Manufacturing method and visual analysis method of oil layer water shutoff and profile control visual model

Abstract

The invention relates to an oil reservoir water shutoff profile control visual model manufacturing method and a visual analysis method.The manufacturing method comprises the steps that a target oil reservoir water injection well serves as an original point, a production well serves as an action point, a space coordinate structure is established, the well position condition of the production well is expressed in the form of a coordinate axis, and an oil reservoir water shutoff profile control visual model is obtained; performing equal proportion equivalence according to X, Y and Z directions of coordinate axes, and establishing a model equivalence principle; designing based on a model equivalence principle to obtain a visual model; the length of the visual model is larger than or equal to 9000 mm, the width is larger than or equal to 360 mm, and the thickness is larger than or equal to 20 mm. According to the manufacturing method of the visual model, actual oil reservoir conditions can be accurately simulated through a model equivalent mode with coordinate equivalence, manufacturing of the large-size and high-pressure-resistant visual large model can be achieved, and therefore the actual effect and influence factors of the water shutoff and profile control technology can be deeply studied.

Description

Technical Field

[0001] The present invention relates to the technical field of oil exploitation, and particularly relates to a method for manufacturing a visualization model of water plugging and profile control in oil reservoirs, a visualization analysis method, and in particular, a method for manufacturing a large-scale visualization model for studying the mechanism of oil reservoir plugging and enhanced oil recovery by profile control and a visualization analysis method. Background Art

[0002] At present, in the process of oil exploitation, with the gradual deepening of oilfield development, many problems have become increasingly prominent. The high water cut problem has led to a significant increase in the water cut in the produced fluid of oil wells, and a large amount of water resources have been produced ineffectively, increasing the production cost; the long well spacing makes it difficult for the oil reservoir pressure to conduct, resulting in a decrease in oil displacement efficiency and continuous decline in production. As an important means to improve the recovery rate of oil reservoirs, the water plugging and profile control technology has been widely used in oilfield development.

[0003] For example, CN103375153A discloses a method for profile control and water plugging in oilfields, which includes: injecting a polymerizable monomer and an initiator into the formation that needs profile control and water plugging, and a polymerization reaction occurs at the formation temperature. The polymerizable monomer contains at least one selected from maleic acid, itaconic acid, and 2-acrylamido-2-methylpropanesulfonic acid.

[0004] CN103374342A discloses a profile control and water plugging agent for oilfields. The profile control and water plugging agent for oilfields contains a polymerizable monomer, lignosulfonate, and an initiator, and the initiator is stored independently of the polymerizable monomer and the lignosulfonate. This solution also provides a method for profile control and water plugging in oilfields, which includes: injecting a polymerizable monomer, lignosulfonate, and an initiator into the formation that needs profile control and water plugging, and a polymerization reaction occurs at the formation temperature.

[0005] However, there are many limitations in the current research on the mechanism of water plugging and profile control. Existing research mostly relies on numerical simulation and theoretical analysis, lacking intuitive visualization experimental means, and it is difficult to directly observe the actual migration process and action effect of the plugging agent in the oil reservoir. The existing indoor small-scale experimental models are small in size, and only local phenomena can be observed. They cannot completely record the dynamic changes of the plugging agent during long-distance migration, and the well completion methods are single. Usually, only one well completion method can be simulated, and it is impossible to comprehensively study the influence of different well completion methods on the plugging effect.

[0006] Therefore, there is an urgent need to develop a large-size and high-pressure-resistant visualization model to more accurately simulate the actual oil reservoir conditions and deeply explore the actual effects and influencing factors of the water plugging and profile control technology. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for fabricating a visualization model of water shutoff and profile control in oil reservoirs and a visualization analysis method, so as to solve the defect that the mechanism of water shutoff and profile control cannot be visually studied at present.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a method for fabricating a visualization model of water shutoff and profile control in oil reservoirs, and the fabrication method includes:

[0010] Taking the injection well in the target oil reservoir as the origin and the production well as the acting point, a spatial coordinate structure is established, the well position of the production well is represented in the form of coordinate axes, and equal-proportion equivalence is carried out according to the X, Y, and Z directions of the coordinate axes to establish a model equivalence principle;

[0011] A visualization model is designed based on the model equivalence principle;

[0012] The length of the visualization model is ≥9000 mm, the width is ≥360 mm, and the thickness is ≥20 mm.

[0013] The method for fabricating the visualization model provided by the present invention can accurately simulate the actual reservoir conditions through the model equivalence method of coordinate equivalence, and can realize the fabrication of a large-size, high-pressure-resistant visualization large model, so as to deeply study the actual effects and influencing factors of water shutoff and profile control technologies.

[0014] As a preferred technical solution of the present invention, the model equivalence principle includes equally proportionally equivalenting the positions of the injection wells, the positions of the production wells, the depths of the injection wells, and the depths of the production wells according to the coordinate axes.

[0015] As a preferred technical solution of the present invention, the material for filling the simulated formation in the visualization model includes quartz sand.

[0016] Preferably, the thickness of the material for filling the simulated formation in the visualization model is <20 mm.

[0017] As a preferred technical solution of the present invention, a completion string is arranged on the side surface of the visualization model.

[0018] Preferably, the visualization model is configured with saturated simulated oil and simulated water of different colors.

[0019] As a preferred technical solution of the present invention, the visualization model includes: a main frame and a transparent material layer arranged on the main frame.

[0020] Preferably, a sealing strip is arranged between the main frame and the transparent material layer.

[0021] Preferably, the main body frame and the transparent material layer are connected by bolts and / or bonding.

[0022] In a second aspect, the present invention provides a visualization analysis method for water plugging and profile control in an oil layer, and the visualization analysis method includes:

[0023] Performing visualization analysis using the visualization model obtained by the production method described in the first aspect.

[0024] As a preferred technical solution of the present invention, the visualization analysis includes:

[0025] Injecting saturated simulated oil into the visualization model until the visualization model is filled with saturated simulated oil, and then performing a water flooding test;

[0026] After the water flooding test is completed, plugging and profile control are performed, and then injection parameters are collected, a relationship formula between the plugging efficiency and the injection parameters is established, and visualization analysis of the water plugging and profile control mechanism is performed.

[0027] As a preferred technical solution of the present invention, the injection rate of the saturated simulated oil is 10 - 15 mL / min.

[0028] Preferably, the injection rate of the simulated water in the water flooding test is obtained by equivalence based on the water line advance rate of the oil reservoir according to the model equivalence principle.

[0029] Preferably, in the water flooding test, a high-speed camera is used to take images at a frame rate ≥ 600 fps to record the advancing process of the oil-water interface.

[0030] As a preferred technical solution of the present invention, the plugging and profile control includes: injecting a water plugging agent into the production well or injecting a profile control agent into the injection well.

[0031] As a preferred technical solution of the present invention, the injection parameters include: the migration rate of the simulated water, the migration rate of the saturated simulated oil, the plugging area, the oil-bearing area, the distance from the water line front to the oil well end, and the water body swept volume.

[0032] Preferably, the relationship formula between the plugging efficiency and the injection parameters is established based on pressure data.

[0033] Preferably, the pressure data includes injection pressure, outlet pressure, and pressure gradient.

[0034] Preferably, the pressure gradient = |injection pressure - outlet pressure| ÷ the length of the visualization model.

[0035] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0036] (1) The visual large-scale model for enhancing oil recovery by plugging and profile control in oil reservoirs provided by the present invention and its manufacturing method provide an intuitive and reliable experimental platform for in-depth study of the water plugging and profile control mechanism through large-scale design, simulation of multiple types of well completion methods, and visualization technology, and have broad application prospects in the research and teaching in the field of oil exploitation.

[0037] (2) The length of the visual model obtained by the manufacturing method provided by the present invention is nearly 1 meter. The large-scale design enables it to more accurately simulate the actual reservoir conditions, effectively improving the reliability of experimental results. With the aid of this model, the degradation and plugging characteristics of the plugging agent during long-distance migration can be studied in depth, providing more valuable reference data for actual oilfield development.

[0038] (3) Through the dyeing fluid and high-speed video technology, the distribution and dynamic changes of the plugging agent in the pores can be visually observed, which helps to deeply understand the water plugging and profile control and profile control drive mechanism, and provides an intuitive basis for optimizing the water plugging and profile control plan.

[0039] (4) The setting of the simulation string for multiple types of well completion methods enables the model to simulate different types of production processes, greatly broadening the application scope of the experiment and providing a powerful tool for studying the influence of different well completion methods on the plugging effect. Specific Embodiments

[0040] To better illustrate the present invention and facilitate understanding of its technical solutions, the typical but non-limiting embodiments of the present invention are as follows:

[0041] Currently, there are many limitations in the research on the water plugging and profile control mechanism. Existing research mostly relies on numerical simulation and theoretical analysis, lacking intuitive visualization experimental means, and it is difficult to directly observe the actual migration process and action effect of the plugging agent in the oil reservoir. The existing indoor small-scale experimental models are small in size, and only local phenomena can be observed. The dynamic changes of the plugging agent during long-distance migration cannot be completely recorded, and the well completion methods are single, usually only able to simulate one well completion method, and it is impossible to comprehensively study the influence of different well completion methods on the plugging effect. Based on this, the present invention realizes the production of a large-scale visual model by adopting the equivalent principle of specific design, which can effectively simulate the actual reservoir conditions, and then explore the actual effects and influencing factors of the water plugging and profile control technology, as follows:

[0042] This embodiment provides a manufacturing method for a visual model of water plugging and profile control in an oil reservoir. The manufacturing method includes:

[0043] Taking the injection well of the target reservoir as the origin and the production well as the action point, a spatial coordinate structure is established, the well position situation of the production well is represented in the form of coordinate axes, and equal-proportion equivalence is carried out according to the X, Y, and Z directions of the coordinate axes to establish the model equivalence principle;

[0044] A visualization model is designed based on the model equivalence principle;

[0045] The length of the visualization model is ≥9000mm, the width is ≥360mm, and the thickness is ≥20mm.

[0046] Among them, the model equivalence principle includes equivalently positioning the injection well, production well, injection well depth, and production well depth according to the coordinate axes in proportion.

[0047] Among them, the material filling the simulated formation in the visualization model includes quartz sand.

[0048] In the present invention, the selection of the used quartz sand is specifically designed reasonably according to parameters such as the particle size distribution and permeability of the simulated target formation. Exemplarily, for a low-permeability reservoir, 80-mesh quartz sand, 100-mesh quartz sand, and 120-mesh quartz sand are mixed and blended; for a high-permeability reservoir, 40-mesh quartz sand, 60-mesh quartz sand, and 80-mesh quartz sand are mixed and blended.

[0049] Among them, the thickness of the material filling the simulated formation in the visualization model is <20mm. For example, it can be 18mm, 16mm, 14mm, 12mm, 10mm, 8mm, 6mm, or 5mm, etc., but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0050] Among them, a completion string is configured on the side of the visualization model.

[0051] In the present invention, different completion strings configured on the side can quickly combine and simulate different completion methods. Exemplarily, such as a perforated completion string and a screen completion string. The size of the completion string can be designed based on the actual string according to the model equivalence principle.

[0052] Among them, the visualization model is configured with saturated simulated oil and simulated water of different colors.

[0053] In the present invention, the colors of the saturated simulated oil and simulated water can be distinguished by adding a dyeing agent. For example, a red dyeing agent is added to the saturated simulated oil, and a blue dyeing agent is added to the simulated water. Then, by adjusting the flow rate and pressure of the injected simulated water and simulated oil, different types of production processes are simulated.

[0054] Among them, the visualization model includes: a main frame and a transparent material layer arranged on the main frame.

[0055] Among them, a sealing strip is arranged between the main frame and the transparent material layer.

[0056] Among them, the main frame and the transparent material layer are connected by bolts and / or bonding.

[0057] In the present invention, when fabricating the visualization model, the main frame can be made of high-strength stainless steel and is fabricated through precision machining and welding processes to ensure its stable structure and ability to withstand large pressures. The transparent material layer, such as transparent glass, uses special glass with high transparency and high strength, and is installed on the main frame after special treatment to form an internal simulation space, ensuring the visualization effect during the experiment.

[0058] Furthermore, this embodiment provides a visualization analysis method based on the visualization model obtained from the foregoing fabrication method. The visualization analysis includes:

[0059] Inject saturated simulated oil into the visualization model until the visualization model is filled with saturated simulated oil, and then conduct a water flooding experiment.

[0060] After the water flooding experiment is completed, conduct plugging and profile control, then collect injection parameters, establish a relationship between the plugging efficiency and injection parameters, and conduct a visualization analysis of the water shutoff and profile control mechanism.

[0061] Among them, the injection rate of the saturated simulated oil is 10 - 15 mL / min. For example, it can be 10 mL / min, 10.5 mL / min, 11 mL / min, 11.5 mL / min, 12 mL / min, 12.5 mL / min, 13 mL / min, 13.5 mL / min, 14 mL / min, 14.5 mL / min, or 15 mL / min, etc., but is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0062] Among them, the injection rate of the simulated water in the water flooding experiment is obtained by equivalence based on the water line advance rate of the oil reservoir according to the model equivalence principle.

[0063] Among them, in the water flooding experiment, a high-speed camera is used to take images at a frame rate ≥ 600 fps to record the process of the oil-water interface advancing.

[0064] In the present invention, in the water flooding experiment, it is possible to select key time nodes and special phenomena for marking, such as when the direction of water line advance changes, when the oil-water interface changes, or when water bypassing occurs.

[0065] In the present invention, when the water flooding front reaches the production well during the water flooding experiment, stop water injection, inject a water plugging agent from the production well, or inject a profile control agent from the injection well, thereby conducting plugging and profile control.

[0066] Among them, the plugging and profile control includes: injecting a water plugging agent into the production well or injecting a profile control agent into the injection well.

[0067] In the present invention, the water plugging agent used can be selected from commonly used water plugging agents in the art such as polymer gels and / or particulate plugging agents, etc.

[0068] In the present invention, displacement and profile control agents such as surfactant-based and / or polymer-based displacement and profile control agents commonly used in the art are used.

[0069] Among them, the injection parameters include: the migration velocity of simulated water, the migration velocity of saturated simulated oil, the plugging area, the oil-bearing area, the distance from the water line front to the wellhead, and the water body swept volume.

[0070] Preferably, the establishment of the relationship between the plugging efficiency and the injection parameters is based on pressure data.

[0071] Preferably, the pressure data includes injection pressure, outlet pressure, and pressure gradient.

[0072] Preferably, the pressure gradient = |injection pressure - outlet pressure| ÷ the length of the visualization model.

[0073] Furthermore, in order to clarify the visualization analysis effect that can be achieved by the oil reservoir water plugging and profile control visualization model obtained by the manufacturing method provided by the present invention, the following practical examples are used for illustration, specifically as follows:

[0074] Example 1

[0075] This example provides a visualization analysis process for oil reservoir water plugging and profile control, specifically as follows:

[0076] 1. Model fabrication

[0077] Select a transparent polymethyl methacrylate (PMMA) sheet with a thickness of 20 mm as the main model material, and process it into a visible board of 9600 mm × 420 mm × 20 mm according to precise dimensional requirements. Fabricate the stainless steel model shell according to the design requirements, and strictly control the dimensional accuracy during the processing to ensure that the shell has sufficient pressure resistance. Install multi-type well completion method simulation strings at symmetric positions on both sides of the model to construct a simulation injection-production system.

[0078] 2. Filling of simulated formation materials

[0079] Select white quartz sand with a suitable particle size distribution as the simulated formation material, fill it into the model, and adjust its permeability and other parameters through professional equipment and methods to make it as close as possible to the actual reservoir conditions.

[0080] 3. Injection of simulated oil and simulated water

[0081] Prepare simulated oil (white oil added with Sudan red dye) and simulated water (purified water added with methylene blue dye).

[0082] Inject the simulated oil and simulated water into the model through the injection-production system, and adjust their flow rates and pressures to simulate different types of production processes.

[0083] 4. Visualized video recording

[0084] Set up a visualized video recording device (such as a high-definition camera) outside the model, adjust the shooting angle and parameters to ensure that the changes in the oil-water distribution during the experiment can be clearly recorded.

[0085] The specific process is as follows:

[0086] (1) Oil saturation process: Inject simulated oil from the injection well at a speed of 10 mL / min, and use sensors to monitor the situation at the outlet end in real time until oil comes out at the outlet end and there is no water flow for 5 consecutive minutes.

[0087] (2) Water flooding experiment: Set the injection speed and inject simulated water.

[0088] (3) During the water flooding experiment, take images at a frame rate of 600 fps with a high-speed camera to record the process of the oil-water interface advancing.

[0089] (4) Plugging and profile control: When the water flooding front reaches the production well, stop water injection, inject a plugging agent from the production well, or inject a profile control agent from the injection well.

[0090] (5) Observation and recording: Observe the retention and plugging effect of the plugging agent in the high-permeability channel and record the changes in the oil-water liquid levels.

[0091] (6) Data processing: After the experiment, use professional data processing software to process and analyze the video data, extract parameters such as fluid migration speed and plugging area, and combine with pressure data to establish a relationship between the plugging efficiency and injection parameters, and deeply study the mechanism of water shutoff and profile control.

[0092] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0093] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any appropriate way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0094] In addition, any combination can be made between different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for making a visualization model of oil layer water plugging and profile control, characterized in that: The production method comprises: Taking the target reservoir water injection well as the origin and the production well as the action point, a spatial coordinate structure is established, the location of the production well is expressed in the form of a coordinate axis, and the X, Y, and Z directions of the coordinate axis are proportionally equivalent to establish the model equivalence principle; A visualization model is designed based on the model equivalence principle; The visualization model has a length ≥ 9000 mm, a width ≥ 360 mm, and a thickness ≥ 20 mm.

2. The method according to claim 1, characterized in that: The model equivalence principle includes proportionally equivalencing the position of the injection well, the position of the production well, the depth of the injection well and the depth of the production well according to the coordinate axes.

3. The method according to claim 1 or 2, characterized in that: The material used to fill the simulated strata in the visualization model includes quartz sand; Preferably, the thickness of the simulated stratum filled in the visualization model is less than 20 mm.

4. The method according to any one of claims 1 to 3, characterized in that: A completion string is disposed on the side of the visualization model; Preferably, the visualization model is configured with saturated simulated oil and simulated water of different colors.

5. The method according to any one of claims 1 to 4, characterized in that: The visualization model comprises: a main frame and a transparent material layer arranged on the main frame; Preferably, a sealing strip is provided between the main frame and the transparent material layer; Preferably, the main frame and the transparent material layer are connected by bolts and / or bonding.

6. A visual analysis method for oil layer water plugging and profile control, characterized in that: The visual analysis method comprises: The visualization model obtained by the preparation method according to any one of claims 1 to 5 is used for visualization analysis.

7. The visualization analysis method according to claim 6, characterized in that: The visual analysis includes: Injecting saturated simulated oil into the visualization model until the visualization model is full of saturated simulated oil, and then performing a water-flooding oil test; After the water drive oil test, plugging and displacement were carried out, and then the injection parameters were collected, the relationship between plugging efficiency and injection parameters was established, and a visual analysis of the water plugging and profile control mechanism was carried out.

8. The visualization analysis method according to claim 6 or 7, characterized in that: The injection speed of the saturated simulated oil is 10-15 mL / min; Preferably, the injection rate of simulated water in the water flooding test is obtained by equivalently calculating the waterline advancement rate of the reservoir based on the model equivalence principle; Preferably, in the water-to-oil drive test, a high-speed camera is used to capture images at a frame rate of ≥600 fps to record the oil-water interface advancement process.

9. The visualization analysis method according to any one of claims 6 to 8, characterized in that: The plugging and displacement control includes: injecting a water plugging agent into the production well or injecting a displacement control agent into the injection well.

10. The visualization analysis method according to any one of claims 6 to 9, characterized in that: The injection parameters include: the migration velocity of simulated water, the migration velocity of saturated simulated oil, the plugging area, the oil-bearing area, the distance between the waterline front and the oil well end, and the water body swept volume; Preferably, the relationship between the plugging efficiency and the injection parameters is established based on pressure data; Preferably, the pressure data includes injection pressure, outlet pressure and pressure gradient; Preferably, the pressure gradient=|injection pressure-outlet pressure|÷length of the visualization model.