阅读说明：本技术 一种套管-水泥环-地层固结体完整性模拟实验装置 (Casing-cement sheath-stratum consolidation body integrity simulation experiment device ) 是由 张毅 李晓蓉 安晨 张超飞 丁泽晨 古丽娟 刘飞 何向阁 于 2020-06-10 设计创作，主要内容包括：本发明公开一种套管-水泥环-地层固结体完整性模拟实验装置,涉及油气钻采领域,包括支撑结构、井身结构、水泥浆注入系统、液压系统和测试系统；支撑结构上安装有井身结构,井身结构包括竖直设置于支架上的地层管柱和套管管柱,地层管柱与套管管柱之间为水泥环腔体,水泥环腔体与水泥浆注入系统连通；地层管柱包括上地层管柱和下地层管柱,上地层管柱与下地层管柱通过斜截板和斜板螺栓固定连接；上地层管柱的外壁连接有液压系统；测试系统包括DAS监测光纤,套管管柱外壁上螺旋缠绕有DAS监测光纤。本发明从实验角度探究套管-水泥环-地层完整性失效原因,阐明井筒完整性失效机理,并为提出相应的防控机制提供理论支撑。(The invention discloses a casing-cement sheath-stratum consolidation body integrity simulation experiment device, which relates to the field of oil and gas drilling and production and comprises a supporting structure, a well body structure, a cement slurry injection system, a hydraulic system and a test system; a well body structure is arranged on the supporting structure and comprises a stratum pipe column and a casing pipe column which are vertically arranged on the support, a cement sheath cavity is arranged between the stratum pipe column and the casing pipe column, and the cement sheath cavity is communicated with the cement slurry injection system; the stratum pipe column comprises an upper stratum pipe column and a lower stratum pipe column, and the upper stratum pipe column and the lower stratum pipe column are fixedly connected through an inclined cutting plate and an inclined plate bolt; the outer wall of the upper stratum pipe column is connected with a hydraulic system; the test system comprises DAS monitoring optical fibers, and the DAS monitoring optical fibers are spirally wound on the outer wall of the casing pipe column. The method explores the reason of casing-cement sheath-stratum integrity failure from the experimental angle, clarifies the mechanism of wellbore integrity failure and provides theoretical support for providing a corresponding prevention and control mechanism.)

1. The utility model provides a sleeve pipe-cement sheath-stratum consolidation body integrality simulation experiment device which characterized in that: the device comprises a supporting structure, a well body structure, a cement slurry injection system, a hydraulic system and a test system; the supporting structure comprises a support, the well body structure is mounted on the support, plugging devices are arranged at two ends of the well body structure, the well body structure comprises a stratum pipe column vertically arranged on the support, a casing pipe column is arranged in the stratum pipe column, a cement sheath cavity is arranged between the stratum pipe column and the casing pipe column, and the cement sheath cavity is communicated with the cement slurry injection system; the stratum pipe column comprises an upper stratum pipe column and a lower stratum pipe column, the bottom of the upper stratum pipe column and the top of the lower stratum pipe column are all inclined planes with the same inclination direction, inclined cut plates are fixedly arranged on the inclined cut planes, and the inclined cut plate of the upper stratum pipe column and the inclined cut plate of the lower stratum pipe column are fixedly connected through inclined plate bolts; the outer wall of the upper stratum pipe column is connected with the hydraulic system; the test system comprises DAS monitoring optical fibers, and the DAS monitoring optical fibers are spirally wound on the outer wall of the casing pipe column.

2. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 1, wherein: the support comprises a horizontally arranged bottom support, and a vertically arranged vertical support is connected to the bottom support; the plugging device comprises a pipe column base and a top cover; the pipe column base is fixedly arranged on the bottom support through a first bolt, a bottom positioning ring is arranged in the pipe column base, and the stratum pipe column and the casing pipe column are arranged on the bottom positioning ring and are fixedly connected with the pipe column base through a fixing ring; the top cover is fixedly connected with the stratum pipe column through a second bolt; a pressure release valve is arranged on the top cover.

3. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 2, wherein: the bottom positioning ring is provided with a stepped hole with the diameter increasing from bottom to top, and the stratum pipe column and the casing pipe column are fixedly sleeved in the stepped hole.

4. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 2, wherein: the cement paste injection system comprises a cement paste stirrer arranged on the bottom support, and the cement paste stirrer is communicated with the cement sheath cavity through a cement paste injection pipe; and an injection pump and a one-way valve are arranged on the cement paste injection pipe.

5. The casing-cement sheath-formation consolidation integrity simulation experiment device according to claim 4, wherein: and the cement slurry injection pipe is respectively connected with a pressure gauge, a flow meter and a temperature sensor.

6. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 2, wherein: the hydraulic system comprises a first hydraulic cylinder connected with the vertical support through a hinge, a hydraulic rod at the tail end of the first hydraulic cylinder is connected with the upper stratum pipe column, a second hydraulic cylinder horizontally arranged is connected to the outer wall above the first hydraulic cylinder, and the second hydraulic cylinder is vertically and fixedly connected with the vertical support; the first hydraulic cylinder and the second hydraulic cylinder are respectively connected with a hydraulic pump through hydraulic pipelines.

7. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 6, wherein: the outer wall of the upper stratum pipe column is sleeved with a movable conical ring, and a hydraulic rod at the tail end of the first hydraulic cylinder is connected with the conical side wall of the movable conical ring.

8. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 6, wherein: a horizontal extension frame is arranged on the vertical support, the tail end of the horizontal extension frame is connected with a clamping jaw through a third bolt, and the clamping jaw is clamped on the outer wall of the lower stratum pipe column; the hydraulic pump is arranged on the horizontal extension frame.

9. The casing-cement sheath-formation consolidation integrity simulation experimental device of claim 2, wherein: and a reinforcing rib which is obliquely arranged is connected between the bottom bracket and the vertical bracket.

Technical Field

The invention relates to the technical field of oil and gas drilling and production, in particular to a casing-cement sheath-stratum consolidation body integrity simulation experiment device.

Background

In the oil and gas drilling and production process, a casing-cement sheath-stratum is the most typical shaft structure form of an oil and gas well, and the integrity of the casing-cement sheath-stratum is the key point for ensuring the stability of a borehole and sealing off stratum fluid. However, with the continuous development of oil and gas resources and the continuous complication of geological environment in China, oil and gas leakage related to the quality of a shaft and shaft integrity failure accidents are in a rapid growing trend. Therefore, the integrity analysis of the casing-cement sheath-formation system has been a key research field for ensuring the safe and efficient production of oil and gas resources.

The failure of the casing-cement sheath-stratum consolidation body is mainly reflected in two aspects of casing deformation and damage and the defects of the cement sheath consolidation body. The causes of failure of casing-cement sheath-formation integrity are many and depend, on the one hand, on complex geological factors: firstly, non-uniform ground stress acting on a shaft is mainly expressed in that measures such as injection and production and the like induce fault activation and stratum interlayer slippage, and further cause the shaft to be sheared and damaged; the temperature difference between the stratum and the shaft causes the volume expansion or contraction phenomenon of the annular cement sheath, thereby causing the cracking failure of the cemented surfaces of the cement sheath-casing pipe and the cement sheath-stratum; and thirdly, the plastic damage of the cement sheath can be caused by the excessive internal pressure of the casing, and the casing starts from the inner wall of the cement sheath and expands outwards until the plastic damage is completely caused. On the other hand, depending on engineering factors during the drilling and completion process: in well cementation operation, the casing is not completely centered in a well hole (the casing is eccentric) due to the self weight of the casing and the like, cement slurry is solidified in an annulus to form a cement sheath with uneven thickness, so that non-uniform external load borne by the casing is aggravated, and further the stress deformation of the casing or the failure of a cementing surface of the cement sheath are caused; in the well completion process, cement casings with different wall thicknesses formed by matching casings with different sizes and boreholes influence the stress characteristics of the casings; and thirdly, cement slurries with different formulas show different permeability characteristics after being cured, thereby influencing the sealing property of the shaft. In summary, casing-cement sheath-formation integrity failure is a multi-factor combination of deformation damage and seal failure.

The existing related research mostly focuses on numerical simulation research of a casing-cement sheath-stratum consolidation body, and the stress distribution condition and the strain damage condition of a shaft under external uniform or non-uniform load are analyzed by establishing a casing-cement sheath-stratum mechanical model under one or more influence factors. However, the numerical simulation result often needs the verification of the related test, and the existing test device is mostly set up by only considering the casing strength test, or a device considering the cement sheath tightness test, and lacks the integrity failure simulation test device of the casing-cement sheath-stratum whole under the comprehensive action of the geological and engineering factors.

Disclosure of Invention

The invention aims to provide a casing-cement sheath-stratum consolidation body integrity simulation experiment device, which is used for solving the problems in the prior art, researching the reason of casing-cement sheath-stratum integrity failure from the experimental angle, clarifying a shaft integrity failure mechanism and providing theoretical support for providing a corresponding prevention and control mechanism.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a casing-cement sheath-stratum consolidation body integrity simulation experiment device which comprises a supporting structure, a well body structure, a cement slurry injection system, a hydraulic system and a test system, wherein the supporting structure is arranged on the well body structure; the supporting structure comprises a support, the well body structure is mounted on the support, plugging devices are arranged at two ends of the well body structure, the well body structure comprises a stratum pipe column vertically arranged on the support, a casing pipe column is arranged in the stratum pipe column, a cement sheath cavity is arranged between the stratum pipe column and the casing pipe column, and the cement sheath cavity is communicated with the cement slurry injection system; the stratum pipe column comprises an upper stratum pipe column and a lower stratum pipe column, the bottom of the upper stratum pipe column and the top of the lower stratum pipe column are all inclined planes with the same inclination direction, inclined cut plates are fixedly arranged on the inclined cut planes, and the inclined cut plate of the upper stratum pipe column and the inclined cut plate of the lower stratum pipe column are fixedly connected through inclined plate bolts; the outer wall of the upper stratum pipe column is connected with the hydraulic system; the test system comprises DAS monitoring optical fibers, and the DAS monitoring optical fibers are spirally wound on the outer wall of the casing pipe column.

Optionally, the support comprises a horizontally arranged bottom support, and a vertically arranged vertical support is connected to the bottom support; the plugging device comprises a pipe column base and a top cover; the pipe column base is fixedly arranged on the bottom support through a first bolt, a bottom positioning ring is arranged in the pipe column base, and the stratum pipe column and the casing pipe column are arranged on the bottom positioning ring and are fixedly connected with the pipe column base through a fixing ring; the top cover is fixedly connected with the stratum pipe column through a second bolt; a pressure release valve is arranged on the top cover.

Optionally, a stepped hole with a diameter increasing from bottom to top is formed in the bottom positioning ring, and the formation pipe column and the casing pipe column are fixedly sleeved in the stepped hole.

Optionally, the cement slurry injection system includes a cement slurry mixer disposed on the bottom bracket, and the cement slurry mixer is communicated with the cement sheath cavity through a cement slurry injection pipe; and an injection pump and a one-way valve are arranged on the cement paste injection pipe.

Optionally, the cement slurry injection pipe is connected with a pressure gauge, a flow meter and a temperature sensor respectively.

Optionally, the hydraulic system includes a first hydraulic cylinder connected to the vertical support through a hinge, a hydraulic rod at a tail end of the first hydraulic cylinder is connected to the upper formation pipe column, a second hydraulic cylinder horizontally arranged is connected to an outer wall above the first hydraulic cylinder, and the second hydraulic cylinder is vertically and fixedly connected to the vertical support; the first hydraulic cylinder and the second hydraulic cylinder are respectively connected with a hydraulic pump through hydraulic pipelines.

Optionally, a movable conical ring is sleeved on the outer wall of the upper formation pipe column, and a hydraulic rod at the tail end of the first hydraulic cylinder is connected with the conical side wall of the movable conical ring.

Optionally, a horizontal extension frame is arranged on the vertical support, a clamping jaw is connected to the tail end of the horizontal extension frame through a third bolt, and the clamping jaw is clamped on the outer wall of the lower stratum pipe column; the hydraulic pump is arranged on the horizontal extension frame.

Optionally, a reinforcing rib arranged obliquely is connected between the bottom bracket and the vertical bracket.

Compared with the prior art, the invention has the following technical effects:

the experimental device can monitor the deformation process and the sealing performance of the casing-cement sheath-stratum consolidation body under the influence of complex geological factors and engineering factors, thereby providing basic data and theoretical support for casing-cement sheath-stratum integrity failure analysis. The cement slurry pumping device has the functions of preparing cement slurry and injecting the cement slurry into the cement annular cavity from the bottom of the casing at a certain temperature and pressure and flow rate. The phenomenon that the injected cement starts to fill from the bottom of the annulus in the actual cementing process is simulated. In addition, the installation of top cap relief valve can guarantee the grout injection in-process, the leakproofness after guaranteeing the cement solidification of the discharge of cavity air. The stratum pipe column is assembled by an upper part and a lower part with an inclined section with a certain inclination angle, and a hydraulic system provides an external load force parallel to the inclined section and is used for simulating the influence of stratum interlayer slippage after a fault is activated at a certain angle on the integrity of a shaft. The DAS monitoring optical fiber is arranged in the whole well section, and the DAS optical fiber is a sensor, so that the DAS optical fiber is equivalent to a row of microphones arranged in the well section to collect underground sound wave signals, and the deformation and strength characteristics of the whole well section in the simulation device can be identified.

Drawings

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

FIG. 1 is a schematic cross-sectional view of the overall structure of the present invention;

FIG. 2 is a schematic representation of a casing string and DAS monitoring fibers disposed on the surface thereof in an apparatus of the present invention;

FIG. 3 is a cross-sectional view of a column base assembly in the apparatus of the present invention;

FIG. 4 is a schematic plan view of a jaw of the apparatus of the present invention;

description of reference numerals: the top cap 1, the snuffle valve 2, activity taper ring 3, the board 4 that cuts to one side, swash plate bolt 5, pressure gauge 6, the injection pump 7, the grout agitator 8, flowmeter 9, temperature sensor 10, check valve 11, grout injection tube 12, stratum tubular column 13, solid fixed ring 14, bottom holding ring 15, sleeve pipe tubular column 16, tubular column base 17, first bolt 18, jack catch 19, third bolt 20, hydraulic pump 21, hydraulic pressure pipeline 22, hinge 23, first pneumatic cylinder 24, second pneumatic cylinder 25, DAS monitoring optical fiber 26, support 27, second bolt 28, cement ring cavity 29.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a casing-cement sheath-stratum consolidation body integrity simulation experiment device, which is used for solving the problems in the prior art, researching the reason of casing-cement sheath-stratum integrity failure from the experimental angle, clarifying a shaft integrity failure mechanism and providing theoretical support for providing a corresponding prevention and control mechanism.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The invention provides a casing-cement sheath-stratum consolidation body integrity simulation experiment device, as shown in figures 1-4, a support 27 is fixed with the ground, and the support 27 is connected and fixed with a pipe column base 17 through a first bolt 18. Fixed ring 14 and bottom holding ring 15 are placed to inside the tubular column base 17 for confirm the position of placing stratum tubular column 13 and casing tubular column 16, fixed ring 14's recess is used for stratum tubular column 13 and casing tubular column 16's inseparable assembly, the upper and lower part of outside stratum tubular column 13 is connected by the cooperation of sloping plate 4 and swash plate bolt 5, DAS monitoring optical fiber 26 spiral winding is in the whole tubular column section of casing tubular column 16, be used for monitoring among the experimentation deformation and the intensity characteristic of cement ring in casing tubular column 16 and cement ring cavity 29. The top of the casing string 16 and the formation string 13 are connected by the top cap 1 and the second bolt 28. The top cover 1 is provided with an air escape valve 2 for discharging air in the process of cement grouting. The lower end of the inclined section of the formation pipe column 13 is fixed through a bracket 27 to limit the displacement in the horizontal direction, the upper end of the inclined section of the formation pipe column 13 is connected with a hydraulic loading system through a movable conical ring 3 and applies external loading force from the hydraulic loading system, the hydraulic loading system comprises a hydraulic pump 21, a first hydraulic cylinder 24, a second hydraulic cylinder 25, a hydraulic pipeline 22 and a hinge 23, the size and the direction of the external loading force acting on the pipe column system can be adjusted through the cooperation of the tools, and the direction adjusting freedom degree is 0-90 degrees. Specifically, the bottom of the support is used for limiting the displacement of the well structure in the vertical direction, and the lower end of the vertical support is used for fixing the lower half part of the well structure separated by the inclined section through a claw 19 and a third bolt 20 to limit the displacement in the horizontal direction. The external load provided by the hydraulic system to the pipe column is parallel to the inclined section of the pipe column. The bottom end of the formation string 13 is provided with a cement slurry injection pipe 12. Thus, a cement sheath cavity 29 is formed between the formation string 13 and the casing string 16 for cement slurry injection and curing. The cement slurry injection pipe 12 is connected with a cement slurry injection system, the cement slurry injection system comprises a pressure gauge 6, an injection pump 7, a cement slurry stirrer 8, a flow meter 9, a temperature sensor 10 and a one-way valve 11, cement slurry can be directly prepared and injected into a cement ring cavity 29, the performance of the whole process from the injection of cement slurry with different formulations into an annulus between the casing pipe column 16 and the stratum pipe column 13 from a liquid state to the solidification of the cement slurry into a solid cement ring can be analyzed, the cement slurry formulation is optimized for a well body structure, and the temperature, pressure and displacement changes of the well body structure are monitored.

A plurality of formation pipe columns 13 with different inclined cross sections are prepared and used for simulating the influence of the dislocation and slippage at a certain inclination angle between the formation layers on the casing force. The bottom retaining ring 15 on the inside of the string base 17 is sized to the casing string and formation string, forming a cement sheath cavity 29 between the casing string 16 and formation string 13 for cement slurry injection. In addition, a plurality of tubular column bases 17 with different groove positions, namely different concentric stepped holes, can be prepared and used for simulating the influence of the eccentricity of a casing, namely the influence of the thickness and the thickness of a cement sheath on the casing force caused by the fact that the casing is not centered.

The experimental principle of the invention is mainly based on the theory of deformation and damage of a casing-cement sheath-stratum consolidation body under the action of complex stratum loads. The complex loads acting on casing-cement sheath-formation consolidation arise from: volume expansion or contraction during the cement paste curing process; the eccentric of the casing and the uneven thickness of the cement sheath influence the load distribution of the casing; formation layer slippage and non-uniform ground stress cause non-uniform loading on the casing, etc. The test device simulates the phenomenon that the injected cement starts to be filled from the bottom of an annulus in the actual well cementation process by simulating the complex loads acting on the casing and monitoring the deformation and damage conditions of the shaft by combining the DAS monitoring optical fiber 26. In addition, the installation of the top cover pressure release valve can ensure that air in the cavity is discharged in the cement slurry injection process, the sealing performance after cement curing is ensured, the integrity failure mechanism of the shaft is further analyzed and clarified, and theoretical support is provided for providing a corresponding prevention and control mechanism.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.