Water-displacing-oil physical simulation experiment device and method for complex sand body

Abstract

The invention discloses a water-oil displacement physical simulation experiment device and method for a complex sand body, and the device comprises a nitrogen cylinder, an ISCO plunger pump, an intermediate container, a heterogeneous stratum model and a meter which are connected in sequence, and the ISCO plunger pump is connected with a beaker; a water injection well connected with the middle container, a producing well connected with the meter and an adjusting well are arranged in the heterogeneous stratum model, and the adjusting well is located between the water injection well and the producing well; the nitrogen cylinder is used for providing gas pressure drive for the ISCO plunger pump, and the ISCO plunger pump is used for stably conveying liquid in the beaker to the corresponding position in the intermediate container through gas pressure drive so as to push the corresponding liquid in the intermediate container to flow into a water injection well of the heterogeneous stratum model, and then the liquid is extracted from an adjusting well or an oil extraction well. The meter is used for recording the oil production, the water production and the production time of the adjusting well or the oil producing well. The device is simple in structure, the oil reservoir form can be flexibly depicted based on the device, the oil reservoir development potential area is accurately defined, and oil reservoir production is effectively guided.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production engineering, in particular to a water-driven oil physical simulation experimental device and method for complex sand bodies. Background Art

[0002] By conducting physical simulation experiments on complex sand bodies, we can gain a deeper understanding of the mechanical, deformation and flow characteristics of sand bodies under different conditions, provide a verification basis for theoretical models, and also help optimize oil and gas field development strategies, increase recovery rates and reduce development costs.

[0003] However, existing waterflooding physical simulation experimental equipment for complex sand bodies requires numerous instruments, valves, and pipelines, resulting in a complex structure. The waterflooding physical simulation experimental methods based on these experimental equipment fail to produce a formation model that flexibly depicts reservoir morphology. Furthermore, the experimental results lack the means to accurately identify reservoir development potential areas and effectively guide production.

[0004] To address the above issues, no effective solutions have been proposed so far. Summary of the Invention

[0005] The embodiments of this specification provide a water-driven oil physical simulation experimental device and method for complex sand bodies to solve the problems of the existing technology in that the device structure is complex, the device cannot flexibly characterize the reservoir morphology based on the device, accurately identify the reservoir development potential area, and effectively guide the reservoir production.

[0006] In a first aspect, the embodiments of this specification provide a physical simulation experimental device for water flooding of complex sand bodies, the device comprising:

[0007] A nitrogen bottle, an ISCO plunger pump, an intermediate container, a heterogeneous formation model, and a meter are connected in sequence. The ISCO plunger pump is connected to a beaker. The heterogeneous formation model has a built-in water injection well connected to the intermediate container, an oil production well connected to the meter, and an adjustment well. The adjustment well is located between the water injection well and the oil production well.

[0008] The nitrogen cylinder is used to provide gas pressure drive for the ISCO plunger pump, and the ISCO plunger pump is used to stably transport the liquid in the beaker to the corresponding position in the intermediate container through gas pressure drive, so as to push the corresponding liquid in the intermediate container to flow into the water injection well of the heterogeneous formation model, and the corresponding liquid is produced from the adjustment well or the oil production well. The meter is used to record the oil production, water production and production time of the adjustment well or the oil production well.

[0009] In some embodiments, the apparatus further comprises a camera located on top of the heterogeneous formation model, for capturing a target image of the top of the heterogeneous formation model during water flooding, wherein the resolution of the target image is greater than a preset resolution threshold.

[0010] In some embodiments, a primary valve is connected between the nitrogen cylinder and the ISCO plunger pump, and the primary valve is used to control the gas flow between the nitrogen cylinder and the ISCO plunger pump. A first six-way valve is connected between the ISCO plunger pump and the intermediate container, and the first six-way valve is used to switch the flow path of the liquid in the beaker so that the liquid is transported to the corresponding position of the intermediate container.

[0011] In some embodiments, a secondary valve, a second six-way valve, and a third-level valve are connected in sequence between the intermediate container and the water injection well in the heterogeneous formation model, a fourth-level valve is connected between the second six-way valve and the oil production well, and a fifth-level valve is connected between the oil production well or the adjustment well and the meter. The secondary valve is used to control the liquid flow between the intermediate container and the second six-way valve, the third-level valve is used to control the liquid flow between the second six-way valve and the water injection well, the fourth-level valve is used to control the liquid flow between the second six-way valve and the oil production well, the fifth-level valve is used to control the liquid flow between the oil production well or the adjustment well and the meter, and the second six-way valve is used to switch the experimental mode, which includes liquid being produced from the oil production well or liquid being produced from the adjustment well.

[0012] In some embodiments, the oil-mixed sand with different particle sizes at horizontal and vertical positions within the heterogeneous formation model is in a fully saturated state.

[0013] In a second aspect, the embodiments of this specification further provide a water flooding physical simulation experimental method for complex sand bodies, the method comprising:

[0014] Opening the first-stage valve, the ISCO plunger pump, the first six-way valve, the second-stage valve, the second six-way valve, and the third-stage valve to create a fully saturated heterogeneous formation model, wherein the heterogeneous formation model has built-in water injection wells, oil production wells, and adjustment wells;

[0015] Close the adjustment well, open the production well, and perform a water flooding on the fully saturated heterogeneous formation model until the water cut at the outlet of the production well reaches 98%, thus forming a heterogeneous formation model with high water cut;

[0016] Open the adjustment well, close the production well, and conduct secondary water flooding on the heterogeneous formation model with high water content until the water content at the outlet of the adjustment well reaches 98%, thus forming a heterogeneous formation model after potential tapping and adjustment.

[0017] A camera is used to capture a target image of the top of a heterogeneous formation model during water flooding. The heterogeneous formation model after potential tapping adjustment is disassembled and sanded to obtain a longitudinal profile image. The resolution of the target image is greater than a preset resolution threshold. The target image and the longitudinal profile image are used to determine the potential area for reservoir development.

[0018] In some embodiments, the method further comprises:

[0019] Heating an acrylic glass plate and shaping it into a simulated river channel, assembling the other parts of the shaped acrylic glass plate except the top glass to form a model body, and arranging a water injection well, an oil production well, and an adjustment well at corresponding positions within the model body, wherein the water injection well is connected to an intermediate container, the oil production well and the adjustment well are connected to a meter, and the adjustment well is located between the water injection well and the oil production well;

[0020] The pre-configured oil-mixed sand with different particle sizes is laid at the horizontal and vertical positions in the main body of the model to form a heterogeneous formation model with a horizontal and vertical heterogeneous structure;

[0021] Assemble the top glass and the model body;

[0022] Accordingly, the step of opening the first-stage valve, the ISCO plunger pump, the first six-way valve, the second-stage valve, the second six-way valve, and the third-stage valve to produce a fully saturated heterogeneous formation model includes:

[0023] Open the first-stage valve, ISCO plunger pump, first six-way valve, second-stage valve, second six-way valve, and third-stage valve. Use the gas pressure provided by the nitrogen bottle to drive the ISCO plunger pump and the first six-way valve, so that the liquid in the beaker is stably transported to the upper part of the intermediate container to push the simulated oil in the intermediate container into the water injection well of the heterogeneous formation model. Through the displacement effect of the simulated oil, the air in the oil-sand mixture is exhausted to form a fully saturated heterogeneous formation model.

[0024] In some embodiments, performing a water flooding on a fully saturated heterogeneous formation model includes:

[0025] Liquid was added to the beaker, and the gas pressure provided by the nitrogen bottle to the ISCO plunger pump and the first six-way valve was used to stably transport the liquid in the beaker to the lower part of the intermediate container, so as to push the water in the intermediate container to flow into the water injection well of the heterogeneous formation model and be produced from the oil production well, thereby performing a water flooding of the heterogeneous formation model until the water content at the outlet end of the oil production well reached 98%.

[0026] In some embodiments, performing secondary water flooding on a heterogeneous formation model with high water content includes:

[0027] Liquid is added to the beaker, and the gas pressure provided by the nitrogen bottle to the ISCO plunger pump is driven and the first six-way valve is used to stably transport the liquid in the beaker to the lower part of the intermediate container, so as to push the water in the intermediate container to flow into the injection well of the heterogeneous formation model and be produced from the adjustment well, so as to perform secondary water flooding on the heterogeneous formation model until the water cut at the outlet of the adjustment well reaches 98%.

[0028] In some embodiments, the method further comprises:

[0029] Determine key development indicators based on the oil production, water production, and production time recorded by the meter, including water saturation, recovery degree, and oil displacement efficiency;

[0030] Carry out reservoir development based on key development indicators and reservoir development potential areas.

[0031] The embodiment of this specification provides a water-displacement oil physical simulation experimental device for complex sand bodies, including: a nitrogen bottle, an ISCO plunger pump, an intermediate container, a heterogeneous formation model, and a meter connected in sequence, the ISCO plunger pump is connected to a beaker, the heterogeneous formation model has a built-in water injection well connected to the intermediate container, an oil production well connected to the meter, and an adjustment well, the adjustment well being located between the water injection well and the oil production well; the nitrogen bottle is used to provide gas pressure drive for the ISCO plunger pump, the ISCO plunger pump is used to stably transport the liquid in the beaker to the corresponding position in the intermediate container through gas pressure drive, so as to push the corresponding liquid in the intermediate container into the water injection well of the heterogeneous formation model, and the corresponding liquid is produced from the adjustment well or the oil production well, and the meter is used to record the oil production, water production, and production time of the adjustment well or the oil production well. In the embodiment of this specification, the ISCO plunger pump can provide gas pressure drive for the ISCO plunger pump by connecting the nitrogen bottle, and the ISCO plunger pump can stably transport the liquid in the beaker to the corresponding position in the intermediate container through gas pressure drive. By connecting the production wells and adjustment wells to meters, the meters can record oil and water production and production time in a timely manner, providing a data basis for the subsequent calculation of key development indicators. The above device has a simple structure and can effectively reduce operational complexity and improve operational efficiency.

[0032] The embodiments of this specification also provide a water flooding physical simulation experimental method for a complex sand body, comprising: opening a first-level valve, an ISCO plunger pump, a first six-way valve, a second-level valve, a second six-way valve, and a third-level valve to create a fully saturated heterogeneous formation model, wherein the heterogeneous formation model has a built-in water injection well, an oil production well, and an adjustment well; closing the adjustment well, opening the oil production well, and performing a water flooding on the fully saturated heterogeneous formation model until the water cut at the outlet of the oil production well reaches 98%, thereby forming a heterogeneous formation model with a high water cut; opening the adjustment well, closing the oil production well, and performing a second water flooding on the heterogeneous formation model with a high water cut until the water cut at the outlet of the adjustment well reaches 98%, thereby forming a heterogeneous formation model with potential tapping and adjustment; using a camera to capture a target image of the top of the heterogeneous formation model during the water flooding process, disassembling the heterogeneous formation model after potential tapping and adjustment and performing sand scraping to obtain a longitudinal profile image, wherein the resolution of the target image is greater than a preset resolution threshold, and the target image and the longitudinal profile image are used to determine the potential area of ​​the reservoir development. In the embodiments of this specification, based on the above-mentioned device, a fully saturated heterogeneous formation model can be produced, thereby flexibly depicting the reservoir morphology. By first performing a water flood on the fully saturated heterogeneous formation model to form a high water-cut state, then opening an adjustment well and closing the production well, a second water flood is performed on the heterogeneous formation model in the high water-cut state. This, in turn, adjusts the heterogeneous formation model in the high water-cut state to tap its potential, facilitating the subsequent identification of the reservoir's development potential areas. By using a camera to capture a target image of the top of the heterogeneous formation model during the water flooding process and obtain a longitudinal profile image, the reservoir's development potential areas can be accurately determined, effectively guiding reservoir production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0034] Figure 1 This is a schematic structural diagram of a water-to-oil physical simulation experimental device for complex sand bodies provided in an embodiment of this specification;

[0035] Figure 2 is a schematic diagram of a heterogeneous formation model provided in an embodiment of this specification;

[0036] Figure 3 This is a flow chart of a physical simulation experimental method for water flooding of complex sand bodies provided in an embodiment of this specification;

[0037] Figure 4 It is a schematic diagram of the wave sweep rules of different longitudinal sections provided in the embodiments of this specification;

[0038] Figure 5 It is a schematic diagram of the wave patterns of different cross-section planes provided in the embodiments of this specification. DETAILED DESCRIPTION

[0039] To help those skilled in the art better understand the technical solutions in this specification, the following will provide a clear and complete description of the technical solutions in the embodiments of this specification, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of them. All other embodiments derived by those skilled in the art based on the embodiments in this specification without creative effort shall fall within the scope of protection of this specification.

[0040] See Figure 1 As shown, the embodiment of this specification provides a water flooding physical simulation experimental device for complex sand bodies. The device may include:

[0041] A nitrogen bottle, an ISCO plunger pump, an intermediate container, a heterogeneous formation model, and a meter are connected in sequence. The ISCO plunger pump is connected to a beaker. The heterogeneous formation model has a built-in water injection well connected to the intermediate container, an oil production well connected to the meter, and an adjustment well. The adjustment well is located between the water injection well and the oil production well.

[0042] The nitrogen cylinder is used to provide gas pressure drive for the ISCO plunger pump, and the ISCO plunger pump is used to stably transport the liquid in the beaker to the corresponding position in the intermediate container through gas pressure drive, so as to push the corresponding liquid in the intermediate container to flow into the water injection well of the heterogeneous formation model, and the corresponding liquid is produced from the adjustment well or the oil production well. The meter is used to record the oil production, water production and production time of the adjustment well or the oil production well.

[0043] Specifically, the corresponding positions in the intermediate container may include the upper portion and the lower portion of the target container. The upper portion of the intermediate container may store simulated oil, while the lower portion may store water. The corresponding liquids in the intermediate container may include simulated oil and water, such as ink (ink can be used as a tracer to help observe fluid movement).

[0044] The above-mentioned ISCO plunger pump can be driven by the gas pressure of the nitrogen bottle to stably transport the liquid in the beaker to the corresponding position in the intermediate container. For example, when it is necessary to expel all the air in the oil-sand mixture of the heterogeneous formation model through displacement to make the heterogeneous formation model reach a fully saturated state, the liquid in the beaker can be stably transported to the upper part of the intermediate container to inject the simulated oil in the intermediate container into the heterogeneous formation model. When it is necessary to water flood the heterogeneous formation, the liquid in the beaker can be stably transported to the lower part of the intermediate container to inject the water in the intermediate container into the heterogeneous formation model. Among them, water flooding of the heterogeneous formation can include primary water flooding and secondary water flooding. During primary water flooding, the liquid can be produced from the oil production well, and during secondary water flooding, the liquid can be produced from the adjustment well.

[0045] In some embodiments, the apparatus may further include a camera located on top of the heterogeneous formation model for capturing a target image of the top of the heterogeneous formation model during water flooding, wherein the resolution of the target image is greater than a preset resolution threshold.

[0046] Specifically, a camera may be used to capture high-resolution images (ie, target images) of each stage at the top of the heterogeneous formation model, so as to accurately identify the potential areas for reservoir development based on the high-resolution images.

[0047] In some embodiments, a primary valve is connected between the nitrogen cylinder and the ISCO plunger pump, and the primary valve can be used to control the gas flow between the nitrogen cylinder and the ISCO plunger pump. A first six-way valve is connected between the ISCO plunger pump and the intermediate container, and the first six-way valve can be used to switch the flow path of the liquid in the beaker so that the liquid is transported to the corresponding position of the intermediate container.

[0048] Specifically, a first-level valve is connected between the nitrogen cylinder and the ISCO plunger pump. When the nitrogen cylinder is needed to provide gas pressure drive for the ISCO plunger pump, the first-level valve can be opened to allow the nitrogen in the nitrogen cylinder to enter the ISCO plunger pump. When it is not needed, the first-level valve can be closed in time to avoid the loss of nitrogen in the nitrogen cylinder. A first six-way valve is connected between the ISCO plunger pump and the intermediate container. The flow path of the liquid in the beaker can be switched according to the first six-way valve. For example, when it is necessary to exhaust all the air in the oil-mixed sand of the heterogeneous formation model through displacement so that the heterogeneous formation model reaches a fully saturated state, the first six-way valve can be connected to the upper part of the intermediate container so that the liquid in the beaker can be transported to the upper part of the intermediate container. When it is necessary to water-flood the heterogeneous formation, the first six-way valve can be connected to the lower part of the intermediate container so that the liquid in the beaker can be transported to the lower part of the intermediate container.

[0049] In some embodiments, a second-level valve, a second six-way valve, and a third-level valve are connected in sequence between the above-mentioned intermediate container and the water injection well in the heterogeneous formation model, a fourth-level valve is connected between the second six-way valve and the oil production well, and a fifth-level valve is connected between the oil production well or the adjustment well and the meter. The second-level valve is used to control the liquid flow between the intermediate container and the second six-way valve, the third-level valve is used to control the liquid flow between the second six-way valve and the water injection well, the fourth-level valve is used to control the liquid flow between the second six-way valve and the oil production well, the fifth-level valve is used to control the liquid flow between the oil production well or the adjustment well and the meter, and the second six-way valve is used to switch the experimental mode, which includes liquid being produced from the oil production well or liquid being produced from the adjustment well.

[0050] Specifically, by connecting a secondary valve between the intermediate container and the second six-way valve, the secondary valve can be closed in time when the heterogeneous formation model does not need to be displaced or water-flooded, so as to avoid the corresponding liquid in the intermediate container from flowing into the heterogeneous formation model and causing waste of liquid. By connecting a tertiary valve between the second six-way valve and the water injection well, the waste of liquid can be further prevented. By connecting a fourth-level valve between the second six-way valve and the oil production well, the second six-way valve can be switched to different experimental modes, such as: when the fourth-level valve is opened, the liquid is extracted from the oil production well, and the first water drive experimental process is carried out at this time (the stage of water-flooding the heterogeneous model to a high water content state); when the fourth-level valve is closed, the liquid is extracted from the arranged adjustment well, and the second water drive experimental process is carried out at this time (the potential adjustment stage). By connecting a five-stage valve between the oil production well or the adjustment well and the meter, the five-stage valve can be opened in time when the meter is needed to record the oil production, water production and production time of the adjustment well or the oil production well, and closed in time when it is not needed, thereby recording the corresponding data according to actual needs and avoiding duplicate recording.

[0051] In some embodiments, the oil-mixed sand with different particle sizes at horizontal and vertical positions within the heterogeneous formation model is in a fully saturated state.

[0052] Specifically, the oil-sand mixture with different particle sizes in the horizontal and vertical positions of the above-mentioned heterogeneous formation model is in a fully saturated state, which can flexibly depict the reservoir morphology. The above-mentioned heterogeneous formation model can be assembled from acrylic glass plates, and the top glass of the heterogeneous formation model is detachable. Figure 2 As shown, the size of the heterogeneous formation model can be 70 cm×30 cm×50 cm.

[0053] See Figure 3 As shown, the embodiment of this specification also provides a water-displacement oil physical simulation experimental method for complex sand bodies. The method uses the above-mentioned water-displacement oil physical simulation experimental device for complex sand bodies, and the method may include:

[0054] S301: Open the first-stage valve, the ISCO plunger pump, the first six-way valve, the second-stage valve, the second six-way valve, and the third-stage valve to create a fully saturated heterogeneous formation model, wherein the heterogeneous formation model has built-in water injection wells, oil production wells, and adjustment wells;

[0055] S302: closing the adjustment well and opening the production well to perform a water flooding on the fully saturated heterogeneous formation model until the water cut at the outlet of the production well reaches 98%, thereby forming a heterogeneous formation model with a high water cut;

[0056] S303: Open the adjustment well, close the production well, and perform secondary water flooding on the heterogeneous formation model with high water content until the water content at the outlet of the adjustment well reaches 98%, thereby forming a heterogeneous formation model after potential tapping and adjustment.

[0057] S304: Using a camera to capture a target image of the top of the heterogeneous formation model during the water flooding process, the heterogeneous formation model after potential tapping adjustment is disassembled and sanded to obtain a longitudinal profile image, wherein the resolution of the target image is greater than a preset resolution threshold. The target image and the longitudinal profile image are used to determine the potential area for reservoir development.

[0058] Specifically, based on the above-mentioned device, a fully saturated heterogeneous formation model can be first produced, and then the fully saturated heterogeneous formation model can be water-driven once to drive it to a high water-cut state, and then the high water-cut heterogeneous formation model can be water-driven a second time, that is, the high water-cut heterogeneous formation model can be adjusted to tap the potential, and finally the acquired high-resolution images and the obtained longitudinal profile images can be processed, so as to accurately identify the potential area for oil reservoir development and effectively guide oil reservoir growth.

[0059] In some embodiments, the above-mentioned step S301 may further include:

[0060] Heating an acrylic glass plate and shaping it into a simulated river channel, assembling the other parts of the shaped acrylic glass plate except the top glass to form a model body, and arranging a water injection well, an oil production well, and an adjustment well at corresponding positions within the model body, wherein the water injection well is connected to an intermediate container, the oil production well and the adjustment well are connected to a meter, and the adjustment well is located between the water injection well and the oil production well;

[0061] The pre-configured oil-mixed sand with different particle sizes is laid at the horizontal and vertical positions in the main body of the model to form a heterogeneous formation model with a horizontal and vertical heterogeneous structure;

[0062] Assemble the top glass and the model body;

[0063] Accordingly, in the above S301, opening the first valve, the ISCO plunger pump, the first six-way valve, the second valve, the second six-way valve, and the third valve to create a fully saturated heterogeneous formation model may include:

[0064] Open the first-stage valve, ISCO plunger pump, first six-way valve, second-stage valve, second six-way valve, and third-stage valve. Use the gas pressure provided by the nitrogen bottle to drive the ISCO plunger pump and the first six-way valve, so that the liquid in the beaker is stably transported to the upper part of the intermediate container to push the simulated oil in the intermediate container into the water injection well of the heterogeneous formation model. Through the displacement effect of the simulated oil, the air in the oil-sand mixture is exhausted to form a fully saturated heterogeneous formation model.

[0065] Specifically, the process of making a fully saturated heterogeneous formation model can be as follows:

[0066] 1. Acrylic glass sheets can be shaped and processed through heat-melt deformation. Heat the acrylic glass sheet to a certain temperature to soften it, then use a mold to shape it into a simulated river channel. Use AB glue to assemble the remaining parts of the shaped acrylic glass sheet, except for the top glass, to form the model body. Place the water injection well, oil production well, and adjustment well at corresponding or designated locations within the model body. For example, the water injection well is connected to the intermediate container in the above device, and the oil production well and adjustment well are connected to the meter in the above device. The adjustment well is located between the water injection well and the oil production well, specifically in an area that requires further development or adjustment.

[0067] 2. The configured simulated oil can be fully mixed with sand of different particle sizes in advance to form mixed oil and sand of different particle sizes, which can be used as the pre-configured mixed oil and sand of different particle sizes. The pre-configured mixed oil and sand of different particle sizes can then be laid out in the horizontal and vertical positions within the main body of the model to form a heterogeneous formation model with a horizontally and vertically heterogeneous structure.

[0068] 3. The top glass and the model body can be assembled using AB glue.

[0069] 4. The first-stage valve, ISCO plunger pump, first six-way valve, second-stage valve, second six-way valve, and third-stage valve can be opened. The gas pressure provided by the nitrogen bottle to the ISCO plunger pump and the first six-way valve can be driven to stably transport the liquid in the beaker to the upper part of the intermediate container, so as to push the simulated oil in the intermediate container into the water injection well of the heterogeneous formation model. The air in the oil-sand mixture can be exhausted through the displacement effect of the simulated oil, forming a fully saturated heterogeneous formation model.

[0070] After exhausting all the air, you can close the first-stage valve, ISCO plunger pump, first six-way valve, second-stage valve, second six-way valve, and third-stage valve.

[0071] Through the above-mentioned production method, the heterogeneous formation model can be fully saturated, the simulated formation interface is consistent with the actual situation, and the reservoir morphology can be flexibly portrayed.

[0072] In some embodiments, the above-mentioned step S302 of performing a water flooding on the fully saturated heterogeneous formation model may include:

[0073] Liquid was added to the beaker, and the gas pressure provided by the nitrogen bottle to the ISCO plunger pump and the first six-way valve was used to stably transport the liquid in the beaker to the lower part of the intermediate container, so as to push the water in the intermediate container to flow into the water injection well of the heterogeneous formation model and be produced from the oil production well, thereby performing a water flooding of the heterogeneous formation model until the water content at the outlet end of the oil production well reached 98%.

[0074] Specifically, the process of water flooding a fully saturated heterogeneous formation model can be as follows:

[0075] Add liquid, such as distilled water, to the beaker. Open the primary valve, ISCO plunger pump, first six-way valve, secondary valve, second six-way valve, third valve, and fourth valve. Using the nitrogen cylinder to drive the ISCO plunger pump and the first six-way valve, the liquid in the beaker is steadily delivered to the lower portion of the intermediate container. Through the second six-way valve, water (or ink) in the intermediate container is pushed into the injection well of the heterogeneous formation model and then out of the production well, performing a water flooding of the heterogeneous formation model until the water cut at the production well outlet reaches 98%, bringing the heterogeneous formation model to a high water cut.

[0076] In some embodiments, the secondary water flooding of the heterogeneous formation model with high water content in S303 may include:

[0077] Liquid is added to the beaker, and the gas pressure provided by the nitrogen bottle to the ISCO plunger pump is driven and the first six-way valve is used to stably transport the liquid in the beaker to the lower part of the intermediate container, so as to push the water in the intermediate container to flow into the injection well of the heterogeneous formation model and be produced from the adjustment well, so as to perform secondary water flooding on the heterogeneous formation model until the water cut at the outlet of the adjustment well reaches 98%.

[0078] Specifically, the process of secondary water flooding for a highly water-rich heterogeneous formation model can be as follows:

[0079] After adding liquid to the beaker, the first valve, ISCO plunger pump, first six-way valve, second valve, second six-way valve, and third valve can be opened. The fourth valve is closed, and the set adjustment well is opened. The gas pressure provided by the nitrogen bottle to the ISCO plunger pump drives the first six-way valve, so that the liquid in the beaker is stably transported to the lower part of the intermediate container. Through the second six-way valve, the water in the intermediate container flows into or enters the water injection well of the heterogeneous formation model and is extracted from the adjustment well, thereby performing a secondary water flooding of the high water-cut heterogeneous formation model, that is, tapping the potential of the high water-cut heterogeneous formation model.

[0080] By adjusting the potential of the heterogeneous formation model with water content, the distribution of remaining oil can be quantitatively analyzed, and the development potential areas of underdeveloped reservoirs can be identified. Based on this, corresponding potential adjustment strategies can be proposed to increase the ultimate recovery rate of the oil field.

[0081] In some embodiments, the target image in S304 is a high-resolution image of each stage of the top of the heterogeneous formation model captured by a camera to record the changes in the oil-water interface. The longitudinal profile image can be obtained by physically disassembling the heterogeneous formation model and scraping the disassembled heterogeneous formation model. The longitudinal profile image is an image of different sections in the longitudinal direction. Afterwards, an image recognition algorithm (such as a growth algorithm) can be used to automatically identify the high-resolution image and the longitudinal profile image, determine the oil-water interface, and calculate the corresponding sweep coefficient and residual oil saturation. The sweep coefficient is obtained by the oil-water distribution area ratio in the oil-water interface. Based on the sweep coefficient and the residual oil saturation, a map is drawn. Based on the drawn map, the potential area for oil reservoir development is identified or determined. The potential area for oil reservoir development is the residual oil area with development potential, which can provide a basis for optimizing the development strategy.

[0082] In some embodiments, the above S304 may further include:

[0083] Determine key development indicators based on the oil production, water production, and production time recorded by the meter, including water saturation, recovery degree, and oil displacement efficiency;

[0084] Carry out reservoir development based on key development indicators and reservoir development potential areas.

[0085] Specifically, during water flooding, five-stage valves can be opened, and meters can be used to promptly record the oil and water production rates, as well as the production time, of the adjustment well or production well. This data can be used to determine key development indicators, such as water saturation, recovery level, and flooding efficiency. High-resolution imagery and longitudinal profile images can be combined to identify potential reservoir development areas and formulate reservoir development strategies for development, production, and utilization.

[0086] In a specific implementation scenario, the sweep coefficient can be quantitatively characterized in a slice-like manner based on the experimental results obtained by the above-mentioned experimental method for complex sand body physical simulation.

[0087] After the experiment, the water drive wave (sweep coefficient) and range can be quantitatively characterized, respectively, from the horizontal (along the width of the river channel) and the vertical (along the thickness of the river channel) direction. In the vertical direction, the sweep coefficient is calculated for different sections from the top of the river channel to the bottom of the river channel, and in the horizontal direction, the sweep coefficient is calculated for different sections from the edge of the river channel to the interior of the river channel. The calculation results are summarized on the characterization result curve. According to the coefficient inflection point in the curve, the entire sweep area is divided into potential areas and non-potential areas. Combined with the experimental results, it is analyzed that the areas in the river channel where the sweep coefficient is lower than the inflection point value of the curve are defined as potential areas. These areas are usually located at the edge and bottom of the river channel, where the water drive effect is insufficient, resulting in relatively high residual oil saturation. The characterization results can further clarify the sweep range and the distribution of residual oil during the development process. By quantitatively characterizing the scope of the potential area, it can provide guidance for subsequent potential tapping and adjustment.

[0088] Throughout the experiment, production time, oil production, and water production at the same fluid production rate were recorded to evaluate waterflooding efficiency and reservoir response, and to quantitatively analyze the impact of different injection-production strategies on the oil-water ratio and reservoir pressure dynamics. Key development metrics such as water cut, recovery, and oil recovery efficiency were calculated and output. Water cut can be determined by comparing the volume of water in the produced fluid to the total volume. Recovery represents the ratio of the reservoir's initial recoverable oil to the total oil produced, while oil recovery efficiency, assessed by the change in oil saturation before and after waterflooding, reflects the effectiveness of waterflooding. Analysis of this comprehensive data optimizes development strategies and further enhances our understanding of complex reservoir behavior.

[0089] See Figure 4 As shown, Figure 4 The horizontal axis represents the dimensionless channel thickness, while the vertical axis represents the sweep coefficient, which reveals the longitudinal sweep variation. As the channel width increases, the sweep range gradually decreases. The highest potential area can be found at the top of the channel, where the sweep effect is weaker and the remaining oil potential is greater.

[0090] See Figure 5 As shown, Figure 5 The horizontal axis represents the dimensionless channel thickness, while the vertical axis represents the sweep coefficient. This reveals the variation in sweep across the surface. As channel width increases, the effective sweep range decreases. Potential areas exhibit weak water flooding effects and relatively high remaining oil potential.

[0091] The present invention has a high degree of visualization, can better analyze the internal utilization situation of the river channel, is reusable, reduces economic costs, can divide the sweep coefficients of different parts of the river channel, clarify the potential areas for oil reservoir development, and effectively guide oil reservoir production.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A water flooding physical simulation experimental device for complex sand bodies, characterized in that: include: A nitrogen bottle, an ISCO plunger pump, an intermediate container, a heterogeneous formation model, and a meter are connected in sequence. The ISCO plunger pump is connected to a beaker. The heterogeneous formation model has a built-in water injection well connected to the intermediate container, an oil production well connected to the meter, and an adjustment well. The adjustment well is located between the water injection well and the oil production well. The nitrogen cylinder is used to provide gas pressure drive for the ISCO plunger pump, and the ISCO plunger pump is used to stably transport the liquid in the beaker to the corresponding position in the intermediate container through gas pressure drive, so as to push the corresponding liquid in the intermediate container to flow into the water injection well of the heterogeneous formation model, and the corresponding liquid is produced from the adjustment well or the oil production well. The meter is used to record the oil production, water production and production time of the adjustment well or the oil production well.

2. The device according to claim 1, characterized in that The device further includes a camera located on the top of the heterogeneous formation model and used to capture a target image of the top of the heterogeneous formation model during water flooding, wherein the resolution of the target image is greater than a preset resolution threshold.

3. The device according to claim 1, characterized in that A primary valve is connected between the nitrogen cylinder and the ISCO plunger pump, and the primary valve is used to control the gas flow between the nitrogen cylinder and the ISCO plunger pump. A first six-way valve is connected between the ISCO plunger pump and the intermediate container, and the first six-way valve is used to switch the flow path of the liquid in the beaker so that the liquid is transported to the corresponding position of the intermediate container.

4. The device according to claim 1, characterized in that A secondary valve, a second six-way valve, and a third-level valve are connected in sequence between the intermediate container and the water injection well in the heterogeneous formation model; a fourth-level valve is connected between the second six-way valve and the oil production well; and a fifth-level valve is connected between the oil production well or the adjustment well and the meter. The secondary valve is used to control the liquid flow between the intermediate container and the second six-way valve; the third-level valve is used to control the liquid flow between the second six-way valve and the water injection well; the fourth-level valve is used to control the liquid flow between the second six-way valve and the oil production well; the fifth-level valve is used to control the liquid flow between the oil production well or the adjustment well and the meter; and the second six-way valve is used to switch the experimental mode, which includes liquid being produced from the oil production well or liquid being produced from the adjustment well.

5. The device according to claim 1, characterized in that The oil-mixed sand with different particle sizes at the horizontal and vertical positions in the heterogeneous formation model is in a fully saturated state.

6. A physical simulation experimental method for water flooding of complex sand bodies, characterized in that: Using the device according to any one of claims 1 to 5, the method comprises: Opening the first-stage valve, the ISCO plunger pump, the first six-way valve, the second-stage valve, the second six-way valve, and the third-stage valve to create a fully saturated heterogeneous formation model, wherein the heterogeneous formation model has built-in water injection wells, oil production wells, and adjustment wells; Close the adjustment well, open the production well, and perform a water flooding on the fully saturated heterogeneous formation model until the water cut at the outlet of the production well reaches 98%, thus forming a heterogeneous formation model with high water cut; Open the adjustment well, close the production well, and conduct secondary water flooding on the heterogeneous formation model with high water content until the water content at the outlet of the adjustment well reaches 98%, thus forming a heterogeneous formation model after potential tapping and adjustment. A camera is used to capture a target image of the top of a heterogeneous formation model during water flooding. The heterogeneous formation model after potential tapping adjustment is disassembled and sanded to obtain a longitudinal profile image. The resolution of the target image is greater than a preset resolution threshold. The target image and the longitudinal profile image are used to determine the potential area for reservoir development.

7. The method according to claim 6, characterized in that The method further comprises: Heating an acrylic glass plate and shaping it into a simulated river channel, assembling the other parts of the shaped acrylic glass plate except the top glass to form a model body, and arranging a water injection well, an oil production well, and an adjustment well at corresponding positions within the model body, wherein the water injection well is connected to an intermediate container, the oil production well and the adjustment well are connected to a meter, and the adjustment well is located between the water injection well and the oil production well; The pre-configured oil-mixed sand with different particle sizes is laid at the horizontal and vertical positions in the main body of the model to form a heterogeneous formation model with a horizontal and vertical heterogeneous structure; Assemble the top glass and the model body; Accordingly, the step of opening the first-stage valve, the ISCO plunger pump, the first six-way valve, the second-stage valve, the second six-way valve, and the third-stage valve to produce a fully saturated heterogeneous formation model includes: Open the first-stage valve, ISCO plunger pump, first six-way valve, second-stage valve, second six-way valve, and third-stage valve. Use the gas pressure provided by the nitrogen bottle to drive the ISCO plunger pump and the first six-way valve, so that the liquid in the beaker is stably transported to the upper part of the intermediate container to push the simulated oil in the intermediate container into the water injection well of the heterogeneous formation model. Through the displacement effect of the simulated oil, the air in the oil-sand mixture is exhausted to form a fully saturated heterogeneous formation model.

8. The method according to claim 6, characterized in that The method of performing a water flooding on a fully saturated heterogeneous formation model includes: Liquid was added to the beaker, and the gas pressure provided by the nitrogen bottle to the ISCO plunger pump and the first six-way valve was used to stably transport the liquid in the beaker to the lower part of the intermediate container, so as to push the water in the intermediate container to flow into the water injection well of the heterogeneous formation model and be produced from the oil production well, thereby performing a water flooding of the heterogeneous formation model until the water content at the outlet end of the oil production well reached 98%.

9. The method according to claim 6, characterized in that The secondary water flooding of the highly water-rich heterogeneous formation model comprises: Liquid is added to the beaker, and the gas pressure provided by the nitrogen bottle to the ISCO plunger pump is driven and the first six-way valve is used to stably transport the liquid in the beaker to the lower part of the intermediate container, so as to push the water in the intermediate container to flow into the injection well of the heterogeneous formation model and be produced from the adjustment well, so as to perform secondary water flooding on the heterogeneous formation model until the water cut at the outlet of the adjustment well reaches 98%.

10. The method according to claim 6, characterized in that The method further comprises: Determine key development indicators based on the oil production, water production, and production time recorded by the meter, including water saturation, recovery degree, and oil displacement efficiency; Carry out reservoir development based on key development indicators and reservoir development potential areas.

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