A method and system for evaluating filling and water flooding effects of fractured oil reservoirs

Abstract

The embodiment of the present application discloses a method and system for evaluating the filling and water flooding effect of a fractured oil reservoir. The method includes: establishing a reservoir model according to the engineering parameters of the fractured oil reservoir; performing a fracture filling test on the reservoir model by adjusting the opening of the filtration control valve, and obtaining the pressure and flow of each valve of the reservoir model under the filtration rate corresponding to different filtration control valve openings during the fracture filling test, and under different fracture positions; for different filtration rates and different fracture positions, respectively, according to the pressure and flow of each valve, the matrix filtration rate and fracture filtration rate corresponding to the fractured oil reservoir are obtained to evaluate the fracture filling effect; the reservoir model after the fracture is filled is subjected to a displacement test to obtain the oil saturation to evaluate the displacement effect. The technical scheme of the present invention can realize the filling technology of the fractured oil reservoir and effectively evaluate the formation water flooding effect before and after the fracture is plugged.

Description

Technical Field

[0001] The invention relates to the technical field of oil and natural gas exploitation, and in particular to a method and system for evaluating the filling and water flooding effects of fractured oil reservoirs. Background Art

[0002] Fracture-type reservoirs are characterized by the development of internal faults, cracks and caves, and the development of reservoir pores, caves and cracks is extremely uneven. During the development of the reservoir, formation water flows along the large fracture channels, which has a strong flow shielding effect on micro-fractures and matrix. Coupled with the difference in oil-water mobility ratio, the oil well quickly enters a period of extremely high water content, resulting in a low degree of utilization of geological reserves.

[0003] Low-density particle filling technology is usually used in the existing technology to achieve the effect of controlling water and increasing oil production in oil wells. However, there is currently a lack of evaluation of filling efficiency and a lack of systematic understanding of the fracture seepage mechanism. Summary of the invention

[0004] The present invention provides a method and system for evaluating the filling and water flooding effects of fractured oil reservoirs, so as to quantitatively evaluate the water control and oil-increasing capabilities of the filling technology of fractured oil reservoirs, and effectively evaluate the water flooding effects of formations before and after fracture plugging.

[0005] According to one aspect of the present invention, a method for evaluating the filling and water flooding effect of a fractured oil reservoir is provided, the method comprising:

[0006] Establish reservoir model according to engineering parameters of fractured reservoir;

[0007] By adjusting the opening of the filtration control valve, the reservoir model is tested for fracture filling, and the pressure and flow of each valve of the reservoir model under the filtration rate corresponding to different filtration control valve openings and different fracture positions during the fracture filling test are obtained;

[0008] For different filtration rates and different fracture locations, the matrix filtration rate and fracture filtration rate corresponding to the fracture reservoir are obtained according to the pressure and flow of each valve, so as to evaluate the fracture filling effect;

[0009] A displacement test is performed on the reservoir model after fracture filling to obtain oil saturation for evaluation of displacement effect.

[0010] According to another aspect of the present invention, there is provided a system for evaluating the filling and water flooding effect of a fractured oil reservoir, comprising: an oil reservoir model, a sand-carrying injection system, an oil / water displacement power system, and a signal acquisition control system;

[0011] The reservoir model is established based on the engineering parameters of the fractured reservoir;

[0012] The sand-carrying injection system is used to inject the sand-mixing liquid into the reservoir model to perform fracture filling test on the reservoir model;

[0013] The oil / water displacement power system is used to perform displacement testing on the reservoir model after fracture filling;

[0014] The signal acquisition control system is used to obtain the pressure and flow of each valve of the reservoir model at different filtration control valve openings corresponding to the filtration rate during the fracture filling test and at different fracture positions;

[0015] The signal acquisition control system is also used to adopt any of the evaluation methods for filling and water flooding effects of fractured oil reservoirs of the present invention to obtain different filtration rates and matrix filtration rates and fracture filtration rates corresponding to different fracture positions to evaluate the fracture filling effect, and to obtain oil saturation to evaluate the displacement effect.

[0016] The technical solution of the embodiment of the present application establishes a reservoir model through the engineering parameters of the fractured reservoir; performs a fracture filling test on the reservoir model by adjusting the opening of the filtration control valve, and obtains the pressure and flow of each valve of the reservoir model under the filtration rate corresponding to different filtration control valve openings during the fracture filling test, and under different fracture positions; for different filtration rates and different fracture positions, the matrix filtration rate and fracture filtration rate corresponding to the fractured reservoir are obtained according to the pressure and flow of each valve, respectively, to evaluate the fracture filling effect; and performs a displacement test on the reservoir model after the fracture is filled to obtain the oil saturation to evaluate the displacement effect. The technical solution realizes the quantitative evaluation of the water control and oil increase capability of the filling technology of the fractured reservoir, and the effective evaluation of the formation water drive effect before and after the fracture plugging.

[0017] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a flow chart of a method for evaluating the filling and water flooding effect of a fractured oil reservoir provided in Example 1 of the present application;

[0020] Figure 2 This is a flow chart of a method for evaluating the filling and water flooding effect of a fractured oil reservoir provided in Example 2 of the present application;

[0021] Figure 3 It is a schematic diagram of a reservoir model of a method for evaluating the filling and water flooding effect of a fractured reservoir provided in Example 2 of the present application;

[0022] Figure 4 It is a schematic diagram of an equivalent calculation model of a reservoir model of a method for evaluating the filling and water flooding effect of a fractured reservoir provided in Example 2 of the present application;

[0023] Figure 5 This is a schematic diagram of oil saturation of a method for evaluating the filling and water flooding effect of a fractured oil reservoir provided in Example 2 of the present application;

[0024] Figure 6 This is another oil saturation schematic diagram of a method for evaluating the filling and water flooding effect of a fractured oil reservoir provided in Example 2 of the present application;

[0025] Figure 7 This is a schematic diagram of the structure of a system for evaluating the filling and water flooding effect of a fractured oil reservoir provided in Example 3 of the present application;

[0026] Figure 8 This is a schematic diagram of the system structure of a filling test and a water flooding test of a fractured oil reservoir provided in Example 3 of the present application;

[0027] Fig. 9 This is a schematic diagram of a sand mixing liquid filling path provided in Example 3 of the present application;

[0028] Fig.10 This is a schematic diagram of the oil and water paths for displacement testing provided in Example 3 of the present application. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", "target", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] Embodiment 1

[0032] Figure 1 A flowchart of a method for evaluating the filling and water flooding effect of a fractured oil reservoir is provided for the first embodiment of the present application. The embodiment of the present application can be applied to the evaluation of the water control and oil-increasing capability of the filling technology of a fractured oil reservoir and the water flooding effect of the formation before and after the fracture plugging. Figure 1 As shown, the method includes:

[0033] S110, establishing a reservoir model according to engineering parameters of the fractured reservoir.

[0034] The embodiment of the present application can be executed by the evaluation system of the filling and water flooding effect of the fractured oil reservoir, and can simulate the migration law of gravel filling under different fracture positions, different filtration rates and different fracture filling degrees and the seepage law of oil-water phase under different crude oil viscosities. Among them, the engineering parameters of the fractured oil reservoir can reflect information such as fracture length, fracture spacing and fracture width. The reservoir model is used to simulate the fractured oil reservoir.

[0035] Specifically, the establishment of the reservoir model requires the determination of various parameters of the reservoir model, such as fracture width, length and other parameters, which can be determined according to the engineering parameters of the fractured reservoir. For example, the ratio of the reservoir model to the actual reservoir corresponding to the engineering parameters of the fractured reservoir can be 1:1.

[0036] S120, performing a fracture filling test on the reservoir model by adjusting the opening of the filtration control valve, and obtaining the pressure and flow of each valve of the reservoir model at the filtration rate corresponding to different filtration control valve openings and different fracture positions during the fracture filling test.

[0037] Among them, the filtration control valve can play the role of controlling the filtration rate. In the embodiment of the present application, the reservoir model can be filled with sand mixing liquid to simulate the fracture filling test. During the filling test, the filtration rate can be controlled by controlling the filtration valve, and the pressure and flow of each valve of the reservoir model under different filtration rates and different fracture positions are recorded to evaluate the filling effect in subsequent steps. Furthermore, the valve position can be located near the fracture of the reservoir model and other positions. The embodiment of the present application does not limit the valve position and number.

[0038] S130, for different filtration rates and different fracture positions, the matrix filtration rate and the fracture filtration rate corresponding to the fracture type reservoir are obtained according to the pressure and flow rate of each valve, so as to evaluate the fracture filling effect.

[0039] Among them, the matrix filtration rate and the fracture filtration rate can reflect the filling effect of the reservoir model. Since there are fractures in the reservoir model, the fracture filtration rate can reflect the filtration rate near the fractures, and the matrix filtration rate can reflect the filtration rate at the matrix position.

[0040] Specifically, the pressure and flow rate of each valve can reflect the degree of filtration at each valve position during the filling process. Since each valve position is located near the fracture and other positions in the reservoir model, the fracture filtration rate and matrix filtration rate corresponding to the fracture-type reservoir can be determined respectively, thereby evaluating the fracture filling effect.

[0041] S140, performing a displacement test on the reservoir model after the fractures are filled to obtain oil saturation for evaluating the displacement effect.

[0042] Among them, displacement test refers to replacing the dyed oil in the reservoir model with water. Displacement test can simulate the replacement of oil and gas in fractured reservoirs. Oil saturation refers to the oil saturation on the surface of the reservoir model after displacement.

[0043] Specifically, the reservoir model is saturated with dyed oil, and the dyed oil is displaced by formation water to obtain a reservoir model after displacement. The oil saturation is determined based on the percentage of the area occupied by the dyed oil on the surface of the reservoir model to evaluate the displacement effect.

[0044] The technical solution of the embodiment of the present application establishes a reservoir model through the engineering parameters of the fractured reservoir; performs a fracture filling test on the reservoir model by adjusting the opening of the filtration control valve, and obtains the pressure and flow of each valve of the reservoir model under the filtration rate corresponding to different filtration control valve openings during the fracture filling test, and under different fracture positions; for different filtration rates and different fracture positions, the matrix filtration rate and fracture filtration rate corresponding to the fractured reservoir are obtained according to the pressure and flow of each valve, respectively, to evaluate the fracture filling effect; and performs a displacement test on the reservoir model after the fracture is filled to obtain the oil saturation to evaluate the displacement effect. The technical solution realizes the quantitative evaluation of the water control and oil increase capability of the filling technology of the fractured reservoir, and the effective evaluation of the formation water drive effect before and after the fracture plugging.

[0045] Embodiment 2

[0046] Figure 2 This is a flow chart of a method for evaluating the filling and water flooding effects of a fractured oil reservoir provided in Example 2 of the present application. This embodiment of the present application concretizes the evaluation of the filling and water flooding effects of a fractured oil reservoir based on the above-mentioned embodiment.

[0047] like Figure 2 As shown, the method of the embodiment of the present application specifically includes the following steps:

[0048] S210, determining key parameters of the reservoir model according to the engineering parameters of the fractured reservoir, wherein the key parameters include annulus filling velocity, sand carrying ratio, annulus spacing, natural high conductivity fracture width, ratio of oil well filling loss velocity to pump speed, and ratio of natural high conductivity fracture width to matrix pore diameter.

[0049] Among them, the annulus filling velocity can reflect the filling speed of the sand-mixing fluid. The sand-carrying ratio can reflect the sand content of the sand-mixing fluid. The annulus spacing can reflect the spacing of the pipes for filling the sand-mixing fluid. The natural high-conductivity fracture width can reflect the fracture width of the fracture-type reservoir. The ratio of the oil well filling loss velocity to the pump speed can reflect the ratio of the filling velocity to the loss velocity during the filling process. The ratio of the natural high-conductivity fracture width to the matrix pore diameter can determine the corresponding parameters of the reservoir model.

[0050] The embodiment of the present application adopts an equivalent substitution method to simulate the reservoir model according to the engineering parameters of the horizontal development wells in the reef limestone fractured reservoir, and its key parameters are in a 1:1 ratio with the corresponding parts of the reservoir model.

[0051] S220, determining the fracture width of the reservoir model according to the natural high conductivity fracture width.

[0052] Illustratively, the reservoir model has a fracture width to particle stacking pore throat ratio approximately equal to a natural high conductivity fracture width to matrix pore diameter ratio.

[0053] Exemplarily, reservoir model size parameters may be set as shown in Table 1.

[0054] Table 1

[0055] Crack cross-sectional area Crack length Crack spacing Main channel cross-sectional area <![CDATA[4.5cm 2 ]]> 50cm 20cm <![CDATA[6cm 2 ]]>

[0056] S230, determining the filling particle size according to the fracture width of the reservoir model and the ratio of the natural high-conductivity fracture width to the matrix pore diameter.

[0057] For example, fractures of the reservoir model with partitions of equal width are selected according to the width of natural high-conductivity fractures, and the mesh size of the oleophilic inert particles is selected based on the 1:1 relationship between the width of natural high-conductivity fractures and the matrix pore diameter.

[0058] S240, by adjusting the opening of the filtration control valve, a fracture filling test is performed on the reservoir model, and the pressure and flow of each valve of the reservoir model at the filtration rate corresponding to different filtration control valve openings and different fracture positions during the fracture filling test are obtained.

[0059] In the embodiment of the present application, it is optional that before the filling test, it is necessary to test the comprehensive flow capacity of the formation, which can be specifically: inject clean water into the formation direction at different displacements, record the pump pressure and displacement data, and calculate the comprehensive seepage coefficient J of the formation. Among them, the displacement range can be 600ml~1500ml. Before the filling test, it is also necessary to test the formation leakage rate, which can be specifically: fully open the liquid outlet pipeline, fully open the formation filtration loss end outlet, and displace at the circulating displacement during construction, that is, the linear velocity, and measure the filtration loss volume of the matrix and cracks in the formation during the displacement time, and then calculate the leakage rate of the matrix and the cracks. The distribution of each pressure flow port is as follows: Figure 3 As shown, the pressure and flow data of ports 0 to 8 and 9 are recorded during the test. Furthermore, by adjusting the opening of the formation end filtration valve, the formation filtration rate under different displacements is tested. The displacement values ​​can be: 60ml / min, 80ml / min, 100ml / min, 120ml / min and 150ml / min. This scheme verifies the instruments and other equipment used in the filling test and various data, ensuring the accuracy of the filling test results.

[0060] In the embodiment of the present application, optionally, obtaining the pressure and flow of each valve of the reservoir model at the filtration rate corresponding to different filtration control valve openings during the fracture filling test and at different fracture positions includes steps A1-A3:

[0061] Step A1, obtaining a pressure measurement value and a flow measurement value of at least one valve for the filtration rate corresponding to different filtration control valve openings and different crack positions during the crack filling test.

[0062] Step A2, calculating the longitudinal integrated permeability and the transverse integrated permeability corresponding to the at least one valve according to the pressure measurement value and the flow measurement value of the at least one valve.

[0063] Step A3, according to the pressure measurement value, flow measurement value, longitudinal comprehensive permeability and transverse comprehensive permeability corresponding to the at least one valve, calculate the pressure value and flow value corresponding to other valves.

[0064] The pressure measurement value can be obtained by a pressure sensor, and the flow measurement value can be obtained by a flow meter. The longitudinal comprehensive permeability can be the comprehensive permeability perpendicular to the stratum bedding direction. The lateral comprehensive permeability refers to the comprehensive permeability along the stratum bedding direction. For example, Figure 3 As shown, each serial number is a valve number, valve 8 corresponds to the sand-carrying liquid injection position, valve 16 corresponds to the sand-carrying liquid return position, and each valve is provided with a flow meter and a pressure sensor. Figure 4 The equivalent calculation model diagram of the reservoir model, where the numbers are the same as Figure 3 The labels of the corresponding ones are mutually corresponding. The newly added labels can be understood as virtual valve ports, for example Figure 4 The position of the number 11 can be understood as Figure 3 The value of the virtual valve set between valve No. 10 and valve No. 12 can be obtained by calculation.

[0065] Exemplarily, the sand ratio of the sand mixing liquid is 5%, the opening of the filtration valve is adjusted to a preset position, and a wellbore-formation gap filling and displacement experiment is carried out according to the experimental design parameters in Tables 2 and 3. The pressure and flow data corresponding to each valve are recorded in Table 4, wherein Q represents flow, P represents pressure, Q1 corresponds to flow at valve 1, and P1 corresponds to pressure at valve 1.

[0066] Table 2 Wellbore filling data record table

[0067]

[0068] Table 3 Fracture filling data record table

[0069]

[0070] Table 4 Pressure and flow records at each valve

[0071]

[0072]

[0073] Further, P9=(P8+P10) / 2, P11=(P10+P12) / 2, P13=(P12+P14) / 2, P15=(P14+P16) / 2.

[0074] The pressure and flow rate of the reservoir model have the following relationship: the flow rate of each valve under different pressure conditions is fitted to obtain the simplified pressure-flow equation of valves 1 to 7: Pn = f (Qn, μ). In order to simplify the calculation, a linear equation can be used for fitting, taking Pn = μ × J × Qn. Among them, n is the valve number, μ is the viscosity of the liquid passing through the valve, Qn is the flow rate passing through the valve, and J is the comprehensive permeability coefficient of the formation.

[0075] Longitudinal comprehensive permeability Ks:

[0076] Ks1=Q1×μ×L1 / A1×(P9-P1);

[0077] Ks2=Q2×μ×L2 / A2×(P10-P2);

[0078] Ks3=Q3×μ×L3 / A3×(P11-P3);

[0079] Ks4=Q4×μ×L4 / A4×(P12-P4);

[0080] Ks5=Q5×μ×L5 / A5×(P13-P5);

[0081] Ks6=Q6×μ×L6 / A6×(P14-P6);

[0082] Ks7=Q7×μ×L7 / A7×(P15-P7).

[0083] Where L is the fracture spacing of the formation and A is the area of ​​the formation.

[0084] Transverse comprehensive permeability Kh:

[0085] Kh1=Q9×μ×L9 / A9×(P8-P9),

[0086] Where Q9=Q1+Q2+Q3+Q4+Q5+Q6+Q7+Q16;

[0087] Kh2=Q10×μ×L10 / A10×(P9-P10),

[0088] Where Q10 = Q2 + Q3 + Q4 + Q5 + Q6 + Q7 + Q16;

[0089] Kh3=Q11×μ×L11 / A11×(P10-P11),

[0090] Where Q11=Q3+Q4+Q5+Q6+Q7+Q16;

[0091] Kh4 = Q12 × μ × L12 / A12 × (P11-P12), where Q12 = Q4 + Q5 + Q6 + Q7 + Q16;

[0092] Kh5 = Q13 × μ × L13 / A13 × (P12-P13), where Q13 = Q5 + Q6 + Q7 + Q16;

[0093] Kh6 = Q14 × μ × L14 / A14 × (P13-P14), where Q14 = Q6 + Q7 + Q16;

[0094] Kh7 = Q15 × μ × L15 / A15 × (P14-P15), where Q15 = Q7 + Q16;

[0095] Kh8 = Q16 × μ × L16 / A16 × (P15-P16), where Q16 = Q16.

[0096] S250, according to the fracture spacing and fracture area of ​​the fracture type reservoir, and the fracture spacing and fracture area of ​​the reservoir model, converting the pressure and flow of each valve into the pressure and flow corresponding to each layer section of the fracture type reservoir.

[0097] According to the fracture spacing L and area A of the real formation, the pressure and flow distribution of each layer can be obtained by solving the above equations. The solution method is as follows:

[0098] The pressure and flow of the valve at the end of the model have the following relationship:

[0099] Kh16=Q16×μ×L16-2 / A16-2×(P15-P8);

[0100] Ks7=Q7×μ×L7-2 / A7-2×(P15-P7);

[0101] Q15 = Q7 + Q16;

[0102] P7 = f(Q7, μ); let Q16 = C, C is a constant; P16 = 0;

[0103] We can solve: Q7, Q15 and P15; similarly, we can solve Q0~Q7, Q9~Q15 and p0~p15.

[0104] The above equations are iteratively solved using software such as execl and Matlble until the model inlet pressure P8 or Q8 is equal to the actual value, and the pressure flow distribution under this condition is obtained. The matrix and fracture leakage flow are calculated separately. The matrix leakage flow Qmatrix = Q1+Q3+Q5+Q7; the fracture leakage flow Qfracture = Q2+Q4+Q6.

[0105] S260, according to the pressure and flow rate corresponding to each layer section of the fractured oil reservoir, the matrix filtration rate and the fracture filtration rate are calculated.

[0106] Record the valve pressure and comprehensive permeability in Table 5.

[0107] Table 5 Calculation results of pressure and comprehensive permeability

[0108]

[0109] The above calculation results are brought into each valve, and Excel is used for iterative solution to obtain the pressure and flow of each node under the current working conditions. According to the size of the actual well depth, the length and area of ​​the wellbore, the length and cross-sectional area of ​​the fracture, the inlet pressure or flow in the model are changed, and the above equations are re-solved to obtain the pressure and flow of each position at the actual well depth under the predicted working conditions. For example, the node gap is enlarged by 10 times, the cross-sectional area of ​​the central pipe unit is enlarged by 5 times, and the injection volume is set to 0.188L / min. The pressure and flow distribution of each node and unit at this time can be obtained by solving again. The obtained results are statistically calculated to obtain the filtration rate of the matrix and fracture at this time, as shown in Table 6.

[0110] Table 6

[0111]

[0112] S270, conduct displacement test on the reservoir model after fracture filling.

[0113] S280: If it is determined that the water content of the sand-carrying injection port of the reservoir model meets the preset requirement, the reservoir model is photographed to obtain an image of the reservoir model.

[0114] The sand-carrying injection port can inject sand-mixing liquid into the reservoir model. The preset requirements can be determined according to actual conditions. The embodiment of the present application is only an example and does not limit the specific requirements.

[0115] For example, the reservoir model after crack filling is saturated with dyed oil, the sand-carrying injection port of the reservoir model is closed, the sand-carrying outflow port is opened, the displacement pump is connected to the filtration control valve, the formation water is displaced and injected, and continuous sampling is performed at intervals of 1 minute during the period from 0% to 100% of the water content. When the water content of the output fluid is 100%, the displacement pump is closed. The reservoir model is photographed, and the photo is converted into a grayscale image by a computer, gray is oil, white is water, the grayscale of the reservoir model image is identified, and the corresponding area is counted.

[0116] S290, determining the oil saturation according to the grayscale of the reservoir model image to evaluate the displacement effect.

[0117] The oil saturation is calculated based on the grayscale area of ​​the reservoir model image to evaluate the displacement effect. Figure 5 Schematic diagram of oil saturation of the reservoir model before the displacement test. The oil saturation before the displacement test was 78.17%. Figure 6 Schematic diagram of oil saturation of the reservoir model after the displacement is completed. The oil saturation after the displacement test is 61.39%.

[0118] In the embodiment of the present invention, the effect of the displacement test is evaluated according to the oil saturation before and after the displacement test. The embodiment does not limit the specific evaluation method.

[0119] Embodiment 3

[0120] Figure 7 This is a schematic diagram of a system for evaluating the filling and water flooding effect of a fractured oil reservoir provided in Example 3 of the present application. The system can execute the evaluation method for the filling and water flooding effect of a fractured oil reservoir provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method. Fig.10 As shown, the system includes: a reservoir model 310 , a sand-carrying injection system 320 , an oil / water displacement power system 330 , and a signal acquisition control system 340 .

[0121] The reservoir model 310 is established based on engineering parameters of fractured reservoirs.

[0122] The sand-carrying injection system 320 is used to inject the sand-mixing liquid into the reservoir model to perform a fracture filling test on the reservoir model.

[0123] The oil / water displacement power system 330 is used to perform displacement testing on the reservoir model after fracture filling.

[0124] The signal acquisition control system 340 is used to obtain the pressure and flow of each valve of the reservoir model at different filtration control valve openings corresponding to the filtration rate during the fracture filling test and at different fracture positions.

[0125] The signal acquisition control system 340 is also used to adopt the evaluation method of filling and water flooding effects of fractured oil reservoirs described in the embodiment of the present application to obtain different filtration rates and matrix filtration rates and fracture filtration rates corresponding to different fracture positions to evaluate the fracture filling effect, and to obtain oil saturation to evaluate the displacement effect.

[0126] In the embodiment of the present application, optionally, the reservoir model 310 includes a model body, an upper cover plate, a sand injection port, a filtration control valve and a pressure sensor; the filtration control valve includes a matrix filtration control valve and a fracture filtration control valve; the pressure sensor is connected to the filtration control valve.

[0127] The model body has a flow gap at the bottom for simulating an open hole annulus filling channel. The model body contains artificial fractures. The fracture width of the artificial fractures is determined by the width of natural high conductivity fractures. The width of the natural high conductivity fractures is determined by the engineering parameters of the fracture-type oil reservoir. Exemplarily, the model body is a stainless steel rectangular experimental model.

[0128] The upper cover plate is made of a visible material, such as high-pressure resistant glass. The sand-carrying injection port is used to allow the sand-carrying injection system to inject sand-mixing liquid into the model body. The filtration control valve is used to adjust the filtration rate by adjusting the opening. The pressure sensor is used to measure the pressure of the filtration control valve. Obviously, the reservoir model 310 also includes components such as a glass clamping flange, a visual glass, a high-pressure ball valve, and a tee.

[0129] In the embodiment of the present application, the evaluation system for filling and water flooding effect of the fractured reservoir may also include various pipelines and instruments. Among them, various pipelines are used to connect the reservoir model 310, the sand injection system 320, the oil / water displacement power system 330, and the signal acquisition control system 340, etc.; further, the various pipelines are stainless steel pipes, which are used for system connection and flow diversion of the test fluid, and the test fluid is oil, water or oil-water mixture. The instrument includes a flow meter and a volumetric grating; further, the instrument is an electromagnetic flow meter, a vortex liquid flow meter, a volumetric grating, etc.

[0130] In the embodiment of the present application, optionally, the sand-carrying injection system 320 includes a sand-beating screw pump and a stirring container; the stirring container is used to stir the added filling particles to obtain a sand-mixed liquid; the sand-beating screw pump is used to inject the sand-mixed liquid into the reservoir model.

[0131] For example, the rated flow rate of the sand blasting screw pump is 0.2-3L / min, the rated pressure is 1.5MPa, the sand carrying ratio is 0-8%, and the sand blasting screw pump is a variable speed pump with the effect of continuous delivery and stable pressure. The stirring container is made of stainless steel, with a volume of 100L, and has a stirring motor and a stirring impeller, and the stirring impeller speed is 50-200 rpm. There are sand adding ports and liquid adding ports on the top of the stirring container. The sand blasting screw pump and the stirring container are placed on the same base, with casters at the bottom for easy movement.

[0132] In the embodiment of the present application, optionally, the oil / water displacement power system 330 includes a plunger pump and a water storage container; the plunger pump is connected to the filtration control valve.

[0133] Wherein, the water storage container is used to provide displacement fluid to the plunger pump; and the plunger pump is used to pump the displacement fluid into the reservoir model.

[0134] Exemplarily, the plunger pump has a rated pressure of 10 MPa, a rated flow rate of 0 to 250 ml / min, and is equipped with a servo control system. The water storage container provides displacement fluid for the plunger pump. The oil / water displacement power system 330 also includes a piston container with a volume of 2000 ml and a pressure of 10 MPa. The volume metering grating is used to measure the liquid level height of the liquid storage tank. The oil / water displacement power system 330 has a system base with casters at the bottom for easy movement.

[0135] In the embodiment of the present application, optionally, the evaluation system for filling and water flooding effects of the fractured oil reservoir further includes a photographing device.

[0136] The photographing device is used to photograph the upper cover plate of the reservoir model to obtain a reservoir model image during the displacement test of the reservoir model after the fracture is filled by the oil / water displacement power system, and send the reservoir model image to the signal acquisition control system 340.

[0137] The signal acquisition control system 340 is also used to determine the oil saturation according to the grayscale of the reservoir model image. The signal acquisition control system 340 is integrated with the equipment start and stop, the pressure and flow data acquisition and recording interval is <1 time / second, the experimental data is recorded and stored in real time for scientific research, and the camera device collects the reservoir model image in real time.

[0138] In a specific example, Figure 8 The schematic diagram of the system structure of the filling test and water flooding test of the fractured oil reservoir is as follows: the mixing container stirs the filling particles to form a sand-mixing liquid, and the sand-making screw pump injects the sand-mixing liquid into the reservoir model for the filling test. Fig. 9 This is a schematic diagram of the sand mixing liquid filling path. During the filling test, the flow path of the sand mixing liquid is as follows: Fig. 9As shown by the arrow in the figure, the plunger pump injects water from the water storage container into the reservoir model to conduct a displacement test. Fig.10 The schematic diagram of oil and water displacement path is shown in Figure 2. Fig.10 As indicated by the arrow in .

[0139] A system for evaluating the filling and water flooding effects of a fractured oil reservoir provided in an embodiment of the present application can execute a method for evaluating the filling and water flooding effects of a fractured oil reservoir provided in any embodiment of the present application, and has functional modules and beneficial effects corresponding to the execution method.

[0140] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for evaluating the filling and water flooding effect of a fractured oil reservoir, characterized in that: include: Establish reservoir model according to engineering parameters of fractured reservoir; By adjusting the opening of the filtration control valve, the reservoir model is tested for fracture filling, and the pressure and flow of each valve of the reservoir model under the filtration rate corresponding to different filtration control valve openings and different fracture positions during the fracture filling test are obtained; For different filtration rates and different fracture locations, the matrix filtration rate and fracture filtration rate corresponding to the fracture reservoir are obtained according to the pressure and flow of each valve, so as to evaluate the fracture filling effect; A displacement test is performed on the reservoir model after fracture filling to obtain oil saturation for evaluation of displacement effect.

2. The method according to claim 1, characterized in that: According to the engineering parameters of fractured reservoirs, a reservoir model is established, including: Determine the key parameters of the reservoir model based on the engineering parameters of the fractured reservoir; The key parameters include annular filling velocity, sand carrying ratio, annular space distance, natural high conductivity fracture width, ratio of oil well filling loss velocity to pumping speed, and ratio of natural high conductivity fracture width to matrix pore diameter; Determine the fracture width of the reservoir model based on the natural high-conductivity fracture width; The filling particle size is determined based on the fracture width of the reservoir model and the ratio of the natural high-conductivity fracture width to the matrix pore diameter.

3. The method according to claim 1, characterized in that Obtain the pressure and flow of each valve in the reservoir model at different filtration control valve openings corresponding to the filtration rate during the fracture filling test, as well as at different fracture locations, including: For the filtration rate corresponding to different filtration control valve openings and different crack positions during the fracture filling test, respectively obtain a pressure measurement value and a flow measurement value of at least one valve; Calculating a longitudinal integrated permeability and a transverse integrated permeability corresponding to the at least one valve according to a pressure measurement value and a flow measurement value of the at least one valve; According to the pressure measurement value, flow measurement value, longitudinal comprehensive permeability and transverse comprehensive permeability corresponding to the at least one valve, the pressure values ​​and flow values ​​corresponding to other valves are calculated.

4. The method according to claim 3, characterized in that: According to the pressure and flow rate of each valve, the matrix loss rate and fracture loss rate corresponding to the fractured reservoir are obtained, including: According to the fracture spacing and fracture area of ​​the fractured reservoir and the fracture spacing and fracture area of ​​the reservoir model, the pressure and flow of each valve are converted into the pressure and flow corresponding to each layer section of the fractured reservoir; According to the pressure and flow rate corresponding to each layer of the fractured reservoir, the matrix loss rate and fracture loss rate are calculated.

5. The method according to claim 1, characterized in that After the fractures are filled, displacement tests are performed on the reservoir model to obtain the oil saturation, including: Carry out displacement test on the reservoir model after fracture filling; If it is determined that the water content of the sand-carrying injection port of the reservoir model meets the preset requirements, the reservoir model is photographed to obtain an image of the reservoir model; The oil saturation is determined based on the grayscale of the reservoir model image.

6. An evaluation system for filling and water flooding effects of fractured oil reservoirs, including an oil reservoir model, a sand-carrying injection system, an oil / water displacement power system, and a signal acquisition control system; The reservoir model is established based on the engineering parameters of the fractured reservoir; The sand-carrying injection system is used to inject the sand-mixing liquid into the reservoir model to perform fracture filling test on the reservoir model; The oil / water displacement power system is used to perform displacement testing on the reservoir model after fracture filling; The signal acquisition control system is used to obtain the pressure and flow of each valve of the reservoir model at different filtration control valve openings corresponding to the filtration rate during the fracture filling test and at different fracture positions; The signal acquisition control system is also used to adopt the evaluation method of filling and water flooding effect of fractured oil reservoirs as described in any one of claims 1 to 5 to obtain different filtration rates and matrix filtration rates and fracture filtration rates corresponding to different fracture positions to evaluate the fracture filling effect, and to obtain oil saturation to evaluate the displacement effect.

7. The system according to claim 6, characterized in that The reservoir model includes a model body, an upper cover plate, a sand-carrying injection port, a filtration control valve and a pressure sensor; the filtration control valve includes a matrix filtration control valve and a fracture filtration control valve; the pressure sensor is connected to the filtration control valve; The bottom of the model body has a flow gap for simulating a naked hole annulus filling channel; The model body includes artificial fractures, the fracture width of the artificial fractures is determined by the width of natural high-conductivity fractures, and the width of the natural high-conductivity fractures is determined by the engineering parameters of the fracture-type oil reservoir; The upper cover plate is made of visible material; The sand-carrying injection port is used to enable the sand-carrying injection system to inject sand-mixing liquid into the model body; The filtration control valve is used to adjust the filtration rate by adjusting the opening; The pressure sensor is used to measure the pressure of the filtration control valve.

8. The system according to claim 7, characterized in that The sand-carrying injection system comprises a sand-blasting screw pump and a stirring container; The stirring container is used to stir the added filling particles to obtain a sand mixing liquid; The sand-beating screw pump is used to inject sand-mixing fluid into the reservoir model.

9. The system according to claim 7, characterized in that The oil / water displacement power system includes a plunger pump and a water storage container; the plunger pump is connected to the filtration control valve; The water storage container is used to provide displacement fluid to the plunger pump; The plunger pump is used to pump the displacement fluid into the reservoir model.

10. The system according to claim 9, characterized in that The evaluation system for filling and water flooding effects of fractured oil reservoirs also includes a photographing device; The photographing device is used to photograph the upper cover plate of the reservoir model to obtain an image of the reservoir model during the process of the oil / water displacement power system performing displacement testing on the reservoir model after the fractures are filled, and send the image of the reservoir model to the signal acquisition control system; The signal acquisition control system is also used to determine the oil saturation according to the grayscale of the reservoir model image.

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