Tight oil nano-agent periodic displacement continuous development method and system

Abstract

The invention belongs to the technical field of oil reservoir development, and relates to a tight oil nano-agent periodic displacement continuous development method and system.The method comprises the steps that S1, the displacement conversion opportunity is determined according to the working fluid level of a producing well; s2, periodic displacement interval time under the oil reservoir condition is calculated according to the soaking time; s3, the displacement agent injection amount is calculated according to the injection-production well group oil reservoir pore volume PV; s4, the injection speed of the displacement agent is calculated according to the liquid production speed and the injection-production ratio of the injection-production well group; and S5, implementing tight oil nano-agent periodic displacement continuous development according to the optimized nano-agent, displacement conversion opportunity, periodic displacement interval time, displacement agent injection amount and displacement agent injection speed. The system comprises a decision module, a first calculation module, a second calculation module, a third calculation module and an implementation module. The method can adapt to the geological characteristics of a compact reservoir, the effects of imbibition and oil discharge of the nano-agent and improvement of the crude oil yield and recovery efficiency are effectively exerted, and flooding is transferred in time after energy storage volume fracturing production, so that normal-pressure displacement is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of oil reservoir development, and in particular relates to a method and system for periodic displacement and successive development of tight oil nano-agents. Background Art

[0002] At present, the research and practice of follow-up development methods after tight oil energy storage volume fracturing are mainly concentrated on more than 20 methods in three categories: fracturing, huff and puff, and displacement, including repeated fracturing, secondary energy replenishment and energy enhancement fracturing, synchronous fracturing, CO2 energy storage fracturing, rapid water injection huff and puff, large liquid water injection huff and puff, dynamic imbibition water injection huff and puff, water injection 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 flat production area well network water drive, synchronous injection and production in the same well, air foam drive, nano-agent drive, carbonized water drive, etc.

[0003] Even if the initial production is high after energy storage volume fracturing, the decline rate is very large. The decline rate of shale oil wells in the first year is as high as 30% to 40%. Therefore, shale oil fields need to be continuously replaced between wells to increase production, which requires large new drilling and investment, and the average oil production rate during the entire development period is low. High cost, rapid decline in single well production, low recovery rate, and continuous high investment are required; water injection and injection throughput are phased and unsustainable development methods; gas injection effect is uneven, and gas channeling is a problem that is difficult to avoid and solve; repeated fracturing methods are diverse, highly targeted, and poor in universality; water drive and improved water drive with different oil displacement agents are widely used development methods for tight oil and shale oil, but for tight oil reservoirs, the continuous displacement microscopic sweep coefficient is low, resulting in ineffective water injection, and water flooding when effective, so it is necessary to introduce nano-agents for periodic displacement. Summary of the invention

[0004] In view of the above problems, the technical solution adopted by the present invention is as follows: a method for periodic displacement and continuous development of tight oil nano-agents, the method comprising the following steps: S1, determining the timing of displacement according to the dynamic liquid level of the oil production well; S2, calculating the periodic displacement interval under reservoir conditions according to the shut-in time; S3, calculating the displacement agent injection volume according to the reservoir pore volume PV of the injection-production well group; S4, calculating the displacement agent injection rate according to the liquid production rate and the injection-production ratio of the injection-production well group; S5, implementing the periodic displacement and continuous development of tight oil nano-agents according to the preferred nano-agents, displacement timing, periodic displacement interval, displacement agent injection volume and displacement agent injection rate.

[0005] Further, S1, determining the timing of driving according to the dynamic liquid level of the oil production well, including: calculating the minimum dynamic liquid level height corresponding to the oil production well according to the saturation pressure, monitoring the dynamic liquid level height, and driving before reaching the minimum dynamic liquid level height.

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

[0007] Further, S2, calculating the periodic displacement interval time under reservoir conditions according to the well soaking time, including:

[0008] Based on the experimental analysis of the well soaking time, the similarity criterion formula is used to calculate the periodic displacement interval under reservoir conditions.

[0009] Furthermore, the similarity criterion formula is:

[0010]

[0011] Wherein, σ and θ are the oil-water interfacial tension and oil-water interfacial wetting angle under indoor experimental conditions and reservoir conditions, respectively; ΔP(t) lab ΔP(t) is the pressure difference between the initial inlet pressure and the pressure stable stage under indoor experimental conditions; feild is the difference between the bottom hole pressure under reservoir conditions and the initial pressure in the pressure-imbibition stage, that is, the difference between the fracturing stable pressure and the bottom hole pressure at the end of soaking; (t 焖井 ) lab ,(t 焖井 ) field represents the time of well soaking under indoor experimental conditions and reservoir conditions respectively; (L c ) lab ,(L c ) field are the characteristic lengths under indoor experimental conditions and reservoir conditions, respectively; r lab 、r field are the effective pore radius under indoor experimental conditions and reservoir conditions, respectively; r is the effective pore radius of the reservoir.

[0012] Furthermore, the characteristic length calculation formula is:

[0013]

[0014] Among them, V b is the core matrix volume; A i is the area of ​​the imbibition contact surface in the i-th direction; l Ai is the distance from the imbibition front along the open surface to the closed boundary; n is the maximum number of contact surfaces.

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

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

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

[0018] Further, the displacement agent injection volume is less than 1.0 PV.

[0019] Further, S4, calculating the displacement agent injection rate according to the liquid production rate of the injection-production well group and the injection-production ratio, comprising:

[0020] V nano =V l ×I R

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

[0022] Furthermore, the injection-production ratio is determined according to the accumulated deficit, and the injection-production ratio is 1.0-1.3.

[0023] Further, S5, according to the preferred nano-agent, the timing of the drive conversion, the interval time of the periodic drive, the injection amount of the displacer and the injection rate of the displacer, the tight oil nano-agent periodic drive successive development is implemented, including: according to the preferred nano-agent, the timing of the drive conversion, the interval time of the periodic drive, the injection amount of the displacer and the injection rate of the displacer, a nano-agent periodic drive reservoir engineering development plan, an oil production process plan, a ground engineering plan and a health, safety and environmental management plan are formulated to implement the tight oil nano-agent periodic drive successive development.

[0024] The present invention also proposes a tight oil nano-agent periodic displacement succession development system, 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 driving according to the dynamic liquid level of the oil well;

[0026] The first calculation module is used to calculate the periodic displacement interval time under reservoir conditions according to the well shut-in time;

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

[0028] The third calculation module is used to calculate the injection rate of the displacement agent according to the liquid production rate of the injection-production well group and the injection-production ratio;

[0029] The implementation module is used to implement the periodic displacement and continuous development of tight oil nano-agents according to the preferred nano-agents, displacement timing, periodic displacement interval, displacement agent injection amount and displacement agent injection speed.

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

[0031] Furthermore, the first calculation module is used to calculate the periodic displacement interval time under reservoir conditions according to the shut-in time, including: the first calculation module is used to calculate the periodic displacement interval time under reservoir conditions according to the experimental analysis of the shut-in time using a similarity criterion formula.

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

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

[0034] Furthermore, the implementation module is used to implement the periodic displacement development of tight oil nano-agents according to the preferred nano-agents, displacement timing, periodic displacement interval, displacement agent injection amount and displacement agent injection speed, including:

[0035] The implementation module is used to formulate 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 based on the preferred nano-agent, displacement timing, periodic displacement interval, displacement agent injection volume, and displacement agent injection speed, and implement the tight oil nano-agent periodic displacement follow-up development.

[0036] In addition, the present invention also relates to a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to implement the above-mentioned method for periodic displacement and development of dense oil nano-agents when executed by a processor.

[0037] The present invention also relates to an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for periodic displacement and development of dense oil nano-agents when executing the computer program.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: it solves a series of problems such as rapid decline in crude oil production, continuous exhaustion of formation energy, rapid drop in formation pressure, crude oil degassing, crack closure, and low crude oil recovery rate in the development of unconventional oil reservoirs such as low-permeability and ultra-low-permeability tight oil and shale oil by relying on energy storage volume fracturing, and can adapt to the geological characteristics of tight oil reservoirs, effectively play the role of nano-agents in oil absorption and drainage, replenishing formation energy, and increasing crude oil production and recovery rate, and can timely switch to drive after energy storage volume fracturing production to achieve normal pressure displacement, achieve stable production and increase production, and obtain higher economic benefits.

[0039] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic diagram of a process for the development of a tight oil nano-agent cyclic displacement succession method;

[0042] Figure 2 This is a schematic diagram of the comparison of the experimental results of oil displacement efficiency and injection pressure between periodic displacement and continuous displacement;

[0043] Figure 3 This is a schematic diagram of the results of the imbibition-followed displacement experiment;

[0044] Figure 4 Schematic diagram of a tight oil nano-agent cyclic flooding and subsequent development system. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0046] The present invention relates to a method for continuous development of tight oil nano-agent periodic displacement, which comprises the following steps: S1, determining the time of displacement according to the dynamic liquid level of the oil production well; S2, calculating the interval time of periodic displacement under reservoir conditions according to the well shut-in time; S3, calculating the injection amount of displacement agent according to the pore volume PV of the oil reservoir of the injection-production well group;

[0047] S4. Calculate the injection rate of the displacing agent according to the production rate of the injection-production well group and the injection-production ratio; S5. Implement the periodic displacement and development of tight oil nano-agent according to the preferred nano-agent, the timing of the displacement, the interval time of the periodic displacement, the injection amount of the displacing agent and the injection rate of the displacing agent.

[0048] In the above-mentioned tight oil nano-agent periodic displacement and development method, the determination of the reasonable well-keeping time and the interval time of the displacement cycle is based on the four-stage mechanism of tight oil imbibition. The results of the static imbibition experiment under the conditions of reservoir temperature and formation oil viscosity show that the efficiency of imbibition oil drainage is staged. The imbibition curve of nano-agents and fracturing fluids can be divided into four stages: imbibition oil drainage window period, high-speed imbibition oil drainage period, rapid imbibition oil drainage period and low-speed imbibition oil drainage period. The imbibition oil drainage window period is an objective existence in the actual reservoir development that has been ignored by previous observations. After the core is immersed in the imbibition fluid, in theory or by online low-field nuclear magnetic resonance measurement, crude oil is instantly replaced and discharged by imbibition. However, due to the small amount, these discharged crude oils cannot reach the liquid surface and cannot gather at the bottom of the well, so they are invisible in production. Only when the crude oil discharged from the medium and large pores and absorbed from the micro-nano pores gathers from the rock to the outside to form small oil droplets, and then merges to form large oil droplets, the buoyancy of the large oil droplets exceeds the gravity, viscosity, etc., and rises to the liquid surface, can it be observed. This period of time is the oil discharge window period. As the imbibition continues, under the action of the confining pressure and the pressure difference inside the rock, the fluid in the medium and large pores discharges oil according to Darcy seepage, which is the high-speed imbibition stage (imbibition stage 2). At the same time, the micro-nano pores of tight oil are also affected by the capillary force and the capillary pressure formed, and the oil is discharged synchronously, but the speed is lower than that of the medium and large pores. As the pressure difference between the inside and outside of the rock decreases and tends to balance, the Darcy seepage oil discharge continues to weaken, and the imbibition turns from high speed to fast imbibition stage (imbibition stage 3). In this stage, the concentration of nano-agents inside the rock increases, and the "wedge squeeze" effect unique to the nanoscale is enhanced, stripping the crude oil from the solid surface of the rock for discharge. Stage 4 is the low-speed imbibition stage. As the water saturation increases, the capillary force and capillary potential energy decrease rapidly, and the ion diffusion effect gradually emerges. However, the oil discharge speed is an order of magnitude different from the previous stage, and is in the slow imbibition stage, which is even difficult to observe in the experiment. After the imbibition front contacts the pore wall with salt ions, the salt ions dissolve into the water, and the imbibition induces ion diffusion, and the crude oil is discharged very slowly.

[0049] In the embodiment of the present invention, taking the tight oil core used in the experiment as an example, the window period of imbibition and oil drainage is 0.5-1 day, the high-speed imbibition and oil drainage period is 1-2 days, and the rapid imbibition and oil drainage period is 8-9.5 days, after which it enters the low-speed imbibition and oil drainage period. This experimental result and understanding have an essential guiding role in the interval time of periodic displacement. It is difficult to reflect the potential recoverable oil volume (accumulated oil volume) at the bottom of the well by determining the opening time of the well by the change of wellhead pressure. The low-speed imbibition and oil drainage period can be continued in production without continuing to shut down the well because of its slow oil drainage speed, long time and poor timeliness; therefore, the reasonable shut-down time of energy storage volume fracturing and the interval time of displacement cycles should be ended with the rapid imbibition and oil drainage period.

[0050] Specifically, step S1 includes: calculating the minimum dynamic liquid level corresponding to the oil production well according to the saturation pressure, monitoring the dynamic liquid level, and driving before reaching the minimum dynamic liquid level. The minimum dynamic liquid level calculation formula is: lc =D w -85P ob / ρ l ; Among them, h lc is the critical or lowest dynamic liquid level, in m; D w Indicates the depth of the oil well, in meters; P ob Indicates the crude oil saturation pressure, in MPa; ρ l Indicates the density of the liquid column, the unit is 1000kg / m 3 .

[0051] Specifically, step S2 includes: analyzing the reasonable soaking time according to the experiment, and calculating the periodic displacement interval under the reservoir conditions using the similarity criterion formula. The reasonable soaking time can be calculated by the end time of the laboratory rapid imbibition period using the similarity criterion formula, which is related to the average size of the rock block after fracturing (characteristic length), reservoir density, micro-nano pore connectivity, and pore structure complexity. The similarity criterion formula is:

[0052] Among them, σ and θ are the oil-water interface tension and oil-water interface wetting angle under indoor experimental conditions and reservoir conditions, respectively; ΔP(t) lab is the pressure difference between the initial inlet pressure and the pressure stable stage under indoor experimental conditions, which is 0; ΔP(t) feild is the difference between the bottom hole pressure under reservoir conditions and the initial pressure in the pressure-imbibition stage, that is, the difference between the fracturing stable pressure and the bottom hole pressure at the end of soaking; (t 焖井 ) lab ,(t 焖井 ) field They represent the well-insertion time under indoor experimental conditions and the well-insertion time under reservoir conditions respectively; (L c ) lab ,(L c ) field are the characteristic lengths under indoor experimental conditions and reservoir conditions, respectively; r lab 、r field are the effective pore radius under indoor experimental conditions and reservoir conditions respectively; r represents the effective pore radius of the reservoir. The characteristic length calculation formula is:

[0053]

[0054] V b is the core matrix volume, in cm 3 ; A i is the area of ​​the imbibition contact surface in the i-th direction, in cm2 ; l Ai is the distance from the imbibition front along the open surface to the closed boundary, in cm; n is the maximum number of contact surfaces. The calculation formula of the effective pore radius r is: r = 0.835*exp(-P / 2.711) + 0.079, 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 value of the inlet and outlet pressures; the net pressure under reservoir conditions is: the difference between the overburden pressure and the pore pressure.

[0055] Specifically, step S3 includes: from the mechanism experiment, it is known that when the nano-agent injection volume multiple (PV) is before 1.0PV, the oil recovery efficiency increases fastest; thereafter, the growth rate and increase of the oil recovery efficiency slow down greatly, so the long horizontal well displacement is 1.0PV as a reasonable limit; in the embodiment of the present invention, the injection amount of the displacement agent is less than 1.0PV.

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

[0057] Specifically, step S5 includes: 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 based on the preferred nano-agent, displacement timing, periodic displacement interval, displacement agent injection amount, and displacement agent injection speed, and implementing the tight oil nano-agent periodic displacement follow-up development.

[0058] It should be noted that the numbers of the steps in the above method (eg, S1, S2, S3, S4) do not represent the order in which the steps are to be performed, but are merely used to distinguish the steps and serve as identifiers. The steps may be performed in other orders (eg, in parallel).

[0059] According to the above-designed method for continuous development of tight oil nano-agent periodic displacement, a nano-agent periodic displacement experiment was carried out: the displacement was temporarily stopped when the water content at the outlet was 20%, 60%, and 80%, and the core was imbibed in the clamp at the formation temperature and pressure for 10 days (determined by referring to the reasonable soaking time under the temperature and pressure conditions of the reservoir). Figure 2The following is a schematic diagram showing the comparison of the experimental results of oil displacement efficiency and injection pressure between periodic displacement and continuous displacement: Figure 2 In the figure, the horizontal axis is the injection volume multiple, the unit is the nano-agent injection volume multiple (PV); the vertical axis is the injection pressure, the unit is MPa; the oil displacement efficiency, the unit is %. The displacement fluid in the periodic displacement and the continuous displacement is the same low-concentration nano-agent with a mass concentration of 0.02%. When the injection volume multiple is 2.36PV in the continuous displacement, the water content at the core outlet is 100%, and the displacement is completed with an oil displacement efficiency of 51.40%. The oil displacement efficiency of the periodic displacement is significantly higher than that of the continuous displacement. Among them, when the injection volume multiple is 0.478PV, the oil displacement efficiency of the periodic displacement is 55.10%, which is 14.10% higher than that of the continuous displacement; when the injection volume multiple is 6.854PV, the oil displacement efficiency reaches 78.60%, which is 27.20% higher than that of the continuous displacement; it reflects that the periodic displacement has a better development effect.

[0060] The core displacement experiment of the same concentration of nano-agent after the oil displacement increment of 0.02% was zero showed that (such as Figure 3 ① The oil displacement efficiency of low-concentration nano-agent after infiltration and displacement reached a maximum of 38.0% (injection volume multiple was 2.69PV). When the injection volume multiple was 1.04PV, the stage oil displacement efficiency had reached 31.3%, indicating that there is still a great potential for improving the recovery rate after infiltration and displacement; ② The initial injection pressure of low-concentration nano-agent after infiltration and displacement was low ( Figure 3 The injection pressure is 18MPa), which shows that it is possible to achieve normal pressure displacement. When the fracturing fluid is high, the injection pressure is 22.0MPa; as the displacement proceeds, the pressure increases, but it is within the achievable pressure range. The maximum pressure of low-concentration nano-agent is only 30.0MPa, and the wellhead pressure is less than 20MPa; ③ The low-concentration nano-agent is imbibed for 50 days, and the oil displacement efficiency is 36.67%. In other words, the initial injection pressure of the low-concentration nano-agent after imbibition is 18MPa, and the oil displacement efficiency is 38.0%; the total oil displacement efficiency with imbibition is 74.67% (38.0% + 36.67%); the oil displacement efficiency is increased by 23.27% compared with direct continuous displacement, and 38% compared with imbibition displacement. The above data can show that the tight oil displacement and subsequent development method can significantly improve the oil displacement efficiency and recovery rate.

[0061] The above-mentioned tight oil nano-agent cyclic displacement and development method was used for field demonstration. The average reservoir permeability of the AN83 block of the DQ oilfield was 0.2mD. After the volume fracturing production of the horizontal wells in the AP21 injection and production well group in the block decreased, an injection test was conducted: the initial oil production of the AN20 well in the same well group as the water injection well was 14.1t / d after volume fracturing transformation, and the oil production dropped to 5.2t / d after 1a of exhaustion production. After the injection displacement of the AP21 well, the oil well stopped production due to water seepage. After the well was shut down for 10 days, the well was opened and the oil production was restored to 12.2t / d at the highest. After 1a, the oil production was stabilized at about 6t / d.

[0062] In addition, the present invention also relates to a system for periodic displacement and continuous development of tight oil nano-agents, which includes: 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 displacement according to the dynamic liquid level of the oil production well; the first calculation module 12 is used to calculate the periodic displacement interval time under reservoir conditions according to the well shut-in time; the second calculation module 13 is used to calculate the displacement agent injection volume according to the reservoir pore volume PV of the injection and production well group; the third calculation module 14 is used to calculate the displacement agent injection rate according to the injection and production well group liquid production rate and the injection-production ratio; the implementation module 15 is used to implement the periodic displacement and continuous development of tight oil nano-agents according to the preferred nano-agent, displacement timing, periodic displacement interval time, displacement agent injection volume and displacement agent injection rate.

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

[0064] Specifically, the first calculation module 12 is used to calculate the periodic displacement interval time under reservoir conditions according to the shut-in time, including: the first calculation module 12 is used to calculate the periodic displacement interval time under reservoir conditions according to the experimental analysis of the shut-in time using a similarity criterion formula.

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

[0066] Specifically, the third calculation module 14 is used to calculate the displacement agent injection rate according to the liquid production rate of the injection-production well group and the injection-production ratio. The displacement agent injection rate V nano =V l ×I R ; V nano Unit: m 3 / d;V lis the liquid production rate of the injection and production well group, in m 3 / d;I R The injection-production ratio is determined based on the accumulated deficit, and is generally between 1.0 and 1.3.

[0067] Specifically, the implementation module 15 is used to implement the tight oil nano-agent periodic displacement follow-up development according to the preferred nano-agent, displacement timing, periodic displacement interval time, displacement agent injection amount and displacement agent injection speed, including: the implementation module 15 is used to compile a nano-agent periodic displacement reservoir engineering development plan, an oil production process plan, a ground engineering plan and a health, safety and environmental management plan according to the displacement timing, periodic displacement interval time, displacement agent injection amount and displacement agent injection speed, and implement the tight oil nano-agent periodic displacement follow-up development.

[0068] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the above-mentioned method for periodic displacement and development of dense oil nano-agents when executed.

[0069] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for periodic displacement and successive development of dense oil nano-agents as described above is implemented.

[0070] In summary, the present invention provides a new method for supplementing formation energy and improving recovery after horizontal well volume fracturing development. The new method is a periodic displacement development method based on the early energy storage volume fracturing development and nanomaterial displacement of tight oil long horizontal wells. The periodic displacement development method and displacement interval time are determined based on mechanism research. When the mass concentration of the nanoagent is 0.02%, the oil recovery efficiency of the periodic displacement development method reaches 78.60%, which is 27.20% higher than continuous displacement and 42.20% higher than the quasi-natural energy development of energy storage volume fracturing.

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

Claims

1. A method for periodic displacement and development of tight oil nanoparticles, characterized in that: The method comprises the following steps: S1. Determine the timing of drive conversion based on the dynamic liquid level of the oil well; S2. Calculate the interval time of periodic displacement under reservoir conditions according to the well soaking time; S3, calculating the injection amount of the displacement agent according to the reservoir pore volume PV of the injection-production well group; S4, calculating the injection rate of the displacement agent according to the liquid production rate of the injection-production well group and the injection-production ratio; S5. Based on the preferred nano-agent, flooding timing, periodic flooding interval, flooding agent injection volume and flooding agent injection speed, implement tight oil nano-agent periodic flooding and continuous development.

2. The method according to claim 1, characterized in that S1. Determine the timing of drive conversion based on the dynamic liquid level of the oil well, including: Calculate the lowest dynamic liquid level height corresponding to the oil production well according to the saturation pressure, monitor the dynamic liquid level height, and drive before reaching the lowest dynamic liquid level height.

3. The method according to claim 2, characterized in that The minimum dynamic liquid level height corresponding to the oil production well calculated according to the saturation pressure is: lc =D w -85P ob / ρ l ; Among them, h lc is the minimum dynamic liquid level; D w is the depth of the oil well; ob is the crude oil saturation pressure; ρ l is the density of the liquid column.

4. The method according to claim 2 or 3, characterized in that: S2. Calculate the periodic displacement interval under reservoir conditions based on the well soaking time, including: Based on the experimental analysis of the well soaking time, the similarity criterion formula is used to calculate the periodic displacement interval under reservoir conditions.

5. The method according to claim 4, characterized in that The similarity criterion formula is: Wherein, σ and θ are the oil-water interfacial tension and oil-water interfacial wetting angle under indoor experimental conditions and reservoir conditions, respectively; ΔP(t) lab ΔP(t) is the pressure difference between the initial inlet pressure and the pressure stable stage under indoor experimental conditions; feild is the difference between the bottom hole pressure under reservoir conditions and the initial pressure in the pressure-imbibition stage, that is, the difference between the fracturing stable pressure and the bottom hole pressure at the end of soaking; (t 焖井 ) lab ,(t 焖井 ) field represents the time of well soaking under indoor experimental conditions and reservoir conditions respectively; (L c ) lab ,(L c ) field are the characteristic lengths under indoor experimental conditions and reservoir conditions, respectively; r lab 、r field are the effective pore radius under indoor experimental conditions and reservoir conditions, respectively; r is the effective pore radius of the reservoir.

6. The method according to claim 5, characterized in that The characteristic length calculation formula is: Among them, V b is the core matrix volume; A i is the area of ​​the imbibition contact surface in the i-th direction; l Ai is the distance from the imbibition front along the open surface to the closed boundary; n is the maximum number of contact surfaces.

7. The method according to claim 5, characterized in that The calculation formula of 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.

8. The method according to claim 7, characterized in that The net pressure under the indoor experimental conditions is: the difference between the confining pressure and the average value of the inlet and outlet pressures; the net pressure under the reservoir conditions is: the difference between the overburden pressure and the pore pressure.

9. The method according to claim 8, characterized in that The displacement agent injection volume is less than 1.0PV.

10. The method according to claim 9, characterized in that S4. Calculate the displacement agent injection rate according to the liquid production rate of the injection-production well group and the injection-production ratio, including: V nano =V l ×I R ; Among them, V nano V is the injection rate of the displacement agent; l I is the liquid production rate of the injection-production well group; R is the injection-production ratio.

11. The method according to claim 10, characterized in that The injection-production ratio is determined according to the accumulated deficit, and the injection-production ratio is 1.0-1.

3.

12. The method according to claim 11, characterized in that S5. Based on the preferred nano-agent, flooding timing, periodic flooding interval, flooding agent injection amount and flooding agent injection speed, implement the tight oil nano-agent periodic flooding successive development, including: Based on the preferred nano-agent, displacement timing, cyclic displacement interval, displacement agent injection volume and displacement agent injection rate, a nano-agent cyclic displacement reservoir engineering development plan, oil production process plan, surface engineering plan and health, safety and environmental management plan are formulated to implement the continuous development of tight oil nano-agent cyclic displacement.

13. A tight oil nano-agent periodic displacement and development system, characterized in that: The system comprises: 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 driving according to the dynamic liquid level of the oil well; The first calculation module is used to calculate the periodic displacement interval time under reservoir conditions according to the well shut-in time; The second calculation module is used to calculate the displacement agent injection amount according to the reservoir pore volume PV of the injection and production well group; The third calculation module is used to calculate the injection rate of the displacement agent according to the liquid production rate of the injection-production well group and the injection-production ratio; The implementation module is used to implement the periodic displacement and development of tight oil nano-agents according to the preferred nano-agents, displacement timing, periodic displacement interval, displacement agent injection amount and displacement agent injection speed.

14. The system according to claim 13, characterized in that The decision module is used to determine the timing of driving according to the dynamic liquid level of the oil production well, and includes: The decision module is used to calculate the minimum dynamic liquid level height corresponding to the oil production well according to the saturation pressure, monitor the dynamic liquid level height, and drive before reaching the minimum dynamic liquid level height.

15. The system according to claim 13, characterized in that The first calculation module is used to calculate the periodic displacement interval time under reservoir conditions according to the well shut-in time, including: The first calculation module is used to analyze the soaking time according to the experiment and calculate the periodic displacement interval time under the reservoir conditions by using the similarity criterion formula.

16. The system according to claim 13, characterized in that The second calculation module is used to calculate the displacement agent injection amount according to the reservoir pore volume PV of the injection and production well group, including: The second calculation module is used to calculate the displacement agent injection volume to be less than 1.0 PV according to the reservoir pore volume PV of the injection and production well group.

17. The system according to claim 13, characterized in that The third calculation module is used to calculate the displacement agent injection rate according to the liquid production rate of the injection-production well group and the injection-production ratio: V nano =V l ×I R ; V nano V is the injection rate of the displacement agent; l I is the liquid production rate of the injection-production well group; R The injection-production ratio is determined based on the accumulated deficit, and the injection-production ratio is between 1.0 and 1.

3.

18. The system according to claim 13, characterized in that The implementation module is used to implement the periodic displacement and development of tight oil nano-agent according to the displacement timing, periodic displacement interval, displacement agent injection amount and displacement agent injection speed, and includes: The implementation module is used to formulate 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 based on the preferred nano-agent, displacement timing, periodic displacement interval, displacement agent injection volume, and displacement agent injection speed, and implement the tight oil nano-agent periodic displacement follow-up development.

19. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement a method for periodic displacement and development of tight oil nano-agents as described in any one of claims 1 to 12 when executed.

20. 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, the method for periodic displacement and successive development of tight oil nano-agents as described in any one of claims 1 to 12 is implemented.

Images