CN104196503A - Visual water displacing oil physical model of fractured reservoir and physical simulation experiment device - Google Patents

Abstract

The present invention provides a visual water flooding physical model of a fractured oil reservoir and a physical simulation experiment device. The physical model of the visual water flooding oil of a fractured oil reservoir includes a matrix (10), and the surface of the matrix (10) is provided with three levels. The three levels of cracks are large-level cracks (11), medium-level cracks (12) and small-level cracks (13). The visual water flooding physical model and physical simulation experiment device for fractured reservoirs can be used for visual water flooding physical simulation experiments of complex fractured reservoirs, to study oil-water movement modes in fracture systems and recovery factors and water cuts at different stages, and to study The flow interference and water-flooding rules of complex structured wells in complex fractured reservoirs provide theoretical basis and technical support for waterflooding development of complex fractured reservoirs.

Description

Visual water flooding physical model and physical simulation experimental device for fractured reservoirs

technical field

The invention relates to the field of oil production engineering, in particular to a physical model of a fractured oil reservoir visualized water flooding oil, and a visual water flooding physical simulation experiment device of a fractured oil reservoir.

Background technique

Fractured reservoirs have become an important reservoir type in my country, and both reserves and production account for a certain proportion. Fractured reservoirs are more complicated to develop than non-fractured reservoirs due to their complex structure, which have strong heterogeneity and complex oil-water relationship. In order to improve the development effect, it is necessary to conduct in-depth research on the development of fractured reservoirs and optimize the scheme to increase production.

Fractures have both disadvantages and advantages for oilfield development. The favorable aspect is that it can increase the oil-extraction capacity and water absorption capacity of the oil layer; the unfavorable aspect is that the fractures provide high-permeability channels, thereby seriously reducing the sweep coefficient of injected water. In addition, some interlayer fractures develop into sensitive interlayers. The water inflow into the sensitive compartment leads to water channeling in the bypass, resulting in waste of water injection, etc. If the understanding of fractures is insufficient, the way of well arrangement does not match the distribution of fractures, which may cause violent water flooding. This is a lesson learned in the process of fractured reservoir development. Therefore, the study of the seepage law of fractured reservoirs is helpful to understand the role of fractures in development, and to use them correctly to improve the development effect and economic benefits of fractured reservoirs. Therefore, in order to develop such oilfields efficiently, it is necessary to study the seepage characteristics of such reservoirs in depth based on the characteristics of fracture development on the basis of seriously strengthening reservoir geological research.

"Special Oil and Gas Reservoirs" No. 3, 2011, pages 109 to 111 introduced a "Fractured Reservoir Large-Scale Visual Water Drive Physical Simulation Experimental Device". Two groups of large-scale visualization models in the form of In this model, the natural core plate is used to artificially extrude the fracture network, and two plexiglass plates are used to seal to form a two-dimensional fracture network physical model. In the upper part of the model, the injection-production well row is designed to simulate oil production wells and water injection wells. Water injection wells are designed at the bottom of the model to simulate bottom water; the large-scale visualization model of fracture filling uses acid etching of plexiglass plates to form fractures, and fills them with quartz sand to simulate different filling conditions in the reservoir fracture network.

Since this model uses natural core plates to artificially press out the fracture network, and uses two plexiglass plates to seal to form a two-dimensional fracture network physical model, this device has the following disadvantages:

1. The shape and size of cracks are uncontrollable;

2. There may be water channeling between the natural core plate and the plexiglass plate due to sealing problems.

Fractured oil and gas reservoirs: The oil and gas reservoirs formed by the accumulation of oil and gas in fractured traps are called fractured oil and gas reservoirs.

Water flooding: water is injected into the reservoir through the water injection well as planned, so that the crude oil in the reservoir can obtain enough energy to be extracted by the production well.

Physical simulation: A method of simulating real physical processes through laboratory physical experiments.

Water channeling: When water is easier to flow than oil between the pores and fractures in the reservoir, water forms a dominant channel, while oil does not flow or it is difficult to flow.

Contents of the invention

In order to solve the problem that the fractures of the existing physical model are quite different from those of the actual fractured reservoir. The present invention provides a visual water flooding physical model and a physical simulation experiment device for fractured oil reservoirs. The present invention summarizes different types of natural fractures according to actual natural fractured oil reservoirs, and determines the relationship between dominant fractures and other fractures. The natural fracture network is independently designed, and the fractures of the physical model of the visual water flooding of the fractured reservoir are closer to the actual reservoir fractures, and the simulation effect is closer to the real fractured oil and gas reservoir.

The technical scheme adopted by the present invention to solve the technical problem is: a visual water flooding physical model of a fractured reservoir, including a matrix, and the surface of the matrix is provided with three levels of cracks, and the three levels of cracks are respectively large-level fractures, Medium-level cracks and small-level cracks, the width of large-level cracks is greater than or equal to 1mm and less than or equal to 5mm; the width of medium-level cracks is greater than or equal to 0.3mm and less than 1mm; the width of small-level cracks is greater than or equal to 0.01mm The ratio of the number of cracks to the number of medium-grade cracks is 1:1.3-4, the ratio of the number of medium-grade cracks to the number of small-grade cracks is 1.3-4:12.6-19, and the ratio of small-grade cracks to large-grade cracks and/or Medium-level fractures are connected, and simulated horizontal wells and water injection channels are also arranged on the surface of the matrix.

Large-scale cracks run through the entire surface of the substrate.

Medium-level cracks run through the entire surface of the substrate.

The surface of the matrix is provided with at least two large-scale cracks, the large-scale cracks are in a straight line, and every two large-scale cracks intersect.

There are at least three medium-level cracks on the surface of the matrix, the medium-level cracks are straight lines, and the medium-level cracks intersect in pairs.

Each large-scale fracture intersects at least two medium-level fractures, and each large-scale fracture is at least parallel to the other two medium-level fractures.

The matrix is a rectangular transparent plexiglass plate. The three levels of cracks and the simulated horizontal wells are set on the upper surface of the matrix. The water injection channel is set on the edge of the upper surface of the matrix. The end of the horizontal well is provided with a liquid outlet conduit interface.

A physical simulation experiment device for visual water-displacement oil in fractured reservoirs, comprising the above-mentioned physical model for visual water-displacement oil in fractured reservoirs, the surface of the physical model for visual water-displacement oil in fractured reservoirs is covered with a transparent plate, the The edge of the transparent plate is sealed and connected by a metal frame. The physical simulation experiment device for visual water flooding of fractured reservoirs also includes a constant-flow pump, a vacuum pump, a bucket, an oil-water separation metering device, and a simulated oil container; the constant-flow pump passes through the pipeline It is connected with the water injection channel of the visual water flooding physical model of the fractured reservoir, the water bucket and the vacuum pump are connected with the water injection channel of the visual water flooding physical model of the fractured reservoir through the pipeline, and the oil-water separation metering device and the simulated oil container are connected with the This fractured reservoir visualizes the simulated horizontal well connectivity of a physical model of water flooding.

The oil-water separation metering device and the simulated oil container are arranged in parallel, and the visual water flooding oil physical simulation experiment device for the fractured reservoir also includes a camera device for recording the experiment process.

The invention has the beneficial effects that: the fractures of the fractured reservoir visual water flooding physical model are closer to the actual reservoir fractures, the simulation effect is closer to the real fractured oil and gas reservoirs, and are especially suitable for simulating complex fractured reservoirs. The invention can be used for physical simulation experiment of visual water flooding in complex fractured oil reservoirs, to study oil-water movement modes in fractured systems, recovery factors and water cuts at different stages, and to study confluence interference and water content of complex structured wells in complex fractured oil reservoirs. It provides theoretical basis and technical support for waterflooding development of complex fractured reservoirs.

Description of drawings

The physical model and physical simulation experiment device for visual water flooding of fractured reservoirs according to the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of a visual water flooding physical model simulating the same-side branch well in a fractured reservoir.

Fig. 2 is a schematic diagram of a fractured reservoir visualized water flooding physical model simulating a lateral branch well.

Fig. 3 is a schematic diagram of a horizontal well simulated by a visual water flooding physical model of a fractured reservoir.

Fig. 4 is a schematic diagram of a fractured horizontal well simulated by a visual water flooding physical model of a fractured reservoir.

Fig. 5 is a schematic diagram of a visual water flooding physical simulation experiment device for a fractured reservoir.

10. Matrix, 11. Large-scale fractures, 12. Medium-scale fractures, 13. Small-scale fractures, 14. Simulated horizontal well, 15. Water injection channel, 16. Liquid injection conduit interface, 17. Liquid outlet conduit interface, 18. Artificial fracturing of cracks;

21. Constant flow pump, 22. Vacuum pump, 23. Valve, 24. Pressure gauge, 25. Valve, 26. Visual water flooding physical model of fractured reservoir, 27. Camera device, 28. Valve, 29. Valve, 30 . Oil-water separation metering device, 31. Simulated oil container, 32. Valve, 33. Pressure gauge, 34. Bucket, 35. Valve.

Detailed ways

The visual water flooding physical model of the fractured reservoir according to the present invention will be further described in detail below in conjunction with the accompanying drawings.

The actual complex fractured reservoirs are complex, and the natural fracture network design needs to observe and describe the outcrop area by observing the fracture shape and distribution in the complex fractured carbonate rock outcrop area in the oilfield, and then establish a fracture network model based on this. These include the direction of the fracture, the density and width of the fracture, whether the fracture is filled or not, and the dip angle of the fracture, etc. The fracture level is the most important consideration when formulating the fracture network design, and there are three fracture levels: large, medium, and small.

Specifically, the visual water flooding physical model of the fractured reservoir includes a matrix 10, the surface of the matrix 10 is provided with three levels of fractures, and the three levels of fractures are respectively large-level fractures 11, medium-level fractures 12 and small-level fractures 13. The width of large-level cracks 11 is greater than or equal to 1mm and less than or equal to 5mm; the width of medium-level cracks 12 is greater than or equal to 0.3mm and less than 1mm; The ratio of the quantity, the number of medium-level fractures 12 and the number of small-level fractures 13 is 1:1.3-4:12.6-19. 13 communicates with large-level fractures 11, or small-level fractures 13 communicate with medium-level fractures 12, or small-level fractures 13 communicate with large-level fractures 11 and medium-level fractures 12), the surface of matrix 10 is also equipped with simulated horizontal wells 14 and water injection channel 15, as shown in Figures 1 to 4. The water injection channel 15 is set at one end of the simulated horizontal well 14, and the simulated horizontal well 14 communicates with one, two, or three of the large-scale fractures 11, medium-scale fractures 12, and small-scale fractures 13.

The fractures of three levels, the simulated horizontal well 14 and the water injection channel 15 are all set on the surface groove of the base body 10 . Large-scale cracks 11 run through the entire surface of the substrate 10 . Medium-level cracks 12 run through the entire surface of the substrate 10 . The locations of the small-scale cracks 13 are then evenly distributed.

The surface of the base body 10 is provided with at least two large-scale cracks 11 , the large-scale cracks 11 are straight lines, and every two large-scale cracks 11 intersect. The surface of the substrate 10 is provided with at least three middle-level cracks 12 , the middle-level cracks 12 are straight lines, and the middle-level cracks 12 intersect in pairs.

Each large-scale crack 11 intersects at least two medium-level cracks 12 , and each large-scale crack 11 is at least parallel to the other two medium-level cracks 12 .

In Fig. 1 and Fig. 2, the parameters of the visual water flooding physical model of the fractured reservoir are shown in Table 1.

Table 1

Substrate length (mm) width (mm) height (mm) 600 400 13.5 crack level Water injection channel(mm) Simulated horizontal well(mm) Small crack(mm) 4 1.5 0.2

In Fig. 3 and Fig. 4, the parameters of the visual water flooding physical model of the fractured reservoir are shown in Table 2.

Table 2

Substrate length (mm) width (mm) height (mm) 600 400 13.5 crack level Water injection channel (mm) Simulated horizontal well(mm) Small crack(mm) 4 2 0.2

In Fig. 4, the black dotted line is the artificial fracturing fracture 18 with a width of 1.5 mm.

In Fig. 1 to Fig. 4, the crack width of the large grade crack 11 is 1 mm; the crack width of the middle grade crack 12 is 0.5 mm; the crack width of the small grade crack 13 is 0.2 mm. Fracture density: In the models of two-branch wells, horizontal wells and fractured horizontal wells on different sides, the ratio of the number of large, medium and small fractures is 1:3:19 (as shown in Figure 2 to Figure 4); In the well model, the ratio of the number of large, medium and small fractures is 3:4:38 (as shown in Figure 1).

The present invention utilizes the laser slit technology to precisely slit the acrylic glass plate according to the design scheme, and the crack size can be as small as 0.1 mm, which can more accurately simulate cracks of various levels. The positions of large-scale fractures 11, medium-scale fractures 12, and small-scale fractures 13, simulated horizontal wells 14, and water injection channels 15 are first manually drawn on a computer in accordance with the above-mentioned standards. The artificially drawn pictures (such as JPG format) shown in 4 are input into the laser engraving machine, and the visual water flooding physical model of the fractured reservoir is engraved by the laser engraving machine.

The base body 10 is a rectangular transparent plexiglass plate, the cracks of the three levels and the simulated horizontal well 14 are arranged on the upper surface of the base body 10, the water injection channel 15 is arranged on the edge of the upper surface of the base body 10, and the two ends of the water injection channel 15 are provided with The liquid injection conduit interface 16 is provided with a liquid outlet conduit interface 17 at the end of the simulated horizontal well 14 . The liquid injection conduit interface 16 and the liquid outlet conduit interface 17 may be through holes passing through the base body 10 .

A physical simulation experiment device for visual water-displacement oil in fractured reservoirs, comprising the above-mentioned physical model 26 for visual water-displacement oil in fractured reservoirs, the surface of the physical model 26 for visual water-displacement oil in fractured reservoirs is covered with a transparent plate , the substrate 10 and the edge of the transparent plate are hermetically connected through a metal frame and a seal, and the visual water flooding physical simulation experiment device for fractured reservoirs also includes a constant flow pump 21, a vacuum pump 22, a water bucket 34, and an oil-water separation metering device 30 And simulated oil container 31; Constant flow pump 21 communicates with the water injection channel 15 of this fractured reservoir visual water flooding oil physical model 26 through pipeline, water bucket 34 and vacuum pump 22 communicate with this fractured reservoir visual water flooding physical model through pipeline The water injection channel 15 of 26 communicates, and the oil-water separation metering device 30 and the simulated oil container 31 communicate with the simulated horizontal well 14 of the visual water flooding physical model 26 of the fractured reservoir through pipelines, as shown in FIG. 5 .

Specifically, the constant flow pump 21 communicates with the liquid injection conduit interface 16 at one end of the water injection channel 15 of the physical model 26 of the fractured reservoir visualized water flooding oil through the pipeline, and the water bucket 34 and the vacuum pump 22 communicate with the visualized water of the fractured reservoir through the pipeline. The liquid injection conduit interface 16 at the other end of the water injection channel 15 of the oil displacement physical model 26 is connected, and the oil-water separation metering device 30 and the simulated oil container 31 are connected with the simulated horizontal well 14 of the fractured reservoir visual water displacement physical model 26 through pipelines. The outlet conduit interface 17 communicates. The oil-water separation metering device 30 and the simulated oil container 31 are arranged in parallel, and the physical simulation experiment device for visual water flooding of fractured reservoirs also includes a camera device 27 for recording the experiment process.

The method of using the visual water flooding physical simulation experiment device for fractured reservoirs is as follows:

Step 1. Take pictures with the camera device 7 and record the initial state of the physical simulation model 26 of the fractured reservoir.

Step 2. Before the start of the experiment, inject water into the fracture space of the fractured reservoir visualized water flooding physical model 26 with an advection pump 11, and accurately measure the total injected water volume and produced water volume. When the fractured reservoir visualized water flooding physical model After the pores in 26 are completely filled with water, the difference between the two is the hydrocarbon storage pore volume.

Step 3. Use the vacuum pump 22 to vacuum the physical model 26 of the fractured reservoir visualized water flooding. When vacuuming, first close valve 28, valve 29 and valve 32, open valve 23 and valve 25, then open vacuum pump 22 to vacuum, when the pressure gauge 24 shows that the pressure is -0.1MPa, close the vacuum pump 22, valve 23 and valve 25 .

Step 4. After vacuuming, close the valve 29, open the valve 28, and use the negative pressure obtained by vacuuming to saturate the simulated oil. This process is relatively slow. Record the simulated oil viscosity. After saturation is complete, valve 28 is closed.

Step 5. Using the camera device 27 to take photos and record the visual water flooding physical model 26 of the fractured reservoir after the simulated oil is saturated.

Step 6. Open the valves 29, 32, 35, use the constant flow pump 21 to inject pure water at a certain constant flow rate or a certain constant pressure, the viscosity is 1mPa·s, and the water is dyed red for easy observation.

Step 7. Use the camera device 27 to record the whole process of displacement and take screenshots. During this process, use a measuring cylinder to record the volume of the produced fluid and the oil-water ratio every 10 minutes. When the oil-water ratio exceeds 98%, turn off the constant flow pump 21 and end the experiment.

Step 8. Analyze the images and data obtained from the experiment, calculate the corresponding water content and recovery degree, and draw conclusions.

Step 9. Repeat experimental steps 2 to 8.

Compared with the physical parameters (such as water content) measured by the visual water flooding physical model of the fractured reservoir described in this application, the measurement results are relatively close to those of real rocks, which shows that the visualized water flooding oil of the fractured reservoir described in this application The fractures of the physical model are closer to the actual reservoir fractures, which can well simulate real fractured oil and gas reservoirs.

The above is only a specific embodiment of the present invention, and cannot limit the scope of the invention, so the replacement of its equivalent components, or the equivalent changes and modifications made according to the patent protection scope of the present invention, should still fall within the scope of this patent. category. In addition, the technical features and technical features, technical features and technical solutions, and technical solutions and technical solutions in the present invention can be used in free combination.

Claims (9)

1. the visual water drive oil physical model of fractured reservoir, it is characterized in that, the visual water drive oil physical model of described fractured reservoir comprises matrix (10), the surface of matrix (10) is provided with the crack of three ranks, the crack of three ranks is respectively large level crack (11), middle rank crack (12) and little rank crack (13), and the width of large level crack (11) is more than or equal to 1mm and is less than or equal to 5mm; The width in middle rank crack (12) is more than or equal to 0.3mm and is less than 1mm; The width in little rank crack (13) is more than or equal to 0.01mm and is less than 0.3mm, the ratio of the quantity in the quantity in large level crack (11) and middle rank crack (12) is 1:1.3～4, the ratio of the quantity in the quantity in middle rank crack (12) and little rank crack (13) is 1.3～4:12.6～19, little rank crack (13) is communicated with large level crack (11) and/or middle rank crack (12), is also provided with Simulated Water horizontal well (14) and waterflood path (15) in this surface of matrix (10).

2. the visual water drive oil physical model of fractured reservoir according to claim 1, is characterized in that: large level crack (11) run through the whole surface of matrix (10).

3. the visual water drive oil physical model of fractured reservoir according to claim 1, is characterized in that: the whole surface of matrix (10) is run through in middle rank crack (12).

4. the visual water drive oil physical model of fractured reservoir according to claim 1, it is characterized in that: the surface of matrix (10) is provided with at least 2 large level cracks (11), linearly, intersect in every 2 large level cracks (11) in large level crack (11).

5. the visual water drive oil physical model of fractured reservoir according to claim 1, it is characterized in that: the surface of matrix (10) is provided with at least 3 middle rank cracks (12), linearly, intersect between two in middle rank crack (12) in middle rank crack (12).

6. the visual water drive oil physical model of fractured reservoir according to claim 1, it is characterized in that: each large level crack (11) is at least crossing with two middle rank cracks (12), each large level crack (11) is at least parallel with rank crack (12) in two other.

7. the visual water drive oil physical model of fractured reservoir according to claim 1, it is characterized in that: matrix (10) is rectangle transparent plexiglass plate, the crack of these three ranks and Simulated Water horizontal well (14) are arranged on the upper surface of matrix (10), waterflood path (15) is located at the edge of the upper surface of matrix (10), the two ends of waterflood path (15) are equipped with injection catheter interface (16), and the end of Simulated Water horizontal well (14) is provided with fluid catheter interface (17).

8. the visual water drive oil physical simulation experiment device of fractured reservoir, it is characterized in that: the visual water drive oil physical simulation experiment device of described fractured reservoir contains the visual water drive oil physical model of the fractured reservoir described in any one claim (26) in claim 1～7, on this surface of the visual water drive oil physical model of this fractured reservoir (26), be coated with transparent panel, the edge of matrix (10) and this transparent panel is tightly connected by metal frame, the visual water drive oil physical simulation experiment device of described fractured reservoir also contains constant flow pump (21), vacuum pump (22), bucket (34), oil-water separation metering device (30) and simulated oil container (31),

Constant flow pump (21) is communicated with by the waterflood path (15) of the visual water drive oil physical model of pipeline and this fractured reservoir (26), bucket (34) and vacuum pump (22) are communicated with by the waterflood path (15) of the visual water drive oil physical model of pipeline and this fractured reservoir (26), and oil-water separation metering device (30) and simulated oil container (31) are communicated with by the Simulated Water horizontal well (14) of the visual water drive oil physical model of pipeline and this fractured reservoir (26).

9. the visual water drive oil physical simulation experiment device of fractured reservoir according to claim 8, it is characterized in that: oil-water separation metering device (30) and simulated oil container (31) are arranged in parallel, the visual water drive oil physical simulation experiment device of described fractured reservoir is also containing being useful on the camera head (27) that records experimentation.