CN103015976B - Test method for simulating restoration of deformation sleeve under stratum confining pressure - Google Patents

Abstract

The invention provides a test method for simulating restoration of a deformation sleeve under stratum confining pressure. The test method is characterized in that a universal hydraulic tester with a YS32-500 tetragonal column is used to generate external force by moving back and forth up and down, an impact reshaping tool fixed at the top center of the hydraulic tester is allowed to be fixed on the deformation sleeve right at the center of the bottom of the hydraulic tester by impact at certain speed, and reshaping force required in restoring the deformation sleeve and tension required by a lifting tool after reshaping of the impact reshaping tool can be tested by a strain plate and a static strain gauge in reshaping process. The deformation sleeve is provided with a clamping tool at a deformation section, and test of restoration of the deformation sleeve under specific confining pressure can be simulated by adjusting magnitude of torque of a bolt on the deformation sleeve. Restoration of the downhole deformation sleeve can be simulated truly, test result is accurate, and accurate construction parameters can be provided for restoration of the sleeve by a pear-shaped tube expander. The test method is suitable for the technical field of oil, natural gas downhole sleeve restoration.

Description

A test method for simulating the repair process of deformed casing under formation confining pressure

technical field

The invention relates to a test method for simulating the repairing process of a deformed casing under formation confining pressure.

Background technique

Casing is a necessary key tool in the process of oil and gas extraction, which plays a role in supporting the well wall and establishing oil and gas passages in the process of oil and gas extraction. However, after a period of production in many oil and gas fields, due to factors such as geology, engineering, and corrosion, many oil and gas wells have casing damage to varying degrees, which seriously affects the safety or normal production of oil and gas fields. The main form of bushing damage is the necking deformation of the bushing, that is, the cross section of the deformed section of the bushing is elliptical. In order to restore the normal production of oil and gas fields, scientific workers have developed many plastic repair tools for the repair of necked and deformed casings, such as: impact ball shaper, impact pear-shaped tube expander, etc., and also proposed some impact shaping technologies. According to the impact principle, the impact shaper is used to apply impact load to the deformed casing to expand the diameter.

However, the current impact shaping technology does not take into account the influence of the actual formation confining pressure on the plastic repair of deformed casing, and lacks accurate control of the impact shaping force and the pulling force required to lift the shaping tool after shaping, which leads to a large number of problems. For: too small shaping force makes the shaping tool unable to pass through the deformed casing, resulting in the failure of shaping and reducing the shaping efficiency; too much shaping force makes the shaping tool pass through the deformed casing forcibly, causing the lifting force after shaping to exceed the maximum load of the power equipment and jamming occurs Drilling accidents, damage to the cement sheath of oil and water wells, and even secondary plastic damage to the casing.

In order to overcome the deficiencies of the existing impact shaper, such as low shaping efficiency, easy occurrence of drill stuck accidents, serious damage to the cement sheath and casing, and increased operating costs when repairing the casing, it is necessary to repair different impact shapers according to the specific formation conditions. The shaping force required for the corresponding deformed casing and the lifting force of the tool are accurately controlled. Therefore, establishing a test method for the repair process of casing under different formation confining pressures by impact shaping tools is of great significance for the further development of casing repair technology.

Contents of the invention

The purpose of the present invention is to provide a test method for simulating the repairing process of deformed casing under formation confining pressure, so as to solve the problem of the shaping force and upper pressure required by various impact shaping tools for repairing deformed casing under different formation depths and different confining pressures. It solves the technical problem that the pulling force is difficult to control accurately, and while achieving the above-mentioned purpose, it simplifies the complexity of the test system and reduces the cost of the equipment.

The present invention adopts the following technical scheme: a test method for simulating the repair process of deformed casing under stratum confining pressure, which is characterized in that: the YS32-500 square column universal hydraulic testing machine (hereinafter referred to as: universal hydraulic testing machine) is used to reciprocate up and down Due to the characteristics of external force generated by movement, the impact shaping tool fixed on the top center of the universal hydraulic testing machine with the top clamp and the matching joint with the strain gauge on the outer wall is used to impact the deformed casing at a certain speed; in order to avoid the deformation of the casing during the plastic repair process When the up and down movement occurs in the middle, open a circular groove at the lower end of the deformed casing and fix it in the center of the bottom of the universal hydraulic testing machine with a matching bottom clamp; at the same time, use a clamping tool that matches the shape of the deformed section of the deformed casing Different confining pressures are applied to the deformed section of the pipe; during the shaping process, the shaping force and shaping force required by the impact shaping tool in the process of repairing the casing can be accurately measured by cooperating with the strain gauge on the joint and the YE-2533 static strain gauge The pulling force required for the lifting of the rear tool is achieved, so as to meet the test purpose of the repair process of the deformed casing under confining pressure.

There are hexagonal bolts on the clamping tool for applying confining pressure to the deformed section of the deformed casing. Adjusting the torque of the hexagonal bolts with a torque wrench can adjust the confining pressure exerted by the clamping tool on the deformed section of the deformed casing.

The power of the universal hydraulic testing machine drives the impact shaping tool to move up and down through the top clamp and the matching joint. When the universal hydraulic testing machine starts to move downward at a certain speed, the impact shaping tool fixed on the top center of the universal hydraulic testing machine begins to correct The deformed casing is reshaped and repaired. During the repair process, the static strain gauge records the compressive strain on the mating joint, and the downward movement of the universal hydraulic testing machine is not stopped until the shaping tool completely passes through the deformed section of the casing; due to the reciprocating The characteristics of the movement, the testing machine drives the shaping tool to move upward at a certain speed until the impact shaping tool is separated from the deformed casing, and at the same time records the tensile strain on the mating joint. In the same way, make the impact shaping tool reshape and repair the deformed casing through up and down reciprocating motion until the strain on the mating joint tends to zero, that is, the minimum inner diameter of the deformed section of the casing is basically equal to the maximum outer diameter of the shaping tool.

The present invention has the following advantages:

(1) According to the purpose of the experiment, the top clamp on the top of the YS32-500 universal hydraulic testing machine and the matching joint with the strain gauge on the outer wall can easily and securely fix impact shaping tools with different cone angles and sizes through threaded connection (such as: Impact pear-shaped tube expander, impact ball shaper and other impact shaping tools), used to test the repair process of various deformed casings under different formation confining pressures and the size and taper angle difference of shaping tools and the shaping required for repairing deformed casings The relationship between the force and the lifting force, so as to realize the systematic simulation of the repair process of the downhole deformed casing;

(2) The YE-2533 static strain gauge can be used to test the shaping force required for casing repair under different confining pressures and the pulling force required for lifting tools after shaping, and the test accuracy is guaranteed, and accurate construction parameters can be provided for the site. So that the on-site shaping force and tool lifting force are strictly controlled;

(3) For the repair of deformed casings in different formations, the confining pressure exerted by the clamping tool on the casing deformation section can be adjusted by adjusting the torque on the hexagonal bolts with a torque wrench, so that the test results are closer to different actual formation conditions The real situation of deformed casing repair;

(4) The structure of the device is simple, the operation is convenient, the test price is low, and the later maintenance is easy.

Description of drawings

Figure 1 is a front view of a schematic diagram of a testing device.

Fig. 2 is a top view of a schematic diagram of a deformed sleeve.

Fig. 3 is a top view of a schematic diagram of a clamping tool for applying confining pressure to a deformed segment of a deformed casing.

Detailed ways

Referring to Fig. 1, the impact pear-shaped tube expander 4 (one of the impact shaping tools) is fixed on the center of the top of the universal hydraulic testing machine 1 with the top clamp 2 and the fitting joint 3 with the strain gauge 9 on the outer wall; The characteristic of the up and down reciprocating movement of the hydraulic testing machine 1 makes the pear-shaped tube expander 4 impact the deformed sleeve 5 at a certain speed. A circular groove 11 is fixed at the center of the bottom of the universal hydraulic testing machine 1 with a matching bottom clamp 7, and at the same time, the deformed section of the casing is clamped by a clamping tool 6 that matches the shape of the deformed section 12 of the deformed casing 5 , adjust the torque of the hexagonal bolt 8 on the clamping tool 6 by using a torque wrench to adjust the confining pressure exerted by the clamping tool 6 on the casing deformation section 12; And the YE-2533 static strain gauge 10 can accurately measure the shaping force required by the impact shaping tool in the process of repairing the deformed casing 5 and the pulling force required for the lifting of the tool after shaping, so as to meet the repair process of the deformed casing under confining pressure testing purpose.

Start the test device, the universal hydraulic testing machine 1 drives the pear-shaped tube expander 4 to reciprocate in the vertical plane through the top clamp 2 and the matching joint 3 . When the universal hydraulic testing machine 1 moves downward at a certain speed, the pear-shaped tube expander 4 fixed at the center of the top of the hydraulic testing machine 1 begins to reshape and repair the deformed casing 5. During the repair process, the static strain gauge 10 Record the compressive strain that occurs on the mating joint 3, and the downward movement of the universal hydraulic testing machine 1 is not stopped until the shaping tool completely passes through the deformation section 12 of the casing; due to the characteristics of the reciprocating motion of the universal hydraulic testing machine 1, Drive the impact pear-shaped tube expander 4 to move upward at a certain speed until the pear-shaped tube expander 4 and the deformed sleeve 5 are completely separated, and record the tensile strain on the mating joint 3 at the same time. In the same way, make the shaping tool reshape and repair the deformed casing 5 by reciprocating up and down until the strain on the mating joint 3 tends to zero, that is, the minimum inner diameter of the casing deformation section 12 is basically equal to the maximum outer diameter of the shaping tool . Thus, by using the same method, the device enables the testing of different impact shaping tool repair procedures.

Of course, when testing with this device, you can choose to apply confining pressure to the deformed casing to simulate the test of the repair process of the deformed casing under the confining pressure, or you can choose to simulate the test of the repair process of the deformed casing under the atmospheric environment.

According to the stress-strain relationship in the theory of elastic mechanics, combined with the strain generated on the mating joint during the deformation and repair of the casing, the plastic force required by the pear-shaped tube expander and the pulling force required for lifting the tool after plastic surgery can be calculated. Right now

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; E\&epsiv;</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}}$

In the formula: d—the diameter of the section where the strain gauge is located, in m;

E—Elastic modulus of mating joint, Mpa;

ε—the strain (tensile strain or compressive strain) produced on the mating joint;

F _t —the shaping force required by the pear-shaped tube expander or the lifting force of the tool after shaping.

According to the relationship between the torque and the axial force of the bolt, the axial force on each hexagonal bolt can be obtained. Right now

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; KD</span>}}$

In the formula: F—the axial force on each hexagonal bolt, N;

M—the torque reading value on the torque wrench, N/m;

k—torque coefficient, look-up table;

D—the nominal diameter of the hexagon bolt, m;

Combined with the size of the deformed section of the casing and the structure of the clamping tool, the confining pressure exerted by the clamping tool on the deformed section of the deformed casing can be obtained, and its size can be adjusted according to the axial force on the bolt. Right now

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; HL</span>}}$

In the formula: P—confining pressure on the deformation section of the casing, MPa;

H—the semi-major axis of the ellipse of the casing deformed section, m;

L—the length of casing deformation section, m;

Claims (2)

1. A test method for simulating the repairing process of deformed casing under confining formation pressure, characterized in that: using the characteristic of YS32-500 square column universal hydraulic testing machine (1) to generate external force by reciprocating up and down, using the top fixture (2) The mating joint (3) with the strain gauge (9) attached to the outer wall is fixed on the impact shaping tool (4) in the center of the top of the universal hydraulic testing machine (1), and impacts back and forth at a certain speed with the clamping tool (6) to apply the surrounding pressure. pressure of the deformed casing (5) to realize the test of the repair process of the deformed casing (5) under different formation confining pressures; at the same time, during the plastic repair process, the strain gauge (9) on the joint (3) and the YE2533 static The strain gauge (10) measures the shaping force required by the impact shaping tool (4) in the process of repairing the deformed casing (5) and the pulling force required to lift the shaping tool after shaping; The joint (3) can easily and securely fix impact pear-shaped expanders and impact ball shapers with different cone angles and sizes through threaded connection, and is used to test the performance of various deformed casings (5) under different formation confining pressures. The repairing process and the relationship between the size and taper angle difference of the shaping tool (4) and the shaping force and lifting force required for repairing the deformed casing (5), thereby realizing the systematic simulation of the repairing process of the downhole deformed casing (5). 2. the method for testing the repair process of deformed casing under simulated formation confining pressure according to claim 1, characterized in that: the clamping tool (6) is clamped on the deformed section (12) of the deformed casing (5); For the repair of the deformed casing (5) in different formations, adjust the torque of the hexagonal bolt (8) on the holding tool (6) with a torque wrench to change the force of the holding tool (6) on the casing deformation section (12) The confining pressure makes the test results closer to the real situation of deformed casing repair under different actual formation conditions.