A chemical plugging process for casing damaged wells without bridging plugs and non-moving strings

A technology of moving pipe and string casing, which is applied in the field of chemical plugging technology of bridge-free moving pipe string casing damaged wells, and achieves the effects of easy availability of raw materials, reduced risks, and avoiding cost and time

Active Publication Date: 2022-02-01
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

There is no relevant report on the chemical plugging technology for casing damaged wells without bridging plugs and non-moving strings

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  • A chemical plugging process for casing damaged wells without bridging plugs and non-moving strings

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Effect test

Embodiment 1

[0036] This embodiment provides a chemical plugging process for a casing damaged well without a bridge plug, including the following steps:

[0037] Step 1) Test the water absorption of casing damaged section under 10MPa pressure, and select wells with water absorption less than 200L / min for plugging;

[0038] Step 2) Run the varnish tubing into the casing of the casing damaged well 200 meters above the casing damage section, and close the casing gate;

[0039] Step 3) After injecting the guar gum liquid, it naturally sinks to the bottom of the well for 20-30 minutes, and the production layer is blocked to keep the liquid level unchanged. Inject clean water until the clean water level is 10-15 meters away from the lower edge of the casing damage section;

[0040] Step 4) After injecting the organic resin plugging agent system, settle naturally for 20-30 minutes to form the first resin plug, and shut down the well;

[0041] Step 5) Prepare the organic resin plugging agent syst...

Embodiment 2

[0045] This embodiment provides a chemical plugging process for a casing damaged well without a bridge plug, including the following steps:

[0046] Step 1) Use a conventional packer to test the water absorption of the casing damaged section of the casing damaged well under a pressure of 10MPa, and select the well with a water absorption of less than 200L / min for plugging;

[0047] Step 2) Run the varnish tubing into the casing of the casing damaged well 200 meters above the casing damage section, and close the casing gate;

[0048] Step 3) Prepare and inject 300-400L of guar gum solution with a mass concentration of 0.35-0.55%, let it sink naturally for 20-30 minutes to the bottom of the well, and plug the production layer, keep the liquid level constant, inject clean water, and calculate the amount of clean water, so that The clear water level is located 10-15 meters away from the lower edge of the casing damage section;

[0049] Step 4) Prepare and inject 100-200L organic ...

Embodiment 3

[0059] In this embodiment, the method of the present invention is used to carry out on-site construction of Yuan A well. Well Yuan A is an oil production well put into production in September 2014. Before casing damage, the oil production was 3.3t / d. In August 2018, casing damage was found, and the water cut after casing damage was 100%. Engineering logging found that the casing damage section was 3 meters (1156m-1159m), the perforation section is 1312-1316m, and the chemical plugging operation is carried out.

[0060] The plugging process is as follows:

[0061] 1. Using a conventional packer to test the casing damage section of the casing damage well, the water absorption is 330L / min under the pressure of 10MPa;

[0062] 2. Lower the light oil pipe to 956 meters in the casing of the casing damaged well, and close the casing gate;

[0063] 3. Prepare and inject 300L of 0.35% guar gum solution, let it sink naturally for 20 minutes to the bottom of the well, and plug the prod...

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Abstract

The invention provides a chemical plugging process for a bridge-free non-moving pipe string casing damaged well, which uses guar gum base liquid to occupy the production layer and uses the density difference and wettability of organic resin, guar gum, and water to pass The injection of suspended organic resin replaces the mechanical bridge plug, and at the same time, the plugging agent is injected for casing damaged wells with high water absorption without moving the string, so as to complete the chemical plugging of casing damaged wells in one trip. The bridge plug-free chemical plugging process for casing damaged wells without bridge plugs reduces the cost, avoids the cost and time wasted in multiple bridge plugging, and avoids the failure of multiple sets of mechanical bridge plugs to damage the inner wall of fragile casings in old wells. Secondary losses and the acceleration of inner wall corrosion. The labor intensity in the construction process is greatly reduced. Since there is no plugging agent in the pipe string, the risk of "flag pole" caused by plugging operations is greatly reduced, and the time for chemical plugging operations is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a chemical plugging process for casing damaged wells without bridging plugs and fixed pipe strings. Background technique [0002] With the increase of the production life of multi-layer oilfields, coupled with the influence of geological conditions and engineering factors, casing damage and fluid leakage outside the casing often occur, affecting the stable production of the oilfield and the smooth implementation of the development plan, and even causing production shutdown, seriously affecting It improves the effective water injection and ultimate recovery of the reservoir. At present, the commonly used channeling and leakage sealing technology mainly uses cement, resin, organic materials, etc. for chemical sealing. Most of the mechanical bridge plugs are used to seal off the production layer. The tool tubing replaces the plugging agent to the vicinity...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B33/13C09K8/44
CPCE21B33/13C09K8/44
Inventor 郭钢李琼玮杨立华卢文伟孙雨来程碧海王小勇李慧谷成义戚建晶
Owner PETROCHINA CO LTD
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