A device and method for simulating the dominant migration direction around an oil-generating depression

Abstract

The present invention relates to a device and method for simulating the dominant migration direction of the periphery of an oil-generating depression. The device comprises an injection structure connected to each other and a two-dimensional seepage model for simulating hydrocarbon expulsion from the depression. The two-dimensional seepage model comprises an upper glass plate and a lower glass plate. The upper glass plate and the lower glass plate are separated by hard sponge strips on all sides. The gap is divided into four regions, namely, a source rock high permeability zone, a source rock hydrocarbon expulsion zone, a conducting layer and a mudstone zone, by using a rubber strip. In the cross-sectional view of the conducting layer, both ends of the conducting layer extend obliquely upward to the left and right sides and reach the edge of the two-dimensional seepage model respectively. The source rock high permeability zone is located in the middle part below the conducting layer, the source rock hydrocarbon expulsion zone is located between the conducting layer and the source rock high permeability zone, and a horizontal flow pump is connected to the source rock high permeability zone through an injection pipeline. The device can simulate the dominant migration direction of the periphery of an oil-generating depression under the influence of multiple factors, including the physical properties of the conducting layer, the morphology of the conducting layer, the contact area between the conducting layer and the source rock hydrocarbon expulsion zone, and the hydrocarbon generation intensity.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration tests, and in particular to a device and a method for simulating the dominant migration direction around an oil-generating depression. Background Art

[0002] Around the oil-generating depression, the physical properties and morphology of the oil and gas transport layers will change with different locations. Determining the dominant channels for oil and gas migration around the oil-generating depression is crucial to guiding oil and gas exploration. Factors such as the dip angle, physical properties of the transport layers, their contact area with the source rock, and the hydrocarbon expulsion intensity of the source rock will affect the dominant migration direction of oil and gas around the oil-generating depression. It is necessary to carry out systematic physical simulation experiments to determine the dominant migration direction of oil and gas around the oil-generating depression under the influence of multiple factors. "Study on the Types of Preferential Oil and Gas Migration Channels and Their Physical Simulation Experiments" studied the effects of five factors on the dominant channels, namely, the differences in the physical properties of the transport layers, the offset of the center of caprock settlement, fluid dynamics, the dip angle of the fault, and the geometric morphology of the fault surface, through two-dimensional physical simulation experiments. The currently available literature has failed to effectively simulate the hydrocarbon expulsion signs of the source rock when studying the dominant migration direction, so it is difficult to simulate the dominant migration direction of oil and gas around the oil-generating depression. Summary of the invention

[0003] In view of the above problems existing in the prior art, the first technical problem to be solved by the present invention is that currently there is no experimental device that can simulate the dominant migration direction of oil and gas around an oil-generating depression.

[0004] The second technical problem to be solved is that existing technologies have failed to effectively simulate the hydrocarbon expulsion signs of source rocks, making it difficult to simulate the dominant migration direction of oil and gas around oil-generating depressions.

[0005] In order to solve the above-mentioned first technical problem, the present invention adopts the following technical solution: a device for simulating the dominant migration direction around an oil-generating depression, comprising an injection structure connected to each other and a two-dimensional seepage model for simulating the hydrocarbon expulsion from the depression, wherein the two-dimensional seepage model comprises an upper glass plate and a lower glass plate of the same shape and size, wherein the upper glass plate and the lower glass plate are separated by hard sponge strips on all sides, and the glass plate and the hard sponge strips on all sides are detachably connected; the upper glass plate, the lower glass plate and the hard sponge strips on all sides of the upper glass plate and the lower glass plate form a The gap is divided into four areas, namely, a source rock high permeability zone, a source rock hydrocarbon expulsion zone, a conducting layer and a mudstone zone, by a rubber strip, wherein both ends of the conducting layer in the cross-sectional view of the conducting layer extend obliquely upward to the left and right sides and reach the edge of the two-dimensional seepage model respectively; the cross section is parallel to the upper glass plate or the lower glass plate; the source rock high permeability zone is located in the middle part below the conducting layer, and the source rock high permeability zone and the conducting layer have the same bending angle toward the bottom edge of the two-dimensional seepage model, and the source rock hydrocarbon expulsion zone is located between the conducting layer and the source rock high permeability zone; the injection structure includes a horizontal flow pump, which is connected to the source rock high permeability zone through an injection pipeline.

[0006] Preferably, the length of the high permeability zone of the source rock extending to one end of the transport layer is longer than the length extending to the other end of the transport layer. In the two-dimensional seepage model, the transport channel simulates the steep slope and gentle slope in actual geology, and the length of the high permeability zone extending in different directions to the transport layer is used to simulate the contact area between the source rock and the transport channel. This method of arranging the two-dimensional seepage model can simulate the contact area between the source rock and the transport channel for the dominant migration direction of oil and gas.

[0007] Preferably, the dip angle of the gentle slope belt on the left side of the transport layer is 15°, and the dip angle of the steep slope belt on the right side of the transport layer is 40°. In actual geological bodies, slopes with a dip angle greater than 30° are generally called gentle slope belts, and slopes with a dip angle less than 30° are called gentle slope belts. In the layout of this two-dimensional permeability model, setting different gentle slope and steep slope angles can be used to simulate the influence of slope angles on the dominant migration direction of oil and gas.

[0008] Preferably, the contact area ratio between the gentle slope zone on the left side and the steep slope zone on the right side of the transport layer and the hydrocarbon expulsion zone of the source rock is 3:1. The contact area ratio between the gentle slope zone and the steep slope zone and the source rock is 3:1. This model arrangement can be used to experiment the influence on the dominant migration direction of oil and gas when the contact area between the gentle slope and the source rock is greater than the contact area between the steep slope and the source rock.

[0009] Preferably, the high permeability zone of the source rock has an oil injection channel extending to the left or right edge of the two-dimensional seepage model. Since the source rock of this model is mainly arranged in the middle part of the model, one end of the high permeability zone of the source rock is extended to the edge of the model for the convenience of crude oil injection. Since the extended area of ​​the high permeability zone of the source rock and the main area of ​​the high permeability zone of the source rock are filled with glass beads of the same particles and have the same permeability, there is no effect on the actual test process.

[0010] Preferably, it also includes an auxiliary structure; the auxiliary structure includes a transparent water tank, and the two-dimensional seepage model is arranged in the transparent water tank. The auxiliary structure also includes a camera with a lens facing the upper glass plate of the two-dimensional seepage model. The auxiliary structure also includes a uniform surface light source located outside the transparent water tank and parallel to the lower glass plate. The camera with a lens facing the two-dimensional seepage model is used to take pictures and record the experimental process during the experiment. At the same time, the uniform surface light source located behind the water tank can make the model part in the experimental environment the brightest, and the camera used to take pictures and record the experimental process can take clear and bright pictures.

[0011] To solve the second technical problem, the present invention adopts the following technical solution: An experimental method for simulating the dominant migration direction around an oil-generating depression. The device for simulating the dominant migration direction around an oil-generating depression comprises the following steps:

[0012] S1: Make a two-dimensional seepage model: lay the lower glass plate flat, and fix hard sponge strips around the upper surface of the lower glass plate; use the strips to separate the high permeability zone of the source rock, the hydrocarbon expulsion zone of the source rock, the transport layer and the mudstone zone;

[0013] Fill the high permeability zone of the source rock, the hydrocarbon expulsion zone of the source rock, the transporting layer and the mudstone zone with the finest particles simulating mudstone, remove the surplus fine particles after leveling and compacting, and make the upper surface of the fine particle accumulation body flush with the surrounding hard sponge strips;

[0014] Remove the finest particles in the high permeability zone of the source rock, the hydrocarbon expulsion zone of the source rock, and the conductive layer, and fill the high permeability zone of the source rock and the conductive layer with coarse particles, and fill the hydrocarbon expulsion zone of the source rock with medium particles, smooth and compact them;

[0015] Remove the rubber strip used to separate the area, and use the smaller particles on both sides of the rubber strip to fill the gap left by the rubber strip;

[0016] Align the cover glass plate, fix the upper and lower glass plates, and make sure that the upper and lower glass plates are in close contact with each other using hard sponge strips all around.

[0017] S2: Put the two-dimensional seepage model in S1 into a transparent water tank, and evacuate the two-dimensional seepage model in the water tank filled with water. After the evacuation is completed, the two-dimensional seepage model is submerged under the water surface.

[0018] S3: Connect the end of the injection pipeline to an injection needle, and the injection needle pierces the hard sponge strip and mudstone area to enter the injection point on the oil injection channel of the high permeability zone of the source rock.

[0019] S4: placing the two-dimensional seepage model horizontally in the water body and then translating it into the transparent water tank, and placing the two-dimensional seepage model vertically or obliquely in the water body of the transparent water tank and fixing it.

[0020] S5: Turn on the uniform surface light source, and use a horizontal flow pump to inject oil and gas into a two-dimensional seepage model that simulates hydrocarbon expulsion from an oil-generating depression to simulate hydrocarbon generation in the source rock. The oil and gas first fill the high permeability zone of the source rock. When the oil and gas fill the pores in the high permeability zone of the source rock, under the combined action of the injection pressure and the buoyancy of the hydrocarbon column in the high permeability zone of the source rock, the oil and gas overcome the capillary force constraint of the hydrocarbon expulsion zone of the source rock and enter the conducting layer. The oil and gas select the dominant migration direction on the left and right sides of the oil-generating depression formed by the hydrocarbon expulsion zone of the source rock and the high permeability zone of the source rock. While the oil and gas are injected into the two-dimensional seepage model, the water in the two-dimensional seepage model is discharged outward through the hard sponge strips around the two-dimensional seepage model. The camera shoots the entire change process of S5.

[0021] In actual oil and gas fields, source rocks have internal high permeability zones and external dense layers. The oil and gas generated by source rocks will first migrate for the first time inside the source rocks and gather in the high permeability zones inside the source rocks. When the oil and gas gather to a certain extent, under the action of pressure and buoyancy, the oil and gas will break through the capillary force constraints of the external dense layer of the source rock and enter the conducting layer, causing secondary migration of oil and gas, and finally gather in the reservoir. In the experimental method of the present invention, the high permeability zones of source rocks and the external dense layers, the dense layers and the hydrocarbon expulsion zones in the two-dimensional seepage model can be simulated. The oil and gas injected into the two-dimensional seepage model can first gather in the high permeability zone. When the oil and gas fill the pores in the high permeability zone area, under the combined action of pressure and buoyancy, the oil and gas break through the capillary force constraints of the hydrocarbon expulsion zone, enter the conducting layer, and undergo secondary migration. The experimental method can simulate the hydrocarbon expulsion process of source rocks under the action of pressure, buoyancy and capillary force.

[0022] Compared with the prior art, the present invention has at least the following advantages:

[0023] 1. It can simulate the dominant migration direction around the oil-generating depression under the influence of multiple factors, including the physical properties of the transport layer, the morphology of the transport layer, the contact area between the transport layer and the hydrocarbon expulsion zone of the source rock, and the hydrocarbon generation intensity.

[0024] 2. Able to fully simulate the hydrocarbon expulsion characteristics of source rocks.

[0025] 3. With selective sealing characteristics, the oil phase is confined in the high permeability area by capillary force, while the water phase flows out of the model through the hard sponge strips in all directions, fully simulating the characteristics of oil, gas and water flow and displacement in the formation.

[0026] 4. It has the characteristics of intuitive visualization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the device structure for simulating the dominant migration direction around the oil-generating sag.

[0028] Figure 2 for Figure 1 Schematic diagram of the structure of the two-dimensional seepage model.

[0029] Figure 3 for Figure 2 Cross-sectional view at AA in the middle.

[0030] Figure 4 This is the dominant hydrocarbon expulsion direction diagram of the oil-generating depression in Example 1.

[0031] Figure 5 This is the dominant hydrocarbon expulsion direction diagram of the oil-generating depression in Example 2.

[0032] In the figure: 1-1. Mudstone area, 1-2. Conducting layer, 1-3. Hydrocarbon expulsion area of ​​source rock, 1-4. High permeability zone of source rock, 1-5. Hard sponge strip, 1-6. C-shaped clamp, 1-7. Upper glass plate, 1-8. Lower glass plate, 1-9. Oil injection channel;

[0033] 2-1. Horizontal flow pump, 2-2. Digital camera, 2-3. Injection pipeline, 2-4. Transparent water tank, 2-5. Two-dimensional seepage model simulating depression hydrocarbon discharge, 2-6. Uniform surface light source. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0035] See also Figure 1-Figure 3 , a device for simulating the dominant migration direction around an oil-generating depression, including an injection structure connected to each other and a two-dimensional seepage model 2-5 for simulating hydrocarbon expulsion from the depression, the two-dimensional seepage model 2-5 adopts a "sandwich" structure, including an upper glass plate 1-7 and a lower glass plate 1-8 of the same shape and size, the upper glass plate 1-7 and the lower glass plate 1-8 are separated by hard sponge strips on all sides, and the glass plates and the hard sponge strips on all sides are detachably connected. Specifically, the upper glass plate 1-7, the lower glass plate 1-8 and the hard sponge strips located on all sides of the upper glass plate 1-7 and the lower glass plate 1-8 can be fixed by a C-shaped clamp.

[0036] The gap surrounded by the upper glass plate 1-7, the lower glass plate 1-8 and the hard sponge strips located around the upper glass plate 1-7 and the lower glass plate 1-8 is divided into four areas, namely, the source rock high permeability zone 1-4, the source rock hydrocarbon expulsion zone 1-3, the conducting layer 1-2 and the mudstone zone 1-1, by rubber strips. Specifically, the thickness of the rubber strips is similar to that of the hard sponge strips, and the conducting layer 1-2, the source rock hydrocarbon expulsion zone 1-3 and the source rock high permeability zone 1-4 are arranged in sequence from top to bottom. In the cross-sectional view of the conducting layer 1-2, both ends of the conducting layer 1-2 extend obliquely upward to the left and right sides, and reach the edges of the two-dimensional seepage model 2-5 respectively; specifically, the left end of the conducting layer 1-2 extends to the left edge of the two-dimensional seepage model 2-5, the right end of the conducting layer 1-2 extends to the top edge of the two-dimensional seepage model 2-5, and the middle part of the conducting layer 1-2 is bent toward the bottom edge of the two-dimensional seepage model 2-5, and the cross section is parallel to the upper glass plate 1-7 or the lower glass plate 1-8.

[0037] The source rock high permeability zone 1-4 is located in the middle part below the conducting layer 1-2, and the source rock high permeability zone 1-4 and the conducting layer 1-2 have the same bending angle toward the bottom edge of the two-dimensional seepage model 2-5, and the source rock hydrocarbon expulsion area 1-3 is located between the conducting layer 1-2 and the source rock high permeability zone 1-4; specifically, the source rock hydrocarbon expulsion area 1-3 and the source rock high permeability zone 1-4 are combined to form an oil generation depression; the oil generation depression is high on the left and right sides and low in the middle, presenting a basin structure.

[0038] The injection structure includes a horizontal flow pump 2-1, which is connected to the high permeability zone 1-4 of the source rock through an injection pipeline 2-3.

[0039] Specifically, the length of the high permeability zone 1-4 of the source rock extending to one end of the transport layer 1-2 is longer than the length extending to the other end of the transport layer 1-2. The dip angle of the gentle slope zone on the left side of the transport layer 1-2 is 15°, and the dip angle of the steep slope zone on the right side of the transport layer 1-2 is 40°. The contact area between the gentle slope zone on the left side of the transport layer 1-2 and the hydrocarbon expulsion zone 1-3 of the source rock is 3:1 compared with the contact area between the steep slope zone on the right side of the transport layer 1-2 and the hydrocarbon expulsion zone 1-3 of the source rock.

[0040] Specifically, the source rock high permeability zone 1-4 has an oil injection channel 1-9 extending to the left or right edge of the two-dimensional seepage model 2-5. The end of the oil injection channel 1-9 is 5-20 mm away from the hard sponge strip at the edge of the two-dimensional seepage model 2-5 as a model injection point.

[0041] It also includes an auxiliary structure; the auxiliary structure includes a transparent water tank 2-4, a camera 2-2 and a uniform surface light source 2-6, and the two-dimensional seepage model 2-5 is arranged in the transparent water tank 2-4. The lens of the camera 2-2 faces the upper glass plate 1-7 of the two-dimensional seepage model 2-5. The uniform surface light source 2-6 is located outside the transparent water tank 2-4 and parallel to the lower glass plate 1-8, and the uniform surface light source 2-6 illuminates the lower glass plate 1-8.

[0042] An experimental method for simulating the dominant migration direction around an oil-generating depression. The device for simulating the dominant migration direction around an oil-generating depression comprises the following steps:

[0043] S1: Making a two-dimensional seepage model 2-5: Lay the lower glass plate 1-8 flat, and fix hard sponge strips around the upper surface of the lower glass plate 1-8; use the strips to separate the high permeability zone 1-4 of the source rock, the hydrocarbon expulsion zone 1-3 of the source rock, the transport layer 1-2, and the mudstone zone 1-1.

[0044] Fill the high permeability zone 1-4 of the source rock, the hydrocarbon expulsion zone 1-3 of the source rock, the transport layer 1-2 and the mudstone zone 1-1 with the finest particles simulating mudstone, remove the surplus fine particles after leveling and compacting, and make the upper surface of the fine particle accumulation body flush with the surrounding hard sponge strips;

[0045] The finest particles in the high permeability zones 1-4 of the source rock, the hydrocarbon expulsion areas 1-3 of the source rock, and the conducting layer 1-2 are removed, and coarse particles are filled in the high permeability zones 1-4 of the source rock and the conducting layer 1-2. The particle sizes of the coarse particles filled in the high permeability zones 1-4 of the source rock and the conducting layer 1-2 may be the same or different. Medium particles are filled in the hydrocarbon expulsion area 1-3 of the source rock, smoothed and compacted; the particle sizes are arranged from large to small in the order of coarse particles, medium particles and fine particles.

[0046] Remove the rubber strip used to separate the area, and use the smaller particles on both sides of the rubber strip to fill the gap left by the rubber strip;

[0047] Align the cover glass plate 1-7, fix the upper glass plate 1-7 and the lower glass plate 1-8, and make the upper glass plate 1-7 and the lower glass plate 1-8 in close contact with the upper glass plate 1-7 and the lower glass plate 1-8 with hard sponge strips around them;

[0048] The model is fixed with C-shaped clamps on all sides. The C-shaped clamps apply prestress to the hard sponge strips around the gap between the upper glass plate 1-7 and the lower glass plate 1-8, so that the hard sponge strips are in close contact with the upper glass plate 1-7 and the lower glass plate 1-8 respectively, achieving a sealing effect.

[0049] S2: Put the two-dimensional seepage model 2-5 in S1 into the transparent water tank 2-4, and evacuate the two-dimensional seepage model 2-5 in the water tank filled with water. After the evacuation, the two-dimensional seepage model 2-5 is submerged under the water surface; ensure that there is no air in the two-dimensional seepage model 2-5.

[0050] S3: Connect the end of the injection pipeline 2-3 to an injection needle, and the injection needle pierces the hard sponge strip and the mudstone area 1-1 to enter the injection point on the oil injection channel 1-9 of the high permeability zone 1-4 of the source rock;

[0051] S4: placing the two-dimensional seepage model 2-5 horizontally in the water body and then translating it into the transparent water tank 2-4, and placing the two-dimensional seepage model 2-5 upright or tilted in the water body of the transparent water tank 2-4 and fixing it;

[0052] S5: Turn on the uniform surface light source 2-6, and use the horizontal flow pump 2-1 to inject oil and gas into the two-dimensional seepage model 2-5 that simulates hydrocarbon expulsion in the oil-generating depression to simulate hydrocarbon generation in the source rock. Constrained by the capillary force of the surrounding mudstone area 1-1 and the hydrocarbon expulsion area 1-3 of the source rock, the oil and gas first fill the high permeability zone 1-4 of the source rock. When the oil and gas fill the pores in the high permeability zone of the source rock, under the combined action of the injection pressure and the buoyancy of the hydrocarbon column in the high permeability zone 1-4 of the source rock, the oil and gas overcome the capillary force of the hydrocarbon expulsion zone 1-3 of the source rock and enter the conducting layer 1-2. Under the influence of factors such as the strength of the source rock expulsion zone 1-3, the contact area between the transport layer 1-2 and the source rock, the physical properties of the transport layer 1-2, and the morphology of the transport layer 1-2, oil and gas choose the dominant migration direction on the left and right sides of the oil generation depression formed by the source rock expulsion zone 1-3 and the source rock high permeability zone 1-4. While the oil and gas are injected into the two-dimensional seepage model 2-5, the water in the two-dimensional seepage model 2-5 is discharged outward through the hard sponge strips around the two-dimensional seepage model 2-5; the camera 2-2 shoots the entire change process of S5.

[0053] The characteristics of the experimental method of the present invention are mainly as follows: 1. The experimental method of the present invention is carried out in a water tank filled with water, and the manufactured two-dimensional seepage model is submerged in water. In the actual geological environment, the underground pores are full of water, and the geological body does not exist in isolation; submerging the two-dimensional seepage model in water is more in line with actual geological phenomena; 2. The two-dimensional seepage model of the present invention adopts semi-sealed technology. After the two-dimensional seepage model is vacuumed and filled with water, it is submerged in a water tank filled with water. The two-dimensional seepage model is connected to the water in the water tank. When oil and gas are injected into the two-dimensional seepage model during the experiment, water in the two-dimensional seepage model will be discharged from various places, which is more in line with actual geological phenomena; 3. The experimental method of the present invention can collect high-definition photos of the experimental process, which is convenient for experimental analysis.

[0054] Embodiment 1: An experimental method for simulating the dominant migration direction around an oil-generating depression, wherein the upper glass plate 1-7 and the lower glass plate 1-8 are 5 mm thick tempered glass, 400 mm wide and 300 mm high, the hard sponge strip is 10 mm wide and 2 mm thick, and the rubber strip used to separate the seepage area is 2 mm thick and 2 mm wide; the granular material filled in the two-dimensional seepage model 2-5 is glass beads, and in the model, the transport layer 1-2 is filled with 40 mesh glass beads, the high permeability zone 1-4 of the source rock is filled with 30 mesh glass beads, the hydrocarbon expulsion zone 1-3 of the source rock is filled with 80 mesh glass beads, and the mudstone zone 1-1 is filled with 100 mesh glass beads.

[0055] S1: Making a two-dimensional seepage model 2-5: Place the lower glass plate 1-8 flat on the table, and fix a 10 mm wide and 2 mm thick hard sponge strip around its upper surface.

[0056] According to the experimental design, the directional area surrounded by the hard sponge strips was divided into source rock high permeability zone 1-4, source rock hydrocarbon expulsion zone 1-3, conductive layer 1-2 and mudstone zone 1-1 by narrow rubber strips, and the thickness of the dividing rubber strips used was 2 mm; the source rock hydrocarbon expulsion zone 1-3 was above the source rock high permeability zone 1-4 and was close to it, and the combination of the two formed an oil-generating depression, which showed a basin structure; the source rock high permeability zone 1-4 extended to the left edge of the model to 5 mm away from the hard sponge strip as a The model injection point; the conducting layer 1-2 is above the source rock hydrocarbon expulsion area 1-3 and is in close contact with it; the conducting layer 1-2 extends from the source rock hydrocarbon expulsion area 1-3 to the left and upward to form a gentle slope zone with a dip angle of 15°. The contact length between the gentle slope zone and the source rock hydrocarbon expulsion area 1-3 is 15 cm; the conducting layer 1-2 extends from the source rock hydrocarbon expulsion area 1-3 to the right and upward to form a steep slope zone with a dip angle of 40°. The contact length between the steep slope zone and the source rock hydrocarbon expulsion area 1-3 is 5 cm.

[0057] First, 100-mesh glass beads simulating mudstone are filled in the source rock high permeability zone 1-4, the source rock hydrocarbon expulsion zone 1-3, the transport layer 1-2 and the mudstone zone 1-1. After smoothing and compacting, the surplus particles are removed to make the upper surface of the particle accumulation body flush with the surrounding hard sponge strips.

[0058] Remove 100-mesh glass beads from the high permeability zones 1-4 of source rocks, hydrocarbon-expulsion areas 1-3 of source rocks, and conductive layers 1-2, and fill the high permeability zones 1-4 of source rocks with 20-mesh glass beads, the conductive layers 1-2 with 30-mesh glass beads, and the hydrocarbon-expulsion areas 1-3 of source rocks with 60-mesh glass beads, smooth and compact.

[0059] Remove the rubber strip used to divide the area, and use the smaller particles on both sides of the rubber strip to fill the gap left by the rubber strip.

[0060] Align the cover with the upper glass plate and fix the model with C-shaped clamps on all sides. The C-shaped clamps apply pressure to seal the model.

[0061] S2: placing the prepared two-dimensional seepage model 2-5 in a sealed container, evacuating the container and adding saturated water;

[0062] S3: Connect the end of the injection pipeline 2-3 to an injection needle, and the injection needle pierces the hard sponge strip and the mudstone area 1-1 to enter the injection point on the oil injection channel 1-9 of the high permeability zone 1-4 of the source rock.

[0063] S4: placing the two-dimensional seepage model 2-5 horizontally in the water body and then moving it horizontally to the transparent water tank 2-4, and placing the two-dimensional seepage model 2-5 upright or tilted in the water body of the transparent water tank 2-4 and fixing it.

[0064] S5: Turn on the uniform surface light source 2-6, and use a horizontal flow pump to inject dyed kerosene at a flow rate of 0.8 ml / min into the two-dimensional seepage model 2-5 to simulate hydrocarbon generation in the source rock. Constrained by the capillary force of the surrounding mudstone layer and the hydrocarbon expulsion zone 1-3 of the source rock, the kerosene is first filled into the high permeability zone 1-4 of the source rock. When the oil and gas fill the pores in the high permeability zone of the source rock, under the combined action of the injection pressure and the buoyancy of the oil column in the high permeability zone 1-4 of the source rock, the oil overcomes the constraint of the capillary force of the hydrocarbon expulsion zone 1-3 of the source rock and enters the conducting layer 1-2.

[0065] from Figure 4 It can be seen that in the actual simulated dominant migration direction of the oil phase around the oil-generating sag, under the influence of the dual factors of the contact area between the transport layer 1-2 and the source rock hydrocarbon expulsion area 1-3 and the dip angle of the transport layer 1-2, the amount of oil migrated in the gentle slope zone on the left side of the transport layer 1-2 is slightly greater than that in the steep slope zone on the right side of the transport layer 1-2.

[0066] Example 2: Compared with Example 1, under the premise of keeping other conditions unchanged, the contact lengths between the left gentle slope zone of the transport layer 1-2 and the right steep slope zone of the transport layer 1-2 and the hydrocarbon source rock expulsion zone 1-3 are adjusted to 5 cm and 15 cm respectively. At this time, the amount of oil migrated in the right steep slope zone of the transport layer 1-2 is significantly greater than that in the left gentle slope zone of the transport layer 1-2, becoming the dominant migration direction, see Figure 5 .

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A device for simulating the dominant migration direction around an oil-generating depression, comprising an injection structure connected to each other and a two-dimensional seepage model (2-5) for simulating hydrocarbon expulsion from the depression, characterized in that: The two-dimensional seepage model (2-5) comprises an upper glass plate (1-7) and a lower glass plate (1-8) of the same shape and size, wherein the upper glass plate (1-7) and the lower glass plate (1-8) are separated by hard sponge strips on all sides, and the glass plates and the hard sponge strips on all sides are detachably connected; The gap formed by the upper glass plate (1-7), the lower glass plate (1-8) and the hard sponge strips located around the upper glass plate (1-7) and the lower glass plate (1-8) is divided into four areas, namely, a source rock high permeability zone (1-4), a source rock hydrocarbon expulsion zone (1-3), a conductive layer (1-2) and a mudstone zone (1-1), by using rubber strips, wherein both ends of the conductive layer (1-2) in the cross-sectional view of the conductive layer (1-2) extend obliquely upward to the left and right sides and reach the edge of the two-dimensional seepage model (2-5) respectively; the cross section is parallel to the upper glass plate (1-7) or the lower glass plate (1-8); The source rock high permeability zone (1-4) is located in the middle part below the conducting layer (1-2), and the source rock high permeability zone (1-4) and the conducting layer (1-2) have the same bending angle toward the bottom edge of the two-dimensional seepage model (2-5), and the source rock hydrocarbon expulsion zone (1-3) is located between the conducting layer (1-2) and the source rock high permeability zone (1-4); The injection structure comprises a horizontal flow pump (2-1), and the horizontal flow pump (2-1) is connected to the high permeability zone (1-4) of the hydrocarbon source rock through an injection pipeline (2-3).

2. The device for simulating the dominant migration direction around an oil-generating depression according to claim 1, characterized in that: The length of the high permeability zone (1-4) of the hydrocarbon source rock extending toward one end of the transport layer (1-2) is longer than the length of the high permeability zone (1-4) extending toward the other end of the transport layer (1-2).

3. The device for simulating the dominant migration direction around an oil-generating depression according to claim 1, characterized in that: The gentle slope zone on the left side of the conducting layer (1-2) has an inclination angle of 15°, and the steep slope zone on the right side of the conducting layer (1-2) has an inclination angle of 40°.

4. The device for simulating the dominant migration direction around an oil-generating depression according to any one of claims 1 to 3, characterized in that: The contact area ratio between the left gentle slope zone and the right steep slope zone of the transport layer (1-2) and the hydrocarbon source rock expulsion zone (1-3) is 3:

1.

5. The device for simulating the dominant migration direction around an oil-generating depression as claimed in claim 4, characterized in that: The high permeability zone (1-4) of the source rock has an oil injection channel (1-9) extending to the left or right edge of the two-dimensional seepage model (2-5).

6. The device for simulating the dominant migration direction around an oil-generating depression as claimed in claim 5, characterized in that: It also includes an auxiliary structure; the auxiliary structure includes a transparent water tank (2-4), and the two-dimensional seepage model (2-5) is arranged in the transparent water tank (2-4).

7. The device for simulating the dominant migration direction around an oil-generating depression as claimed in claim 6, characterized in that: The auxiliary structure also includes a camera (2-2) with a lens facing the upper glass plate (1-7) of the two-dimensional seepage model (2-5).

8. The device for simulating the dominant migration direction around an oil-generating depression as claimed in claim 7, characterized in that: The auxiliary structure also includes a uniform surface light source (2-6) located outside the transparent water tank (2-4) and parallel to the lower glass plate (1-8).

9. An experimental method for simulating the dominant migration direction around an oil-generating depression, characterized in that: The device for simulating the dominant migration direction around an oil-generating depression as claimed in claim 8 comprises the following steps: S1: making a two-dimensional seepage model (2-5): placing the lower glass plate (1-8) flat, fixing hard sponge strips around the upper surface of the lower glass plate (1-8); using the strips to separate the source rock high permeability zone (1-4), the source rock hydrocarbon expulsion zone (1-3), the transport layer (1-2) and the mudstone zone (1-1); Fill the high permeability zone (1-4) of the source rock, the hydrocarbon expulsion zone (1-3) of the source rock, the transport layer (1-2) and the mudstone zone (1-1) with the finest particles simulating mudstone, smooth and compact them, and remove the excess fine particles, so that the upper surface of the fine particle accumulation body is flush with the surrounding hard sponge strips; The finest particles in the high permeability zone (1-4) of the source rock, the hydrocarbon expulsion zone (1-3) of the source rock, and the transport layer (1-2) are removed, and coarse particles are filled in the high permeability zone (1-4) of the source rock and the transport layer (1-2), and medium particles are filled in the hydrocarbon expulsion zone (1-3) of the source rock, and the mixture is leveled and compacted; Remove the rubber strip used to separate the area, and use the smaller particles on both sides of the rubber strip to fill the gap left by the rubber strip; Align the cover glass plate (1-7), fix the upper glass plate (1-7) and the lower glass plate (1-8), and make the upper glass plate (1-7) and the lower glass plate (1-8) in close contact with the upper glass plate (1-7) and the lower glass plate (1-8) using hard sponge strips around them; S2: placing the two-dimensional seepage model (2-5) in S1 into a transparent water tank (2-4), and evacuating the two-dimensional seepage model (2-5) in the water tank filled with water. After the evacuation is completed, the two-dimensional seepage model (2-5) is submerged under the water surface; S3: Connect the end of the injection pipeline (2-3) to an injection needle, and pierce the hard sponge strip and the mudstone area (1-1) to the injection point on the oil injection channel (1-9) of the high permeability zone (1-4) of the source rock; S4: placing the two-dimensional seepage model (2-5) horizontally in the water body and then moving it horizontally into the transparent water tank (2-4), and placing the two-dimensional seepage model (2-5) vertically or obliquely in the water body of the transparent water tank (2-4) and fixing it; S5: Turn on the uniform surface light source (2-6), use the horizontal flow pump (2-1) to inject oil and gas into the two-dimensional seepage model (2-5) that simulates the hydrocarbon expulsion of the oil generation depression to simulate the hydrocarbon generation of the source rock. The oil and gas first fill the high permeability zone (1-4) of the source rock. When the oil and gas fill the pores of the high permeability zone of the source rock, under the combined action of the injection pressure and the buoyancy of the hydrocarbon column of the high permeability zone (1-4) of the source rock, the oil and gas overcome the capillary force of the hydrocarbon expulsion zone (1-3) of the source rock and enter the conducting layer (1-2). The oil and gas select the dominant migration direction on the left and right sides of the oil generation depression formed by the hydrocarbon expulsion zone (1-3) of the source rock and the high permeability zone (1-4). When the oil and gas are injected into the two-dimensional seepage model (2-5), the water in the two-dimensional seepage model (2-5) is discharged outward through the hard sponge strips around the two-dimensional seepage model (2-5); the camera (2-2) takes pictures of the entire change process of S5.

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