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Method for increasing success rate of chemical plugging of leaking casing damage well

A technology with high success rate and chemistry, applied in chemical instruments and methods, earthwork drilling, sealing/isolation, etc., can solve the problems of poor plugging agent retention, short validity period, low pass rate, etc., and improve the pressure bearing capacity of the formation , prolong the validity period, and improve the success rate of plugging

Active Publication Date: 2016-10-12
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the problems of poor retention of plugging agent in chemical plugging of lost casing damaged wells, low pass rate of 15MPa pressure test after plugging, and short valid period after pressure test is qualified

Method used

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  • Method for increasing success rate of chemical plugging of leaking casing damage well
  • Method for increasing success rate of chemical plugging of leaking casing damage well
  • Method for increasing success rate of chemical plugging of leaking casing damage well

Examples

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Effect test

Embodiment 1

[0034] In order to overcome the problems of poor retention of plugging agent in chemical plugging of lost casing damaged wells, low pass rate of 15MPa pressure test after plugging, and short validity period after passing the pressure test, this embodiment provides a method such as figure 1 The method shown to increase the success rate of chemical plugging in leaky casing damaged wells, for the casing damaged wells whose casing damage is within 1000m, can be one casing damage point or multiple casing damage points. The casing damaged well with a length of less than 100m can basically be successfully completed at one time, including the following steps:

[0035] Step 1) Determine the remaining wall thickness t of the casing according to the MIT+MTT wellbore detection;

[0036] Step 2) calculate casing pressure bearing capacity;

[0037] Step 3) Squeeze 20m at the front section of casing 3 Cleaning liquid, cleaning slug, cleaning casing outer wall oil and corrosion products;

...

Embodiment 2

[0042] On the basis of Example 1, this example provides a method for improving the success rate of chemical plugging of leaky casing damaged wells. In the step 1), MIT is a multi-arm caliper imager, which is a well developed by the British Sondex company. The diameter imaging logging tool can detect the inner diameter of the casing, and the MTT is a magnetic wall thickness logging tool, which is a casing wall thickness damage imaging logging tool developed by the British Sondex company, which can detect the remaining casing wall thickness.

Embodiment 3

[0044] On the basis of Embodiment 2, this embodiment provides a method for improving the success rate of chemical plugging of leakage casing damaged wells. In the step 2), the pressure bearing capacity of the casing is calculated according to the formula: p j =4δt

[0045] In the formula: p j , casing pressure, MPa;

[0046] t, remaining wall thickness of casing, obtained from well logging, mm;

[0047] δ: circumferential uneven corrosion coefficient.

[0048]The circumferential uneven corrosion coefficient δ is related to the corrosion mechanism and time. When it is uniform corrosion of sheet and step, δ is 0.8-0.9, and when it is localized corrosion of point and groove, δ is 0.7-0.8.

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Abstract

The invention relates to a method for increasing the success rate of chemical plugging of a leaking casing damage well. A casing pipe horizontal pushing method and a three-slug theory are adopted for the casing damage well with a casing damage part located within 1,000 m, wherein the front section is a washing slug, formation water is replaced, oil dirt and corrosive products on the outer wall of a casing pipe are washed, the wettability is changed, and a good gelling environment is provided for a plugging slug; the middle plugging stratum is a main body cementing section and can effectively prevent leaking and plug the stratum, and a pressure bearing section can be built to isolate the formation water from the casing pipe; the tail section is an intermittent replacement slug, multiple times of replacement are performed intermittently, the main body cementing section can be checked and improved, the plugging success rate is increased, and the validity is prolonged.

Description

technical field [0001] The invention relates to the field of treatment of casing damaged wells in oil and gas fields, in particular to a method for improving the success rate of chemical plugging of leakage casing damaged wells. Background technique [0002] Oil and water wells are cased, and the integrity of the wellbore needs to be re-established. Treatment technologies include chemical plugging, casing subsidy, small casing cementing and small casing sidetracking. The latter three technologies all have the problem that the well diameter becomes smaller after treatment, which affects various downhole constructions in the later stage. This problem exists. The existing chemical plugging technology is mainly researched on plugging agents, such as application number: 201410401797.6, fiber ultrafine cement extrusion sealant and its preparation method, application number: 201410404560.3, a high water loss solidification pressure-bearing plugging agent, Application No.: 2013.10...

Claims

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Application Information

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IPC IPC(8): E21B33/13E21B47/002E21B47/08E21B37/06C04B28/06C04B28/34C09K8/52C09K8/467
CPCC04B28/06C04B28/34C09K8/467C09K8/52E21B33/13E21B37/06E21B47/002E21B47/08C04B7/00C04B2103/12C04B2103/0068C04B14/06C04B14/28C04B14/285Y02P20/141
Inventor 王小勇慕立俊李琼玮杨立华奚运涛赵文何治武程碧海张鑫柱饶辰威张育超邱家友
Owner PETROCHINA CO LTD
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