Evaluation device for water-non-dispersible cement paste

Abstract

The embodiment of the utility model relates to the technical field of oil and gas engineering, and discloses a water-non-dispersible cement paste evaluation device. The evaluation device for the water-non-dispersible cement paste comprises an inner container assembly and an outer container assembly. The inner container assembly is of a hollow structure and used for containing water-non-dispersed cement paste, the top of the inner container assembly is open, the bottom of the inner container assembly is closed, and the inner container assembly is sequentially provided with a first solid wall, a porous wall and a second solid wall from the open end to the closed end. The outer container assembly is arranged around the inner container assembly, a certain gap is formed between the outer container assembly and the inner container assembly, the outer container assembly is used for circulating liquid water, and the liquid water enters the inner container assembly through the porous wall and erodes the cement paste in the inner container assembly. According to the evaluation device for the water-non-dispersible cement slurry provided by the embodiment of the invention, the water erosion resistance of a cement slurry system can be intuitively observed and evaluated.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of oil and gas engineering, and particularly to a water-non-dispersible cement slurry evaluation device. Background Art

[0002] Oil and gas well cementing refers to the construction process of lowering a casing into a well and injecting cement slurry into the annular space between the wellbore and the casing during the drilling and completion operation. Generally, during the cementing operation, the hydrostatic pressure of the cement slurry is higher than the formation water pressure. Therefore, in high-water-content and highly permeable formations, the cement slurry leaks into the formation. During the waiting-for-setting process, the cement slurry experiences weight loss, resulting in a continuous decrease in the hydrostatic pressure generated by the cement slurry, and an increasing risk of formation water scouring and dispersing the cement slurry. If the water-non-dispersible effect of the cement slurry is poor, due to the dilution, dispersion, and migration of the formation water, the cement slurry will be carried away, causing the stability, thickening performance, mechanical properties, etc. of the cement slurry to deteriorate before the cement slurry develops sufficient strength, and even problems such as insufficient reverse height may occur, seriously affecting the cementing quality of the upper formation. Water-non-dispersible cement slurry can maintain the integrity of its own gel structure when water invasion occurs, has good water-non-dispersible and anti-scouring capabilities when encountering water, has good construction performance, can prevent the invasion of formation water, and ensure the bonding quality between the cement slurry, the casing, and the formation. Therefore, the water-non-dispersibility of the cement slurry system is one of the key factors affecting the cementing quality. Conducting an evaluation test on the water-non-dispersibility of the cement slurry system before cementing is a very important step.

[0003] The evaluation of existing water-non-dispersible cement slurry often involves pouring the cement slurry into water and observing the erosion of the water on the cement slurry to judge the quality of the water-non-dispersible slurry system. This rough judgment method has a large subjective factor and poor accuracy. It is necessary to design a set of evaluation devices for the non-dispersible cement slurry system to visually observe and evaluate the water erosion resistance of the cement slurry system. Utility Model Content

[0004] The purpose of the embodiments of the present application is to provide a water-non-dispersible cement slurry evaluation device that can visually observe and evaluate the water erosion resistance of the cement slurry system.

[0005] To solve the above technical problems, the embodiments of the present application provide a water-non-dispersible cement slurry evaluation device, which includes an inner container assembly and an outer container assembly. The inner container assembly has a hollow structure for placing the water-non-dispersible cement slurry. The top of the inner container assembly is open and the bottom is closed. The inner container assembly is sequentially provided with a first solid wall, a porous wall, and a second solid wall from the open end to the closed end. The outer container assembly is arranged around the inner container assembly and forms a certain gap with the inner container assembly. The outer container assembly is used for circulating liquid water, and the liquid water enters the inner container assembly through the porous wall and erodes the cement slurry in the inner container assembly.

[0006] The water-insoluble cement slurry evaluation device provided by the embodiments of the present application, by setting the inner container assembly, after the prepared cement slurry is cured in an atmospheric thickening instrument for 20 minutes, it is poured into the inner container assembly and weighed, and then the inner container assembly is placed in the outer container assembly. Liquid water enters the inner container assembly through the porous wall of the inner container assembly and erodes the cement slurry. After the cement slurry is completely solidified, the inner container assembly is taken out and weighed, and the external corrosion condition of the cement slurry is observed from the porous wall, and the mass loss of the cement slurry is calculated, so as to evaluate the water erosion resistance of the cement slurry. In this way, the water erosion resistance of the cement slurry system can be visually observed and evaluated.

[0007] In some embodiments, the outer container assembly is provided with an outlet and an inlet, and the inlet and the outlet are axially located at both ends of the porous wall respectively.

[0008] In some embodiments, the inlet is arranged at the lower end of one side of the outer container assembly, and the outlet is arranged at the upper end of the other side of the outer container assembly.

[0009] In some embodiments, a water pump is connected to the inlet.

[0010] In some embodiments, the water pump is a booster water pump and is connected to the outlet to form a water cycle, and a sealing cover is arranged at the top of the outer container assembly.

[0011] In some embodiments, the porous wall is a screen structure.

[0012] In some embodiments, the mesh number of the screen structure is 100 meshes, 200 meshes or 300 meshes.

[0013] In some embodiments, the inner container assembly is a cylindrical plastic barrel.

[0014] In some embodiments, the height of the inner container assembly is greater than the height of the outer container assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, the drawings in the figures do not constitute a proportional limitation.

[0016] Figure 1 is a schematic cross-sectional structure diagram of the water-insoluble cement slurry evaluation device provided by some embodiments of the present application;

[0017] Figure 2 is a schematic cross-sectional structure diagram of the water-insoluble cement slurry evaluation device when the outlet and the inlet are in a water cycle provided by some embodiments of the present application.

[0018] Explanation of the reference numerals: 11 - inner container assembly; 111 - first solid wall; 112 - porous wall; 113 - second solid wall; 12 - outer container assembly; 121 - outlet; 122 - inlet; 13 - water pump; 14 - water storage tank. DETAILED DESCRIPTION

[0019] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in each embodiment of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is for the convenience of description, and the specific implementation of the present application should not constitute any limitation, and the various embodiments can be combined with each other and referenced to each other without contradiction.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0021] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0022] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0023] Oil and gas well cementing refers to the construction process of running casing into the well and injecting cement slurry into the annulus between the wellbore and the casing during the drilling and completion operations. Generally, during the cementing operation, the hydrostatic pressure of the cement slurry is higher than that of the formation water. Therefore, in high-water-permeability formations, the cement slurry leaks into the formation. During the waiting-for-set period, the cement slurry experiences weight loss, resulting in a continuous decrease in the hydrostatic pressure generated by the cement slurry and an increasing risk of formation water scouring and dispersing the cement slurry. If the water-non-dispersible effect of the cement slurry is poor, the formation water will carry away the cement slurry due to dilution, dispersion, and migration, causing the stability, thickening performance, mechanical properties, etc. of the cement slurry to deteriorate before it develops sufficient strength, and even problems such as insufficient top height may occur, seriously affecting the cementing quality of the upper formations. Therefore, the water-non-dispersibility of the cement slurry system is one of the key factors affecting cementing quality. Conducting an evaluation test on the water-non-dispersibility of the cement slurry system before cementing is a very important step.

[0024] In the prior art, the evaluation of water-non-dispersible cement slurry often involves pouring the cement slurry into water and observing the erosion of the water on the cement slurry to judge the quality of the water-non-dispersible slurry system. This rough judgment method has a large subjective factor and poor accuracy. It is necessary to design an evaluation device for the non-dispersible cement slurry system to visually observe and evaluate the water erosion resistance of the cement slurry system.

[0025] Therefore, in order to more visually observe and evaluate the water erosion resistance of the cement slurry system. Some embodiments of the present application provide a water-non-dispersible cement slurry evaluation device. After the prepared cement slurry is cured in an atmospheric thickening instrument for a period of time (about 20 minutes), it is poured into the inner container assembly and weighed. Then, the inner container assembly is placed in the outer container assembly. Liquid water enters the inner container assembly through the porous wall of the inner container assembly and erodes the cement slurry. After the cement slurry is completely solidified, the inner container assembly is taken out and weighed. The external corrosion condition of the cement slurry is observed from the porous wall, and the mass loss of the cement slurry is calculated to evaluate the water erosion resistance of the cement slurry.

[0026] The following Figure 1 describes the water-non-dispersible cement slurry evaluation device provided by some embodiments of the present application.

[0027] As Figure 1 shown, the water-non-dispersible cement slurry evaluation device provided by some embodiments of the present application includes:

[0028] A water-insoluble cement slurry evaluation device includes an inner container assembly 11 and an outer container assembly 12. The inner container assembly 11 has a hollow structure and is used to place the water-insoluble cement slurry. The top of the inner container assembly 11 is open and the bottom is closed. The inner container assembly 11 is sequentially provided with a first solid wall 111, a porous wall 112, and a second solid wall 113 from the open end to the closed end; the outer container assembly 12 is arranged around the inner container assembly 11 and forms a certain gap with the inner container assembly 11. The outer container assembly 12 is used for circulating liquid water, and the liquid water enters the inner container assembly 11 through the porous wall 112 and erodes the cement slurry in the inner container assembly 11.

[0029] It should be noted that the inner container assembly 11 can be a cylinder or a cuboid, and can be made of plastic material or metal material. The porous wall 112 is located in the middle of the inner container assembly 11, and can be biased towards the open end or the closed end, as long as the porous wall 112 can be completely submerged in water. The porous wall 112 and the solid walls at both ends can be integrally formed by three-dimensional printing or mold casting, or can be welded or detachably installed. The two ends of the porous wall 112 can have external threads, and the solid walls at both ends have corresponding internal threads and are connected together by threads. The outer container assembly 12 can also be a cylinder or a cuboid, and the material can also be plastic or metal. The inner container assembly 11 and the outer container assembly 12 are detachably arranged together, and the inner container assembly 11 is located in the middle of the outer container assembly 12. Similar to the inner container assembly 11, the outer container assembly 12 has an opening at the top for the passage to place the inner container; the bottom is sealed to form a cavity to accommodate liquid water. A water pipe can be placed at the opening and reach above the inner bottom wall, and liquid water is injected. The liquid water surges from the bottom and overflows from the opening, thus forming the flow of liquid water. It can also be that an outlet 121 and an inlet 122 are provided on the outer container assembly 12 and a water pump 13 is connected to form the circulation of liquid water. The circulating liquid water can scour the cement slurry to simulate the scouring process of the water in the formation on the cement slurry. The water in the formation affects the cement slurry after flowing out from the pores. The liquid water enters the inner container assembly 11 through the porous wall 112 and erodes the cement slurry in the inner container assembly 11. There are many small holes distributed in a circle of the porous wall 112, and the small holes can be round holes, square holes, special-shaped holes, etc. with different sizes. The small holes in the porous wall 112 can simulate the pores in the formation.

[0030] In addition, the cement slurry needs to be cured for a certain period of time to reach a certain strength before being poured into the inner container assembly 11. Specifically, after curing the prepared cement slurry in an atmospheric thickening instrument for 20 minutes, weigh 600 g of the cement slurry and pour it into a specially made inner container assembly 11 with a height of 30 cm, a diameter of 5 cm, and a capacity of 500 ml (where the porous wall 112 is 10 cm long and the total length of the first solid wall 111 and the second solid wall 113 is 20 cm). Then place it in a container with circulating water until the cement slurry is completely solidified. Take out the inner container assembly 11, weigh the inner container assembly 11 and the cement slurry as a whole, calculate the loss of cement mass, and observe the external corrosion condition of the cement slurry. During actual operation, a layer of vaseline will be applied to the inner wall of the inner container assembly 11 so that the solidified cement slurry can be taken out easily.

[0031] The water-non-dispersible cement slurry evaluation device provided by some embodiments of the present application, by setting the inner container assembly 11, after curing the prepared cement slurry in an atmospheric thickening instrument for a period of time (about 20 minutes), pour it into the inner container assembly 11 and weigh it. Then place the inner container assembly 11 in the outer container assembly 12. Liquid water enters the inner container assembly 11 through the porous wall 112 of the inner container assembly 11 and erodes the cement slurry. After the cement slurry is completely solidified, take out the inner container assembly 11 and weigh it. Observe the external corrosion condition of the cement slurry from the porous wall 112, and calculate the mass loss of the cement slurry, so as to evaluate the water erosion resistance of the cement slurry. In this way, the water erosion resistance of the cement slurry system can be visually observed and evaluated.

[0032] In some embodiments of the present application, the outer container assembly 12 is provided with an outlet 121 and an inlet 122, and the inlet 121 and the outlet 122 are axially located at both ends of the porous wall 112 respectively.

[0033] It should be noted that the inlet 122 and the outlet 122 are connected with pipelines. Water flows in from the inlet 122 and flows out from the outlet 121, forming flowing water in the annulus between the inner container assembly 11 and the outer container assembly 12, simulating the flow of water in the formation, so that the measured water-non-dispersible performance of the cement slurry is closer to the actual water-non-dispersible performance in the formation. The inlet 121 and the outlet 122 are axially located at both ends of the porous wall 112 respectively to ensure that the porous wall 112 is at both ends of the inlet 121 and the outlet 122, and the water flow formed by the inlet 121 and the outlet 122 can wash the cement slurry at the porous wall 112.

[0034] In some embodiments of the present application, the inlet 122 is arranged at the lower end of one side of the outer container assembly 12, and the outlet 121 is arranged at the upper end of the other side of the outer container assembly 12.

[0035] It should be noted that the inlet 122 and the outlet 121 need to be arranged oppositely so that water can form flowing water in the annulus between the inner container component 11 and the outer container component 12. The inlet 122 is at the lower end and the outlet 121 is at the upper end. The formed water flow can better scour the mud at the porous wall 112, which is a preferred solution.

[0036] In some embodiments of the present application, a water pump 13 is connected to the inlet 122.

[0037] It should be noted that the water pump 13 is connected to the inlet 122 through a pipeline. The water pump 13 pumps the water at the water source into the outer container component 12, providing sufficient flowing water for the outer container component 12. After the pumped water flows out of the outer container component 12, it can be discharged into the sewer or can flow back into the water source through a pipeline and then be pumped into the outer container component 12 again to form the entire water cycle.

[0038] In some embodiments of the present application, the water pump 13 is a booster water pump and is connected to the outlet 121 to form a water cycle. A sealing cover 15 is provided at the top of the outer container component 12.

[0039] It should be noted that the booster water pump 13 provides a certain pressure for the circulating water, simulating the pressure of water in the formation and increasing the accuracy of the device for evaluating the water-non-dispersible cement slurry system. The sealing cover 15 is provided to keep the water inside the outer container component 12 at a certain pressure. As Figure 2 shown, a device such as a water storage tank 14 can be provided between the water pump 13 and the outlet 121. The water flowing out of the outlet 121 flows into the water storage tank 14, and the water in the water storage tank 14 is pumped into the outer container component 12 and then flows from the outlet 121 into the water storage tank 14, thus completing the closed water cycle. The water storage tank 14 is connected to the outlet 121 and the water pump 13 through pipelines. Using circulating water can, on the one hand, save water resources, and on the other hand, observe the turbidity of the water to evaluate the water non-dispersibility of the cement slurry from the side.

[0040] In some embodiments of the present application, the porous wall 112 is a screen structure.

[0041] It should be noted that the small holes in the screen structure can be round holes, square holes, irregular holes of different sizes, etc., or a porous structure with the same size and the same regular shape. Through the screen structure, the pores in the formation are simulated to more accurately detect the water non-dispersible performance of the cement slurry in the formation. After the cement slurry is cured in an atmospheric thickening instrument for a period of time (about 20 minutes) and then poured into the inner container component 11, since the water-non-dispersible cement slurry has thixotropy, at this time, while maintaining a certain fluidity of the cement slurry, it also has a certain plastic viscosity, so that it will not or only a small amount flows out from the screen structure.

[0042] In some embodiments of the present application, the mesh number of the screen structure is 100 mesh, 200 mesh or 300 mesh.

[0043] It should be noted that different mesh numbers of the screen can be used to compare different formation porosities. The more the mesh number, the denser the pores, and the smaller the simulated formation porosity. The porosities of the formations simulated by the three types of screens with 100 mesh, 200 mesh and 300 mesh are 25%, 16% and 10% respectively.

[0044] In some embodiments of the present application, the inner container assembly 11 is a cylindrical plastic barrel.

[0045] It should be noted that with the same material, a cylinder can be made into a container with the largest volume. The inner container assembly 11 uses a cylinder shape for two reasons. On the one hand, it saves materials, and on the other hand, it makes the water flow outside the inner container assembly 11 more uniform, and the water pressure around the porous wall 112 is basically the same. A lightweight plastic material is used because it occupies less weight during weighing and has the least impact on the evaluation experiment.

[0046] In some embodiments of the present application, the height of the inner container assembly 11 is greater than the height of the outer container assembly 12.

[0047] That is to say, the inner container assembly 11 protrudes outside the outer container assembly 12, which facilitates the taking and placing of the inner container assembly 11 from the outer container assembly 12. If the height of the inner container assembly 11 is less than the height of the outer container assembly 12, a handle needs to be provided at the opening of the inner container assembly 11 for easy taking and placing. On the other hand, in the vertical direction, the higher the height, the greater the liquid pressure. The height of the inner container assembly 11 being greater than the height of the outer container assembly 12 can ensure that the mud pressure in the inner container assembly 11 is greater than the water pressure in the outer container assembly 12.

[0048] Those of ordinary skill in the art can understand that the above embodiments are specific examples for implementing the present application, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application.

Claims

1. An apparatus for evaluating a water-non-dispersible cement slurry, characterized in that, Comprising: An inner container component, which is of a hollow structure and is used for placing water-non-dispersible cement slurry. The top of the inner container component is open and the bottom is closed. The inner container component is sequentially provided with a first solid wall, a porous wall and a second solid wall from the open end to the closed end; An outer container component, which is arranged around the inner container component and forms a certain gap with the inner container component. The outer container component is used for circulating liquid water, and the liquid water enters the inner container component through the porous wall and erodes the cement slurry in the inner container component.

2. The water-insoluble cement slurry evaluation device according to claim 1, characterized in that The outer container component is provided with an outlet and an inlet, and the inlet and the outlet are axially located at both ends of the porous wall respectively.

3. The water-insoluble cement slurry evaluation device according to claim 2, wherein The inlet is arranged at the lower end of one side of the outer container component, and the outlet is arranged at the upper end of the other side of the outer container component.

4. The water-insoluble cement slurry evaluation device according to claim 3, characterized in that, The inlet is communicated with a water pump.

5. The water-insoluble cement slurry evaluation device according to claim 4, wherein The water pump is a booster water pump and is communicated with the outlet to form a water cycle. A sealing cover is arranged on the top of the outer container component.

6. The water-insoluble cement slurry evaluation device according to claim 1, characterized in that The porous wall is a screen structure.

7. The water-insoluble cement slurry evaluation device according to claim 6, characterized in that, The mesh number of the screen structure is 100 mesh, 200 mesh or 300 mesh.

8. The water-insoluble cement slurry evaluation device according to claim 1, characterized in that The inner container component is a cylindrical plastic cylinder.

9. The water-insoluble cement slurry evaluation device according to claim 1, characterized in that, The height of the inner container component is greater than the height of the outer container component.

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