CN-121994605-A - Casing thread damage simulation test method and device based on multistage volume fracturing parameters

CN121994605ACN 121994605 ACN121994605 ACN 121994605ACN-121994605-A

Abstract

The invention discloses a casing thread damage simulation test method and device based on multistage volume fracturing parameters, which comprises the steps of firstly placing two casing nipple connected through coupling threads into a test device, wherein the end part of one casing nipple is connected with an axial load mechanism, and the coupling is connected with a radial load mechanism; the method comprises the steps of starting a radial load mechanism and an axial load mechanism respectively, enabling the radial load mechanism to act on a coupling in the radial direction to force a connected sleeve to bend eccentrically, enabling the axial load mechanism to act on the end part of the sleeve in the axial direction to enable the sleeve to be axially pressed, starting a vibrator on a sleeve nipple, stopping vibration, injecting internal pressure into the sleeve to observe the internal pressure condition of the sleeve, starting the next vibration and internal pressure test, and finally recording the vibration frequency, the vibration amplitude and the internal pressure of the sleeve when the threaded seal of the sleeve fails. The method can simulate the construction parameters of the multi-section volume fracturing site, analyze and study the early seal failure of the sleeve screw thread, and further guide the site production.

Inventors

GAO YONGWEI
WANG PEIFENG
YANG XIAOFENG
XU CHAOYANG
LI YANZE
CHEN CAIZHENG
LI XIAOLI
ZHAO WENZHUANG
GUO BAILI
SHI CHONGDONG

Assignees

中国石油天然气集团有限公司
中国石油集团川庆钻探工程有限公司

Dates

Publication Date: 20260508
Application Date: 20241106

Claims (10)

1. A casing thread damage simulation test method based on multistage volume fracturing parameters is characterized by comprising the following steps: S1, supporting the end parts of two casing nipple joints connected through coupling threads on a supporting seat respectively, and then connecting the end part of one of the casing nipple joints with an axial load mechanism and connecting the coupling with a radial load mechanism; s2, starting a radial load mechanism, wherein the radial load mechanism acts on the coupling in the radial direction to force the connected sleeve to bend eccentrically; S3, starting an axial load mechanism, wherein the axial load mechanism acts on the end part of the sleeve in the axial direction to axially compress the sleeve; S4, starting a vibrator on the casing nipple, starting vibration of the vibrator, and adjusting and recording vibration parameters of the vibrator; S5, stopping vibration, injecting internal pressure into the sleeve, observing the site construction pressure condition, then unloading the internal pressure of the sleeve, starting the next vibration and internal pressure test, and recording the vibration frequency, the vibration amplitude and the internal pressure and the displacement of the sleeve when the threaded seal of the sleeve fails.
2. The method for simulating the damage to the casing thread based on the multistage volumetric fracturing parameters according to claim 1, further comprising the steps of S6, detaching the casing nipple, and then observing the development condition of the thread crack of the two connected casing nipples to evaluate the failure of the sealing of the casing thread in the horizontal well multistage volumetric fracturing parameters.
3. The method for simulating casing thread damage test based on multistage volumetric fracturing parameters according to claim 1, wherein the vibrators are symmetrically distributed on casing pup joints on two sides of the coupling.
4. The method for simulating casing thread damage test based on multistage volumetric fracturing parameters according to claim 1, wherein the vibrator is an electronically controlled vibrator.
5. A method of casing thread damage simulation test based on multi-segment volumetric fracturing parameters according to claim 1, wherein said radial load mechanism comprises a first hydraulic cylinder.
6. A method of simulating casing thread damage based on a multi-segment volumetric fracturing parameter according to claim 1, wherein said axial loading mechanism comprises a second hydraulic cylinder.
7. The method for simulating the damage to the sleeve thread based on the multistage volumetric fracturing parameters, according to claim 1, is characterized in that the vibration frequency of the vibrator is 180-220hz, the vibration amplitude is 2-3mm, and the vibration time is 120 minutes each time.
8. The method for simulating the damage to the casing thread based on the multistage volumetric fracturing parameters according to claim 1, wherein the internal pressure of the casing is 40-50Mpa.
9. A casing thread damage simulation test device based on multistage volumetric fracturing parameters is used for realizing the simulation test method according to any one of the claims 1-8, and is characterized by comprising a support, a stress-strain detection mechanism, an internal pressure injection mechanism, an axial load mechanism, a radial load mechanism and a vibrator, The support is used for supporting the ends of two casing pup joints connected through coupling threads; the stress-strain detection mechanism is connected with the casing nipple and is used for detecting the stress-strain of the casing nipple; the internal pressure injection mechanism is used for injecting fracturing fluid into the connected casing nipple; The axial load mechanism is connected with one end of the two connected casing pup joints and is used for applying axial force to the casing; the radial load mechanism is connected with the coupling at the connecting part of the two casing pup joints and is used for applying radial force to the casing; The vibrator is arranged on the casing nipple to enable the casing nipple to vibrate.
10. The casing thread damage simulation test device based on the multistage volumetric fracturing parameters, according to claim 9, further comprising a man-machine interaction device, wherein the stress-strain detection mechanism, the internal pressure injection mechanism, the axial load mechanism, the radial load mechanism and the vibration generator are respectively connected with the man-machine interaction device.

Description

Casing thread damage simulation test method and device based on multistage volume fracturing parameters Technical Field The invention relates to the technical field of oil and gas well drilling and completion pipe evaluation, in particular to an oilfield horizontal well casing damage evaluation method, and more particularly relates to a casing thread damage simulation test method and device based on multistage volume fracturing parameters. Background The shale oil exploitation technology of the Changqing oilfield takes a large well group, a long horizontal section and multi-section volume fracturing as main technologies, and aims to improve the well yield to the greatest extent, but in the development process of the shale oil horizontal well of the Changqing oilfield, the sleeve sealing failure frequently occurs due to the fact that the offset distance of the shale oil horizontal well is large and the horizontal section is long. Because the casing of the shale oil horizontal well of the Changqing oilfield is large in friction resistance, the casing of the wellhead is lifted and lowered to make the repeated bending stress of the casing of the well complicated, so that the stress alternating thread sealing environment of the local casing is deteriorated, and the casing thread is subjected to bending vibration again in the process of multiple volume fracturing in the later stage, so that the casing sealing is invalid. The method is widely used for inquiring the problem of casing thread damage in the process of volume fracturing transformation of a tight oil and gas reservoir, and related technical information is obtained as follows: Firstly, according to elastoplastic mechanics and contact mechanics theory and combining with actual conditions of volume fracturing transformation construction, a full three-dimensional casing-cement ring-stratum coupling finite element analysis model is established, asymmetric areas of volume fracturing transformation are represented by different elliptic cylinders, an ABAQUS solver is subjected to intervention and secondary development by adopting a Fortran subroutine, and physical and dynamic evolution and mechanical properties of hydration expansion of the volume fracturing transformation area are simulated. The result shows that the non-uniformity of the external load around the shaft is enhanced along with the increase of the ratio of the length to the short axis of the elliptical transformation area, the non-uniformity degree transmitted to the casing through the cement sheath is increased firstly and then tends to be stable, the non-uniformity degree of the external load of the casing is increased along with the increase of the volume expansion rate, the stress level of the casing is greatly increased by the enhancement of the non-uniformity of the external load of the casing, and the problem of casing failure is easily caused. And secondly, realizing global embedding Cohesive units and seepage nodes in the volume fracturing area, prefabricating natural cracks in the volume fracturing area, and completing the description of the non-uniform expansion process of the complex crack network at two sides of the sleeve in the volume fracturing process and performing simulation initial exploration by using a stress-seepage coupling method. Initial detection results show that the non-uniform expansion of the cracks changes the periodic change rule of the stress on the inner wall of the sleeve, so that the maximum stress area of the sleeve is deviated, and the periodic symmetric distribution of the stress on the inner wall of the sleeve is destroyed. The main factors influencing the failure of the shale gas well casing are considered to be two aspects of the characteristics of the shale reservoir and the fracturing construction mode by combining the site construction condition, the physical property of the shale reservoir, the volume fracturing characteristic and the conventional oil-gas casing failure comparative analysis, wherein the initial crack development condition of the reservoir, the fracturing construction pressure and the shale hydration expansion are the main factors. Fourthly, the sleeve is characterized in that a 'suspended' state appears in the stratum according to different degrees, so that the sleeve generates a certain degree of deflection deformation along the radial direction of the sleeve, and the sleeve is in an 'S' -shaped deformation along the axial direction. The spacing between the fracturing sections is properly increased, the effective length of the multi-shower hole fracturing section is shortened, and the S-shaped deformation of the horizontal section sleeve can be effectively reduced or controlled. Through consulting and analyzing the data, the problem of damage to the casing thread by the multi-section volume fracturing parameters is considered, and the method and the measure are mainly provided from the aspects of finite element simulation, casing fr