A system and method for evaluating bridge plug breakthrough pressure of a temporary plugging chemical

Abstract

This invention provides a system for evaluating the breakthrough pressure of temporarily plugged chemical bridge plugs, comprising: a high-temperature oven; a breakthrough pressure main device for holding the base fluid of the temporarily plugged chemical bridge plug, which can be arranged inside the high-temperature oven, the breakthrough pressure main device having an inlet pipeline and an outlet pipeline; a horizontal flow pump for injecting a displacement medium, the horizontal flow pump being connected to the inlet pipeline; a first pressure sensor and a second pressure sensor respectively installed on the inlet pipeline and the outlet pipeline; a pressure sensor workstation connected to the first pressure sensor and the second pressure sensor for recording the data measured by the first pressure sensor and the second pressure sensor; and a camera for capturing the breakthrough process of the temporarily plugged chemical bridge plug. This invention also provides a method for evaluating the breakthrough pressure of temporarily plugged chemical bridge plugs.

Description

Technical Field

[0001] This invention belongs to the field of petroleum technology, specifically relating to a system for evaluating the breakthrough pressure of temporarily plugged chemical bridge plugs. This invention also relates to a method for evaluating the breakthrough pressure of temporarily plugged chemical bridge plugs. Background Technology

[0002] Looking at the global oil exploration landscape, the potential for discovering large, exploitable oil and gas fields on land and offshore is relatively low, and the exploitability of deep-sea oil and gas resources is limited by current technologies. To meet the demand for oil, the focus of current oil field exploration is on the exploration and development of oil fields under complex geological conditions, unconventional oil and gas resources, and the modification and potential tapping of mid- to late-stage oil fields.

[0003] In conventional oilfield drilling, long-term over-balanced drilling often leads to reservoir contamination and blockage. However, in the later stages of development, oil and gas reservoirs are in low-pressure zones, making under-balanced drilling technology a trend. Temporary chemical bridge plugs are used to seal the well fluid and crude oil using a high-strength gel. Taking advantage of the fact that drilled crude oil does not contaminate the well's reservoir, a certain length of gel slug is injected onto the top of the crude oil, and the injection of drilling fluid is adjusted based on formation pressure. Breakthrough pressure is a crucial indicator for evaluating the effectiveness of temporary chemical bridge plugs. However, both domestically and internationally, the evaluation of breakthrough pressure often uses profile control and water shut-off agents. These agents are injected into a core holder, gelled, and then displacing water is injected. The breakthrough pressure is calculated by measuring the pressure at the injection port. However, when using a core holder for evaluation, an artificial core must be placed inside. The permeability of the artificial core has a significant impact on the breakthrough pressure. Typically, using a low-permeability artificial core results in a breakthrough pressure tens of times higher than using a high-permeability artificial core.

[0004] Furthermore, since the inlet and outlet of the core holder are connected by 3 mm diameter pipes, the pressure is further inflated due to outlet blockage when evaluating the breakthrough pressure.

[0005] Therefore, there is an urgent need for a system and method for evaluating the breakthrough pressure of temporary plugging chemical bridge plugs that can effectively improve oilfield recovery. Summary of the Invention

[0006] To address the technical problems described above, this invention aims to propose a system and method for evaluating the breakthrough pressure of temporary plugged chemical bridge plugs. This method can effectively avoid the problem of inflated breakthrough pressure measured by the core holder evaluation method, and it is more accurate, which is very beneficial to improving oilfield recovery.

[0007] Therefore, according to a first aspect of the present invention, a system for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug is provided, comprising: a high-temperature oven; a breakthrough pressure main device for holding the base fluid of the temporarily plugged chemical bridge plug, which can be arranged inside the high-temperature oven, the breakthrough pressure main device having an inlet line and an outlet line; a horizontal flow pump for injecting a displacement medium, the horizontal flow pump being connected to the inlet line; a first pressure sensor and a second pressure sensor respectively disposed on the inlet line and the outlet line; a pressure sensor workstation connected to the first pressure sensor and the second pressure sensor for recording the data measured by the first pressure sensor and the second pressure sensor; and a camera for capturing the breakthrough process of the temporarily plugged chemical bridge plug.

[0008] In one embodiment, it further includes at least one intermediate container connected in the inlet line, the intermediate container being located between the advection pump and the breakthrough pressure main device.

[0009] In one embodiment, the pressure breakthrough device includes a tubing body and sealing heads fixedly connected to both ends of the tubing body, and the inlet pipeline and the outlet pipeline are respectively connected to the pressure breakthrough device through the corresponding sealing heads.

[0010] In one embodiment, the sealing head is made of Hastelloy.

[0011] In one embodiment, the pressure breaking body device is arranged inside the high-temperature oven via a model support, which enables the pressure breaking body device to rotate 180°.

[0012] In one embodiment, the model support includes a main support and a support base fixed inside the high-temperature oven, and the pressure breaking main device is adapted to be installed on the support base and is rotatable relative to the support base.

[0013] In one embodiment, a six-way valve is provided between the horizontal flow pump and the intermediate container, and the outlet end of the six-way valve is connected to the inlet end of each of the intermediate containers.

[0014] According to a second aspect of the present invention, a method for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug is provided, comprising the following steps:

[0015] Provide a system as described above for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug;

[0016] A predetermined amount of temporary plugging chemical bridging fluid is injected into the main body device for breaking through pressure.

[0017] The main device for breaking through pressure is arranged in the high-temperature oven through a model support, and the temperature of the high-temperature oven is set to the gelation temperature;

[0018] After the temporary plugging chemical bridge base liquid gels, the breakthrough pressure evaluation device is rotated 180° through the model support.

[0019] The advection pump is turned on to inject the displacement medium, and the injection pressure is measured by the first pressure sensor. At the same time, the camera is used to take pictures, and the changes in the injection pressure are observed by the workstation.

[0020] The advection pump 3 is shut off after the breakthrough pressure reaches its peak and then suddenly decreases, so as to obtain the peak value of the breakthrough pressure and thus obtain the breakthrough pressure of the temporarily plugged chemical bridge plug.

[0021] In one embodiment, the injection volume of the temporary plugging chemical bridging fluid into the breakthrough pressure body device is set according to the slug length.

[0022] In one embodiment, the advection pump is a constant speed and constant pressure advection pump with a flow rate of 0.01 ~ 10 mL / min and a pressure of less than 40 MPa.

[0023] Compared with the prior art, the advantages of this application are:

[0024] The system and method for evaluating the breakthrough pressure of temporary chemical bridge plugs according to the present invention, compared with the core holder evaluation method used in the prior art, provides breakthrough pressures that are more relevant to actual field applications and effectively avoid the problem of inflated breakthrough pressures determined by the core holder evaluation method. Furthermore, the method for evaluating the breakthrough pressure of temporary chemical bridge plugs according to the present invention is more accurate and closer to the actual field application results, which is of great significance for improving oilfield recovery. In addition, the system for evaluating the breakthrough pressure of temporary chemical bridge plugs according to the present invention has a simple structure, low cost, and is easy to operate, which helps to improve the evaluation efficiency of breakthrough pressure of temporary chemical bridge plugs. Attached Figure Description

[0025] The present invention will now be described with reference to the accompanying drawings.

[0026] Figure 1 The structure of a system according to the invention for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug is schematically shown.

[0027] Figure 2 This is the breakthrough process of the ZD-1 type temporary chemical bridge plug.

[0028] Figure 3 This is a breakthrough process for the ZD-2 type temporary chemical bridge plug.

[0029] Figure 4 This is a breakthrough process for the ZD-3 type temporary chemical bridge plug.

[0030] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0031] The present invention will now be described with reference to the accompanying drawings. It should be noted that these descriptions are provided merely to illustrate the principles of the invention and do not limit the scope of the invention.

[0032] Figure 1 The structure of a system 100 for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug, according to the present invention, is schematically shown. Figure 1 As shown, a system 100 for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug includes a high-temperature oven 1, a breakthrough pressure main unit 2, a horizontal flow pump 3, an intermediate container 4, a first pressure sensor 5, a second pressure sensor 6, a pressure sensor workstation 7, and a camera (not shown). The high-temperature oven 1 can be set to a predetermined temperature to simulate a high-temperature environment. The breakthrough pressure main unit 2 is used to hold the base liquid for the temporarily plugged chemical bridge plug and can be arranged inside the high-temperature oven 1. The breakthrough pressure main unit 2 has an inlet line 21 and an outlet line 22. The first pressure sensor 5 and the second pressure sensor 6 are respectively installed on the inlet line 21 and the outlet line 22 to measure the line pressure, and both the first pressure sensor 5 and the second pressure sensor 6 are connected to the workstation 7. The horizontal flow pump 3 is connected to the inlet line 21 and is used to inject the displacement medium. The workstation 7 is used to record the data measured by the first pressure sensor 5 and the second pressure sensor 6 and can transmit the data to a computer 12 connected to the workstation. The camera is used to film the breakthrough process of the temporarily plugged chemical bridge plug. The system 100 for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug according to the present invention calculates the actual breakthrough pressure of the temporarily plugged chemical bridge plug system by injecting a displacing medium and measuring the inlet pressure.

[0033] like Figure 1 As shown, the system 100 for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug also includes at least one intermediate container 4 connected in the inlet line 21, the intermediate container 4 being located between the advection pump 3 and the breakthrough pressure main unit 2. When multiple intermediate containers 4 are provided, they are arranged in parallel. Figure 1 In the illustrated embodiment, two intermediate containers 4 are provided, and the two intermediate containers 4 are connected in parallel. The intermediate containers 4 are used to hold the displacement medium. Under the action of the displacement water from the horizontal flow pump 3, the intermediate containers 4 can inject the displacement medium into the breakthrough pressure evaluation device 2. Preferably, the intermediate containers 4 can be made of stainless steel.

[0034] Preferably, the advection pump 3 is a constant-speed, constant-pressure advection pump. The flow rate of the advection pump 3 is 0.01 ~ 10 mL / min, and the pressure is less than 40 MPa.

[0035] A horizontal flow pump 3 is used to connect to deionized water 10. In one embodiment, a six-way valve 9 is provided between the horizontal flow pump 3 and the intermediate container 4. The outlet end of the six-way valve 9 is connected to the inlet end of each intermediate container 4. Figure 1 The lower end of the intermediate container 4 is connected to the outlet. A switch valve is installed at the outlet end of each intermediate container 4. A first pressure sensor 5 is installed at the junction of the outlet ends of each intermediate container 4 to measure the injection pressure in real time. Deionized water 10 is used as the displacement medium.

[0036] According to the present invention, the pressure breakthrough device 2 includes an oil pipe body and sealing heads fixedly connected to both ends of the oil pipe body. The inlet pipeline 21 and the outlet pipeline 22 are respectively connected to the pressure breakthrough device 2 through corresponding sealing heads. Figure 1 In the illustrated embodiment, the inlet line 21 is connected to a sealing head at the lower end of the breakthrough pressure main device 2, and the outlet line 22 is connected to a sealing head at the upper end of the breakthrough pressure main device 2. The breakthrough pressure main device 2 can be placed inside a high-temperature oven 1 for temporarily blocking the chemical bridge plug during gelation.

[0037] For example, in one implementation, the tubing body of the breakthrough pressure main unit 21 can be modified from a scrap tubing on site, with threads at both ends for fastening the sealing head. The sealing head is preferably made of Hastelloy alloy. This allows the breakthrough pressure main unit 21 to withstand temperatures up to 200°C and pressures up to 40 MPa. The Hastelloy sealing head can accommodate Hastelloy pipelines, and either end can be designated as the inlet.

[0038] According to the present invention, the breakthrough pressure main body device 2 is arranged in a high-temperature oven 1 via a model support 7, which is configured to allow the breakthrough pressure main body device 2 to rotate 180°. The model support 7 supports the breakthrough pressure main body device 2 and includes a main support and a support base fixed within the high-temperature oven 2. The breakthrough pressure main body device 2 is adapted to be mounted on the support base and can rotate relative to the support base. For example, the breakthrough pressure main body device 2 can be rotated with the support base via a bearing. Because the liquid deposits at the lower part of the main body device 2 after addition, the gel will be located at the lower part of the main body device 2 after gelation, while there will be some voids at the upper part. After gelation and rotation by 180°, the original lower part becomes the upper part, and the upper part becomes the lower part. Then, water is injected, and the water enters the new lower voids, thereby displacing the liquid upwards.

[0039] In one implementation, the model support 7 can be made of stainless steel.

[0040] like Figure 1 As shown, a beaker 11 is provided at the end of the outlet pipeline 22 for recovering the liquid discharged through the outlet pipeline 22.

[0041] According to the present invention, the workstation 7 is connected to the computer via signal. The workstation 7 is used to record the real-time pressure measured by the first pressure sensor 5 and the second pressure sensor 6, and can perform data analysis on the measured data. It can also generate a pressure curve over time, which is finally displayed on the computer 12.

[0042] According to the present invention, the high-temperature oven 1 is configured to adjust its internal temperature through a stepped heating mode, thereby enabling the high-temperature oven 1 to achieve temperature regulation, and the temperature inside the high-temperature oven 1 can be adjusted to reach 160°C. This makes it very convenient to provide a high-temperature environment.

[0043] According to the present invention, a method for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug is also provided, which uses the system 100 for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug as described above. The method for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug is described in detail below.

[0044] First, a system 100 for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug according to the present invention is provided.

[0045] Next, a predetermined amount of temporary plugging chemical bridging liquid is injected into the breakthrough pressure main body device 2. Specifically, the sealing head at one end of the breakthrough pressure main body device 2 is opened, and a predetermined amount of temporary plugging chemical bridging liquid is injected into the breakthrough pressure main body device 2, wherein the injection amount is set according to the gel length after gelation. After the injection of the temporary plugging chemical bridging liquid is completed, the sealing head is reinstalled, thereby encapsulating the temporary plugging chemical bridging liquid within the breakthrough pressure main body device 2.

[0046] Then, the breakthrough pressure main body device 2, which is injected with temporary plugging chemical bridge base liquid, is placed in the high temperature oven 1 through the model support 7, and the temperature of the high temperature oven 1 is set to the gelation temperature.

[0047] After the temporary plugging chemical bridge base liquid gels, the breakthrough pressure evaluation device 2 is rotated 180° through the model support 7.

[0048] Afterwards, the displacement medium is injected by the horizontal flow pump 3, and the injection pressure is measured by the first pressure sensor 5. At the same time, the camera takes pictures, and the change of injection pressure is observed by the workstation 7.

[0049] The advection pump 3 is shut off after the breakthrough pressure reaches its peak and then suddenly decreases. At this point, the peak breakthrough pressure is the breakthrough pressure of the temporarily plugged chemical bridge plug. Thus, the breakthrough pressure of the temporarily plugged chemical bridge plug is obtained.

[0050] Compared with the core holder evaluation method used in the prior art, the method for evaluating the breakthrough pressure of temporary plugged chemical bridge plugs according to the present invention has more practical significance in the field and can avoid the problem of inflated breakthrough pressure measured by the core holder evaluation method. Moreover, the method for evaluating the breakthrough pressure of temporary plugged chemical bridge plugs according to the present invention is more accurate and closer to the actual field application effect, which is of great significance for improving oilfield recovery.

[0051] To further illustrate the system and method of the present invention for evaluating the breakthrough pressure of temporarily plugged chemical bridge plugs, detailed descriptions are provided below with specific embodiments.

[0052] Example 1:

[0053] The breakthrough pressure of the ZD-1 type temporary plugged chemical bridge plug was evaluated using the system 100 for evaluating the breakthrough pressure of temporary plugged chemical bridge plugs according to the present invention, and the evaluation method described above was performed. The breakthrough process of the ZD-1 type temporary plugged chemical bridge plug is shown in Figure 2. As can be seen from Figure 2, the breakthrough process of the ZD-1 type temporary plugged chemical bridge plug is an intermediate breakthrough, which indicates that the ZD-1 type temporary plugged chemical bridge plug has good adhesion to the pipe wall, and the breakthrough pressure of the ZD-1 type temporary plugged chemical bridge plug is 960 kPa / m. In this embodiment, the temperature in the high-temperature oven 1 is 140°C, and the flow rate of the advection pump 3 is 10 mL / s.

[0054] Example 2:

[0055] The breakthrough pressure of the ZD-2 type temporary plugged chemical bridge plug was evaluated using the system 100 for evaluating the breakthrough pressure of temporary plugged chemical bridge plugs according to the present invention, and the evaluation method described above was performed. The breakthrough process of the ZD-2 type temporary plugged chemical bridge plug is shown in Figure 3. As can be seen from Figure 3, the breakthrough process of the ZD-2 type temporary plugged chemical bridge plug is intermediate bubbling breakthrough, which indicates that the ZD-2 type temporary plugged chemical bridge plug has good adhesion to the pipe wall and good viscoelasticity. The breakthrough pressure of the ZD-2 type temporary plugged chemical bridge plug was found to be 245 kPa / m. In this embodiment, the temperature inside the high-temperature oven 1 was 140°C, and the flow rate of the advection pump 3 was 10 mL / s.

[0056] Example 3:

[0057] The breakthrough pressure of the ZD-3 type temporary plugging chemical bridge plug was evaluated using the system 100 for evaluating the breakthrough pressure of temporary plugging chemical bridge plugs according to the present invention, and the evaluation method described above was performed. The breakthrough process of the ZD-3 type temporary plugging chemical bridge plug is shown in Figure 4. As can be seen from Figure 4, the breakthrough process of the ZD-3 type temporary plugging chemical bridge plug is an intermediate breakthrough, indicating that the ZD-3 type temporary plugging chemical bridge plug has good adhesion to the pipe wall, and the breakthrough pressure of the ZD-3 type temporary plugging chemical bridge plug is 2128 kPa / m. The breakthrough pressure of the ZD-3 type temporary plugging chemical bridge plug is relatively high, making it very suitable for application in blocks with harsh reservoir conditions. In this embodiment, the temperature in the high-temperature oven 1 is 140°C, and the flow rate of the advection pump 3 is 10 mL / s.

[0058] Therefore, by using the system 100 of the present invention for evaluating the breakthrough pressure of temporary plugging chemical bridge plugs to evaluate different temporary plugging chemical bridge plug systems using the evaluation method described above, and finally through comparative analysis, it can be concluded that the ZD-3 type temporary plugging chemical bridge plug has the highest breakthrough pressure and is the most suitable temporary plugging chemical bridge plug for reservoir conditions.

[0059] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0060] Furthermore, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug, comprising: High-temperature drying oven (1); The breakthrough pressure main device (2) for placing the temporary plugging chemical bridge base liquid can be arranged in the high temperature oven. The breakthrough pressure main device is provided with an inlet pipeline (21) and an outlet pipeline (22). A horizontal flow pump (3) for injecting the displacement medium, the horizontal flow pump being connected to the inlet pipeline; A first pressure sensor (5) and a second pressure sensor (6) are respectively installed on the inlet pipeline and the outlet pipeline. The pressure sensor workstation (7), connected to the first pressure sensor and the second pressure sensor, is used to record the data measured by the first pressure sensor and the second pressure sensor; and Camera used to film the breakthrough process of the temporarily plugged chemical bridge plug. The breakthrough pressure main device includes an oil pipe body and sealing heads fixedly connected to both ends of the oil pipe body. The inlet pipeline and the outlet pipeline are respectively connected to the breakthrough pressure main device through the corresponding sealing heads. The breakthrough pressure main device is arranged in the high temperature oven through a model bracket (8). The model bracket enables the breakthrough pressure main device to rotate 180°.

2. The system for evaluating bridge plug breakthrough pressure of a temporary plugging chemical of claim 1, wherein, It also includes at least one intermediate container (4) connected in the inlet pipeline, the intermediate container being located between the advection pump and the breakthrough pressure main device.

3. The system for evaluating bridge plug breakthrough pressure of a temporary plugging chemical of claim 2, wherein, The sealing head is made of Hastelloy alloy.

4. The system for evaluating the bridge plug breakthrough pressure of a temporary plugging chemical of claim 3, wherein, The model support includes a main support and a support base fixed inside the high-temperature oven. The pressure breaking main device is adapted to be installed on the support base and can rotate relative to the support base.

5. The system for evaluating bridging pressure of a temporary plugging chemical of claim 2, wherein, A six-way valve (9) is provided between the horizontal flow pump and the intermediate container, and the outlet end of the six-way valve is connected to the inlet end of each of the intermediate containers.

6. A method for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug, comprising the following steps: Provide a system for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug according to any one of claims 1 to 5; A predetermined amount of temporary plugging chemical bridging fluid is injected into the main body device for breaking through pressure. The main device for breaking through pressure is arranged in the high-temperature oven through a model support, and the temperature of the high-temperature oven is set to the gelation temperature; After the temporary plugging chemical bridge base liquid gels, the breakthrough pressure evaluation device is rotated 180° through the model support. The advection pump is turned on to inject the displacement medium, and the injection pressure is measured by the first pressure sensor. At the same time, the camera is used to take pictures, and the changes in the injection pressure are observed by the workstation. The advection pump (3) is shut off after the breakthrough pressure reaches its peak and then suddenly decreases to obtain the peak value of the breakthrough pressure, thereby obtaining the breakthrough pressure of the temporarily plugged chemical bridge plug.

7. The method for evaluating the breakthrough pressure of a temporarily plugged chemical bridge plug according to claim 6, characterized in that, The injection volume of the temporary plugging chemical bridging fluid into the main body device for breaking pressure is set according to the slug length.

8. The method for evaluating bridging pressure of a temporary plugging chemical bridge according to claim 6, characterized in that, The advection pump is a constant speed and constant pressure advection pump with a flow rate of 0.01 ~ 10 mL / min and a pressure of less than 40 MPa.

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