阅读说明：本技术 一种可用于模拟固井疲劳极限的实验装置及方法 (Experimental device and method for simulating well cementation fatigue limit ) 是由 王宴滨 高德利 辛世琳 王金铎 于 2021-01-15 设计创作，主要内容包括：本发明提供一种可用于模拟固井疲劳极限的实验装置及方法,其中,一种可用于模拟固井疲劳极限的实验装置,包括：用于容纳测试总成的主体结构；所述测试总成包括外层测试管柱、内层测试管柱、以及位于外层测试管柱和内层测试管柱之间的模拟水泥环；所述外层测试管柱内部设有高压流体环空腔；所述内层测试管柱的外部设有高温流体环空腔；所述外层测试管柱上设有射孔孔眼；与所述高温流体环空腔和所述高压流体环空腔相连通的高温高压实验系统；用于检测所述外层测试管柱和所述内层测试管柱之间疲劳破坏情况的疲劳检测单元。(The invention provides an experimental device and a method for simulating a well cementation fatigue limit, wherein the experimental device for simulating the well cementation fatigue limit comprises the following steps: a main body structure for receiving a test assembly; the test assembly comprises an outer test pipe column, an inner test pipe column and a simulated cement sheath positioned between the outer test pipe column and the inner test pipe column; a high-pressure fluid ring cavity is arranged in the outer layer test pipe column; a high-temperature fluid ring cavity is arranged outside the inner layer test pipe column; the outer layer test pipe column is provided with a perforation hole; the high-temperature and high-pressure experimental system is communicated with the high-temperature fluid ring cavity and the high-pressure fluid ring cavity; and the fatigue detection unit is used for detecting the fatigue failure condition between the outer layer test pipe column and the inner layer test pipe column.)

1. An experimental apparatus for simulating a fatigue limit of a well cementation, comprising:

a main body structure for receiving a test assembly; the test assembly comprises an outer test pipe column, an inner test pipe column and a simulated cement sheath positioned between the outer test pipe column and the inner test pipe column; a high-pressure fluid ring cavity is arranged in the outer layer test pipe column; a high-temperature fluid ring cavity is arranged outside the inner layer test pipe column; the outer layer testing pipe column and the inner layer testing pipe column are provided with perforation holes;

the high-temperature and high-pressure experimental system is communicated with the high-temperature fluid ring cavity and the high-pressure fluid ring cavity;

and the fatigue detection unit is used for detecting the fatigue failure condition between the outer layer test pipe column and the inner layer test pipe column.

2. The assay device of claim 1, wherein said host structure comprises an outer shell and dummy bases attached to opposite ends of said outer shell; the outer layer testing pipe column, the inner layer testing pipe column and the simulation cement sheath are fixed between the two simulation bases.

3. The experimental apparatus of claim 2, wherein the high temperature and high pressure experimental system comprises: a pressure injection end and a high temperature fluid injection end arranged on the main body structure; the pressure injection end is communicated with the high-pressure fluid ring cavity; the high-temperature fluid injection end is communicated with the high-temperature fluid ring cavity; the high-temperature fluid injection end is arranged on the pipe wall of the outer-layer annular sleeve; and the pressure injection end passes through the simulation base through a communicating pipe and is introduced into the high-pressure fluid ring cavity.

4. The experimental device according to claim 3, wherein the fatigue detecting unit includes: the displacement sensor and the strain sensor are arranged on the simulated cement sheath; the displacement sensor and the strain sensor are respectively connected with a test lead; the test lead extends in the simulation cement ring, penetrates out of the simulation base and is connected with the detection controller.

5. The experimental apparatus of claim 4 wherein a plurality of said displacement sensors are positioned between said simulated cement sheath and said inner test string; the plurality of displacement sensors are arranged at equal intervals along the axial direction.

6. The experimental apparatus of claim 4 wherein a plurality of said strain sensors are positioned between said simulated cement sheath and said outer test string; the strain sensors are arranged at equal intervals along the axial direction.

7. The experimental device as claimed in claim 4, wherein a fixing block for axially limiting the inner layer test string is further fixed in the simulation base.

8. The experimental device as claimed in claim 4, wherein two ends of the outer layer test column are respectively fixedly inserted into the simulation base and fixedly connected with the simulation base through screw threads.

9. The experimental apparatus as claimed in claim 8, wherein an axial block for limiting two ends of said simulated cement sheath is further provided in said test assembly.

10. An experimental method for simulating a fatigue limit of a well cementation based on the experimental apparatus of any one of claims 1 to 9, comprising:

when the temperature is constant, a circulated high-pressure fluid is injected into the high-pressure fluid annular cavity from the pressure injection end so as to test the well cementation fatigue limit rule of the inner layer test pipe column under the state of applying the circulating pressure;

when the pressure is constant, injecting circulating high-temperature fluid from a high-temperature fluid injection end, and testing the well cementation fatigue limit rule of the high-temperature fluid ring cavity and the fatigue limit rule of the cement ring;

and when the temperature and the pressure are not constant, the recyclable high-temperature high-pressure fluid is simultaneously injected into the pressure injection end and the high-temperature fluid injection end, and the fatigue limit rule of the inner surface and the outer surface of the cement sheath under the combined action of the recyclable high-temperature high-pressure fluid is tested.

Technical Field

The invention relates to a set of experimental device and method for simulating well cementation fatigue limit, in particular to an experimental device and method for testing the well cementation fatigue limit rule under the action of circulating high-temperature and high-pressure fluid.

Background

Cementing is an important operation in the process of producing oil and gas. After setting, the well cementing slurry will form a hydraulic packing system in the longitudinal direction of the entire well, which must achieve effective zonal packing during the entire life of the well and after abandonment. In the process of injection and production operation, the cement sheath is easily subjected to fatigue damage under the action of circulating high-pressure high-temperature fluid, so that the defects of sliding dislocation, microcracks and the like of materials in the cement sheath are caused, the mechanical property of the cement sheath is changed along with the defects, and finally the crack damage on a macroscopic structure is caused.

Therefore, it is necessary to design an experimental device and method for simulating the fatigue limit of well cementation, which is helpful to understand the mechanical properties and fatigue limit rule of the cement sheath of well cementation, so as to ensure that the strength of the oil well cement meets the well cementation requirements at different temperatures and pressures.

Disclosure of Invention

In view of the above-mentioned shortcomings, an object of the present invention is to provide an experimental apparatus and method for simulating the fatigue limit of well cementation, which is helpful for understanding the mechanical properties and fatigue limit law of the cement sheath of well cementation, so as to ensure that the strength of the oil well cement meets the well cementation requirements at different temperatures and pressures.

In order to achieve the purpose, the invention adopts the following technical scheme:

an experimental apparatus useful for simulating a well cementation fatigue limit, comprising:

a main body structure for receiving a test assembly; the test assembly comprises an outer test pipe column, an inner test pipe column and a simulated cement sheath positioned between the outer test pipe column and the inner test pipe column; a high-pressure fluid ring cavity is arranged in the outer layer test pipe column; a high-temperature fluid ring cavity is arranged outside the inner layer test pipe column; the outer layer testing pipe column and the inner layer testing pipe column are provided with perforation holes;

the high-temperature and high-pressure experimental system is communicated with the high-temperature fluid ring cavity and the high-pressure fluid ring cavity;

and the fatigue detection unit is used for detecting the fatigue failure condition between the outer layer test pipe column and the inner layer test pipe column.

In a preferred embodiment, the main body structure comprises an outer layer ring sleeve and simulation bases fixed at two ends of the outer layer ring sleeve; the outer layer testing pipe column, the inner layer testing pipe column and the simulation cement sheath are fixed between the two simulation bases.

As a preferred embodiment, the high temperature and high pressure experimental system comprises: a pressure injection end and a high temperature fluid injection end arranged on the main body structure; the pressure injection end is communicated with the high-pressure fluid ring cavity; the high-temperature fluid injection end is communicated with the high-temperature fluid ring cavity; the high-temperature fluid injection end is arranged on the pipe wall of the outer-layer annular sleeve; and the pressure injection end passes through the simulation base through a communicating pipe and is introduced into the high-pressure fluid ring cavity.

As a preferred embodiment, the fatigue detection unit includes: the displacement sensor and the strain sensor are arranged on the simulated cement sheath; the displacement sensor and the strain sensor are respectively connected with a test lead; the test lead extends in the simulation cement ring, penetrates out of the simulation base and is connected with the detection controller.

In a preferred embodiment, a plurality of said displacement sensors are positioned between said simulated cement sheath and said inner test string; the plurality of displacement sensors are arranged at equal intervals along the axial direction.

In a preferred embodiment, a plurality of said strain sensors are positioned between said simulated cement sheath and said outer test string; the strain sensors are arranged at equal intervals along the axial direction.

As a preferred embodiment, a fixing block for axially limiting the inner layer test string is further fixed in the simulation base.

As a preferred embodiment, two ends of the outer layer test string are respectively fixedly inserted into the simulation base and fixedly connected with the simulation base through a screw fastener.

In a preferred embodiment, an axial block for limiting two ends of the simulated cement sheath is further arranged in the test assembly.

An experimental method for simulating a well cementation fatigue limit based on the experimental device of any one of the above embodiments comprises the following steps:

when the temperature is constant, a circulated high-pressure fluid is injected into the high-pressure fluid annular cavity from the pressure injection end so as to test the well cementation fatigue limit rule of the inner layer test pipe column under the state of applying the circulating pressure;

when the pressure is constant, injecting circulating high-temperature fluid from a high-temperature fluid injection end, and testing the well cementation fatigue limit rule of the high-temperature fluid ring cavity and the fatigue limit rule of the cement ring;

and when the temperature and the pressure are not constant, the recyclable high-temperature high-pressure fluid is simultaneously injected into the pressure injection end and the high-temperature fluid injection end, and the fatigue limit rule of the inner surface and the outer surface of the cement sheath under the combined action of the recyclable high-temperature high-pressure fluid is tested.

Has the advantages that:

the invention designs an experimental device and a method for simulating the fatigue limit of well cementation, wherein the experimental device mainly comprises a simulation test pipe column, a simulation cement sheath, a high-temperature and high-pressure experimental system, a test receiving terminal and a simulation base, wherein the simulation inner layer pipe column and the simulation outer layer pipe column are subjected to perforation treatment in the early stage and are cemented with the simulation cement sheath, the simulation cement sheath is provided with a displacement test sensor and a strain test sensor, and a test lead is pulled to a detection controller (the displacement and strain receiving terminal). Two cavities are contained in the main structure: the high-pressure fluid cavity and the high-temperature fluid cavity are used for carrying out high-temperature and high-pressure physical simulation, so that simulation and test of the well cementation fatigue limit are realized.

In addition, the simulation inner test pipe column and the simulation outer test pipe column are completely cemented together with the simulation cement sheath and are respectively used for simulating the mechanical integrity of the cement sheath in the well cementation process.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the invention are not so limited in scope.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

FIG. 1 is a schematic diagram of an experimental apparatus that can be used to simulate the fatigue limit of cementing wells;

FIG. 2 is an enlarged view of a portion of FIG. 1;

fig. 3 is a partially enlarged view of fig. 1.

Wherein, 1, the outer layer is sleeved with a loop; 2. testing the pipe column on the outer layer; 3. a strain sensor test lead; 4. simulating a cement sheath; 5. a strain sensor; 6. a displacement sensor test lead; 7. a displacement sensor; 8. a high temperature fluid injection end; 9. a displacement sensor receiving end; 10. a pressure relief outlet; 11. a strain sensor receiving end; 12. simulating a base; 13. perforating holes; 14. an inner layer test pipe column; 15. a high temperature fluid ring cavity; 16. a high pressure fluid ring cavity; 17. a seal ring; 18. a pressure injection end; 19. a test lead outlet; 20. screwing; 21. a fixed block; 22. an axial block.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, fig. 2, and fig. 3, an embodiment of the present invention provides an experimental apparatus for simulating a fatigue limit of a well cementation, including: a main body structure for receiving a test assembly; the test assembly comprises an outer test string 2, an inner test string 14 and a simulated cement sheath 4 positioned between the outer test string 2 and the inner test string 14; a high-pressure fluid ring cavity 16 is arranged in the outer layer test pipe column 2; a high-temperature fluid ring cavity 15 is arranged outside the inner layer test string 14; the outer layer test pipe column 2 and the inner layer test pipe column 14 are provided with perforation holes 13; a high temperature and high pressure experimental system in communication with the high temperature fluid ring cavity 15 and the high pressure fluid ring cavity 16; and the fatigue detection unit is used for detecting the fatigue failure condition between the outer layer test string 2 and the inner layer test string 14.

The main body structure comprises an outer layer ring sleeve 1 and simulation bases 12 fixed at two ends of the outer layer ring sleeve 1; the outer layer test string 2, the inner layer test string 14 and the simulated cement sheath 4 are fixed between the two simulated foundations 12.

The high temperature and high pressure experiment system comprises: a pressure injection end 18 and a hot fluid injection end 8 disposed on the body structure. The pressure injection end 18 communicates with the high pressure fluid annulus cavity 16. The hot fluid injection end 8 is in communication with the hot fluid annulus cavity 15. The high-temperature fluid injection end 8 is arranged on the pipe wall of the outer-layer ring sleeve 1. The pressure injection port 18 opens into the high pressure fluid annulus cavity 16 through the dummy base 12 via a communication tube.

The fatigue detection unit includes: the displacement sensor 7 and the strain sensor 5 are arranged on the simulated cement sheath 4; the displacement sensor 7 and the strain sensor 5 are respectively connected with a test lead; the test leads extend through the simulated cement sheath 4 and out of the simulated base 12 for connection to a test controller.

In this embodiment, the dummy base 12 has a test lead outlet 19 thereon. Wherein the test leads include a strain sensor test lead 3 connected to a strain sensor 5 and a displacement sensor test lead 6 connected to a displacement sensor 7. More specifically, a displacement receiving end 9 and a strain receiving end 11 are provided outside the simulation base 12. The strain sensor test lead 3 is connected with a strain receiving end 11, and the displacement sensor test lead 6 is connected with a displacement receiving end 9. The detection controller comprises a displacement receiving end 9, a strain receiving end 11 and an internal calculation module for fatigue judgment.

To achieve fatigue detection accuracy, a plurality of displacement sensors 7 are located between the simulated cement sheath 4 and the inner test string 14. A plurality of the displacement sensors 7 are arranged at equal intervals along the axial direction. A plurality of said strain sensors 5 are located between said simulated cement sheath 4 and said outer test string 2; a plurality of the strain sensors 5 are arranged at equal intervals in the axial direction. The strain sensor 5 and the displacement sensor 7 are offset from the perforation hole 13.

A fixed block 21 for axially limiting the inner layer test pipe column 14 is further fixed in the simulation base 12. The fixed block 21 is fixedly sleeved between the communicating rod and the simulation base 12, and a sealing ring 17 is arranged between the fixed block 21 and the communicating rod for sealing. Two ends of the outer layer test pipe column 2 are respectively fixedly inserted into the simulation base 12 and fixedly connected with the simulation base 12 through a screw thread 20 (a thread buckle). And an axial block 22 for limiting two ends of the simulated cement sheath 4 is also arranged in the test assembly.

An embodiment of the present invention further provides an experimental method for simulating a fatigue limit of a well cementation, where the experimental method may be performed by using the experimental apparatus of the above embodiment, and the experimental method includes:

when the temperature is constant, a recyclable high-pressure fluid is injected into the high-pressure fluid ring cavity 16 from the pressure injection end 18 so as to test the well cementation fatigue limit rule of the inner test string 14 under the state of applying the circulating pressure;

when the pressure is constant, injecting circulating high-temperature fluid from the high-temperature fluid injection end 8, and testing the well cementation fatigue limit rule of the high-temperature fluid ring cavity 15 and the fatigue limit rule of the cement ring;

and when the temperature and the pressure are not constant, the circulated high-temperature and high-pressure fluid is injected into the pressure injection end 18 and the high-temperature fluid injection end 8 at the same time, and the fatigue limit rule of the inner surface and the outer surface of the cement sheath under the combined action of the circulated high-temperature and high-pressure fluid is tested.

In summary, the present embodiment provides an experimental apparatus and method for simulating the fatigue limit of a well cementation, which are mainly used for testing whether the internal and external test strings are affected by the circulating action force under the action of the circulating high-temperature high-pressure fluid to further affect the mechanical behavior of the test string, so that the internal and external test strings reach the fatigue limit, and thus the integrity of the well cementation cement sheath fails.

The experimental device of the embodiment mainly comprises an internal and external testing tubular column, a simulation cement sheath 4, a displacement and strain receiving terminal and a simulation base 12. The inner and outer test pipe columns are perforated in the early stage of the simulated cement sheath 4 experimental test, and are cemented with the inner and outer test pipe columns 2, and a pressure and strain sensor 5 is arranged in the cement sheath to pull a pressure and strain test lead to a displacement and strain receiving terminal outside the test cavity.

The simulation base 12 of the present embodiment has good weldability and sealing performance, and a hydraulic piston (high-pressure fluid injection end) and a high-temperature fluid injection end 8 are added outside the test chamber (the high-temperature fluid ring cavity 15 and the high-pressure fluid ring cavity 16) to inject high-pressure and high-temperature fluids, respectively. The test device and the test method can carry out simulation test on the well cementation fatigue limit, and study the experimental rule of the well cementation fatigue limit under the laboratory condition, thereby predicting safe and efficient well cementation and the fatigue phenomenon of well cementation and achieving the purpose of efficient and safe well cementation.

The present invention will be better understood by describing in detail the assembly and use of the experimental apparatus for simulating the fatigue limit of well cementation provided in the present embodiment.

(1) And a displacement receiving end 9 and a strain receiving end 11 are arranged on the outer surface of the main body structure and connected with a displacement sensor testing lead 7 and a strain sensor testing lead 3, a displacement sensor 6 and a strain sensor 5 which are arranged on the simulated cement sheath 4 are connected with the testing leads, the testing leads are arranged in the simulated cement sheath 4 and are pulled to a signal receiving terminal (the displacement receiving end 9 and the strain receiving end 11) outwards. Of course, the displacement sensor 6 and the strain sensor 5 can also be arranged in the simulated cement sheath 4, so that the measured data are more real and accurate.

(2) Completely cementing the outer layer test pipe column 2, the simulated cement sheath 5 and the inner layer test pipe column 14 together, wherein the cementing property is complete; in addition, the inner and outer layer test pipe columns can be subjected to early perforation treatment before cementing to obtain corresponding perforation holes 13; the end parts of the inner and outer layer testing pipe column and the simulated cement sheath 4 are provided with axial blocks 22 which are mainly used for fixing the stability of each part in the testing process;

(3) a high-pressure fluid ring cavity 17 and a high-temperature fluid ring cavity 16 are respectively arranged inside the outer layer test pipe column 2 and outside the inner layer test pipe column 14, and the fluid cavities (the high-pressure fluid ring cavity 17 and the high-temperature fluid ring cavity 16) are mainly arranged for respectively injecting circulating high-temperature high-pressure fluid to test the well cementation fatigue limit rule under the condition;

(4) setting the inner layer testing pipe column 14, the outer layer testing pipe column 2, the simulation cement sheath 5, the outer layer ring sleeve 1 and the simulation base 12 into a testing assembly, and completely sealing the testing assembly to ensure that the sealing performance is better and realize a stratum well cementation simulation system;

(5) when the temperature is constant, a circulated high-pressure fluid is injected into the high-pressure fluid ring cavity 14 from the pressure injection end 18, and the method is mainly used for testing the well cementation fatigue limit rule of the inner layer test pipe column 14 under the state of applying the circulating pressure; when the pressure is constant, injecting circulating high-temperature fluid from the high-temperature fluid injection end 8, and testing the well cementation fatigue limit rule of the high-temperature fluid ring cavity 15 and the fatigue limit rule at the cement ring; the pressure injection end 18 and the high-temperature fluid injection end 8 are simultaneously injected with recyclable high-temperature high-pressure fluid, and the fatigue limit rule of the inner surface and the outer surface of the cement ring under the combined action of the pressure injection end and the high-temperature high-pressure fluid is tested;

(6) the outer portion of the simulation test piece assembly is connected with a displacement sensor receiving end 9 and a strain sensor receiving end 11, through injection of circulating high-temperature and high-pressure fluid, whether sliding dislocation and microcrack can occur on the inner surface and the outer surface of the cement ring and the inner layer test pipe column 14 and the outer layer test pipe column 2 or not is judged, so that a cementing surface cannot be cemented completely, a gap occurs, the acquisition system can detect that test strain and test displacement can fluctuate greatly, and the well cementation fatigue limit can be further determined according to related strain and displacement rules.

Any numerical value recited herein includes all values from the lower value to the upper value, in increments of one unit, provided that there is a separation of at least two units between any lower value and any higher value. For example, if it is stated that the number of a component or a value of a process variable (e.g., temperature, pressure, time, etc.) is from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, it is intended that equivalents such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also expressly enumerated in this specification. For values less than 1, one unit is suitably considered to be 0.0001, 0.001, 0.01, 0.1. These are only examples of what is intended to be explicitly recited, and all possible combinations of numerical values between the lowest value and the highest value that are explicitly recited in the specification in a similar manner are to be considered.

Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. The use of "about" or "approximately" with a range applies to both endpoints of the range. Thus, "about 20 to about 30" is intended to cover "about 20 to about 30", including at least the endpoints specified.

All articles and references disclosed, including patent applications and publications, are hereby incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, or steps herein also contemplates embodiments that consist essentially of such elements, components, or steps. By using the term "may" herein, it is intended to indicate that any of the described attributes that "may" include are optional.

A plurality of elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, component or step is not intended to foreclose other elements, ingredients, components or steps.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the present teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are hereby incorporated by reference for all purposes. The omission in the foregoing claims of any aspect of subject matter that is disclosed herein is not intended to forego such subject matter, nor should the inventors be construed as having contemplated such subject matter as being part of the disclosed subject matter.