Evaluation methods, equipment, and media for assessing the impact of different injection media on crude oil recovery efficiency.

Abstract

This invention provides a method, apparatus, and medium for evaluating the impact of different injected media on crude oil recovery, belonging to the field of unconventional oil reservoir development. Applied to a fracturing simulation system, the evaluation method includes: based on a fracturing fluid control system, fracturing a pre-constructed formation model to create fractures; injecting a first medium and a second medium into the natural core column of the formation model at different time intervals using a displacement system, and obtaining the crude oil volumes recovered after the injection of the first and second media respectively; and evaluating the effectiveness of the first and second media in crude oil recovery based on these two crude oil volumes. Thus, after fracturing, different media are injected into the pre-constructed formation model, and the crude oil volumes recovered after each injection are obtained, evaluating the effect of different media on crude oil recovery. Furthermore, in subsequent development, the injected media can be further optimized based on these effects to improve crude oil production and extraction efficiency.

Description

Technical Field

[0001] This invention relates to the field of unconventional oil reservoir development technology, specifically to an evaluation method, apparatus, and medium for assessing the impact of injecting different media on crude oil recovery. Background Technology

[0002] With increasing global demand for oil and gas resources, increasing reserves and production from conventional oil and gas resources is becoming increasingly difficult and can no longer meet the demand. Unconventional oil and gas, with its huge resource potential, has received more and more attention. Although unconventional reservoirs are rich in resources, they also have characteristics such as poor physical properties, complex pore structure, low reservoir pressure coefficient, and low single-well productivity. Relying on conventional development methods, crude oil production is very low or even non-existent. Summary of the Invention

[0003] The purpose of this invention is to provide a method, apparatus, and medium for evaluating the effect of injecting different media on crude oil recovery, in order to solve the technical problems existing in the prior art.

[0004] To achieve the above objectives, embodiments of the present invention provide an evaluation method for the impact of injecting different media on crude oil recovery, applied to a fracturing simulation system. The fracturing simulation system includes a fracturing fluid control system, a displacement system, and a fluid metering system. The analysis method includes:

[0005] Based on the fracturing fluid control system, a pre-constructed formation model is fracturing to cause fractures in the formation model. The pre-constructed formation model is based on the natural core column, horizontal well, and three layers of cast formation.

[0006] The displacement system injects a first medium into the formation model, and the liquid metering system obtains the volume of crude oil extracted from the formation model after the injection of the first medium.

[0007] The second medium is injected into the formation model through the displacement system, and the volume of crude oil extracted from the formation model after the injection of the second medium is obtained based on the liquid metering system.

[0008] The effectiveness of injecting the first medium and injecting the second medium in extracting crude oil is evaluated based on the volume of crude oil extracted after injecting the first medium and the volume of crude oil extracted after injecting the second medium.

[0009] Optionally, the fracturing simulation system further includes a microcomputer system, and the fracturing of the pre-constructed formation model based on the fracturing fluid control system includes:

[0010] The fracturing fluid control system injects fracturing fluid into the horizontal well in the pre-constructed formation model. The microcomputer system controls the discharge rate of the fracturing fluid. When the fracturing fluid overflows from the formation model, the injection of the fracturing fluid is stopped.

[0011] Optionally, the evaluation method further includes:

[0012] The effectiveness of crude oil recovery is evaluated based on the injection method of the injection medium.

[0013] The volume of crude oil extracted by the formation model during displacement under the displacement system and the volume of crude oil extracted during huff and puff operations under the displacement system are obtained based on the liquid metering system.

[0014] The effectiveness of crude oil recovery from displacement injection and blotting injection is evaluated based on the volume of crude oil recovered during displacement and the volume of crude oil recovered during blotting.

[0015] Optionally, obtaining the volume of crude oil produced by the formation model during displacement under the displacement system and the volume of crude oil produced during huff and puff operations based on the liquid metering system includes:

[0016] While the displacement system is turned on, the fracturing fluid system is turned off, and the injection pressure is adjusted so that the pressure inside the horizontal well reaches the pressure value required for displacement. The volume of crude oil produced during displacement is obtained through the liquid metering system.

[0017] After the displacement system is turned on for a period of time, it is turned off to allow for pressure suppression. After counting the pressure suppression time, the volume of crude oil produced during the injection and discharge process is obtained through the liquid metering system.

[0018] Optionally, the evaluation method further includes:

[0019] To obtain the distribution of saturated crude oil in the natural core column after fracturing;

[0020] The natural core column was taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the displacement process of the injected medium, and the crude oil mobilization of the natural core column with different pore sizes after the huff and puff process.

[0021] The first comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium.

[0022] A second comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different sized pores in the natural core column after the injection medium undergoes the huff and puff process.

[0023] Based on the first comparison results and the second comparison results, evaluate the effects of displacement injection and huff-and-puff injection on crude oil recovery.

[0024] Optionally, the method further includes:

[0025] After the media displacement injection, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different pore sizes in the natural core column after the displacement process.

[0026] After the medium is injected, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the injection process.

[0027] The crude oil recovery efficiency of displacement injection and huff-and-puff injection is evaluated by comparing the crude oil recovery of different pore sizes in the natural core column after displacement injection and the crude oil recovery of different pore sizes in the natural core column after huff-and-puff injection.

[0028] Optionally, the construction of the pre-built stratigraphic model includes:

[0029] The horizontal well and the natural core column are placed in a mold, wherein the horizontal well is placed in the middle of the mold, and the natural core column is arranged at equal angles around the horizontal well.

[0030] Actual rock was selected as the interlayer between the upper and middle layers and the middle and lower layers of the three-layer cast strata, and the strata were cast in layers to obtain the strata model, wherein the strata model is heterogeneous.

[0031] Optionally, before placing the natural core column into the mold, the evaluation method further includes:

[0032] After the natural core column is cleaned and dried, it is placed in the core holder, confining pressure is applied, the core is evacuated, and simulated oil is injected to saturate it.

[0033] Optionally, before placing the horizontal well into the mold, the evaluation method further includes:

[0034] Holes are drilled at equal intervals along the axial direction of the horizontal well to simulate perforation holes for injecting the first medium or the second medium.

[0035] Accordingly, embodiments of the present invention also provide an evaluation device for assessing the impact of injecting different media on crude oil recovery, comprising:

[0036] A fracturing unit is used to fracture a pre-constructed formation model based on the fracturing fluid control system, so that the formation model has fractures, wherein the pre-constructed formation model is constructed based on the natural core column, horizontal well and three layers of cast formation;

[0037] The acquisition unit is configured to inject a first medium into the formation model through the displacement system and acquire the volume of crude oil extracted from the formation model after the injection of the first medium based on the liquid metering system; and to inject a second medium into the formation model through the displacement system and acquire the volume of crude oil extracted from the formation model after the injection of the second medium based on the liquid metering system.

[0038] The evaluation unit is used to evaluate the effectiveness of injecting the first medium and injecting the second medium to extract crude oil based on the volume of crude oil extracted after injecting the first medium and the volume of crude oil extracted after injecting the second medium.

[0039] Optionally, the fracturing unit is used for:

[0040] The fracturing fluid control system injects fracturing fluid into the horizontal well in the pre-constructed formation model. The microcomputer system controls the discharge rate of the fracturing fluid. When the fracturing fluid overflows from the formation model, the injection of the fracturing fluid is stopped.

[0041] Optionally, the evaluation unit is further used for:

[0042] The effectiveness of crude oil recovery is evaluated based on the injection method of the injection medium.

[0043] The volume of crude oil extracted by the formation model during displacement under the displacement system and the volume of crude oil extracted during huff and puff operations under the displacement system are obtained based on the liquid metering system.

[0044] The effectiveness of crude oil recovery from displacement injection and blotting injection is evaluated based on the volume of crude oil recovered during displacement and the volume of crude oil recovered during blotting.

[0045] Optionally, the evaluation unit is used for:

[0046] While the displacement system is turned on, the fracturing fluid system is turned off, and the injection pressure is adjusted so that the pressure inside the horizontal well reaches the pressure value required for displacement. The volume of crude oil produced during displacement is obtained through the liquid metering system.

[0047] After the displacement system is turned on for a period of time, it is turned off to allow for pressure suppression. After counting the pressure suppression time, the volume of crude oil produced during the injection and discharge process is obtained through the liquid metering system.

[0048] Optionally, the evaluation unit is further used for:

[0049] To obtain the distribution of saturated crude oil in the natural core column after fracturing;

[0050] The natural core column was taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the displacement process of the injected medium, and the crude oil mobilization of the natural core column with different pore sizes after the huff and puff process.

[0051] The first comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium.

[0052] A second comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different sized pores in the natural core column after the injection medium undergoes the huff and puff process.

[0053] Based on the first comparison results and the second comparison results, evaluate the effects of displacement injection and huff-and-puff injection on crude oil recovery.

[0054] Optionally, the acquisition unit is further configured to:

[0055] After the media displacement injection, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different pore sizes in the natural core column after the displacement process.

[0056] After the medium is injected, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the injection process.

[0057] The crude oil recovery efficiency of displacement injection and huff-and-puff injection is evaluated by comparing the crude oil recovery of different pore sizes in the natural core column after displacement injection and the crude oil recovery of different pore sizes in the natural core column after huff-and-puff injection.

[0058] Optionally, the fracturing unit is also used for:

[0059] The construction of the pre-built stratigraphic model includes:

[0060] The horizontal well and the natural core column are placed in a mold, wherein the horizontal well is placed in the middle of the mold, and the natural core column is arranged at equal angles around the horizontal well.

[0061] Actual rock was selected as the interlayer between the upper and middle layers and the middle and lower layers of the three-layer cast strata, and the strata were cast in layers to obtain the strata model, wherein the strata model is heterogeneous.

[0062] Optionally, the fracturing unit is also used for:

[0063] After the natural core column is cleaned and dried, it is placed in the core holder, confining pressure is applied, the core is evacuated, and simulated oil is injected to saturate it.

[0064] Optionally, the fracturing unit is also used for:

[0065] Holes are drilled at equal intervals along the axial direction of the horizontal well to simulate perforation holes for injecting the first medium or the second medium.

[0066] On the other hand, embodiments of the present invention also provide a processor for running a program, wherein the program is run to perform the evaluation method described above.

[0067] On the other hand, embodiments of the present invention also provide a computer-readable medium having computer instructions stored thereon, wherein when the computer instructions are executed by a processor, the evaluation method described above is performed.

[0068] With the above technical solution, after fracturing is completed, different media are injected into the pre-constructed formation model to obtain the volume of crude oil extracted after each injection. The effect of different media on the extracted crude oil is evaluated, and in the later stage of mining, the injection media can be further optimized based on the effect to improve crude oil production and mining efficiency.

[0069] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0070] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0071] Figure 1 This is a flowchart of an implementation method for evaluating the effect of injecting different media on crude oil recovery, provided by an embodiment of the present invention.

[0072] Figure 2 This is a schematic diagram of a fracturing simulation system provided in an embodiment of the present invention;

[0073] Figure 3 This is a schematic diagram of a pre-constructed stratigraphic model provided in an embodiment of the present invention;

[0074] Figure 4 This is a flowchart illustrating the implementation of an evaluation method for assessing the impact of different injection methods on crude oil recovery, provided in an embodiment of the present invention.

[0075] Figure 5 This is a flowchart of an implementation method for evaluating the effect of different injection methods of the medium on crude oil recovery, provided in an embodiment of the present invention.

[0076] Figure 6 This is an evaluation device provided by an embodiment of the present invention to evaluate the effect of injecting different media on crude oil recovery, and a schematic diagram of the evaluation device is shown.

[0077] Explanation of reference numerals in the attached figures

[0078] 11 horizontal wells, 12 natural core columns

[0079] 13 Speed ​​sensor 14 Pressure sensor

[0080] 15. Casting Specimen 1; 16. Casting Specimen 2; 17. Casting Specimen 3

[0081] 2. Fracturing fluid control system 21. Fracturing fluid pipeline 22. Fracturing fluid one-way flow valve

[0082] 3 Liquid metering system 31 Mixed liquid pipeline

[0083] 4 Displacement System 41 Displacement Pipeline 42 Displacement One-Way Flow Valve

[0084] 5. Confining Pressure System 5.1 Confining Pressure Piping

[0085] 6. Microcomputer control system 6.1 Signal transmission line Detailed Implementation

[0086] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0087] See Figure 1 The diagram shows an implementation flowchart of an evaluation method for assessing the impact of injecting different media on crude oil recovery, provided by an embodiment of the present invention. This evaluation method is applied to a fracturing simulation system, as illustrated in the schematic diagram of the fracturing simulation system. Figure 2 As shown, the fracturing fluid control system 2, the fluid metering system 3, and the displacement system 4 are included. The implementation flowchart of this evaluation method includes the following execution steps:

[0088] Step 100: Based on the fracturing fluid control system, the pre-constructed formation model is fracturing to create cracks in the formation model.

[0089] The pre-constructed formation model is based on the natural core column, horizontal well, and three-layer cast formation.

[0090] In some implementations, see Figure 2 As shown, the simulation system also includes a microcomputer system 23, which performs the following steps to fracturing the pre-built formation model in step 100:

[0091] The fracturing fluid control system injects fracturing fluid into the horizontal well in the pre-constructed formation model. The microcomputer system controls the discharge rate of the fracturing fluid. When the fracturing fluid overflows from the formation model, the injection of the fracturing fluid is stopped.

[0092] In some implementations, the construction of the pre-built stratigraphic model includes the following steps:

[0093] S1: Place the horizontal well and the natural core column in the mold, wherein the horizontal well is placed in the middle of the mold, and the natural core column is placed at equal angles around the horizontal well;

[0094] In some implementations, before placing the natural core column into the three-dimensional model, the natural core column is first soaked in simulated oil to saturate it with oil. Then, CT scanning technology is used to obtain the pore structure and microscopic distribution of fractures in the natural core column before fracturing. At the same time, the distribution of crude oil is determined by the T2 spectrum of nuclear magnetic resonance.

[0095] S2: Select actual rock as the interlayer between the upper and middle layers and the middle and lower layers in the three-layer casting strata, and cast it in layers to obtain the strata model, wherein the strata model is heterogeneous.

[0096] In some embodiments, before performing step S1, the natural core column is cleaned, dried, and placed in a core holder. After applying confining pressure, the core is evacuated and then injected with simulated oil to saturate it.

[0097] In some implementations, prior to step S1, equidistant drilling along the horizontal well axis is performed to simulate perforation holes for injection of the first or second medium.

[0098] In some implementations, a schematic diagram of the pre-constructed stratigraphic model is shown below. Figure 3As shown, four sections are drilled at equal intervals along the axial direction of horizontal well 11, with six holes drilled at equal angles in each section, for a total of 24 holes, to simulate perforation holes. The dimensions of horizontal well 11 are an outer radius of 53.97 mm, an inner radius of 30.34 mm, and a length of 500 mm. Horizontal well 11 and natural core column 12 are placed inside the mold (50 mm above the bottom of the mold), with the following arrangement: horizontal well 11 is placed in the center, and the natural core column 12 is divided into three pieces, placed 100 mm away from the horizontal well at equal angles around it. The dimensions of natural core column 12 are an outer radius of 100 mm, an inner radius of 30 mm, and a height of 600 mm. Actual rock is selected and cut into two pieces using a saw blade cutter to serve as interlayer 16, with dimensions of 600 mm × 600 mm × 10 mm. A model was constructed by casting a 600mm×600mm×600mm cube sample 1 in layers. The model includes a three-dimensional stratum (divided into three layers, namely 17, 18 and 19), a horizontal well 11, and a natural core column 12, all of which penetrate the three layers of the model. By configuring cement, the permeability of the three layers of the sample is made heterogeneous, so that the model simulation results are closer to the actual stratum conditions.

[0099] In some embodiments, the fracturing fluid control system 2 is connected to the fracturing fluid one-way flow valve 22 via the fracturing fluid pipeline 21 and the liquid metering system 3. The liquid metering system 3 is connected to the formation model via the mixed liquid pipeline. The displacement system 4 is connected to the microcomputer system 6 via the signal transmission line 61. The displacement system 4 is connected to the natural core column via the displacement pipeline 41 and the displacement one-way flow valve 42.

[0100] In some implementations, see Figure 2 As shown, the fracturing simulation system also includes a confining pressure system 24, which connects the cast sample 1 to the confining pressure system 5 and ensures boundary sealing. The fracturing fluid control system 2 is connected, and the fracturing source pipeline 25 is connected. The microcomputer system 6 controls the discharge rate and monitors the pressure-time curve in real time. When fracturing fluid is observed overflowing from the edge of the cast sample 1, the fracturing fluid injection is stopped through the control program.

[0101] In some implementations, after fracturing, during the depressurization and flowback stage, the pressure inside the horizontal well 11 is continuously monitored by the pressure sensor 14. The internal pressure of the horizontal well is changed by the fracturing fluid control system 2 to set different flowback rates, which are monitored by the velocity sensor 13. The functional relationship between the well pressure and the flowback rate is established, and the influence of the flowback rate on the degree of crude oil recovery is analyzed. CT scan is used to monitor the influence of the velocity change on the fracture distribution and pore characteristics throughout the flowback process. The changes in the seepage field and crude oil saturation field after fracturing are calculated by measuring the signal through nuclear magnetic resonance T2 spectrum.

[0102] Current technologies primarily employ hydraulic fracturing to expand the contact area between the wellbore and the formation, creating a fracture network that enhances conductivity and effectively increases single-well production. However, due to factors such as increased differential stress caused by hydraulic fracturing and reservoir heterogeneity defects, the reservoir rock typically experiences not only tension-shear failure of small-scale fractures but also complex mechanical behaviors involving tension, shear, slip, and faulting of large-scale structural planes like joints and faults. If natural fractures of varying densities develop within the reservoir, channeling of the injected medium can occur, causing the well to rapidly break through the injected medium within a short period, leading to a rapid decline in production.

[0103] Step 101: Inject a first medium into the natural core column of the formation model through the displacement system, and obtain the volume of crude oil extracted from the formation model after the injection of the first medium based on the liquid metering system.

[0104] Step 102: Inject the second medium into the natural core column in the formation model through the displacement system, and obtain the volume of crude oil extracted from the formation model after the injection of the second medium based on the liquid metering system;

[0105] In some implementations, the first and second media injected are not the same; the first and second media can be water and different gases, such as carbon dioxide.

[0106] Step 103: Evaluate the effectiveness of injecting the first medium and injecting the second medium to extract crude oil based on the volume of crude oil extracted after injecting the first medium and the volume of crude oil extracted after injecting the second medium.

[0107] In some implementations, in addition to evaluating the crude oil production volume in steps 100-103, the crude oil production effect can also be evaluated using the following second method: The evaluation of the crude oil production effect is based on the injection method of the injection medium, specifically including the following steps:

[0108] S200: Based on the liquid metering system, obtain the volume of crude oil extracted by the formation model when it is displaced under the displacement system, and the volume of crude oil extracted when it is churned in the displacement system.

[0109] In some implementations, when executing S200, the following steps may be performed:

[0110] While the displacement system is turned on, the fracturing fluid system is turned off, and the injection pressure is adjusted so that the pressure inside the horizontal well reaches the pressure value required for displacement. The volume of crude oil produced during displacement is obtained through the liquid metering system.

[0111] After the displacement system is turned on for a period of time, it is turned off to allow for pressure suppression. After counting the pressure suppression time, the volume of crude oil produced during the injection and discharge process is obtained through the liquid metering system.

[0112] S201: Evaluate the effectiveness of crude oil recovery from displacement injection and injection based on the volume of crude oil recovered during displacement and injection.

[0113] In some implementations, see Figure 4 As shown, the crude oil recovery effect can also be evaluated based on the injection method of the injection medium. The crude oil recovery effect can also be evaluated through the following steps:

[0114] S400: Obtain the distribution of saturated crude oil in the natural core column after fracturing.

[0115] S401: Take out the natural core column from the fracturing simulation system and perform T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the displacement process of the injected medium, and the crude oil mobilization of the natural core column with different pore sizes after the huff and puff process.

[0116] S402: A first comparative result is obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium.

[0117] S403: A second comparative result is obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different sized pores in the natural core column after the injection medium undergoes the huff and puff process.

[0118] S404: Based on the first comparison results and the second comparison results, evaluate the effects of displacement injection and huff-and-puff injection on crude oil recovery.

[0119] In some implementations, see Figure 5 As shown, the effectiveness of crude oil recovery can be evaluated based on the injection method of the injection medium. The following steps can also be used to evaluate the effectiveness of crude oil recovery:

[0120] S500: After the media displacement injection, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different sized pores in the natural core column after the displacement process.

[0121] S501: After the medium is injected, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the injection process.

[0122] Macroscopically, unconventional reservoirs, after large-scale fracturing, form complex fracture networks, transforming what were originally single-medium reservoirs into dual-medium reservoirs with both fractures and matrix, making it difficult to determine the distribution characteristics of remaining oil. Microscopically, directly observing and measuring the crude oil mobilization characteristics in different pores is also challenging. Currently, research on the distribution of remaining oil within pores mainly employs methods such as core thin-section micro-models, online CT scanning, and nuclear magnetic resonance (NMR). Core thin-section micro-models are one-dimensional simulations, making it difficult to quantitatively characterize the overall remaining oil. While online CT scanning can provide intuitive images of the remaining oil distribution, the accuracy of the scan results is highly dependent on image processing and resolution, and is significantly influenced by subjectivity, making it impossible to quantitatively analyze changes in oil phases within pore throats of different sizes. Therefore, NMR is employed to analyze the microscopic crude oil mobilization characteristics and remaining oil distribution characteristics before and after fracturing in real core samples.

[0123] S502: The crude oil recovery effect of displacement injection and huff-and-puff injection is evaluated by comparing the crude oil utilization of different pore sizes in the natural core column after displacement injection and the crude oil utilization of different pore sizes in the natural core column after huff-and-puff injection.

[0124] In some implementations, a displacement system is used to inject different media for displacement schemes. The injection pressure is continuously adjusted based on the displacement system to ensure the horizontal well pressure reaches the required displacement value. The crude oil production volume is calculated, and injection parameters are optimized. Alternatively, a huff-and-puff scheme is adopted. The displacement system is continuously adjusted based on the displacement system to ensure the horizontal well pressure reaches the required displacement value. The displacement system is then shut down, and after a period of well shut-in, it is reopened to resume production. After the huff-and-puff process ends, the produced crude oil volume is calculated again, injection parameters are optimized, the optimal well shut-in time is determined, and the operation is repeated. The number of huff-and-puff cycles is counted to optimize the huff-and-puff cycle. The produced crude oil volumes of displacement and huff-and-puff are compared, and the development effects of different injection methods with different injection media are evaluated.

[0125] The two most common injection methods for fracturing and energy replenishment are displacement and huff-and-puff. Displacement-based replenishment involves the injected medium directly penetrating the production well along fractures or high-permeability channels, resulting in lower recovery rates. Huff-and-puff, on the other hand, effectively avoids cross-flow of the injected medium through three stages: injection, well shut-in, and production. This not only extends the breakthrough time of the injected medium in the well but also effectively replenishes formation energy, offering advantages such as strong targeting, short cycle time, rapid results, and higher recovery rates.

[0126] Accordingly, the present invention also provides an evaluation device for assessing the effect of injecting different media on crude oil recovery, as shown in the schematic diagram of the evaluation device. Figure 6 As shown, it includes:

[0127] The fracturing unit 600 is used to fracture a pre-constructed formation model based on the fracturing fluid control system, so that the formation model has fractures. The pre-constructed formation model is based on the natural core column, horizontal well and three layers of cast formation.

[0128] The acquisition unit 601 is used to inject a first medium into the natural core column of the formation model through the displacement system, and to acquire the volume of crude oil extracted from the formation model after the injection of the first medium based on the liquid metering system; and to inject a second medium into the natural core column of the formation model through the displacement system, and to acquire the volume of crude oil extracted from the formation model after the injection of the second medium based on the liquid metering system.

[0129] Evaluation unit 602 is used to evaluate the effectiveness of injecting the first medium and injecting the second medium to extract crude oil based on the volume of crude oil extracted after injecting the first medium and the volume of crude oil extracted after injecting the second medium.

[0130] In some embodiments, the fracturing unit 600 is used for:

[0131] The fracturing fluid control system injects fracturing fluid into the horizontal well in the pre-constructed formation model. The microcomputer system controls the discharge rate of the fracturing fluid. When the fracturing fluid overflows from the formation model, the injection of the fracturing fluid is stopped.

[0132] In some embodiments, the evaluation unit 602 is further configured to:

[0133] The effectiveness of crude oil recovery is evaluated based on the injection method of the injection medium.

[0134] The volume of crude oil extracted by the formation model during displacement under the displacement system and the volume of crude oil extracted during huff and puff operations under the displacement system are obtained based on the liquid metering system.

[0135] The effectiveness of crude oil recovery from displacement injection and blotting injection is evaluated based on the volume of crude oil recovered during displacement and the volume of crude oil recovered during blotting.

[0136] In some embodiments, the evaluation unit 602 is used for:

[0137] While the displacement system is turned on, the fracturing fluid system is turned off, and the injection pressure is adjusted so that the pressure inside the horizontal well reaches the pressure value required for displacement. The volume of crude oil produced during displacement is obtained through the liquid metering system.

[0138] After the displacement system is turned on for a period of time, it is turned off to allow for pressure suppression. After counting the pressure suppression time, the volume of crude oil produced during the injection and discharge process is obtained through the liquid metering system.

[0139] In some embodiments, the evaluation unit 602 is further configured to:

[0140] To obtain the distribution of saturated crude oil in the natural core column after fracturing;

[0141] The natural core column was taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the displacement process of the injected medium, and the crude oil mobilization of the natural core column with different pore sizes after the huff and puff process.

[0142] The first comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium.

[0143] A second comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different sized pores in the natural core column after the injection medium undergoes the huff and puff process.

[0144] Based on the first comparison results and the second comparison results, evaluate the effects of displacement injection and huff-and-puff injection on crude oil recovery.

[0145] In some embodiments, the acquisition unit 601 is further configured to:

[0146] After the media displacement injection, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different pore sizes in the natural core column after the displacement process.

[0147] After the medium is injected, the natural core is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the injection process.

[0148] The crude oil recovery efficiency of displacement injection and huff-and-puff injection is evaluated by comparing the crude oil recovery of different pore sizes in the natural core column after displacement injection and the crude oil recovery of different pore sizes in the natural core column after huff-and-puff injection.

[0149] In some embodiments, the fracturing unit 600 is further used for:

[0150] The construction of the pre-built stratigraphic model includes:

[0151] The horizontal well and the natural core column are placed in a mold, wherein the horizontal well is placed in the middle of the mold, and the natural core column is arranged at equal angles around the horizontal well.

[0152] Actual rock was selected as the interlayer between the upper and middle layers and the middle and lower layers of the three-layer cast strata, and the strata were cast in layers to obtain the strata model, wherein the strata model is heterogeneous.

[0153] In some embodiments, the fracturing unit 600 is further used for:

[0154] After the natural core column is cleaned and dried, it is placed in the core holder, confining pressure is applied, the core is evacuated, and simulated oil is injected to saturate it.

[0155] In some embodiments, the fracturing unit 600 is further used for:

[0156] Holes are drilled at equal intervals along the axial direction of the horizontal well to simulate perforation holes for injecting the first medium or the second medium.

[0157] On the other hand, the present invention also provides a processor for running a program, wherein the program is run to perform the evaluation method described in any of the above embodiments.

[0158] On the other hand, the present invention also provides a computer-readable medium having computer instructions stored thereon, wherein when the computer instructions are executed by a processor, the evaluation method described in any of the above embodiments is performed.

[0159] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0160] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0161] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0162] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0163] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0164] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0165] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0166] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0167] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for evaluating the effect of injecting different media on crude oil recovery, applied to a fracturing simulation system, characterized in that, The fracturing simulation system includes a fracturing fluid control system, a displacement system, and a fluid metering system. The evaluation method includes: Based on the fracturing fluid control system, a pre-constructed formation model is fracturing to cause cracks to appear in the formation model. The pre-constructed formation model is based on a natural core column, a horizontal well, and three layers of cast formation. The displacement system injects a first medium into the natural core column of the formation model, and the liquid metering system obtains the volume of crude oil extracted from the formation model after the injection of the first medium. The second medium is injected into the natural core column in the formation model through the displacement system, and the volume of crude oil extracted from the formation model after the injection of the second medium is obtained based on the liquid metering system. The effectiveness of the crude oil extraction after injecting the first medium and the second medium is evaluated based on the volume of crude oil extracted after injecting the first medium and the volume of crude oil extracted after injecting the second medium. The evaluation method further includes: evaluating the crude oil recovery effect based on the injection method of the injection medium; obtaining the crude oil volume recovered by the formation model during displacement under the displacement system and the crude oil volume recovered during huff and puff injection based on the liquid metering system; and evaluating the crude oil recovery effect of displacement injection and huff and puff injection based on the crude oil volume recovered during displacement and the crude oil volume recovered during huff and puff injection. The evaluation method further includes: obtaining the distribution of saturated crude oil in the natural core column after fracturing; extracting the natural core column from the fracturing simulation system and performing T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium, and the crude oil mobilization of different pore sizes in the natural core column after the huff and puff process; obtaining a first comparison result by comparing the distribution of saturated crude oil in the natural core column after fracturing and the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium; obtaining a second comparison result by comparing the distribution of saturated crude oil in the natural core column after fracturing and the crude oil mobilization of different pore sizes in the natural core column after the huff and puff process of the injected medium; and evaluating the recovery effect of displacement injection and huff and puff injection on crude oil based on the first comparison result and the second comparison result. The construction of the pre-constructed formation model includes: placing the horizontal well and the natural core column in a mold, wherein the horizontal well is placed in the middle of the mold and the natural core column is placed at equal angles around the horizontal well; selecting actual rock as the interlayer between the upper and middle layers and the middle and lower layers of the three-layer cast formation, and casting in layers to obtain the formation model, wherein the formation model is heterogeneous, the formation model includes three-dimensional formation, horizontal well, and natural core column, all of which penetrate the three-layer model, and the permeability of the three-layer sample is made heterogeneous by configuring cement.

2. The evaluation method according to claim 1, characterized in that, The fracturing simulation system also includes a microcomputer system, and the fracturing of the pre-constructed formation model based on the fracturing fluid control system includes: The fracturing fluid control system injects fracturing fluid into the horizontal well in the pre-constructed formation model. The microcomputer system controls the discharge rate of the fracturing fluid. When the fracturing fluid overflows from the formation model, the injection of the fracturing fluid is stopped.

3. The evaluation method according to claim 1, characterized in that, The process of obtaining the volume of crude oil produced by the formation model during displacement under the displacement system and the volume of crude oil produced during huff and puff operations based on the liquid metering system includes: While activating the displacement system, the fracturing fluid control system is deactivated, and the injection pressure is adjusted so that the internal pressure of the horizontal well reaches the pressure value required for displacement. The volume of crude oil produced during displacement is obtained through the liquid metering system. After the displacement system is turned on for a period of time, it is turned off to allow for pressure stagnation. After counting the stagnation time, the volume of crude oil produced during the injection and discharge process is obtained through the liquid metering system.

4. The evaluation method according to claim 1, characterized in that, The method further includes: After the media displacement injection, the natural core column is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different pore sizes in the natural core column after the displacement process. After the medium is injected, the natural core column is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the injection process. The crude oil recovery efficiency of displacement injection and huff-and-puff injection is evaluated by comparing the crude oil recovery of different pore sizes in the natural core column after displacement injection and the crude oil recovery of different pore sizes in the natural core column after huff-and-puff injection.

5. The evaluation method according to claim 1, characterized in that, The evaluation method further includes, prior to placing the natural core column into the mold: After the natural core column is cleaned and dried, it is placed in the core holder, confining pressure is applied, the core is evacuated, and simulated oil is injected to saturate it.

6. The evaluation method according to claim 1, characterized in that, The evaluation method further includes, prior to placing the horizontal well into the mold: Holes are drilled at equal intervals along the axial direction of the horizontal well to simulate perforation holes for injecting the first medium or the second medium.

7. An evaluation device for assessing the effect of injecting different media on crude oil recovery based on the evaluation method according to any one of claims 1-6, characterized in that, include: A fracturing unit is used to fracture a pre-constructed formation model based on the fracturing fluid control system, so that the formation model has fractures, wherein the pre-constructed formation model is constructed based on the natural core column, horizontal well and three layers of cast formation; The acquisition unit is configured to inject a first medium into the formation model through the displacement system and acquire the volume of crude oil extracted from the formation model after the injection of the first medium based on the liquid metering system; and to inject a second medium into the formation model through the displacement system and acquire the volume of crude oil extracted from the formation model after the injection of the second medium based on the liquid metering system. The evaluation unit is used to evaluate the effectiveness of injecting the first medium and injecting the second medium to extract crude oil based on the volume of crude oil extracted after injecting the first medium and the volume of crude oil extracted after injecting the second medium.

8. The evaluation device according to claim 7, characterized in that, The fracturing simulation system also includes a microcomputer system, and the fracturing unit is used for: The fracturing fluid control system injects fracturing fluid into a pre-built formation model. The microcomputer system controls the flow rate of the fracturing fluid. When the fracturing fluid overflows from the formation model, the injection of the fracturing fluid is stopped.

9. The evaluation device according to claim 7, characterized in that, The evaluation unit is also used for: The effectiveness of crude oil recovery is evaluated based on the injection method of the injection medium. The volume of crude oil extracted by the formation model during displacement under the displacement system and the volume of crude oil extracted during huff and puff operations under the displacement system are obtained based on the liquid metering system. The effectiveness of crude oil recovery from displacement injection and blotting injection is evaluated based on the volume of crude oil recovered during displacement and the volume of crude oil recovered during blotting.

10. The evaluation device according to claim 9, characterized in that, The evaluation unit is used for: While activating the displacement system, the fracturing fluid control system is deactivated, and the injection pressure is adjusted so that the internal pressure of the horizontal well reaches the pressure value required for displacement. The volume of crude oil produced during displacement is obtained through the liquid metering system. After the displacement system is turned on for a period of time, it is turned off to allow for pressure stagnation. After counting the stagnation time, the volume of crude oil produced during the injection and discharge process is obtained through the liquid metering system.

11. The evaluation device according to claim 9, characterized in that, The evaluation unit is also used for: To obtain the distribution of saturated crude oil in the natural core column after fracturing; The natural core column was taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the displacement process of the injected medium, and the crude oil mobilization of the natural core column with different pore sizes after the huff and puff process. The first comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different pore sizes in the natural core column after the displacement process of the injected medium. A second comparative result was obtained by comparing the distribution of saturated crude oil in the natural core column after fracturing with the crude oil mobilization of different sized pores in the natural core column after the injection medium undergoes the huff and puff process. Based on the first comparison results and the second comparison results, evaluate the effects of displacement injection and huff-and-puff injection on crude oil recovery.

12. The evaluation device according to claim 8, characterized in that, The acquisition unit is also used for: After the media displacement injection, the natural core column is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of different pore sizes in the natural core column after the displacement process. After the medium is injected, the natural core column is taken out from the fracturing simulation system and subjected to T2 spectrum sampling and nuclear magnetic resonance to obtain the crude oil mobilization of the natural core column with different pore sizes after the injection process. The crude oil recovery efficiency of displacement injection and huff-and-puff injection is evaluated by comparing the crude oil recovery of different pore sizes in the natural core column after displacement injection and the crude oil recovery of different pore sizes in the natural core column after huff-and-puff injection.

13. The evaluation device according to claim 7, characterized in that, The fracturing unit is also used for: The construction of the pre-built stratigraphic model includes: The horizontal well and the natural core column are placed in a mold, wherein the horizontal well is placed in the middle of the mold, and the natural core column is arranged at equal angles around the horizontal well. Actual rock was selected as the interlayer between the upper and middle layers and the middle and lower layers of the three-layer cast strata, and the strata were cast in layers to obtain the strata model, wherein the strata model is heterogeneous.

14. The evaluation device according to claim 13, characterized in that, The fracturing unit is also used for: After the natural core column is cleaned and dried, it is placed in the core holder, confining pressure is applied, vacuum is drawn off the core column, and simulated oil is injected to saturate it.

15. The evaluation device according to claim 13, characterized in that, The fracturing unit is also used for: Holes are drilled at equal intervals along the axial direction of the horizontal well to simulate perforation holes for injecting the first medium or the second medium.

16. A processor, characterized in that, Used to run a program, wherein the program is run to perform the evaluation method as described in any one of claims 1-6.

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