Method and equipment for tertiary oil recovery after water flooding in a strongly heterogeneous reservoir

Abstract

The application provides a method and equipment for simulating a post-water-flooding tertiary oil recovery of a strong heterogeneous oil reservoir. The method comprises the following steps: determining corresponding formation particle size distribution information according to drilling and logging data of a target reservoir to obtain a first core sample; using a standard formation water solution and formation crude oil to perform displacement saturation treatment on the first core sample to obtain a second core sample; placing the second core sample and the standard formation water solution into a target displacement device to establish a target displacement environment, and controlling the target displacement device to monitor the second core sample in real time according to the target displacement environment; obtaining a corresponding initial picture through the target displacement device, and performing multiple displacement treatments on the second core sample by using multiple displacement phases; and obtaining a corresponding target picture through the target displacement device when each displacement treatment is completed, and determining target oil recovery data according to the initial picture and the target picture, so that the technical effect of improving the oil recovery efficiency of the heterogeneous oil reservoir is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas field development, and in particular to a method and equipment for simulating tertiary oil recovery after water flooding in a highly heterogeneous oil reservoir. Background Art

[0002] With the continuous advancement of science and technology, oil and gas field exploration and development technologies are becoming increasingly sophisticated. Vertical reservoir heterogeneity is a common problem in secondary and tertiary oil recovery processes in oil and gas field development, significantly impacting the effectiveness of waterflooding in oilfields. Due to the vertical heterogeneity of the reservoir, injected water tends to flow toward high-permeability layers, resulting in ineffective development of oil and gas resources in low-permeability layers. Therefore, to address this key issue that restricts efficient oilfield development, tertiary oil recovery methods after waterflooding in highly heterogeneous reservoirs have become a promising research direction.

[0003] In the existing technology, the tertiary oil recovery method after water flooding in highly heterogeneous reservoirs is mainly carried out through indoor displacement experiments. Under the conditions of simulating a single reservoir unit, operators inject different profile control agents into it to change the permeability distribution of the reservoir, thereby improving the oil and gas recovery rate of the low-permeability layer.

[0004] Because the existing technology lacks intuitive observation methods during the overall displacement process, and some experimental devices are complicated in design and rely on manual operation, the displacement process consumes a lot of time and manpower costs. For heterogeneous reservoirs, there is a technical problem of low oil recovery efficiency in heterogeneous reservoirs. Summary of the Invention

[0005] The embodiments of the present application provide a method and apparatus for simulating tertiary oil recovery after water flooding in a highly heterogeneous reservoir, so as to achieve the technical effect of improving the oil recovery efficiency of the heterogeneous reservoir.

[0006] In a first aspect, the present application provides a method for simulating tertiary oil recovery after water flooding in a highly heterogeneous reservoir, comprising:

[0007] Determine the corresponding formation grain size distribution information based on the drilling and logging data of the target reservoir to obtain the corresponding initial core sample, wherein the initial core sample is a heterogeneous core sample prepared after simulating the formation grain size distribution;

[0008] A first core sample is subjected to a displacement saturation treatment using a standard formation water solution and formation crude oil to obtain a second core sample, wherein the first core sample is a core sample obtained by drying the initial core sample, and the second core sample is a core sample obtained by displacing and saturating the first core sample;

[0009] The second core sample and a standard formation water solution are placed into a target displacement device to establish a target displacement environment, and the target displacement device is controlled to monitor the second core sample in real time according to the target displacement environment;

[0010] The target displacement device is used to obtain a corresponding initial picture, and the second core sample is subjected to multiple displacement treatments by using multiple displacement phases, wherein the displacement phases include a chemical displacement agent, the standard formation water solution, and a target gas, the displacement treatments include chemical displacement treatment, water displacement treatment, and gas displacement treatment, the chemical displacement agent includes a chemical plugging agent or a crosslinking agent, and the initial picture is used to indicate a nuclear magnetic imaging picture of the second core sample before the displacement treatment.

[0011] When each displacement treatment is completed, the target displacement device is used to obtain a corresponding target picture, and target oil production data is determined according to the initial picture and the target picture, wherein the target oil production data includes an injection end pressure change rate with respect to a seepage distance and a recovery rate, and the target picture is used to indicate a nuclear magnetic imaging picture of the second core sample after each displacement treatment.

[0012] Optionally, the first core sample is subjected to displacement saturation treatment by using the standard formation water solution and formation crude oil to obtain the second core sample, including:

[0013] The experimental beaker with the initial core sample is subjected to vacuum treatment, and a simulated formation water solution is added to the experimental beaker after the vacuum treatment;

[0014] After it is determined that the simulated formation water solution submerges the initial core sample and there is no obvious gas bubble on the surface of the initial core sample, the initial core sample is subjected to water displacement treatment by using the standard formation water solution to obtain a third core sample after the treatment;

[0015] The third core sample is subjected to displacement saturation treatment by using formation crude oil to obtain a fourth core sample after the treatment;

[0016] After the fourth core sample is placed into the formation crude oil and pressurized to a target pressure, the fourth core sample is subjected to standing treatment;

[0017] After it is determined that a standing time length of the fourth core sample reaches a first threshold value, a corresponding second core sample is obtained.

[0018] Optionally, the target displacement device includes:

[0019] A core holder is configured to fix and clamp the second core sample;

[0020] A displacement pump is configured to control a flow rate of the displacement phase and an injection speed of the second core sample;

[0021] An intermediate container is configured to store and supply the displacement phase required for the displacement treatment.

[0022] A dual-cylinder constant-rate constant-pressure displacement system for controlling and regulating the working state of the displacement pump;

[0023] An axial confining pressure pump for simulating the pressure of the stratum in the longitudinal direction;

[0024] A radial confining pressure pump for simulating the pressure of the stratum in the horizontal direction;

[0025] A heating circulation pump for setting and maintaining the internal temperature of the core holder;

[0026] A core holder front and rear end needle valve for controlling the injection and discharge of the displacement phase at the front and rear ends of the core holder;

[0027] A magnet for generating a stable magnetic field environment;

[0028] A data acquisition imaging system for real-time monitoring and collecting the nuclear magnetic imaging pictures in the displacement process according to the magnetic field environment, and determining the signal quantity corresponding to the nuclear magnetic imaging pictures;

[0029] A back pressure pump for setting the outlet pressure value required by the displacement process, adjusting and controlling the back pressure in the displacement process;

[0030] A measuring cylinder for receiving the produced fluid generated by the back pressure pump valve pressure release when the pressure corresponding to the back pressure pump reaches the second threshold value.

[0031] Optionally, the second core sample and the standard stratum water solution are placed into the target displacement device to establish a target displacement environment, including:

[0032] According to the target displacement device, the second core sample is fixed to the core holder, and the standard stratum water solution is placed into the intermediate container;

[0033] According to the dual-cylinder constant-rate constant-pressure displacement system, the pressures of the axial confining pressure pump and the radial confining pressure pump are set to the target pressure value, and the heating circulation pump is set to the third threshold value;

[0034] After determining that the internal temperature of the core holder is constant at the third threshold value, the core holder front and rear end needle valve is controlled to close the valve;

[0035] After determining that the pressure of the upper end of the core holder reaches the fourth threshold value, the core holder front and rear end needle valve is controlled to open the valve, and the outlet pressure value of the back pressure pump is set to the fifth threshold value to establish the target displacement environment.

[0036] Optionally, a plurality of displacement phases are used to perform a plurality of displacement processes on the second core sample, including:

[0037] According to the double-cylinder constant-speed constant-pressure displacement system, the displacement pump flow is set as a target flow, and a standard formation water solution with a target injection amount is injected into the second core sample according to the target flow to perform water flooding treatment;

[0038] After determining that the displacement pump displacement volume reaches a sixth threshold value, the standard formation water solution is replaced by a chemical displacement agent, and the chemical displacement agent with a target injection amount is injected into the second core sample to perform chemical flooding treatment;

[0039] After determining that the chemical flooding treatment is completed, the chemical displacement agent is replaced by the standard formation water solution, and the standard formation water solution with a target injection amount is injected into the second core sample to perform water flooding treatment on the second core sample;

[0040] After determining that the water flooding treatment is completed, the standard formation water solution is replaced by a target gas, and the target gas with a target injection amount is injected into the second core sample to perform gas flooding treatment.

[0041] Optionally, according to the second fragment sequence, the target injection amount is obtained by:

[0042] According to the initial core sample, a corresponding initial weight is determined, and according to the second core sample, a corresponding target weight and a pore volume are determined;

[0043] According to the initial weight and the target weight, a corresponding weight difference is determined;

[0044] According to the weight difference and the density of the standard formation water solution, a corresponding pore volume is obtained, and according to the pore volume, a corresponding target injection amount is determined.

[0045] Optionally, after the second core sample is injected with the target gas with the target injection amount to perform gas flooding treatment, the method further comprises:

[0046] According to the target displacement device, the second core sample is monitored;

[0047] After determining that the second core sample has gas channeling, the second core sample is injected with a chemical plugging agent with a target injection amount to perform plugging;

[0048] After determining that the second core sample has no gas channeling, the chemical plugging agent is replaced by the target gas, and the target gas with a target injection amount is injected into the second core sample to perform gas flooding treatment.

[0049] Optionally, according to the initial picture and the target picture, target oil production data is determined, comprising:

[0050] According to the initial picture and the corresponding target picture after water drive treatment, an injection end pressure curve corresponding to the second core sample is obtained, wherein the injection end pressure curve is used to indicate the penetration distance of the displacement phase in the second core sample and the change trend of the injection end pressure with time or the injection amount of the displacement phase during the displacement treatment;

[0051] According to the injection end pressure curve, the rate of change of the injection end pressure of the second core sample with the seepage distance is determined;

[0052] According to the data acquisition imaging system, an initial signal quantity corresponding to the initial picture is obtained, and according to each target picture, a target signal quantity corresponding to each target picture is obtained;

[0053] According to the initial signal quantity and the target signal quantity, the recovery rate of the second core sample is determined.

[0054] In a second aspect, the application provides a device for simulating tertiary oil recovery after water drive in a strongly heterogeneous reservoir, comprising:

[0055] The first obtaining module is configured to determine the corresponding formation grain size distribution information according to the drilling and logging data of the target reservoir, so as to obtain the initial core sample corresponding thereto, wherein the initial core sample is a heterogeneous core sample prepared after simulating the formation grain size distribution;

[0056] The second obtaining module is configured to perform displacement saturation treatment on the first core sample by using a standard formation water solution and formation crude oil, to obtain the second core sample, wherein the first core sample is a core sample obtained after drying treatment on the initial core sample, and the second core sample is a core sample obtained after displacement saturation treatment on the first core sample;

[0057] The first processing module is configured to place the second core sample and the standard formation water solution into a target displacement device to establish a target displacement environment, and to control the target displacement device to monitor the second core sample in real time according to the target displacement environment;

[0058] The second processing module is configured to obtain the initial picture corresponding thereto by using the target displacement device, and to perform multiple displacement treatments on the second core sample by using multiple displacement phases, wherein the displacement phase includes a chemical displacement agent, a standard formation water solution and a target gas, the displacement treatment includes chemical displacement treatment, water drive treatment and gas drive treatment, the chemical displacement agent includes a chemical plugging agent or a crosslinking agent, and the initial picture is used to indicate the nuclear magnetic imaging picture of the second core sample before the displacement treatment;

[0059] The third acquisition module is configured to acquire a target picture corresponding to each displacement treatment by using the target displacement device, and determine target oil production data according to the initial picture and the target picture, wherein the target oil production data includes an injection end pressure change rate with respect to a seepage distance and a recovery rate, and the target picture is used to indicate a nuclear magnetic imaging picture of the second core sample after each displacement treatment.

[0060] Optionally, the second acquisition module is further configured to:

[0061] The experimental beaker with the initial core sample is subjected to vacuum treatment, and a simulated formation water solution is added into the experimental beaker after the vacuum treatment.

[0062] After determining that the simulated formation water solution submerges the initial core sample and there is no obvious bubble on the surface of the initial core sample, the initial core sample is subjected to water flooding treatment by using a standard formation water solution to obtain a third core sample after the treatment.

[0063] The third core sample is subjected to displacement saturation treatment by using formation crude oil to obtain a fourth core sample after the treatment.

[0064] After the fourth core sample is placed in the formation crude oil and pressurized to a target pressure, the fourth core sample is subjected to static treatment.

[0065] After determining that a static duration of the fourth core sample reaches a first threshold value, a second core sample corresponding to the fourth core sample is obtained.

[0066] Optionally, the first treatment module is further configured to the target displacement device, and the target displacement device includes:

[0067] The core holder is configured to fix and hold the second core sample.

[0068] The displacement pump is configured to control a flow rate of a displacement phase and a speed of injecting the second core sample.

[0069] The intermediate container is configured to store and supply the displacement phase required for the displacement treatment.

[0070] The double-cylinder constant-speed constant-pressure displacement system is configured to control and adjust a working state of the displacement pump.

[0071] The axial confining pressure pump is configured to simulate a pressure of a formation in a longitudinal direction.

[0072] The radial confining pressure pump is configured to simulate a pressure of the formation in a horizontal direction.

[0073] The heating circulating pump is configured to set and maintain an internal temperature of the core holder.

[0074] The needle valves at front and rear ends of the core holder are configured to control injection and discharge of the displacement phase at the front and rear ends of the core holder.

[0075] magnets for generating a stable magnetic field environment;

[0076] a data acquisition imaging system for monitoring and collecting nuclear magnetic imaging pictures in real time during the displacement process according to the magnetic field environment, and determining the signal amount corresponding to the nuclear magnetic imaging pictures;

[0077] a back pressure pump for setting an outlet pressure value required for the displacement process, adjusting and controlling the back pressure in the displacement process;

[0078] a cylinder for receiving the produced fluid generated by the back pressure pump valve pressure release when the pressure corresponding to the back pressure pump reaches a second threshold value.

[0079] Optionally, the first processing module is further configured to:

[0080] According to the target displacement device, the second core sample is fixed to the core holder, and the standard formation water solution is put into the intermediate container;

[0081] According to the double-cylinder constant-speed constant-pressure displacement system, the pressures of the axial confining pressure pump and the radial confining pressure pump are set to the target pressure value, and the heating circulating pump is set to a third threshold value;

[0082] After determining that the temperature inside the core holder is constant at the third threshold value, the front and rear needle valves of the core holder are controlled to close the valves;

[0083] After determining that the pressure at the upper end of the core holder reaches a fourth threshold value, the front and rear needle valves of the core holder are controlled to open the valves, and the outlet pressure value of the back pressure pump is set to a fifth threshold value to establish a target displacement environment.

[0084] Optionally, the second processing module is further configured to:

[0085] According to the double-cylinder constant-speed constant-pressure displacement system, the displacement pump flow is set to a target flow, and the second core sample is injected with a standard formation water solution with a target injection amount according to the target flow to perform water flooding treatment;

[0086] After determining that the displacement pump replacement volume reaches a sixth threshold value, the standard formation water solution is replaced with a chemical displacement agent, and the second core sample is injected with a chemical displacement agent with a target injection amount to perform chemical flooding treatment;

[0087] After determining that the chemical flooding treatment is completed, the chemical displacement agent is replaced with a standard formation water solution, and the second core sample is injected with a standard formation water solution with a target injection amount to perform water flooding treatment on the second core sample;

[0088] After determining that the water flooding treatment is completed, the standard formation water solution is replaced with a target gas, and the second core sample is injected with a target gas with a target injection amount to perform gas flooding treatment.

[0089] Optionally, the second processing module is further configured to:

[0090] determine a corresponding initial weight according to the initial core sample, and determine a corresponding target weight and a pore volume according to the second core sample;

[0091] determine a corresponding weight difference according to the initial weight and the target weight;

[0092] obtain a corresponding pore volume according to the weight difference and a density of the standard formation water solution, and determine a corresponding target injection amount according to the pore volume.

[0093] Optionally, the second processing module is further configured to:

[0094] monitor the second core sample through the target displacement device;

[0095] after determining that the second core sample has gas channeling, inject a chemical plugging agent with a size of the target injection amount into the second core sample for plugging;

[0096] after determining that the second core sample has no gas channeling, replace the chemical plugging agent with a target gas, and inject the target gas with a size of the target injection amount into the second core sample for gas drive treatment.

[0097] Optionally, the third obtaining module is further configured to:

[0098] obtain an injection end pressure curve corresponding to the second core sample according to the initial picture and a target picture corresponding to water drive treatment, wherein the injection end pressure curve is used to indicate a penetration distance of a displacement phase in the second core sample and a change trend of an injection end pressure with time or a displacement phase injection amount during the displacement treatment process;

[0099] determine a rate of change of the injection end pressure of the second core sample with respect to a seepage distance according to the injection end pressure curve;

[0100] obtain an initial signal amount corresponding to the initial picture according to the data acquisition and imaging system, and obtain a target signal amount corresponding to each target picture according to each target picture;

[0101] determine a recovery rate of the second core sample according to the initial signal amount and the target signal amount.

[0102] In a third aspect, the present application provides a device for simulating tertiary oil recovery after water drive in a strong heterogeneous reservoir, comprising:

[0103] a processor and a memory;

[0104] the memory stores computer execution instructions;

[0105] The processor executes the computer-executed instructions stored in the memory, so that the processor executes various possible implementation manners in the first aspect.

[0106] In a fourth aspect, the present application provides a computer-readable storage medium, and the computer-readable storage medium stores computer-executed instructions, and the computer-executed instructions are executed by the processor to implement various possible implementation manners in the first aspect.

[0107] In a fifth aspect, the present application provides a computer program product, and the computer program is executed by the processor to implement various possible implementation manners in the first aspect.

[0108] The method and device for simulating the tertiary oil recovery after water flooding in a strong heterogeneous oil reservoir provided by the present application can determine the corresponding formation particle size distribution information according to the drilling and logging data of the target reservoir to obtain the initial core sample; the standard formation water solution and the formation crude oil are used to perform the displacement saturation treatment on the first core sample to obtain the second core sample; the second core sample and the standard formation water solution are placed into the target displacement device to establish the target displacement environment, and the target displacement device is controlled to monitor the second core sample in real time according to the target displacement environment; the corresponding initial picture is obtained according to the target displacement device, and the second core sample is subjected to multiple displacement treatments by using multiple displacement phases; when each displacement treatment is completed, the corresponding target picture is obtained according to the target displacement device, and the target oil recovery data is determined according to the initial picture and the target picture, so that the second core sample is subjected to multiple displacement treatments by the target displacement device using multiple displacement phases flexibly, which not only significantly improves the convenience and rapidity of the overall displacement treatment process, but also effectively reduces the cost consumption in terms of manpower, material resources and time. In addition, the target displacement device generates the corresponding initial picture and target picture while monitoring the change of the second core sample in the displacement experiment in real time, which provides a more intuitive observation means for the overall displacement treatment process, and the corresponding target oil recovery data is obtained by analyzing the initial picture and the target picture, which ensures the reliability and accuracy of the data, solves the technical problem of low oil recovery efficiency of the heterogeneous oil reservoir, and achieves the technical effect of improving the oil recovery efficiency of the heterogeneous oil reservoir. BRIEF DESCRIPTION OF DRAWINGS

[0109] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0110] Figure 1 The flowchart of the method for simulating the tertiary oil recovery after water flooding in a strong heterogeneous oil reservoir provided by the embodiment of the present application Figure One ;

[0111] Figure 2A schematic diagram of the structure of the initial core sample provided in the embodiment of the present application;

[0112] Figure 3 The process of simulating tertiary oil recovery after water flooding in a highly heterogeneous reservoir provided in the embodiment of this application Figure Two ;

[0113] Figure 4 A schematic structural diagram of a target displacement device provided in an embodiment of the present application;

[0114] Figure 5 The process of simulating tertiary oil recovery after water flooding in a highly heterogeneous reservoir provided in the embodiment of this application Figure Three ;

[0115] Figure 6 The process of simulating tertiary oil recovery after water flooding in a highly heterogeneous reservoir provided in the embodiment of this application Figure Four ;

[0116] Figure 7 The process of simulating the tertiary oil recovery method after water flooding in a highly heterogeneous reservoir provided in the embodiment of this application Figure Five ;

[0117] Figure 8 A schematic diagram of a target image provided in an embodiment of the present application;

[0118] Figure 9 This is a schematic diagram of the structure of a tertiary oil recovery device after water flooding in a simulated highly heterogeneous oil reservoir provided in an embodiment of the present application;

[0119] Figure 10 This is a hardware structure diagram of the tertiary oil recovery equipment for simulating water flooding in a highly heterogeneous reservoir provided in an embodiment of the present application.

[0120] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0121] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0122] Due to the lack of intuitive observation means in the whole displacement process in the prior art, and the complicated design of part of the experimental devices, a large amount of time cost and labor cost is consumed in the displacement process, and for the heterogeneous reservoir, there is a technical problem of low oil extraction efficiency of the heterogeneous reservoir.

[0123] To solve the above problems, the method and device for simulating tertiary oil recovery after water flooding of strong heterogeneous reservoirs are provided, which can flexibly use multiple displacement phases to displace the relatively heterogeneous core samples through the target displacement device, which not only significantly improves the convenience and speed of the whole displacement process, but also effectively reduces the cost of manpower, material resources and time. In addition, the target displacement device can generate the initial picture before displacement and the target picture after displacement while monitoring the changes of the core sample in the displacement experiment in real time, which provides a more intuitive observation means for the whole displacement process, and through the analysis of the initial picture and the target picture, the change rate of the injection end pressure with the seepage distance and the recovery rate of the core sample are obtained, which ensures the reliability and accuracy of the data, solves the technical problem of low oil extraction efficiency of the heterogeneous reservoir, and achieves the technical effect of improving the oil extraction efficiency of the heterogeneous reservoir.

[0124] The technical solutions of the present application and how the technical solutions solve the above technical problems will be described in detail in the following specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0125] Figure 1 The process of the method for simulating tertiary oil recovery after water flooding of strong heterogeneous reservoirs provided by the embodiments of the present application Figure One As shown in Figure 1 , the method for simulating tertiary oil recovery after water flooding of strong heterogeneous reservoirs provided by the embodiments of the present application comprises:

[0126] S101, determining the corresponding formation particle size distribution information according to the drilling and logging data of the target reservoir, to obtain the corresponding initial core sample;

[0127] In this embodiment, the initial core sample is a heterogeneous core sample prepared after simulating the formation particle size distribution, the target reservoir includes multiple different reservoirs, and the drilling and logging data includes but is not limited to porosity, permeability, oil and gas saturation, lithology, particle size, and sorting.

[0128] According to the drilling and logging data of the multiple different reservoirs in the target reservoir, the corresponding formation particle size distribution information is determined, and the corresponding initial core sample is prepared according to the formation particle size distribution information.

[0129] Specifically, Figure 2A structural schematic diagram of an initial core sample provided by an embodiment of the present application, relying on drilling and logging data obtained in a drilling and logging process, obtains stratum granularity distribution information of different reservoirs corresponding to a target reservoir, and according to the stratum granularity distribution information, the sand is layered into a core preparation mold, and a heterogeneous core sample as shown in Figure 2 is pressed by a hydraulic machine.

[0130] S102, using a standard stratum water solution and a stratum crude oil, performing displacement saturation processing on the first core sample to obtain a second core sample;

[0131] In the embodiment, the first core sample is a core sample after drying treatment of the initial core sample, and the second core sample is a core sample after displacement saturation treatment of the first core sample.

[0132] After the initial core sample is prepared, the initial core sample is dried to obtain a first core sample, and a standard stratum water solution and a stratum crude oil are selected to perform displacement saturation treatment on the first core sample to obtain a second core sample.

[0133] Specifically, the initial core sample is dried for 48 hours at a temperature not higher than 60 DEG C and a relative humidity of about 40% to 50% according to the SY / T5336 standard, and after 48 hours, the weight difference is controlled to be less than 10 mg by measuring every 8 hours, and the dried core sample is placed on an analytical balance to measure the weight. After the weight of the core sample is determined to be constant, the dried core sample is determined as the first core sample; the standard stratum water solution and the stratum crude oil are selected to perform displacement saturation treatment on the first core sample to obtain a second core sample.

[0134] S103, placing the second core sample and the standard stratum water solution into a target displacement device to establish a target displacement environment, and controlling the target displacement device to monitor the second core sample in real time according to the target displacement environment;

[0135] The second core sample and the standard stratum water solution are placed in the target displacement device, the target displacement device is adjusted internally to establish a target displacement environment suitable for displacement treatment, and after the target displacement environment is determined to be established, the target displacement device is started and controlled to facilitate real-time detection of the second core sample before and after displacement treatment.

[0136] S104, obtaining a corresponding initial picture through the target displacement device, and performing multiple displacement treatments on the second core sample using multiple displacement phases.

[0137] In the embodiment, the displacement phase includes a chemical displacement agent, a standard formation water solution and a target gas, the displacement treatment includes a chemical displacement treatment, a water displacement treatment and a gas displacement treatment, the chemical displacement agent includes a chemical plugging agent or a crosslinking agent, and the initial picture is used to indicate a nuclear magnetic imaging picture of the second core sample before the displacement treatment.

[0138] Before the displacement treatment starts, the target displacement device is controlled, the initial picture corresponding to the second core sample is obtained, and the second core sample is subjected to multiple displacement treatments by using the chemical displacement agent, the standard formation water solution and the target gas respectively.

[0139] S105, when each displacement treatment is completed, the target picture corresponding to the displacement treatment is obtained by the target displacement device, and the target oil production data is determined according to the initial picture and the target picture.

[0140] In the embodiment, the target oil production data includes an injection end pressure change rate with respect to a seepage distance and a recovery rate, the target picture is used to indicate a nuclear magnetic imaging picture of the second core sample after each displacement treatment, and each displacement treatment corresponds to one target picture.

[0141] The target displacement device generates corresponding nuclear magnetic imaging pictures in real time during monitoring of the displacement treatment, obtains the target picture after the treatment according to the nuclear magnetic imaging pictures when each displacement phase completes a displacement treatment, combines the initial picture with the target picture, determines the change of the second core sample before and after the treatment and analyzes the change, so as to determine the target oil production data of the second core sample after the displacement treatment.

[0142] The application provides a method for simulating tertiary oil recovery after water flooding in a strong heterogeneous reservoir, which comprises the following steps: determining the corresponding formation particle size distribution information according to the drilling and logging data of the target reservoir to obtain the initial core sample; using a standard formation water solution and formation crude oil to perform displacement saturation treatment on the first core sample to obtain the second core sample; placing the second core sample and the standard formation water solution into a target displacement device to establish a target displacement environment, and controlling the target displacement device to monitor the second core sample in real time according to the target displacement environment; obtaining the corresponding initial picture according to the target displacement device, and performing multiple displacement treatments on the second core sample by using multiple displacement phases; when each displacement treatment is completed, obtaining the corresponding target picture according to the target displacement device, and determining the target oil recovery data according to the initial picture and the target picture, so that the initial core sample of heterogeneity is prepared individually according to the drilling and logging data of the target reservoir, the sample fully reflects the heterogeneity of the reservoir in the vertical interlayer and the heterogeneity of the sediment particle size, the representativeness and accuracy of the core sample are further improved by determining the fine formation particle size distribution information, and meanwhile, after the displacement saturation treatment of the first core sample by using the standard formation water solution and the formation crude oil, the second core sample is placed in the target displacement device, the device has the capability of nondestructive monitoring, can monitor and evaluate the changes of the second core sample in real time and accurately during the displacement process; in addition, the target displacement device can not only obtain the initial picture at the beginning of the experiment, but also can flexibly use multiple displacement phases to perform multiple displacement treatments on the second core sample, which significantly improves the convenience and speed of the overall displacement treatment process, and effectively reduces the cost consumption in manpower, material resources and time; the target displacement device generates the corresponding initial picture and target picture while monitoring the changes of the second core sample in the displacement experiment process, which provides a more intuitive observation means for the overall displacement treatment process, and the corresponding target oil recovery data are obtained by analyzing the initial picture and the target picture, so as to ensure the reliability and accuracy of the data, solve the technical problem of low oil recovery efficiency of the heterogeneous reservoir, achieve the technical effect of improving the oil recovery efficiency of the heterogeneous reservoir, solve the technical problem of low oil recovery efficiency of the heterogeneous reservoir, and achieve the technical effect of improving the oil recovery efficiency of the heterogeneous reservoir.

[0143] Figure 3 The method for simulating tertiary oil recovery after water flooding in a strong heterogeneous reservoir provided by the embodiment of the application Figure Two As shown in Figure 3 , the embodiment is based on the above-mentioned embodiment, and the process of obtaining the second core sample is supplemented, which comprises the following steps:

[0144] S301, vacuum treatment is performed on the experimental beaker with the initial core sample, and the simulated formation water solution is added into the experimental beaker after vacuum treatment;

[0145] The experimental beaker with the initial core sample is placed in a vacuum pump, and the experimental beaker is vacuumized by the vacuum pump. After the vacuum treatment is completed, the simulated formation water solution is added to the experimental beaker.

[0146] Specifically, the experimental beaker with the initial core sample is placed in a vacuum pump, and the vacuum pump is continuously vacuumized for 12 hours. After it is determined that the vacuum treatment is completed, the simulated formation water solution is added to the experimental beaker.

[0147] S302, after it is determined that the water surface of the simulated formation water solution submerges the initial core sample and there is no obvious bubble on the surface of the initial core sample, a standard formation water solution is used to perform water flooding treatment on the initial core sample, and a third core sample after treatment is obtained.

[0148] After it is determined that the water surface of the simulated formation water solution submerges the initial core sample and there is no obvious bubble on the surface of the initial core sample, the standard formation water solution is used to continue to perform displacement treatment on the initial core sample, and a third core sample after treatment is obtained.

[0149] Specifically, after it is determined that the water surface of the simulated formation water solution submerges the initial core sample and there is no obvious bubble on the surface of the initial core sample, the initial core sample is placed in a corresponding displacement device to displace 5 PV of the standard formation water solution, so as to obtain a corresponding third core sample.

[0150] S303, a formation crude oil is used to perform displacement saturation treatment on the third core sample, and a fourth core sample after treatment is obtained.

[0151] The displacement saturation treatment on the third core sample by the formation crude oil is continued, and the core sample after treatment is determined as the fourth core sample.

[0152] S304, the fourth core sample is placed in the formation crude oil and pressurized to a target pressure, and then static treatment is performed on the fourth core sample. After it is determined that the static duration of the fourth core sample reaches a first threshold value, a corresponding second core sample is obtained.

[0153] For the fourth core sample, the fourth core sample is placed in the formation crude oil, pressurized to a target pressure, and then static treatment is performed on the fourth core sample. After it is determined that the static duration reaches a first threshold value, a corresponding second core sample is obtained.

[0154] Specifically, for the fourth core sample, the fourth core sample is placed in the formation crude oil, pressurized to 20 MPa, and then static treatment is performed for 12 hours. After the static treatment is completed, the core sample is taken out and determined as the second core sample.

[0155] The present application provides a tertiary oil recovery method for simulating water flooding in a strongly heterogeneous reservoir. Before the flooding treatment, the heterogeneous core sample is subjected to vacuum, flooding saturation, pressurization and static treatment in sequence to obtain a simulated experimental sample that is identical to the actual core sample. While ensuring the authenticity and reliability of the target data after the subsequent flooding treatment, the complexity of sample preparation is reduced, the cost consumption in terms of manpower, material resources and time is effectively reduced, and the technical problem of low oil recovery efficiency in heterogeneous reservoirs is solved, thereby achieving the technical effect of improving the oil recovery efficiency in heterogeneous reservoirs.

[0156] Figure 4 A schematic diagram of the structure of the target displacement device provided in the embodiment of the present application is shown in FIG. Figure 4 As shown, the target displacement device includes: 1. a dual-cylinder constant speed and constant pressure displacement system; 2. an axial confining pressure pump; 3. a pressure sensor; 4. a radial confining pressure pump; 5. a magnet; 6. a data acquisition and imaging system; 7. a core holder; 8. a rock sample; 9. needle valves at the front and rear ends of the core holder; 10. an intermediate container; 11. a displacement pump; 12. fluorocarbon oil; 13. a heating circulation pump; 14. a back pressure pump; 15. a measuring cylinder; 16. a back pressure valve; wherein the core holder is used to fix and clamp the second core sample; the displacement pump is used to control the flow rate of the displacement phase and the speed of injecting the second core sample; the intermediate container is used to store and supply the displacement phase required for the displacement treatment; the dual-cylinder constant speed and constant pressure displacement system is used to control and adjust the working state of the displacement pump; the axial confining pressure ... A pressure pump is used to simulate the pressure of the formation in the vertical direction; a radial confining pressure pump is used to simulate the pressure of the formation in the horizontal direction; a heating circulation pump is used to set and maintain the internal temperature of the core holder; needle valves at the front and rear ends of the core holder are used to control the injection and discharge of the displacement phase at the front and rear ends of the core holder; a magnet is used to generate a stable magnetic field environment; a data acquisition and imaging system is used to monitor and collect nuclear magnetic resonance imaging images during the displacement treatment process in real time according to the magnetic field environment, and to determine the signal quantity corresponding to the nuclear magnetic resonance imaging images; a back pressure pump is used to set the outlet pressure value required for the displacement treatment and to adjust and control the back pressure during the displacement treatment; a measuring cylinder is used to receive the produced fluid generated when the pressure corresponding to the back pressure pump is determined to have reached the second threshold value.

[0157] Figure 5 The process of simulating tertiary oil recovery after water flooding in a highly heterogeneous reservoir provided in the embodiment of this application Figure Three .like Figure 5 As shown, this embodiment provides a supplementary explanation of the process of establishing the target displacement environment based on the above embodiment, including:

[0158] S501. According to the target displacement device, fix the second core sample to the core holder and put the standard formation water solution into the intermediate container;

[0159] Put the saturated core sample into the core holder, and screw the right plug tightly, fill the left plug, and put the standard formation water solution required for displacement treatment in the middle container.

[0160] S502, according to the double-cylinder constant-speed constant-pressure displacement system, set the pressure of the axial confining pressure pump and the radial confining pressure pump to the target pressure value, and set the heating circulating pump to the third threshold value;

[0161] Control the associated equipment through the double-cylinder constant-speed constant-pressure displacement system, that is, increase the pressure of the axial confining pressure pump and the radial confining pressure pump to the target pressure value to simulate the pressure of the formation in the longitudinal and horizontal directions, and turn on the heating circulating pump and heat the core holder to the third threshold value.

[0162] S503, after determining that the temperature inside the core holder is constant at the third threshold value, control the needle valves at the front and rear ends of the core holder to close the valves;

[0163] When the temperature inside the core holder is constant at the preset third threshold value, close the needle valves at the front and rear ends of the core holder.

[0164] S504, after determining that the pressure at the upper end of the core holder reaches the fourth threshold value, control the needle valves at the front and rear ends of the core holder to open the valves, and set the outlet pressure value of the back pressure pump to the fifth threshold value to establish a target displacement environment.

[0165] When the pressure at the upper end of the core holder reaches the preset fourth threshold value, open the needle valves at the front and rear ends of the core holder from top to bottom, and set the outlet pressure value of the back pressure pump to the fifth threshold value. After the pressure value of the back pressure pump reaches the fifth threshold value, it is determined that the target displacement environment is established.

[0166] The method provided by the application can simulate the tertiary oil recovery after water flooding in a strong heterogeneous reservoir. Before displacement treatment, the components in the target displacement device are controlled through preset conditions, and the actual oil recovery environment is simulated, thereby ensuring the authenticity and reliability of the target oil recovery data after subsequent displacement treatment, improving the rapidity and convenience of the target displacement environment establishment process, effectively reducing the cost of manpower, material resources and time, solving the technical problem of low oil recovery efficiency in a heterogeneous reservoir, and achieving the technical effect of improving the oil recovery efficiency in a heterogeneous reservoir.

[0167] Figure 6 The method for simulating the tertiary oil recovery after water flooding in a strong heterogeneous reservoir provided by the embodiment of the application Figure Four As shown in Figure 6 , the embodiment supplements the description of the displacement process of the second core sample based on the above-mentioned embodiment, including:

[0168] S601, according to the double-cylinder constant-speed constant-pressure displacement system, set the displacement pump flow to the target flow, and according to the target flow, inject the standard formation water solution with a target injection amount into the second core sample to perform water displacement treatment;

[0169] According to the double-cylinder constant-speed constant-pressure displacement system, set the displacement pump flow to the target flow, and at the flow rate corresponding to the target flow, inject the standard formation water solution with a target injection amount into the second core sample to perform water displacement treatment.

[0170] Specifically, according to the double-cylinder constant-speed constant-pressure displacement system, set the displacement pump flow to 0.01 ml / min, and inject the standard formation water solution with a target injection amount into the second core sample to perform water displacement treatment at a flow rate of 0.01 ml / min.

[0171] S602, after determining that the displacement pump replacement volume reaches the sixth threshold, replace the standard formation water solution with a chemical displacement agent, and inject the chemical displacement agent with a target injection amount into the second core sample to perform chemical displacement treatment;

[0172] In this embodiment, the target injection amount is obtained by the following method:

[0173] According to the initial core sample, determine the corresponding initial weight, and according to the second core sample, determine the corresponding target weight and pore volume;

[0174] According to the initial weight and the target weight, determine the corresponding weight difference;

[0175] According to the weight difference and the density of the standard formation water solution, obtain the corresponding pore volume, and according to the pore volume, determine the corresponding target injection amount.

[0176] When the displacement pump replacement volume reaches the sixth threshold, replace the standard formation water solution in the intermediate container with a chemical displacement agent, and inject the chemical displacement agent with a target injection amount into the second core sample to perform chemical displacement treatment.

[0177] Specifically, when the displacement pump replacement volume reaches 1 PV, replace the standard formation water solution in the intermediate container with a chemical displacement agent, and inject the chemical displacement agent with a target injection amount into the second core sample to perform chemical displacement treatment on the second core sample.

[0178] S603, after determining that the chemical displacement treatment is completed, replace the chemical displacement agent with a standard formation water solution, and inject the standard formation water solution with a target injection amount into the second core sample to perform water displacement treatment on the second core sample;

[0179] When the chemical flooding treatment is completed, the chemical displacing agent in the intermediate container is replaced back to the standard formation water solution, and the standard formation water solution with a capacity of the target injection amount is injected into the second core sample to continue the water flooding treatment.

[0180] S604, after determining that the water flooding treatment is completed, the standard formation water solution is replaced by the target gas, and the second core sample is injected with the target gas with a capacity of the target injection amount to perform the gas flooding treatment.

[0181] In this embodiment, the target gas includes but is not limited to carbon dioxide, nitrogen, oxygen, air, flue gas, or methane.

[0182] After determining that the water flooding treatment is completed, the standard formation water solution in the intermediate container is replaced by the target gas, and the target gas with a capacity of the target injection amount is injected into the second core sample to continue the gas flooding treatment.

[0183] S605, according to the target displacement device, the second core sample is monitored, and after determining that the second core sample has gas channeling, the second core sample is injected with the chemical plugging agent with a capacity of the target injection amount to perform plugging.

[0184] Through the data acquisition and imaging system of the target displacement device, the second core sample is continuously detected during the entire displacement treatment process, and corresponding nuclear magnetic imaging pictures are collected. According to these nuclear magnetic imaging pictures, after the gas channeling of the second core sample is found, the chemical plugging agent with a capacity of the target injection amount is injected into the second core sample to perform chemical plugging.

[0185] S606, after determining that the second core sample has no gas channeling, the chemical plugging agent is replaced by the target gas, and the second core sample is injected with the target gas with a capacity of the target injection amount to perform the gas flooding treatment.

[0186] After the chemical plugging is completed, the nuclear magnetic imaging pictures collected by the data acquisition and imaging system of the target displacement device are continuously used to determine the gas channeling condition of the second core sample. After determining that the second core sample has no gas channeling, the chemical plugging agent in the intermediate container is replaced by the target gas, and the target gas with a capacity of the target injection amount is injected into the second core sample to continue the gas flooding treatment.

[0187] The application provides a method for simulating the tertiary oil recovery after water flooding in a strong heterogeneous oil reservoir, which comprises the following steps: water flooding, chemical flooding and gas flooding are performed on the second core sample by using three different displacement phases; after gas channeling occurs in the second core sample, a chemical plugging agent with a capacity equal to the target injection amount is injected into the second core sample to plug the second core sample; after it is determined that there is no gas channeling in the second core sample, the chemical plugging agent is replaced by target gas, and the target gas with a capacity equal to the target injection amount is injected into the second core sample to continue the gas flooding process. The method can flexibly use multiple displacement phases to perform multiple displacement processes on the second core sample by using the target displacement device, which can significantly improve the convenience and speed of the overall displacement process, effectively reduce the cost of manpower, material resources and time, and ensure the accuracy and reliability of the target data after the subsequent displacement process. The method can solve the technical problem of low oil recovery efficiency of the heterogeneous oil reservoir and improve the oil recovery efficiency of the heterogeneous oil reservoir.

[0188] Figure 7 The method for simulating the tertiary oil recovery after water flooding in a strong heterogeneous oil reservoir provided by the application Figure Five As shown in Figure 7 , the application further provides a method for simulating the tertiary oil recovery after water flooding in a strong heterogeneous oil reservoir, which comprises the following steps:

[0189] S701, obtaining an injection end pressure curve corresponding to the second core sample according to the initial picture and the target picture after water flooding, and determining the change rate of the injection end pressure of the second core sample with respect to the seepage distance according to the injection end pressure curve.

[0190] In the embodiment, the injection end pressure curve is used to indicate the penetration distance of the displacement phase in the second core sample and the change trend of the injection end pressure with respect to time or the injection amount of the displacement phase during the displacement process. The change rate of the injection end pressure with respect to the seepage distance is used to quantitatively evaluate the connectivity of the seepage channel of the second core sample. The change rate of the injection end pressure with respect to the seepage distance is positively correlated with the connectivity of the seepage channel. The higher the change rate of the injection end pressure with respect to the seepage distance, the better the connectivity of the seepage channel of the second core sample.

[0191] The data acquisition imaging system in the target displacement device continuously detects the second core sample during the whole displacement process, and collects nuclear magnetic imaging pictures in the whole process. The initial picture of the second core sample before displacement processing and the target picture after water displacement processing are obtained in the nuclear magnetic imaging pictures for analysis. The pressure at the injection port of the second core sample in the initial picture and the target picture after water displacement processing is observed, and the injection end pressure curve corresponding to the second core sample is determined. According to the curve, the change rate of the injection end pressure of the second core sample with the seepage distance is determined.

[0192] S702, according to the data acquisition imaging system, the initial signal quantity corresponding to the initial picture is obtained, and the target signal quantity corresponding to each target picture is obtained according to each target picture.

[0193] The initial signal amplitude corresponding to the initial picture of the second core sample before displacement processing is obtained by the data acquisition imaging system in the target displacement device. The initial signal amplitude is integrated to obtain the corresponding initial signal quantity. At the same time, a plurality of target pictures after the above water displacement, chemical displacement and gas displacement processing of the second core sample are obtained, and the corresponding target signal amplitude of each target picture is obtained according to the target picture. Each target signal amplitude is integrated to obtain a plurality of corresponding target signal quantities.

[0194] S703, according to the initial signal quantity and the target signal quantity, the recovery rate of the second core sample is determined.

[0195] The difference value of the sum of the initial signal quantity and each target signal quantity is calculated, and the ratio of the difference value to the initial signal quantity is taken as the recovery rate of the second core sample.

[0196] Figure 8 The schematic diagram of the target picture provided by the embodiment of the application, the data acquisition imaging system in the target displacement device continuously monitors the second core sample before and after displacement processing of the second core sample. The original oil-containing picture corresponding to the second core sample before displacement processing, the nuclear magnetic imaging picture corresponding to the displacement volume of 0.5PV and 2PV during water displacement processing, the nuclear magnetic imaging picture corresponding to the displacement volume of 0.5PV during chemical displacement processing, and the nuclear magnetic imaging picture corresponding to the displacement volume of 1PV during gas displacement processing are shown in Figure 8 It can be understood that, Figure 8 It is only a schematic diagram of the target picture, which does not affect the protection content of the embodiment of the application.

[0197] Figure 9 The structure schematic diagram of the three times oil extraction device after water displacement of the simulated strong heterogeneous oil reservoir provided by the embodiment of the application. The device of the embodiment can be in the form of software and / or hardware. As Figure 9As shown, the third oil recovery device provided by the embodiment of the application after water flooding of a strong heterogeneous reservoir comprises a first obtaining module 901, a second obtaining module 902, a first processing module 903, a second processing module 904, and a third obtaining module 905.

[0198] The first obtaining module 901 is configured to determine corresponding formation grain size distribution information according to drilling and logging data of a target reservoir, and obtain an initial core sample.

[0199] The second obtaining module 902 is configured to use standard formation water solution and formation crude oil to perform displacement saturation processing on the first core sample to obtain a second core sample, wherein the first core sample is a core sample obtained by drying the initial core sample, and the second core sample is a core sample obtained by performing displacement saturation processing on the first core sample.

[0200] The first processing module 903 is configured to place the second core sample and the standard formation water solution into a target displacement device to establish a target displacement environment, and control the target displacement device to monitor the second core sample in real time according to the target displacement environment.

[0201] The second processing module 904 is configured to obtain a corresponding initial picture according to the target displacement device, and perform multiple displacement processes on the second core sample using multiple displacement phases, wherein the displacement phases include a chemical displacement agent, the standard formation water solution, and a target gas, the displacement processes include chemical displacement processing, water flooding processing, and gas flooding processing, the chemical displacement agent includes a chemical plugging agent or a crosslinking agent, and the initial picture is used to indicate a nuclear magnetic imaging picture of the second core sample before the displacement processes.

[0202] The third obtaining module 905 is configured to obtain a corresponding target picture according to the target displacement device when each displacement process is completed, and determine target oil recovery data according to the initial picture and the target picture, wherein the target oil recovery data includes an injection end pressure change rate with respect to seepage distance and recovery efficiency, the target picture is used to indicate a nuclear magnetic imaging picture of the second core sample after each displacement process is completed, and each displacement process corresponds to one target picture.

[0203] In a possible implementation, the second obtaining module 902 is further configured to:

[0204] perform vacuum processing on the experimental beaker with the initial core sample, and add the simulated formation water solution to the experimental beaker after the vacuum processing;

[0205] after determining that the water surface of the simulated formation water solution submerges the initial core sample and there is no obvious air bubble on the surface of the initial core sample, perform water flooding processing on the initial core sample using the standard formation water solution to obtain a third core sample after the processing.

[0206] The third core sample is subjected to displacement saturation treatment by using formation crude oil to obtain a fourth core sample after treatment;

[0207] The fourth core sample is placed in formation crude oil and pressurized to a target pressure, and then the fourth core sample is subjected to standing treatment;

[0208] After determining that the standing duration of the fourth core sample reaches a first threshold value, a second core sample corresponding to the fourth core sample is obtained.

[0209] In a possible implementation, the first processing module 903 is further configured to target a displacement device, and the displacement device includes:

[0210] A core holder configured to fix and hold the second core sample;

[0211] A displacement pump configured to control the flow rate of a displacement phase and the injection speed of the second core sample;

[0212] An intermediate container configured to store and supply the displacement phase required for displacement treatment;

[0213] A double-cylinder constant-speed constant-pressure displacement system configured to control and adjust the working state of the displacement pump;

[0214] An axial confining pressure pump configured to simulate the pressure of a formation in a longitudinal direction;

[0215] A radial confining pressure pump configured to simulate the pressure of the formation in a horizontal direction;

[0216] A heating circulating pump configured to set and maintain the internal temperature of the core holder;

[0217] Needle valves at the front and rear ends of the core holder configured to control the injection and discharge of the displacement phase at the front and rear ends of the core holder;

[0218] A magnet configured to generate a stable magnetic field environment;

[0219] A data acquisition imaging system configured to monitor and collect nuclear magnetic imaging pictures in real time during displacement treatment according to the magnetic field environment, and determine the signal amount corresponding to the nuclear magnetic imaging pictures;

[0220] A back pressure pump configured to set an outlet pressure value required for displacement treatment, and adjust and control the back pressure in displacement treatment;

[0221] A measuring cylinder configured to receive produced fluid generated by the pressure release of the back pressure pump valve when it is determined that the pressure corresponding to the back pressure pump reaches a second threshold value.

[0222] In a possible implementation, the first processing module 903 is further configured to:

[0223] According to the target displacement device, the second core sample is fixed to the core holder, and the standard formation water solution is put into the intermediate container;

[0224] According to the double-cylinder constant-speed constant-pressure displacement system, the pressures of the axial confining pressure pump and the radial confining pressure pump are set to the target pressure value, and the heating circulating pump is set to the third threshold value;

[0225] After determining that the temperature inside the core holder is constant at the third threshold value, the front and rear needle valves of the core holder are controlled to close the valves;

[0226] After determining that the pressure at the upper end of the core holder reaches the fourth threshold value, the front and rear needle valves of the core holder are controlled to open the valves, and the outlet pressure value of the back pressure pump is set to the fifth threshold value to establish the target displacement environment.

[0227] In a possible implementation, the second processing module 904 is further configured to:

[0228] According to the double-cylinder constant-speed constant-pressure displacement system, the displacement pump flow is set to the target flow, and the second core sample is injected with the standard formation water solution with a size of the target injection amount according to the target flow to perform water flooding treatment;

[0229] After determining that the displacement pump replacement volume reaches the sixth threshold value, the standard formation water solution is replaced with the chemical displacement agent, and the second core sample is injected with the chemical displacement agent with a size of the target injection amount to perform chemical flooding treatment;

[0230] After determining that the chemical flooding treatment is completed, the chemical displacement agent is replaced with the standard formation water solution, and the second core sample is injected with the standard formation water solution with a size of the target injection amount to perform water flooding treatment on the second core sample;

[0231] After determining that the water flooding treatment is completed, the standard formation water solution is replaced with the target gas, and the second core sample is injected with the target gas with a size of the target injection amount to perform gas flooding treatment.

[0232] In a possible implementation, the second processing module 904 is further configured to:

[0233] According to the initial core sample, a corresponding initial weight is determined, and according to the second core sample, a corresponding target weight and a pore volume are determined;

[0234] According to the initial weight and the target weight, a corresponding weight difference value is determined;

[0235] According to the weight difference value and the density of the standard formation water solution, a corresponding pore volume is obtained, and according to the pore volume, a corresponding target injection amount is determined.

[0236] In a possible implementation, the second processing module 904 is further configured to:

[0237] monitoring the second core sample according to the target displacement device;

[0238] after determining that the second core sample has gas channeling, injecting the chemical plugging agent with a size of a target injection amount into the second core sample to perform plugging;

[0239] after determining that the second core sample has no gas channeling, replacing the chemical plugging agent with a target gas, and injecting the target gas with a size of a target injection amount into the second core sample to perform gas displacement treatment.

[0240] In a possible implementation, the third obtaining module 905 is further configured to:

[0241] obtaining an injection end pressure curve corresponding to the second core sample according to the initial picture and the target picture after water displacement treatment, wherein the injection end pressure curve is used to indicate a change trend of a penetration distance of a displacement phase in the second core sample and an injection end pressure with time or a displacement phase injection amount during the displacement treatment process;

[0242] determining a rate of change of the injection end pressure of the second core sample with respect to the seepage distance according to the injection end pressure curve;

[0243] obtaining an initial signal amount corresponding to the initial picture according to the data acquisition and imaging system, and obtaining a target signal amount corresponding to each target picture according to each target picture;

[0244] determining a recovery rate of the second core sample according to the initial signal amount and the target signal amount.

[0245] The device for simulating tertiary oil recovery after water displacement of a strong heterogeneous reservoir provided in the application can implement the method embodiments described above, and has similar implementation principles and technical effects, which will not be described here again in this embodiment.

[0246] Figure 10 A hardware structure diagram of the device for simulating tertiary oil recovery after water displacement of a strong heterogeneous reservoir provided in the embodiment of the application is shown in FIG. 1. Figure 10 As shown in FIG. 1, the device 1000 for simulating tertiary oil recovery after water displacement of a strong heterogeneous reservoir includes:

[0247] a processor 1001 and a memory 1002;

[0248] The memory stores computer execution instructions;

[0249] The processor executes the computer execution instructions stored in the memory 1002, so that the device for simulating tertiary oil recovery after water displacement of a strong heterogeneous reservoir performs the method for simulating tertiary oil recovery after water displacement of a strong heterogeneous reservoir as described above.

[0250] It should be appreciated that the processor 1001 described above can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), or the like. The general-purpose processor can be a microprocessor or the like. The steps of the method disclosed in the application can be directly embodied as hardware processor execution, or executed by a combination of hardware and software modules in the processor.

[0251] The memory 1002 can include a high-speed random access memory (RAM), and can also include a non-volatile memory (NVM), such as at least one disk memory, and can also be a U disk, a mobile hard disk, a read-only memory, a magnetic disk or an optical disk, etc.

[0252] The embodiment of the present application also provides a computer readable storage medium, and the computer readable storage medium stores computer execution instructions. When the computer execution instructions are executed by a processor, the computer execution instructions are used to implement the method for simulating the strong heterogeneous oil reservoir water drive after the third oil recovery.

[0253] The embodiment of the present application also provides a computer program product, and the computer program is executed by a processor to implement the method for simulating the strong heterogeneous oil reservoir water drive after the third oil recovery.

[0254] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the application is not limited to the action sequence described, because according to the application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to optional embodiments, and the actions and modules involved are not necessarily required by the application.

[0255] It should be further noted that, although the various steps in the flowchart are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps may be performed in other orders. Moreover, at least a portion of the steps in the flowchart may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but may be performed at different times. The execution order of these sub-steps or stages is not necessarily to be performed in sequence, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0256] It should be understood that the above-described device embodiments are merely illustrative, and the device of the present application may also be implemented in other ways. For example, the division of units / modules in the above-described embodiments is merely a logical functional division, and actual implementations may employ other division methods. For example, multiple units, modules, or components may be combined or integrated into another system, or some features may be omitted or not implemented.

[0257] In addition, unless otherwise specified, the functional units / modules in the various embodiments of the present application may be integrated into a single unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated together. The aforementioned integrated units / modules may be implemented in the form of hardware or software program modules.

[0258] If an integrated unit / module is implemented in hardware, the hardware may be digital circuits, analog circuits, etc. The physical implementation of the hardware structure includes, but is not limited to, transistors, memristors, etc. Unless otherwise specified, the processor may be any appropriate hardware processor, such as a CPU, GPU, FPGA, DSP, and ASIC. Unless otherwise specified, the storage unit may be any appropriate magnetic storage medium or magneto-optical storage medium, such as resistive random access memory (RRAM), dynamic random access memory (DRAM), static random access memory (SRAM), enhanced dynamic random access memory (EDRAM), high-bandwidth memory (HBM), hybrid memory cube (HMC), etc.

[0259] If the integrated units / modules are implemented in the form of software program modules and sold or used as independent products, they can be stored in a computer readable memory. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a memory and includes a number of instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the embodiments of the method of the present application. The aforementioned memory includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0260] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0261] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The application is intended to cover any variations, uses or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice in the art to which the application pertains or can relate. The specification and examples are to be regarded as exemplary only, and the true scope and spirit of the application are indicated by the following claims.

[0262] It should be understood that the application is not limited to the precise construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the application is limited only by the claims that follow.

Claims

1. A tertiary oil recovery method after water flooding in a simulated highly heterogeneous reservoir, characterized in that: include: Determine the corresponding formation grain size distribution information based on the drilling and logging data of the target reservoir to obtain a corresponding initial core sample, wherein the initial core sample is a heterogeneous core sample prepared by simulating the formation grain size distribution; Performing a displacement saturation treatment on a first core sample using a standard formation water solution and formation crude oil to obtain a second core sample, wherein the first core sample is a core sample obtained by drying the initial core sample, and the second core sample is a core sample obtained by performing a displacement saturation treatment on the first core sample; placing the second core sample and the standard formation water solution into a target displacement device to establish a target displacement environment, and controlling the target displacement device to monitor the second core sample in real time according to the target displacement environment; The target displacement device is used to obtain a corresponding initial image, and multiple displacement treatments are performed on the second core sample using multiple displacement phases, wherein the displacement phases include a chemical displacement agent, the standard formation water solution, and a target gas, the displacement treatment includes a chemical flooding treatment, a water flooding treatment, and a gas flooding treatment, and the chemical displacement agent includes a chemical plugging agent or a cross-linking agent. The initial image is used to indicate a nuclear magnetic resonance imaging image of the second core sample before the displacement treatment. The target displacement device includes a magnet and a data acquisition imaging system. The magnet is used to generate a stable magnetic field environment. The data acquisition imaging system is used to monitor and collect the nuclear magnetic resonance imaging images during the displacement treatment in real time according to the magnetic field environment, and determine the signal amount corresponding to the nuclear magnetic resonance imaging image. Upon completion of each displacement treatment, a corresponding target image is obtained through the target displacement device, and corresponding target oil production data is determined based on the initial image and the target image; wherein the target oil production data includes the injection end pressure change rate with the seepage distance and the recovery rate, and the target image is used to indicate the nuclear magnetic resonance imaging image of the second core sample after each displacement treatment is completed, and each displacement treatment corresponds to one target image; the determining of the corresponding target oil production data based on the initial image and the target image includes: obtaining the second core sample based on the initial image and the target image corresponding to the water flooding treatment; an injection end pressure curve corresponding to the core sample, the injection end pressure curve being used to indicate the penetration distance of the displacement phase in the second core sample during the displacement treatment and the variation trend of the injection end pressure with time or the injection amount of the displacement phase; determining the rate of change of the injection end pressure of the second core sample with seepage distance based on the injection end pressure curve; obtaining an initial signal amount corresponding to the initial image through the data acquisition and imaging system, and obtaining a target signal amount corresponding to each target image based on each target image; and determining the recovery factor of the second core sample based on the initial signal amount and the target signal amount.

2. The method according to claim 1, characterized in that The method of using a standard formation water solution and formation crude oil to perform a displacement saturation treatment on the first core sample to obtain a second core sample includes: subjecting the experimental beaker containing the initial core sample to vacuum treatment, and adding simulated formation water solution into the vacuum treated experimental beaker; After determining that the surface of the simulated formation water solution submerges the initial core sample and there are no obvious bubbles on the surface of the initial core sample, performing the water flooding treatment on the initial core sample using the standard formation water solution to obtain a third core sample after treatment; Using the formation crude oil, perform the displacement saturation treatment on the third core sample to obtain a treated fourth core sample; placing the fourth core sample into the formation crude oil and pressurizing it to a target pressure, and then subjecting the fourth core sample to a static treatment; After determining that the resting time of the fourth core sample reaches a first threshold, the corresponding second core sample is obtained.

3. The method according to claim 2, characterized in that The target displacement device further includes: a core holder for fixing and holding the second core sample; a displacement pump for controlling the flow rate of the displacement phase and the injection rate of the second core sample; an intermediate container for storing and supplying the displacement phase required for the displacement process; A dual-cylinder constant-speed and constant-pressure displacement system, used to control and adjust the working state of the displacement pump; Axial confining pressure pump, used to simulate the pressure of the formation in the vertical direction; Radial confining pressure pump, used to simulate the horizontal pressure of the formation; a heating circulation pump for setting and maintaining the internal temperature of the core holder; Needle valves at the front and rear ends of the core holder are used to control the injection and discharge of the displacement phase at the front and rear ends of the core holder; a back pressure pump, used to set the outlet pressure value required for the displacement process, and to adjust and control the back pressure during the displacement process; The measuring cylinder is used to receive the produced liquid generated when the pressure of the back pressure pump valve is released when it is determined that the pressure corresponding to the back pressure pump reaches a second threshold.

4. The method according to claim 3, characterized in that Placing the second core sample and the standard formation water solution into a target displacement device to establish a target displacement environment includes: According to the target displacement device, fixing the second core sample to the core holder and placing the standard formation water solution into the intermediate container; According to the dual-cylinder constant speed and constant pressure displacement system, the pressures of the axial confining pressure pump and the radial confining pressure pump are set to target pressure values, and the heating circulation pump is set to a third threshold value; After determining that the temperature inside the core holder is constant at the third threshold, controlling the front and rear end needle valves of the core holder to close; After determining that the upper end pressure of the core holder reaches the fourth threshold, the front and rear end needle valves of the core holder are controlled to open the valves, and the outlet pressure value of the back pressure pump is set to the fifth threshold to establish the target displacement environment.

5. The method according to claim 4, characterized in that The method of using multiple displacement phases to perform multiple displacement treatments on the second core sample includes: According to the dual-cylinder constant-speed and constant-pressure displacement system, the displacement pump flow rate is set to a target flow rate, and according to the target flow rate, the standard formation water solution of the target injection volume is injected into the second core sample to perform the water flooding treatment; After determining that the displacement volume of the displacement pump reaches a sixth threshold, replacing the standard formation water solution with the chemical displacement agent, and injecting the chemical displacement agent with a target injection volume into the second core sample to perform the chemical flooding treatment; After determining that the chemical flooding treatment is completed, replacing the chemical flooding agent with the standard formation water solution, and injecting the standard formation water solution having the target injection volume into the second core sample, thereby performing the water flooding treatment on the second core sample; After determining that the water flooding treatment is completed, the standard formation water solution is replaced with the target gas, and the target gas having the target injection volume is injected into the second core sample to perform the gas flooding treatment.

6. The method according to claim 5, characterized in that The target injection volume is obtained by: Determining a corresponding initial weight based on the initial core sample, and determining a corresponding target weight and pore volume based on the second core sample; determining a corresponding weight difference according to the initial weight and the target weight; The corresponding pore volume is obtained according to the weight difference and the density of the standard formation water solution, and the corresponding target injection volume is determined according to the pore volume.

7. The method according to claim 6, characterized in that After injecting the target gas having the target injection amount into the second core sample to perform the gas drive treatment, the method further includes: monitoring the second core sample according to the target displacement device; After determining that gas channeling occurs in the second core sample, injecting the chemical plugging agent in a target injection amount into the second core sample to perform plugging; After determining that there is no gas channeling in the second core sample, the chemical plugging agent is replaced with the target gas, and the target gas having the target injection volume is injected into the second core sample to perform the gas drive treatment.

8. A tertiary oil recovery equipment for simulating strong heterogeneity of oil reservoir after water flooding, characterized in that: include: Memory, processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 7 when executed by a processor.

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