-speed seepage and drainage period begins. This experimental result and understanding has fundamental guiding significance for the cycle displacement interval. Determining the well opening time based on wellhead pressure changes is difficult to reflect the potential recoverable oil volume (already accumulated oil) at the bottom of the well. The low-speed seepage and drainage period, due to its slow drainage rate, long duration, and poor timeliness, can continue during production without requiring further well shut-in; therefore, the reasonable well shut-in time for energy storage volumetric fracturing and the cycle displacement interval should ideally coincide with the end of the rapid seepage and drainage period.

[0050] Specifically, step S1 includes: calculating the minimum dynamic fluid level corresponding to the oil well based on the saturation pressure, monitoring the dynamic fluid level, and switching the drive before reaching the minimum dynamic fluid level. The formula for calculating the minimum dynamic fluid level is: h lc =D w -85P ob / ρ l ; where h lc The critical or lowest dynamic liquid level, measured in meters (m); D w Indicates the depth of the oil well, in meters; P ob ρ represents the saturation pressure of crude oil, in MPa. l This represents the density of the liquid column, with units of 1000 kg / m³. 3 .

[0051] Specifically, step S2 includes: calculating the periodic displacement interval under reservoir conditions using the similarity criterion formula based on the experimental analysis of a reasonable well-sinking time. The reasonable well-sinking time can be calculated from the end time of the rapid absorption period in the laboratory using the similarity criterion formula, and is related to the average size (characteristic length) of the rock block after fracturing, reservoir tightness, micro-nano pore connectivity, and pore structure complexity. The similarity criterion formula is:

[0052] Where σ and θ represent the oil-water interfacial tension and oil-water interfacial wetting angle under indoor experimental conditions and reservoir conditions, respectively; ΔP(t) lab ΔP(t) represents the pressure difference between the initial inlet pressure and the pressure during the steady-state phase under indoor experimental conditions; this value is 0. feild This represents the difference between the bottom hole pressure under reservoir conditions and the initial pressure during the pressurized seepage stage, i.e., the difference between the fracturing stabilization pressure and the bottom hole pressure at the end of the well shut-in period; (t) 焖井 ) lab 、(t 焖井 ) field These represent the well-sinking time under indoor experimental conditions and the well-sinking time under reservoir conditions, respectively; (L c ) lab 、(L c ) field The characteristic lengths under indoor experimental conditions and reservoir conditions are respectively; r lab r field Here, r represents the effective pore radius under indoor experimental conditions and reservoir conditions, respectively; the characteristic length is calculated using the following formula:

[0053]

[0054] V b This refers to the volume of the core matrix, in cm³. 3 A i The area of ​​the contact surface for permeation in the i-th direction is expressed in cm².2 ;l Ai The distance from the infiltration front along the open surface to the closed boundary is in cm; n is the maximum number of contact surfaces. The effective pore radius r is calculated as: r = 0.835 * exp(-P / 2.711) + 0.079, where the effective pore radius r is in μm; P is the net pressure under indoor experimental conditions and the net pressure under reservoir conditions, in MPa; the net pressure under indoor experimental conditions is the difference between the confining pressure and the average inlet and outlet pressures; the net pressure under reservoir conditions is the difference between the overlying strata pressure and the pore pressure.

[0055] Specifically, step S3 includes: it is known from the mechanism experiment that the oil displacement efficiency increases the fastest before the nano-agent injection volume multiple (PV) is 1.0PV; after that, the rate of increase and the rate of increase of oil displacement efficiency slow down greatly. Therefore, the displacement of long horizontal wells is reasonably limited to 1.0PV; in the embodiment of the present invention, the amount of displacement agent injected is less than 1.0PV.

[0056] Specifically, step S4 includes: determining the displacement agent injection rate based on the fluid production rate of the nano-agent injection-production well group, a reasonable injection-production ratio, etc.; V nano =V l ×I R V nano The displacement agent injection rate is expressed in meters (m). 3 / d;V l The fluid production rate of the injection-production well group is expressed in meters (m). 3 / d;I R The injection-production ratio is determined based on the accumulated deficit, and is generally set between 1.0 and 1.3.

[0057] Specifically, step S5 includes: based on the preferred nano-agent, the timing of the shift, the periodic displacement interval, the amount of displacement agent injected, and the displacement agent injection rate, formulating a nano-agent periodic displacement reservoir engineering development plan, an oil production process plan, a surface engineering plan, and a health, safety, and environmental management plan, and implementing the tight oil nano-agent periodic displacement follow-up development.

[0058] It should be noted that the step numbers in the above method (e.g., S1, S2, S3, S4) do not represent the execution order of the steps; they are merely used as identifiers to distinguish each step. Other execution orders (e.g., parallel execution) are possible between the steps.

[0059] Based on the above-designed method for the continuous development of tight oil using nano-agent cyclic displacement, a nano-agent cyclic displacement experiment was conducted: the displacement was temporarily stopped when the water cut at the outlet end reached 20%, 60%, and 80%, and the core was allowed to infiltrate and absorb within a clamping device under formation temperature and pressure for 10 days (determined by referring to the reasonable well-keeping time under reservoir temperature and pressure conditions). Figure 2The diagram shows a comparison of experimental results regarding oil displacement efficiency and injection pressure between periodic and continuous displacement: Figure 2 In the figure, the horizontal axis represents the injection volume ratio (PV), and the vertical axis represents the injection pressure (MPa) and the oil displacement efficiency (%). Both cyclic and continuous displacement used low-concentration nanoparticles (0.02% by mass) as the displacing fluid. In continuous displacement, at an injection volume ratio of 2.36 PV, the water content at the core outlet was 100%, and the oil displacement efficiency was 51.40% at the end of displacement. Cyclic displacement showed significantly higher oil displacement efficiency than continuous displacement. Specifically, at an injection volume ratio of 0.478 PV, the oil displacement efficiency was 55.10%, an increase of 14.10% compared to continuous displacement; at an injection volume ratio of 6.854 PV, the oil displacement efficiency reached 78.60%, an increase of 27.20% compared to continuous displacement. This reflects the better development effect of cyclic displacement.

[0060] After the incremental oil discharge from the percolation of a low-concentration nanoparticle (0.02% by mass) was zero, core transfer experiments with the same concentration of nanoparticles showed (e.g.) Figure 3 As shown): ① The oil displacement efficiency after low-concentration nanoparticles are infiltrated and then displaced reaches a maximum of 38.0% (injection volume multiple of 2.69 PV). When the injection volume multiple is 1.04 PV, the stage oil displacement efficiency has reached 31.3%, indicating that there is still great potential to improve oil recovery after infiltration and then displacement; ② The initial injection pressure after low-concentration nanoparticles are infiltrated and then displaced is relatively low ( Figure 3 The injection pressure was 18 MPa, indicating that atmospheric pressure displacement could be achieved. The injection pressure reached 22.0 MPa when the fracturing fluid was higher. As displacement progressed, the pressure increased, but remained within the achievable range, with the highest pressure for low-concentration nano-agent reaching only 30.0 MPa, and the wellhead pressure less than 20 MPa. ③ After 50 days of low-concentration nano-agent infiltration, the infiltration displacement efficiency was 36.67%. In other words, after low-concentration nano-agent infiltration, the initial injection pressure for displacement was 18 MPa, and the displacement efficiency was 38.0%. The combined displacement efficiency with infiltration was 74.67% (38.0% + 36.67%), representing a 23.27% increase in displacement efficiency compared to direct continuous displacement and a 38% increase compared to infiltration displacement. These data demonstrate that the tight oil displacement followed by development significantly improves oil displacement efficiency and recovery rate.

[0061] Field verification was conducted using the aforementioned tight oil nanoparticle-based cyclic displacement and continuous development method. In the AN83 block of the DQ oilfield, where the average reservoir permeability is 0.2 mD, an injection test was performed after the production of the horizontal wells in the AP21 injection-production group decreased due to volumetric fracturing. The initial production of well AN20, located in the same well group as the water injection well, was 14.1 t / d after volumetric fracturing, but decreased to 5.2 t / d after one year of depletion. After displacement via injection in well AP21, water channeling caused production to stop. After a 10-day shutdown, production recovered to a peak of 12.2 t / d, stabilizing at around 6 t / d after one year.

[0062] In addition, the present invention also relates to a tight oil nanoparticle-based periodic displacement and continuous development system, the system comprising: a decision module 11, a first calculation module 12, a second calculation module 13, a third calculation module 14, and an implementation module 15; the decision module 11 is used to determine the timing of the shift drive based on the dynamic fluid level of the oil well; the first calculation module 12 is used to calculate the periodic displacement interval time under reservoir conditions based on the well stagnation time; the second calculation module 13 is used to calculate the displacement agent injection amount based on the reservoir pore volume (PV) of the injection-production well group; the third calculation module 14 is used to calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group; the implementation module 15 is used to implement the tight oil nanoparticle-based periodic displacement and continuous development based on the preferred nanoparticle, the timing of the shift drive, the periodic displacement interval time, the displacement agent injection amount, and the displacement agent injection rate.

[0063] Specifically, the decision module 11 is used to determine the timing of the drive based on the dynamic fluid level of the oil well, including: the decision module 11 is used to calculate the corresponding minimum dynamic fluid level height of the oil well based on the saturation pressure, monitor the dynamic fluid level height, and drive before reaching the minimum dynamic fluid level height.

[0064] Specifically, the first calculation module 12 is used to calculate the periodic displacement interval time under reservoir conditions based on the well stagnation time, including: the first calculation module 12 is used to calculate the periodic displacement interval time under reservoir conditions based on the experimental analysis of the well stagnation time and the similarity criterion formula.

[0065] Specifically, the second calculation module 13 is used to calculate the displacement agent injection amount based on the reservoir pore volume PV of the injection-production well group, including: the second calculation module 13 is used to calculate the displacement agent injection amount as less than 1PV based on the reservoir pore volume PV of the injection-production well group.

[0066] Specifically, the third calculation module 14 is used to calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group, where the displacement agent injection rate V is... nano =V l ×I R V nano The unit is m 3 / d;V lThe fluid production rate of the injection-production well group is expressed in meters (m). 3 / d;I R The injection-production ratio is determined based on the accumulated deficit, and is generally set between 1.0 and 1.3.

[0067] Specifically, the implementation module 15 is used to implement the continuous development of tight oil nanoparticle-based periodic displacement based on the preferred nanoparticles, the timing of the shift, the periodic displacement interval, the amount of displacer injected, and the rate of displacer injection. This includes: the implementation module 15 is used to formulate a nanoparticle-based periodic displacement reservoir engineering development plan, an oil production process plan, a surface engineering plan, and a health, safety, and environmental management plan based on the shift timing, the periodic displacement interval, the amount of displacer injected, and the rate of displacer injection, and to implement the continuous development of tight oil nanoparticle-based periodic displacement.

[0068] The present invention also provides a computer-readable storage medium storing computer instructions for causing a processor to execute a method for the periodic displacement and succession development of a dense oil nanoparticle as described above.

[0069] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements a method for the continuous development of dense oil nanoparticles through periodic displacement as described above.

[0070] In summary, this invention provides a novel method for replenishing formation energy and enhancing oil recovery after horizontal well volumetric fracturing development. This new method is a cyclic displacement development approach based on early-stage energy storage volumetric fracturing development and nanomaterial displacement in long horizontal wells for tight oil production. The determination of the cyclic displacement development method and displacement interval is based on mechanistic studies. When the nanomaterial concentration is 0.02%, the cyclic displacement development method achieves an oil displacement efficiency of 78.60%, which is 27.20% higher than continuous displacement and 42.20% higher than quasi-natural energy development through energy storage volumetric fracturing.

[0071] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for the continuous development of dense oil nanoparticles through periodic displacement, characterized in that, The method comprises the following steps: S1. Determine the timing of the drive based on the dynamic fluid level in the oil well. S2. Calculate the periodic displacement interval time under reservoir conditions based on the well shut-in time; S3. Calculate the displacement agent injection volume based on the reservoir pore volume PV of the injection-production well group; S4. Calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group; S5. Based on the selected nano-agent, the timing of the displacement, the periodic displacement interval, the amount of displacement agent injected, and the speed of displacement agent injection, implement the periodic displacement and sequential development of tight oil nano-agents. S1. Determine the timing of the drive transition based on the dynamic fluid level in the oil well, including: Calculate the minimum dynamic fluid level height corresponding to the oil well based on the saturation pressure, monitor the dynamic fluid level height, and switch the drive before reaching the minimum dynamic fluid level height; The minimum dynamic fluid level height corresponding to the oil well, calculated based on saturation pressure, is: h lc = D w - 85P ob / ρ l ; where h lc D is the minimum dynamic liquid level height. w P represents the depth of the oil well. ob ρ is the saturation pressure of crude oil. l ρ is the density of the liquid column.

2. The method according to claim 1, characterized in that, S2. Calculate the periodic displacement interval under reservoir conditions based on the well shut-in time, including: Based on the experimental analysis of well simmering time, the periodic displacement interval under reservoir conditions was calculated using the similarity criterion formula. The formula for the similarity criterion is: ； in, In σ、 θ、 r These are the oil-water interfacial tension, oil-water interfacial wetting angle, and effective pore radius of the reservoir under indoor experimental conditions. In ∆P(t) This represents the pressure difference between the initial inlet pressure and the pressure steady-state pressure under indoor experimental conditions. In σ、 θ、 r These are the oil-water interfacial tension, oil-water interfacial wetting angle, and effective pore radius of the reservoir under reservoir conditions. In ∆P(t) It is the difference between the bottom hole pressure under reservoir conditions and the initial pressure during the pressurized seepage stage, that is, the difference between the fracturing stabilization pressure and the bottom hole pressure at the end of the well shut-in period; （t 焖井 ） lab、 （t 焖井 ） field These represent the well-sinking time under indoor experimental conditions and reservoir conditions, respectively; （L c ） lab、 （L c ） field These are the characteristic lengths under indoor experimental conditions and reservoir conditions, respectively; r lab、 r field These represent the effective pore radii under indoor experimental conditions and reservoir conditions, respectively.

3. The method according to claim 2, characterized in that, The formula for calculating the feature length is: ； in, V b This represents the volume of the core matrix. A i Let be the area of ​​the contact surface for absorption in the i-th direction; l Ai is the distance from the front edge of the seepage to the closed boundary along the opening surface; n is the maximum number of contact surfaces.

4. The method according to claim 2, characterized in that, The formula for calculating the effective pore radius of the reservoir is: r = 0.835 × exp(-P / 2.711) + 0.079; Wherein, P is the net pressure under indoor experimental conditions or the net pressure under reservoir conditions; The net pressure under the indoor experimental conditions is the difference between the confining pressure and the average inlet and outlet pressures; the net pressure under the reservoir conditions is the difference between the pressure of the overlying strata and the pore pressure.

5. The method according to claim 1, characterized in that, The amount of displacing agent injected is less than 1.0 PV.

6. The method according to claim 5, characterized in that, S4. Calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group, including: V nano = V l ×I R ; Among them, V nano V is the injection rate of the displacing agent. l I represents the fluid production rate of the injection-production well group; R For injection ratio.

7. The method according to claim 6, characterized in that, The injection-production ratio is determined based on the accumulated deficit, and the injection-production ratio is between 1.0 and 1.

3.

8. The method according to claim 7, characterized in that, S5. Based on the selected nano-agent, displacement timing, cycle displacement interval, displacement agent injection amount, and displacement agent injection rate, implement the cycle displacement sequential development of tight oil nano-agents, including: Based on the selected nano-agents, the timing of the shift, the periodic displacement interval, the amount of displacement agent injected, and the displacement agent injection rate, an engineering development plan, an oil production process plan, a surface engineering plan, and a health, safety, and environmental management plan for the periodic displacement of tight oil reservoirs using nano-agents are formulated, and the periodic displacement of tight oil reservoirs is carried out.

9. A system for the continuous development of dense oil nanoparticles through periodic displacement, characterized in that, The system includes: a decision module, a first calculation module, a second calculation module, a third calculation module, and an implementation module; The decision module is used to determine the timing of the drive based on the dynamic fluid level height of the oil well. The first calculation module is used to calculate the periodic displacement interval time under reservoir conditions based on the well simmering time; The second calculation module is used to calculate the displacement agent injection amount based on the reservoir pore volume PV of the injection-production well group; The third calculation module is used to calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group. The implementation module is used to carry out the continuous development of tight oil nano-agent cycle displacement based on the preferred nano-agent, displacement timing, cycle displacement interval, displacement agent injection amount and displacement agent injection speed. The decision module is used to determine the timing of the drive transition based on the dynamic fluid level of the oil well, including: The decision module is used to calculate the minimum dynamic fluid level height corresponding to the oil well based on the saturation pressure, monitor the dynamic fluid level height, and switch the drive before reaching the minimum dynamic fluid level height. The minimum dynamic fluid level height corresponding to the oil well, calculated based on saturation pressure, is: h lc = D w - 85P ob / ρ l ; where h lc D is the minimum dynamic liquid level height. w P represents the depth of the oil well. ob ρ is the saturation pressure of crude oil. l ρ is the density of the liquid column.

10. The system according to claim 9, characterized in that, The first calculation module is used to calculate the periodic displacement interval time under reservoir conditions based on the well stagnation time, including: The first calculation module is used to calculate the periodic displacement interval under reservoir conditions based on the experimental analysis of the well simmering time and the similarity criterion formula. The formula for the similarity criterion is: ； in, In σ、 θ、 r These are the oil-water interfacial tension, oil-water interfacial wetting angle, and effective pore radius of the reservoir under indoor experimental conditions. In ∆P(t) This represents the pressure difference between the initial inlet pressure and the pressure steady-state pressure under indoor experimental conditions. In σ、 θ、 r These are the oil-water interfacial tension, oil-water interfacial wetting angle, and effective pore radius of the reservoir under reservoir conditions. In ∆P(t) It is the difference between the bottom hole pressure under reservoir conditions and the initial pressure during the pressurized seepage stage, that is, the difference between the fracturing stabilization pressure and the bottom hole pressure at the end of the well shut-in period; （t 焖井 ） lab、 （t 焖井 ） field These represent the well-sinking time under indoor experimental conditions and reservoir conditions, respectively; （L c ） lab、 （L c ） field These are the characteristic lengths under indoor experimental conditions and reservoir conditions, respectively; r lab、 r field These represent the effective pore radii under indoor experimental conditions and reservoir conditions, respectively.

11. The system according to claim 9, characterized in that, The second calculation module is used to calculate the displacement agent injection volume based on the reservoir pore volume PV of the injection-production well group, including: The second calculation module is used to calculate the displacement agent injection amount as less than 1.0PV based on the reservoir pore volume PV of the injection-production well group.

12. The system according to claim 9, characterized in that, The third calculation module is used to calculate the displacement agent injection rate based on the fluid production rate and injection-production ratio of the injection-production well group: V nano = V l ×I R V nano V is the injection rate of the displacing agent. l I represents the fluid production rate of the injection-production well group. R The injection-production ratio is determined based on the accumulated deficit, and its value ranges from 1.0 to 1.

3.

13. The system according to claim 9, characterized in that, The implementation module is used to carry out the continuous development of dense oil nanoparticle-based periodic displacement based on the timing of the displacement, the periodic displacement interval, the amount of displacement agent injected, and the injection rate of the displacement agent, including: The implementation module is used to formulate a nano-agent periodic displacement reservoir engineering development plan, oil production process plan, surface engineering plan, and health, safety and environmental management plan based on the selected nano-agent, the timing of the shift, the periodic displacement interval, the amount of displacement agent injected and the displacement agent injection rate, and to implement the continuous development of tight oil nano-agent periodic displacement.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause a processor to execute and implement the method for the periodic displacement and successive development of dense oil nanoparticles as described in any one of claims 1-8.

15. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements a method for the periodic displacement and successive development of dense oil nanoparticles as described in any one of claims 1-8.

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