Experimental device and method for simulating edge-bottom water reservoir development

Abstract

The invention provides an experimental device and method for simulating edge-bottom water reservoir development. The experimental device comprises a sand filling model, a water injection assembly, an oil injection assembly and a plurality of simulated oil wells. The sand filling model is filled with a plurality of sand layers and interlayers, the sand layers and the interlayers are alternately distributed at intervals in the height direction, and the permeability of the interlayers is lower than that of the sand layers; the sand layer and the interlayer have the same inclination angle; the water injection assembly is arranged at the bottom of the sand-packed model and used for injecting water into the bottom of the sand-packed model so as to simulate the upward coning process of bottom water and the invasion process of edge water in the sand layer dip angle direction at the same time. The oil injection assembly is used for saturating crude oil to the sand layer to target reservoir pressure to simulate the reservoir; and the plurality of simulated oil wells are arranged in the sand layer, are distributed along the height direction of the sand-packed model and the dip angle direction of the sand layer, and are used for producing oil from the sand-packed model at set pressure. The influence of the combined action of edge water and bottom water on the edge-bottom water reservoir development effect can be simulated, so that the actual well spacing and oil production process is guided.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas reservoir exploitation experiments, and in particular to an experimental device and method for simulating the development of edge and bottom water reservoirs. Background Art

[0002] An edge-bottom water reservoir is one in which both edge and bottom water drive the development process. Bottom water refers to the water that fills the bottom of the oil and gas reservoir and supports the oil and gas during oilfield production; edge water refers to the water surrounding the periphery of the reservoir, usually a natural extension of the bottom water. During the development of edge-bottom water reservoirs, the impact of edge and bottom water and the utilization of its energy are important issues that must be considered. The most direct factors affecting the development effect of edge-bottom water reservoirs are bottom water coning and edge water fingering. Unlike layered reservoirs driven entirely by edge water or massive reservoirs driven entirely by bottom water, the development effect of edge-bottom water reservoirs is affected by the combined effects of both edge and bottom water.

[0003] Physical simulation is an important means of simulating oil and gas field development and an important basis for numerical simulation of oil and gas reservoirs. It is of great significance for obtaining development effect parameters, influencing factors and their influence degree.

[0004] Currently, when using physical simulation experimental devices to study factors influencing reservoir development, the focus is generally on simulating the impact of bottom water coning on reservoir development outcomes. The typical technical approach involves a high-pressure-resistant rectangular model filled with sand layers at a specific permeability. Multiple holes are installed at the bottom of the model, connected to a high-pressure water pump, to simulate bottom water at a specific pressure. After the model is filled with sand and connected, it is first saturated with water and then with crude oil. Once the model is fully saturated with crude oil and reaches the set pressure, the experiment begins. By observing and analyzing the produced water content of the oil wells and the degree of crude oil recovery within the model, the impact of bottom water coning on reservoir development outcomes is studied. Summary of the Invention

[0005] In order to simulate the impact of the combined effects of edge water and bottom water on the development of edge and bottom water reservoirs, and to further observe and compare the order in which oil wells at different locations in edge and bottom water reservoirs are affected by edge and bottom water, this application proposes a water invasion simulation experimental device and method for bottom water reservoirs, and adopts the following technical solutions:

[0006] In a first aspect, the present application discloses a water invasion simulation experimental device for a bottom water reservoir, the device comprising a sand filling model, a water injection component, an oil injection component, and a plurality of simulated oil wells;

[0007] The sand filling model is filled with a plurality of sand layers and interlayers, wherein the plurality of sand layers and interlayers are alternately spaced along the height direction, and the permeability of the interlayers is lower than the permeability of the sand layers;

[0008] The sand layer and the interlayer have the same inclination angle;

[0009] The water injection assembly is arranged at the bottom of the sand filling model, and is used to inject water into the bottom of the sand filling model to simultaneously simulate the upward cone advance of bottom water and the invasion of edge water along the inclination direction of the sand layer;

[0010] The oil injection assembly is used to saturate the sand layer with crude oil to a target reservoir pressure to simulate an oil reservoir;

[0011] A plurality of simulated oil wells are arranged in the sand layer and distributed along the height direction of the sand packing model and the dip direction of the sand layer, and are used to produce oil from the sand packing model at a set pressure.

[0012] Optionally, the longitudinal section of the sand filling model is triangular;

[0013] The longest sides of the longitudinal sections of the sand layer, the interlayer and the sand filling model are parallel to each other.

[0014] Optionally, the inclination angle ranges from 15° to 75°.

[0015] Optionally, the water injection assembly includes a water pump and a water injection pipe;

[0016] One end of the water injection pipe is communicated with the water pump, and the other end is communicated with the sand layer at the bottom of the sand filling model.

[0017] Optionally, the water injection pipe is provided with a plurality of water inlets, and the plurality of water inlets are evenly spaced along the length direction of the sand filling model.

[0018] Optionally, the number of sand layers ranges from 2 to 4 layers.

[0019] Optionally, the outer wall of the sand-filled model is made of transparent material.

[0020] Optionally, the ratio of the length to the height of the sand-filled model is in the range of 10:1 to 20:1, and the ratio of the width to the height is in the range of 1:2 to 1:5.

[0021] Optionally, an oil-water separator is provided at the outlet of each simulated oil well;

[0022] The oil-water separator is used to separate the oil-water mixture produced by the simulated oil well.

[0023] In a second aspect, the present application discloses an experimental method for simulating the development of an edge-bottom water reservoir. The method is applied to the experimental device for simulating the development of an edge-bottom water reservoir as described in the first aspect. The method comprises:

[0024] Saturating the sand pack model with water and crude oil to the target reservoir pressure to simulate the reservoir;

[0025] Water is injected into the bottom of the sandfill model through the water injection component to simulate the upward cone advance of bottom water and the invasion of edge water along the dip direction of the sand layer.

[0026] Oil is produced through each simulated oil well, the water content of the oil produced by each simulated oil well is recorded, and the invasion sequence of bottom water and edge water into the simulated oil wells at different positions in the sand filling model is observed and compared.

[0027] Based on the above technical solution, the beneficial effects of this application compared with the prior art are as follows:

[0028] The experimental apparatus for simulating the development of an edge-water reservoir in the embodiments of this application utilizes a wedge-shaped sandfill model to simulate an oil reservoir by filling sand bodies and interlayers. The wedge-shaped high-pressure model is filled with sand layer by layer, with the inclination of the sand layers used to simulate the inclination of the oil layer, and the orientation of the interlayers parallel to the inclination of the wedge. A water injection assembly pumps water into the bottom of the sandfill model and continuously supplies water at a constant pressure, thereby simultaneously simulating the upward coning of bottom water and the intrusion of edge water along the inclination of the sand layers. Specifically, the uppermost sand layers within the sandfill model are mostly separated from the bottom water by interlayers. When bottom water at the bottom of the sandfill model moves vertically upward into the upper sand layers along the minimum distance, it needs to pass through the interlayers with lower permeability to simulate the upward coning of bottom water. Furthermore, for most sand layers within the sandfill model, their edges are connected to the bottom water. Therefore, a portion of the bottom water within the sandfill model also acts as edge water in these sand layers. Edge water can invade obliquely upward along the highly permeable sand layers, affecting the production process of the simulated oil wells. However, because the oblique distance is always longer than the vertical distance, the distance of edge water invading obliquely upward along the sand layers is longer than the vertical upward coning of bottom water. Therefore, both bottom water coning and edge water invasion within the sandfill model are subject to corresponding resistance. When simultaneously simulating the impact of both edge and bottom water on the development of edge and bottom water reservoirs, further observation and comparison of the order in which simulated oil wells at different locations are affected by edge and bottom water invasion can guide actual well placement and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an overall schematic diagram of an experimental device for simulating the development of edge and bottom water reservoirs in an embodiment of the present application;

[0030] Figure 2 This is a flow chart of an experimental method for simulating the development of edge and bottom water reservoirs in an embodiment of the present application;

[0031] Description of reference numerals:

[0032] 1. Sand filling model; 11. Sand layer; 12. Interlayer; 13. Water inlet; 2. Water injection assembly; 21. Water pump; 22. Water injection pipe; 3. Oil injection assembly; 4. Simulated oil well; 5. Pressure regulating valve; 6. Oil-water separator. DETAILED DESCRIPTION

[0033] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0034] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0035] In the description of this disclosure, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this disclosure and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this disclosure. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on the specific circumstances.

[0037] According to the positional relationship between the groundwater body and the oil reservoir, the groundwater body can be divided into bottom water and edge water. Among them, the water in the lower part of the oil-bearing edge that supports the oil reservoir is called bottom water; the water in the oil-bearing edge that sets off the oil reservoir is called edge water. The edge and bottom water reservoir is generally a layered oil reservoir with a certain inclination angle, and the thickness of its oil layer gradually increases from the low part to the high part. Correspondingly, the distance between the oil layer and the edge and bottom water also gradually increases. The inventors found that the development of the edge and bottom water reservoir is affected by both edge water and bottom water, and the influence of the edge and bottom water on different positions of the oil reservoir varies greatly. However, the physical simulation experimental device in the prior art can usually only simulate the intrusion process of bottom water or edge water separately, which makes the evaluation model of the development effect of the edge and bottom water reservoir relatively simple, and cannot comprehensively and accurately simulate the development process of the edge and bottom water reservoir.

[0038] Therefore, in order to simulate the impact of the combined effects of edge water and bottom water on the development effect of edge and bottom water oil reservoirs, further observe and compare the order of invasion of edge water and bottom water in oil wells at different positions in edge and bottom water oil reservoirs, and thus provide guidance for the actual well layout and oil production process, the inventors further developed and made the present invention based on the existing technology.

[0039] In the first aspect, an embodiment of the present application discloses an experimental device for simulating the development of edge and bottom water oil reservoirs, which includes a sand filling model 1, a water injection component 2, an oil injection component 3 and several simulated oil wells 4; the sand filling model 1 is filled with several sand layers 11 and interlayers 12, and the several sand layers 11 and interlayers 12 are alternately distributed along the height direction, and the permeability of the interlayers 12 is lower than the permeability of the sand layers 11; the sand layers 11 and the interlayers 12 have the same inclination; the water injection component 2 is arranged at the bottom of the sand filling model 1, and is used to inject water into the bottom of the sand filling model 1 to simultaneously simulate the upward coning of bottom water and the invasion process of edge water along the inclination direction of the sand layer 11; the oil injection component 3 is used to saturate the sand layer 11 with crude oil to the target reservoir pressure to simulate the oil reservoir; several simulated oil wells 4 are arranged in the sand layer 11 and distributed along the height direction of the sand filling model 1 and the inclination direction of the sand layer 11, and are used to produce oil from the sand filling model 1 at a set pressure.

[0040] The experimental apparatus for simulating the development of an edge-water reservoir in the embodiments of the present application employs a wedge-shaped sandfill model 1, which is constructed by filling a sand body and interlayers 12 to simulate an oil reservoir. The wedge-shaped high-pressure model is filled with sand layer by layer, with the inclination of the sand layer 11 used to simulate the inclination of the oil layer, and the orientation of the interlayers 12 is parallel to the inclination of the wedge. Water is pumped into the bottom of the sandfill model 1 via a water injection assembly 2, and water is continuously supplied to the bottom of the sandfill model 1 at a constant pressure, thereby simultaneously simulating the upward coning of bottom water and the intrusion of edge water along the inclination of the sand layer 11. Specifically, the upper sand layer 11 in the sand filling model 1 is separated from the bottom water by the interlayer 12 in most areas. When the bottom water at the bottom of the sand filling model 1 enters the upper sand layer 11 vertically upward along the minimum distance, it needs to pass through the interlayer 12 with lower permeability to simulate the upward cone-shaped process of the bottom water. At the same time, for most of the sand layers 11 in the sand filling model 1, their edges are connected to the bottom water. Therefore, a part of the bottom water in the sand filling model 1 also acts as the edge water of this part of the sand layer 11. The edge water will invade obliquely upward along the highly permeable sand layer 11 and affect the oil production process of the simulated oil well 4. However, since the oblique distance is always longer than the vertical distance, the distance that the edge water invades obliquely upward along the sand layer 11 is longer than the vertical cone-shaped process of the bottom water. Therefore, both bottom water coning and edge water invasion in the sandfill model 1 are subject to corresponding resistance. When simulating the impact of edge water and bottom water on the development effect of edge and bottom water reservoirs at the same time, the order of edge water and bottom water invasion of simulated oil wells 4 at different locations in the edge and bottom water reservoirs is further observed and compared to guide actual well layout and production.

[0041] In an optional embodiment, the sandfill model 1 is specifically a hard shell capable of withstanding a certain pressure. Furthermore, the longitudinal cross-section of the sandfill model 1 is preferably triangular, with the sand layers 11, interlayers 12, and the longest sides of the longitudinal cross-section of the sandfill model 1 being parallel to each other. Preferably, in this embodiment, the longitudinal cross-section of the sandfill model 1 is preferably a right triangle, with the sand layers 11 and interlayers 12 arranged in a direction parallel to the hypotenuse of the right triangle. This allows the injection assembly 2 to simultaneously inject water into each sand layer 11 during the initial stage. For each angled sand layer 11, water is injected from its end, with a portion of the injected water coning upward in a vertical direction, while the remaining portion acts as edge water, invading along the corresponding low-permeability sand layer 11. Therefore, the bottom water coning process and the edge water intrusion process at each injection point begin simultaneously, making it easy to compare which of the bottom water and edge water invades the simulated oil well 4 in the corresponding sand layer 11 first, while keeping other factors constant.

[0042] In an optional embodiment, the sand layer 11 can be made of a mixture of gravel, soil, etc., and the interlayer 12 can be made of carbon fiber, plastic, construction adhesive, etc., and its permeability is about 1 / 100 of the sand layer 11.

[0043] In an optional embodiment, the number of sand layers 11 is in the range of 2-3 layers, and the inclination angle between the sand layer 11 and the interlayer 12 is in the range of 15° to 75°. Preferably, in this embodiment, the number of sand layers 11 is 3 layers, the number of interlayers 12 is 2 layers, and the inclination angle between the sand layer 11 and the interlayer 12 is specifically 30°.

[0044] In an optional embodiment, the length-to-height ratio of the sandfill model 1 ranges from 10:1 to 20:1, and the width-to-height ratio ranges from 1:3 to 1:5. In this embodiment, the length-to-height ratio of the sandfill model 1 is preferably 20:1, and the width-to-height ratio is preferably 1:5. This creates a two-dimensional model for comparative observation of the effects of top and bottom water on the oil well in a longitudinal section, saving significant material and achieving the purpose and effectiveness of the experimental simulation.

[0045] In an optional embodiment, the water injection assembly 2 includes a water pump 21 and a water injection pipe 22. One end of the water injection pipe 22 is connected to the water pump 21, and the other end is connected to the bottommost sand layer 11 within the sand-filled model 1. The water injection pipe 22 is provided with water inlets 13. Several water inlets 13 are evenly spaced along the length of the sand-filled model 1, thereby facilitating uniform water inflow to the bottom of the sand-filled model 1. To control the water inflow process, a control valve can be further provided on the water injection pipe 22 to control the water injection process.

[0046] In an optional embodiment, in order to facilitate real-time observation of the bottom water coning and edge water intrusion processes of the sand filling model 1, the outer wall of the sand filling model 1 can be made of transparent material, and the pressure bearing value of the sand filling model 1 is 1-2 MPa.

[0047] In an optional embodiment, the experimental apparatus further includes an oil injection assembly 3, which is used to saturate the sand layer 11 with crude oil to a set pressure to simulate an oil reservoir. Specifically, a displacement pump can be used for the oil injection assembly 3. Similar to the water injection ports, the oil injection ports can also be evenly distributed along the height or length of the sandfill model 1. Furthermore, to control the oil injection process, a control valve can be added to the oil injection pipe to provide control over the oil injection process.

[0048] In an optional embodiment, a pressure sensor is externally connected to the sand filling model 1. The pressure sensor is used to monitor the pressure of the crude oil in the sand filling model 1, so that the pressure of the crude oil reaches the simulated reservoir formation pressure when the crude oil is saturated.

[0049] In an optional embodiment, the simulated oil wells 4 are evenly distributed both vertically and along the dip angle of the sand layer 11. This allows for observation of edge and bottom water intrusion during the development of the simulated oil wells 4 to determine whether edge water or bottom water primarily influences the development performance of the simulated oil wells 4 at different locations. Specifically, in this embodiment, three simulated oil layers can be evenly distributed within each upper sand layer 11 along the dip angle of the corresponding sand layer 11 (the accompanying figure shows only a portion of the simulated oil wells 4).

[0050] Furthermore, in an optional embodiment, in order to conduct a comparative analysis of the oil production of each simulated oil well 4, an oil-water separator 6 is provided at the outlet of each simulated oil well 4. The oil-water separator 6 is used to separate the oil-water mixture produced by the simulated oil well 4. At the same time, a pressure regulating valve 5 is provided between the oil-water separator 6 and the wellhead to adjust the outlet pressure of the oil well so that the outlet pressure is lower than the internal pressure of the sand filling model 1, thereby achieving the oil production process. Therefore, by providing the oil-water separator 6, the water content of the oil produced by oil wells at different locations can be measured, and the changes in the water content of the oil produced by oil wells at different locations can be further simulated. In this way, the influence of the bottom water coning and edge water intrusion processes on the simulated oil wells 4 at different locations can be combined to reflect the influence of the synergistic effect of the edge and bottom water on the production effect of the oil well.

[0051] In a second aspect, the present application discloses an experimental method for simulating the development of an edge-bottom water reservoir. The method is applied to the experimental device for simulating the development of an edge-bottom water reservoir as in the first aspect, and the method comprises:

[0052] S1: Saturate the sandfill model 1 with crude oil to a set pressure to simulate an oil reservoir. Specifically, saturate the sandfill model 1 with water first and then with crude oil until the pressure inside the sandfill model 1 reaches the formation pressure of the reservoir simulation.

[0053] S2: inject water into the bottom of the sand filling model 1 through the water injection component 2 to simultaneously simulate the upward cone advance of the bottom water and the invasion of the edge water along the dip direction of the sand layer 11.

[0054] S3: Produce oil through the simulated oil well 4, and observe the invasion of bottom water and edge water on the simulated oil well 4 at different positions in the sand filling model 1. Specifically, adjust the pressure regulating valve 5 at the wellhead so that the outlet pressure of the simulated oil well 4 is lower than the internal pressure of the sand filling model 1, and at the same time keep the lower water pump 21 continuously supplying water to the bottom of the sand filling model 1 at a certain pressure to simulate the bottom water. The bottom water can pass through the interlayer 12 and affect the water content of the production of the simulated oil well 4. As the oil well continues to produce, the internal pressure of the sand filling model 1 gradually decreases, and the edge water also invades the simulated oil well 4 along the high permeability sand layer 11 in the upward direction. In the specific experiment, the production pressure difference of the simulated oil well 4 can be controlled, that is, by changing the pressure value of the pressure regulating valve 5, the pressure difference between the outlet of the sand filling model 1 and the simulated oil well 4 can be adjusted to observe the influence of the production pressure parameters on the invasion of edge water and bottom water.

[0055] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it will be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, to the extent that the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including", as explained by the use of "including" as a transitional word in the claims. In addition, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".

Claims

1. An experimental device for simulating the development of edge and bottom water reservoirs, characterized in that: The device comprises a sand filling model (1), a water injection component (2), an oil injection component (3) and a plurality of simulated oil wells (4); The sand filling model (1) is filled with a plurality of sand layers (11) and interlayers (12), the plurality of sand layers (11) and interlayers (12) are alternately spaced along the height direction, and the permeability of the interlayers (12) is lower than the permeability of the sand layers (11); The sand layer (11) and the interlayer (12) have the same inclination angle; The water injection assembly (2) is arranged at the bottom of the sand filling model (1) and is used to inject water into the bottom of the sand filling model (1) to simultaneously simulate the process of bottom water cone-shaped upward and edge water intrusion along the dip direction of the sand layer (11); The oil injection assembly (3) is used to saturate the sand layer (11) with crude oil to a target reservoir pressure to simulate an oil reservoir; A plurality of simulated oil wells (4) are arranged in the sand layer (11) and distributed along the height direction of the sand filling model (1) and the dip direction of the sand layer (11), and are used to produce oil at a set pressure from the sand filling model (1).

2. The experimental device according to claim 1, characterized in that The longitudinal section of the sand filling model (1) is triangular; The longest sides of the longitudinal sections of the sand layer (11), the interlayer (12) and the sand filling model (1) are parallel to each other.

3. The experimental device according to claim 1, characterized in that The inclination angle ranges from 15° to 75°.

4. The experimental device according to claim 1, characterized in that The water injection assembly (2) comprises a water pump (21) and a water injection pipe (22); One end of the water injection pipe (22) is connected to the water pump (21), and the other end is connected to the sand layer (11) at the bottom of the sand filling model (1).

5. The experimental device according to claim 4, characterized in that: The water injection pipe (22) is provided with a plurality of water inlets (13), and the plurality of water inlets (13) are evenly spaced along the length direction of the sand filling model (1).

6. The experimental device according to claim 1, characterized in that The number of layers of the sand layer (11) ranges from 2 to 4 layers.

7. The experimental device according to claim 1, characterized in that The outer wall of the sand-filled model (1) is made of transparent material.

8. The experimental device according to claim 1, characterized in that: The ratio of the length to the height of the sand-filled model (1) is in the range of 10:1 to 20:1, and the ratio of the width to the height is in the range of 1:3 to 1:

5.

9. The experimental device according to claim 1, characterized in that: An oil-water separator (6) is provided at the outlet of each simulated oil well (4); The oil-water separator (6) is used to separate the oil-water mixture produced by the simulated oil well (4).

10. An experimental method for simulating the development of edge and bottom water reservoirs, characterized in that: The method is applied to the experimental device for simulating edge and bottom water reservoir development according to any one of claims 1 to 9, and the method comprises: Saturating the sand pack model (1) with water and crude oil to the target reservoir pressure to simulate the reservoir; Water is injected into the bottom of the sand filling model (1) through the water injection component (2) to simultaneously simulate the upward cone advance of bottom water and the invasion of edge water along the dip direction of the sand layer (11); Oil is produced through each simulated oil well (4), the water content of the oil produced by each simulated oil well (4) is recorded, and the invasion sequence of bottom water and edge water into the simulated oil wells (4) at different positions in the sand filling model (1) is observed and compared.

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