Gel breaking liquid evaluation device

Abstract

The utility model provides a gel breaking liquid evaluation device which comprises a gel breaking container, solidified gel and gel breaking liquid to be evaluated are contained in the gel breaking container, and the gel and the gel breaking liquid are arranged to be close to the outlet end and the inlet end of the gel breaking container respectively and make contact with each other in an end-to-end mode in the initial state of the device. The device further comprises a drying oven used for simulating the temperature condition in the shaft, and the gel breaking container is arranged in the drying oven. The device further comprises a pressurizing device used for pressurizing the gel breaking container so as to simulate the pressure building state in the shaft in the gel breaking process. According to the utility model, the actual working condition of the temporary plugging gel breaking operation in the shaft is specifically simulated, and the evaluation accuracy of the gel breaking liquid and the field applicability of the screened gel breaking liquid are favorably improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of oilfield development tests, and particularly relates to a gel breaker evaluation device. Background Art

[0002] Gels (or liquid plugs) are widely used in wellbore temporary plugging fields such as annulus pressure control, sectional water shutoff, sectional fracturing, temporary plugging and leakage control, and potential tapping of old wells. With the continuous increase of deep wells and high-pressure wells, more and more wellbore operations have put forward higher requirements for the strength of gels. High-strength gels such as nano gels, multi-component polymer gels, multi-crosslinked gels, and inorganic gels have emerged one after another. However, the core requirement of temporary plugging operations is "capable of plugging and releasing". Although these gels can meet the pressure-bearing (plugging) requirements during temporary plugging and sealing operations, it is quite difficult to remove the gel blockage (release) after the sealing operation. It has to cost to use mechanical drilling and grinding to remove the blockage, and for gels with too high viscosity, drilling and grinding may not have good effects. "Plugging and releasing" has always been the focus of attention of scholars at home and abroad. With the increase in gel strength, gel breaking has also become a difficult point (gel breaking is also called gel breaker). High-strength gels and rapid gel breaking seem to be an irreconcilable contradiction. Especially in medium-low temperature reservoirs (<120 °C), most gels have low strength under low temperature conditions. To meet the requirements of pressure-bearing operations, it is necessary to increase the strength of gels, but after reaching high strength, gel breaking is a thorny problem.

[0003] Injecting a gel breaker is one of the most economical methods to remove gel blockage in the wellbore. The aspect ratio of the on-site wellbore (i.e., the ratio of the wellbore length to the wellbore diameter) is very large. During the actual wellbore gel breaking process, the gel plugging the wellbore and the gel breaker can only be in end-to-end contact, and the contact area is very small. However, there is no unified standard for the experimental evaluation method of screening gel breakers for gel blockage in the wellbore at present. Most still adopt the experimental evaluation method for removing particle plugging agents in the wellbore, cutting the gel into pieces and soaking it in the gel breaker to evaluate the effect of the gel breaker, and then screening the gel breaker system. There is no experimental device that specifically simulates the end-to-end contact state of the gel breaking process in the wellbore with a high aspect ratio. The huge difference between the gel breaking state in the experimental evaluation process and the actual gel breaking state leads to the unsatisfactory on-site use effect of the system screened by the existing evaluation method. Therefore, it is urgent to design a targeted gel breaker evaluation device according to the specific working conditions of the wellbore temporary plugging gel to simulate the state of the wellbore temporary plugging gel breaking, realize the accurate evaluation of the gel breaker, and improve the on-site applicability of the screened gel breaker. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a gel breaker evaluation device, which can improve the accuracy of gel breaker evaluation by specifically simulating the gel breaking state and process of the temporary plugging gel in the wellbore, ultimately improve the on-site applicability of the screened gel breaker, and better guide production.

[0005] According to the present utility model, a gel breaker evaluation device is provided, which includes a gel breaking container. The gel breaking container contains a cured gel and a gel breaker to be evaluated. Among them, the gel and the gel breaker are arranged to be respectively close to the outlet end and the inlet end of the gel breaking container, and are in end-to-end contact with each other in the initial state of the device.

[0006] In a preferred embodiment, the gel breaking container is a pressure-resistant pipe with a length-to-diameter ratio higher than 100, which is used to simulate the gel breaking environment in the wellbore.

[0007] In a preferred embodiment, a plurality of the gel breaking containers are included, which are used to evaluate multiple gel breakers simultaneously.

[0008] In a preferred embodiment, the device further includes an oven, which is used to simulate the temperature conditions in the wellbore, and the gel breaking container is arranged in the oven.

[0009] In a preferred embodiment, the device further includes a pressurizing device, which is used to pressurize the gel breaking container to simulate the pressure buildup state during the gel breaking process in the wellbore.

[0010] In a preferred embodiment, the pressurizing device includes a peristaltic pump and a liquid storage tank. The peristaltic pump pumps the liquid in the liquid storage tank into the gel breaking container to pressurize the gel breaking container.

[0011] In a preferred embodiment, the pressurizing device further includes a six-way valve, which is arranged between the peristaltic pump and the gel breaking container and is used to control the volume of the liquid pumped by the peristaltic pump into the gel breaking container.

[0012] In a preferred embodiment, the pressurizing device further includes a pressure gauge, which is arranged on the six-way valve and is used to monitor the pressure at the inlet end of the gel breaking container. The six-way valve and the peristaltic pump are configured to close when the reading of the pressure gauge reaches a set value, which is used to simulate the pressure buildup state during the gel breaking process in the wellbore.

[0013] In a preferred embodiment, the device further includes a bracket arranged in the oven and a clamping device installed on the bracket. The clamping device includes two semi-circular clamps, which are used to clamp the outer periphery of the gel breaking container in a snap-fit manner.

[0014] In a preferred embodiment, the clamping device is configured to be rotatable, so as to keep the gel breaking container in a horizontal state or a vertical state, which is used to simulate the gel breaking process in the horizontal well section or the vertical well section.

[0015] The present utility model has at least the following technical effects:

[0016] The gel breaker evaluation device provided by the present utility model includes a gel breaking container, in which a solidified gel and a gel breaker to be evaluated are contained. Among them, the gel and the gel breaker are arranged to be respectively close to the outlet end and the inlet end of the gel breaking container, and are in end-to-end contact with each other in the initial state of the device. The gel breaker evaluation device further includes an oven to simulate the temperature conditions in the wellbore, and the gel breaking container is arranged in the oven. The gel breaker evaluation device further includes a pressurizing device for pressurizing the gel breaking container to simulate the pressure buildup state during the gel breaking process in the wellbore. The gel breaker evaluation device provided by the present utility model specifically simulates the end-to-end contact between the gel and the gel breaker in the initial stage of the temporary plugging gel breaking in the on-site wellbore, the temperature conditions in the wellbore, and the pressure buildup state during the temporary plugging gel breaking process in the wellbore, which is closer to the actual working conditions of the temporary plugging gel breaking in the wellbore, and is beneficial to improving the accuracy of the gel breaker evaluation and the on-site applicability of the selected gel breaker.

[0017] The gel breaking container of the gel breaker evaluation device provided by the present utility model is a pressure-resistant pipe with a length-to-diameter ratio higher than 100, which is closer to the actual working conditions of the temporary plugging gel breaking in the wellbore, and is also beneficial to improving the accuracy of the gel breaker evaluation and the on-site applicability of the selected gel breaker.

[0018] The gel breaker evaluation device provided by the present utility model includes a plurality of gel breaking containers, which can evaluate multiple gel breakers simultaneously and improve the evaluation efficiency of the gel breaker.

[0019] The gel breaker evaluation device provided by the present utility model includes a bracket arranged in the oven and a clamping device installed on the bracket. The clamping device includes two semi-circular jigs for clamping the outer periphery of the gel breaking container in a snap-fit manner. The clamping device is configured to be rotatable so that the gel breaking container can be kept in a horizontal state or a vertical state to simulate the gel breaking process in the horizontal well section or the vertical well section. Moreover, under the support and clamping action of the bracket and the clamping device installed on the bracket, the gel breaking container does not contact the inner wall of the oven, is heated more evenly during the gel breaking process, reduces the error caused by uneven heating of the gel breaking container to the gel breaker evaluation result, and is also beneficial to improving the accuracy of the gel breaker evaluation of the gel breaker evaluation device and the on-site applicability of the selected gel breaker, and is more suitable for guiding the on-site gel breaking operation in the wellbore. Description of the Drawings

[0020] Figure 1Schematically shows an overall structural diagram of a gel breaker evaluation device according to an embodiment of the present utility model. Among them, 1 - pressurizing device; 11 - peristaltic pump; 12 - liquid storage tank; 13 - water; 14 - six-way valve; 15 - pressure gauge; 2 - oven; 3 - gel breaking container; 31 - inlet end of the gel breaking container; 32 - outlet end of the gel breaking container; 33 - solidified gel; 34 - gel breaker to be evaluated; 4 - bracket; 5 - clamping device.

[0021] In this application, all the drawings are schematic drawings, only used to illustrate the principle of the present utility model and are not drawn according to the actual ratio. Detailed implementation manners

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0023] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by the terms "bottom", "top", "inner", "upper", "lower", "near", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0024] In the present utility model, unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0025] Such as Figure 1As shown in the figure, an embodiment of the present utility model provides a gel breaker evaluation device, which includes a gel breaking container 3. The gel breaking container 3 contains a solidified gel 33 and a gel breaker 34 to be evaluated. Among them, the gel and the gel breaker are arranged to be respectively close to the outlet end 32 and the inlet end 31 of the gel breaking container, and are in end-to-end contact with each other in the initial state of the gel breaker evaluation device. The type of the solidified gel 33 can be the gel that has been injected in the well section where gel breaking and plug removal are required, or the gel that is expected to be injected into the wellbore for temporary plugging and for which the best gel breaker for subsequent gel breaking needs to be screened. The dosage between the solidified gel 33 and the gel breaker 34 to be evaluated can be adjusted according to on-site needs.

[0026] When breaking and removing the plug of the temporary plugging gel in the on-site wellbore with a high length-to-diameter ratio, generally, a gel breaker is injected into the wellbore. When the gel breaker is just injected into the wellbore, it cannot penetrate into the interior of the gel and the gap between the gel and the inner wall of the gel breaking container. At this time, the gel breaker and the gel in the wellbore are in end-to-end contact with each other. In the gel breaker evaluation device provided by the present utility model, the gel breaking container 3 contains a solidified gel 33 and a gel breaker 34 to be evaluated. Among them, the gel and the gel breaker are arranged to be respectively close to the outlet end 32 and the inlet end 31 of the gel breaking container, and are in end-to-end contact with each other in the initial state of the gel breaker evaluation device. This is consistent with the contact state between the gel breaker and the gel when the gel breaker is just injected during the operation of breaking and removing the plug of the temporary plugging gel in the on-site wellbore. That is to say, when the gel breaker evaluation device provided by the present utility model is operated, the gel breaker is evaluated in the same initial state as the actual working condition of breaking the temporary plugging gel in the on-site wellbore. This is crucial for improving the accuracy of the gel breaker evaluation result and the on-site applicability of the selected gel breaker.

[0027] In one embodiment, the gel breaker container 3 is a pressure-resistant pipe with a length-to-diameter ratio higher than 100. The on-site wellbore has a very large length-to-diameter ratio. During the gel breaking process in a wellbore with such a high length-to-diameter ratio, since the contact area between the gel breaker fluid and the gel is very small, while the length of the gel column formed by the gel solidification in the wellbore is very long, it will seriously affect the gel breaking speed of the gel breaker fluid. The gel breaker fluid selected without considering the length-to-diameter ratio factor of the wellbore is difficult to achieve an ideal gel breaking effect in the gel breaking operation of the wellbore temporary plugging gel. On the premise of realizing the important influence of the high length-to-diameter ratio factor of the wellbore on the evaluation of the gel breaker fluid, in this embodiment, the gel breaker container 3 is set as a pressure-resistant pipe with a length-to-diameter ratio higher than 100, considering the high length-to-diameter ratio factor of the wellbore, fully simulating the physical form of the wellbore, and more pertinently simulating the gel breaking environment in the wellbore. Further, in this embodiment, the gel breaker fluid evaluation device includes a plurality of the gel breaker containers 3, which can evaluate multiple gel breaker fluids simultaneously, and can also screen suitable gel breaker fluids for multiple gels. In the illustrated embodiment, the gel breaker fluid evaluation device includes 8 gel breaker containers 3, and can evaluate no more than 8 gel breaker fluids simultaneously, or screen suitable gel breaker fluids for no more than 8 gels simultaneously, which can greatly improve the evaluation efficiency of the gel breaker fluid, is conducive to quickly understanding the gel breaking ability of multiple gel breaker fluids, and quickly matches a suitable gel breaker fluid for the target gel that needs to be broken.

[0028] In one embodiment, the pressure-resistant pipe is generally a steel pipe, and the internal pressure resistance strength of the steel pipe only needs to be consistent with that of the target wellbore.

[0029] In one embodiment, the gel breaker fluid evaluation device further includes an oven 2 for simulating the temperature conditions in the wellbore, and the gel breaker container 3 is arranged in the oven 2. The temperature setting in the oven 2 can be determined according to the temperature in the wellbore of the wellbore where temporary plugging gel breaking is required. The gel breaker container 3 is arranged in the oven 2, and the oven 2 can be used to make the gel and the gel breaker fluid approach the outlet end 32 and the inlet end 31 of the gel breaker container respectively, and contact end to end with each other in the initial state of the device. Specifically, first, the gel is injected from the inlet end 31 of the gel breaker container, baked in the oven 2 to solidify the gel, and a solidified gel 33 is formed near the outlet end 32 of the gel breaker container. Then, the gel breaker fluid 34 to be evaluated is injected into the gel breaker container 3, and the gel breaker fluid 34 to be evaluated approaches the inlet end 31 of the gel breaker container, so that the solidified gel 33 and the gel breaker fluid 34 to be evaluated contact end to end with each other in the initial stage of the gel breaker fluid evaluation device.

[0030] In one embodiment, the breaker fluid evaluation device further includes a pressurizing device 1 for pressurizing the breaker container 3 to simulate the pressure buildup state during the breaker process in the wellbore. In this embodiment, the pressurizing device 1 includes a peristaltic pump 11 and a liquid storage tank 12. The liquid storage tank 12 contains a liquid, which is water 13 in this embodiment. The peristaltic pump 11 and the liquid storage tank 12 are connected by a pipeline. During the evaluation of the breaker fluid, the peristaltic pump 11 pumps the water 13 in the liquid storage tank 12 into the breaker container 3 to pressurize the breaker container 3. In this embodiment, the pressurizing device 1 further includes a six-way valve 14. The six-way valve 14 is arranged between the peristaltic pump 11 and the breaker container 3 and is used to control the volume of water 13 pumped by the peristaltic pump 11 into the breaker container 3, thereby controlling the pressurizing degree of the breaker container 3. In this embodiment, the pressurizing device 1 further includes a pressure gauge 15. The pressure gauge 15 is arranged on the six-way valve 14 and is used to monitor the pressure at the inlet end 31 of the breaker container. The six-way valve 14 and the peristaltic pump 11 are configured to close when the reading of the pressure gauge 15 reaches a set value, so that the breaker container 3 maintains a pressure buildup state for a certain period of time to simulate the pressure buildup state during the breaker process in the wellbore. The outlet end 32 of the breaker container is configured to open for pressure relief after the pressure buildup state ends. The duration of the pressure buildup can be determined according to the on-site situation.

[0031] In one embodiment, the set value of the pressure at the inlet end 31 of the breaker container is 0.2 MPa - 1 MPa. It should be noted that this embodiment only provides a range of 0.2 MPa - 1 MPa for the pressurizing pressure during the breaker process of the temporary plugging gel in the wellbore under normal circumstances. In actual production, the set value of the pressure at the inlet end 31 of the breaker container can be adjusted according to the data of the on-site wellbore.

[0032] The present utility model specifically simulates the pressure buildup process in the wellbore during the breaker process of the temporary plugging gel in the field, where after the wellbore is filled with the breaker fluid, pumping continues and pressure is built up to accelerate the invasion of the breaker fluid into the gel, by setting the pressurizing device 1 in the breaker fluid evaluation device, the peristaltic pump 11, the liquid storage tank 12, the liquid contained in the liquid storage tank 12, the six-way valve 14 arranged between the peristaltic pump 11 and the breaker container 3, and the pressure gauge 15 arranged on the six-way valve. This is closer to the actual working conditions of the breaker process of the temporary plugging gel in the wellbore and helps to accurately evaluate the breaker fluid.

[0033] In one embodiment, the breaker fluid evaluation device further includes a bracket 4 disposed in the oven 2 and a clamping device 5 mounted on the bracket 4. The clamping device 5 includes two semi-circular clamps (not shown in the figure) for clamping the outer periphery of the breaker container 3 in a snap-fit manner. Supported and clamped by the bracket 4 and the clamping device 5, the breaker container 3 does not contact the inner wall of the oven 2 and is in a state of uniform heating, avoiding the problem that the breaker process is affected by uneven local heating of the breaker container 3, which in turn brings errors to the screening results of the breaker fluid.

[0034] In one embodiment, the clamping device 5 is configured to be rotatable so that the breaker container 3 can be kept in a horizontal state or a vertical state, for simulating the breaker process in a horizontal well section or a vertical well section. For example, by rotating the clamping device 5 to keep the breaker container 3 in a horizontal state, the breaker process in the horizontal well section is simulated; or for another example, by rotating the clamping device 5 to keep the breaker container 3 in a vertical state, the breaker process in the vertical well section is simulated.

[0035] The operation of the breaker fluid evaluation device according to the present invention is as follows.

[0036] First, according to the actual situation, determine the gel for which the most suitable breaker fluid needs to be screened and the breaker fluid to be evaluated, and confirm the dosage ratio, total volume of the two, the temperature of gel curing, and the temperature during the breaker fluid evaluation process. Weigh the gel and the breaker fluid to be evaluated separately and set them aside for use.

[0037] Then, inject a set volume of gel into the breaker container 3 from the inlet end 31 of the breaker container. After sealing, place the breaker container 3 filled with gel into the oven 2. At this time, the clamping device 5 disposed on the bracket 4 in the oven 2 can be rotated, and then the two semi-circular clamps of the clamping device 5 are used to clamp the outer periphery of the breaker container 3 in a snap-fit manner to keep the breaker container 3 in a vertical state. Adjust the oven 2 to the set gel curing temperature to cure the gel in the breaker container 3, and a cured gel 33 is formed near the outlet end 32 of the breaker container. Then take out the breaker container 3 from the oven, and then inject a set volume of the breaker fluid 34 to be evaluated into the breaker container 3 from the inlet end 31 of the breaker container. The breaker fluid 34 to be evaluated is near the inlet end 31 of the breaker container. At this time, in the initial state of the breaker fluid evaluation device, the cured gel 33 and the breaker fluid 34 to be evaluated are in end-to-end contact with each other.

[0038] Next, place the gel breaker container 3 back into the oven 2, rotate the clamping device 5 installed on the bracket 4 inside the oven 2, and then clamp the outer periphery of the gel breaker container 3 in a snap-fastening manner by the two semi-circular clamps of the clamping device 5 to keep the gel breaker container 3 in a horizontal or vertical state. Connect the pipelines between the various parts of the gel breaker evaluation device, confirm that the temperature of the oven 2 is set to the pre-determined gel breaking temperature, turn on the peristaltic pump 11, extract the liquid from the liquid storage tank 12, and pump it into the gel breaker container 3 through the six-way valve 14 to pressurize the gel breaker container 3. Monitor the reading of the pressure gauge 15. When the pressure gauge 15 shows that the pressure at the inlet end 31 of the gel breaker container reaches 0.2 MPa - 1 MPa, close the switches of each pipeline of the six-way valve 14, and then turn off the peristaltic pump 11 to keep the gel breaker container 3 in a pressure-holding state. After holding the pressure for a certain period of time, open the outlet end 32 of the gel breaker container to relieve the pressure, check the gel breaking state of the solidified gel 33 in the gel breaker container 3, and evaluate the gel breaker liquid.

[0039] The following is an operation example of the gel breaker evaluation device provided by the present utility model.

[0040] For acrylamide monomer gel, evaluate the gel breaker liquid composed of "water + hydrogen peroxide + sodium hydroxide" (where the mass of water is counted as 100%, hydrogen peroxide accounts for 3 wt%, and sodium hydroxide accounts for 2 wt%). Among them, the gel breaker container 3 uses a steel pipe with a length-to-diameter ratio of 200. The volume ratio of the acrylamide monomer gel initial solution to the gel breaker liquid is 1:2. The gel curing temperature is set to 80 °C, and the temperature during the gel breaking process is also set to 80 °C. The specific operations are as follows:

[0041] 1) Add acrylamide monomer gel initial solution with a volume of one-third of the volume of the gel breaker container 3 into the gel breaker container 3. After sealing, rotate the clamping device 5 installed on the bracket 4 inside the oven 2, and then clamp the outer periphery of the gel breaker container 3 in a snap-fastening manner by the two semi-circular clamps of the clamping device 5 to keep the gel breaker container 3 in a vertical state. Set the temperature of the oven 2 to 80 °C. After the acrylamide monomer gel initial solution ages in the oven 2 for 6 h, it solidifies into a gel, and a solidified gel 33 is formed near the outlet end 32 of the gel breaker container. Then, take out the gel breaker container 3, and inject the set volume of the gel breaker liquid 34 to be evaluated into the gel breaker container 3 from the inlet end 31 of the gel breaker container. The gel breaker liquid 34 to be evaluated is near the inlet end 31 of the gel breaker container. At this time, in the initial state of the gel breaker evaluation device, the solidified gel 33 and the gel breaker liquid 34 to be evaluated are in end-to-end contact with each other.

[0042] 2) Place the gel breaker container 3 back into the oven 2, rotate the clamping device 5 installed on the bracket 4 inside the oven 2, and then clamp the outer periphery of the gel breaker container 3 in a snap-fastening manner by the two semi-circular clamps of the clamping device 5 to keep the gel breaker container 3 in a vertical state, simulating the gel breaking process in the vertical well section; According to Figure 1Connect the pipelines between the devices, open the six-way valve 14, and then turn on the peristaltic pump 11 to pump water 13 into the gel-breaking container 3. During this period, observe the reading of the pressure gauge 15 set on the six-way valve 14. When the pressure gauge 15 shows that the pressure at the inlet end 31 of the gel-breaking container reaches 0.5 MPa, close the pipelines of the six-way valve 14, and then turn off the peristaltic pump 11 to keep the gel-breaking container 3 under pressure for 24 h. Then open the outlet end 32 of the gel-breaking container to relieve the pressure and observe the degradation state of the acrylamide monomer gel in the gel-breaking container.

[0043] The experimental results show that the acrylamide monomer gel is completely degraded after being under pressure for 24 h, proving that the gel-breaking liquid composed of "water + hydrogen peroxide + sodium hydroxide" (where the mass of water is counted as 100%, hydrogen peroxide accounts for 3 wt%, and sodium hydroxide accounts for 2 wt%) has good gel-breaking performance for the acrylamide monomer gel.

[0044] Evaluation result verification: In a vertical well section where acrylamide monomer gel is internally solidified on-site, inject the above-mentioned evaluated gel-breaking liquid composed of "water + hydrogen peroxide + sodium hydroxide" (where the mass of water is counted as 100%, hydrogen peroxide accounts for 3 wt%, and sodium hydroxide accounts for 2 wt%) with a volume twice that of the acrylamide monomer gel in the wellbore. The temperature during the gel-breaking process in the wellbore is also 80°C. The results show that the acrylamide monomer gel solidified in the on-site vertical well section is completely degraded. The above-mentioned evaluated gel-breaking liquid composed of "water + hydrogen peroxide + sodium hydroxide" (where the mass of water is counted as 100%, hydrogen peroxide accounts for 3 wt%, and sodium hydroxide accounts for 2 wt%) has good gel-breaking performance for the acrylamide monomer gel in the on-site wellbore, proving that the results obtained by evaluating the gel-breaking liquid through the gel-breaking liquid evaluation device provided by the present invention are accurate, and the selected gel-breaking liquid has good on-site applicability.

[0045] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and its components can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A gel breaker evaluation device, characterized in that, Comprising: A gel breaker container filled with solidified gel and gel breaker fluid to be evaluated. The gel and the gel breaker fluid are arranged to be respectively close to the outlet end and the inlet end of the gel breaker container, and are in end-to-end contact with each other in the initial state of the device. The gel breaker container is a pressure-resistant pipe with a length-to-diameter ratio higher than 100, used to simulate the gel breaking environment in the wellbore. An oven for simulating the temperature conditions in the wellbore, with the gel breaker container disposed therein. A pressurizing device for pressurizing the gel breaker container to simulate the pressure build-up state during the gel breaking process in the wellbore.

2. The device according to claim 1, characterized in that, Comprising a plurality of the gel breaker containers for simultaneously evaluating multiple gel breaker fluids.

3. The device according to claim 1, characterized in that The pressurizing device includes a peristaltic pump and a liquid storage tank. The peristaltic pump pumps the liquid in the liquid storage tank into the gel breaker container to pressurize the gel breaker container.

4. The device according to claim 3, characterized in that, The pressurizing device further includes a six-way valve disposed between the peristaltic pump and the gel breaker container for controlling the volume of the liquid pumped by the peristaltic pump into the gel breaker container.

5. The device according to claim 4, characterized in that, The pressurizing device further includes a pressure gauge disposed on the six-way valve for monitoring the pressure at the inlet end of the gel breaker container. The six-way valve and the peristaltic pump are configured to close when the pressure gauge reading reaches a set value, for simulating the pressure build-up state during the gel breaking process in the wellbore.

6. The device according to claim 1, characterized in that The device further includes a bracket disposed in the oven and a clamping device mounted on the bracket. The clamping device includes two semi-circular clamps for clamping the outer periphery of the gel breaker container in a snap-fit manner.

7. The device according to claim 6, characterized in that The clamping device is configured to be rotatable so that the gel breaker container can be maintained in a horizontal state or a vertical state, for simulating the gel breaking process in the horizontal well section or the vertical well section.

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