An elastic gel temporary plugging and killing fluid used in gas well combination and its construction technology

A technology of elastic gel and construction technology, which is applied in the direction of wellbore/well components, drilling compositions, chemical instruments and methods, etc. It can solve the problems of difficult gel breaking, low reservoir pressure coefficient, and controllable strong gel gender issues

Active Publication Date: 2022-03-29
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] In order to solve the problem that the old gas wells in carbonate reservoirs have been produced for a long time, due to the low reservoir pressure coefficient and the unclear development of acid-dissolved pores / fractures, there are problems in the workover process, such as large volume of conventional workover fluid and resumption of production. Long period, poor controllability of strong gel, difficult gel breaking, high cost of villi, poor passability of solid phase particles, easy jamming and other problems. The purpose of the present invention is to provide a temporary plugging of elastic gel used in combination with gas wells. Killing fluid and construction technology to realize temporary plugging of old gas wells in carbonate reservoirs, reduce reservoir damage, and restore gas well productivity in time

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] According to the formation pressure coefficient and wellbore structure of Well A, the artificial bottom hole is 3300m, the tubing depth is 3100m, the predicted formation pressure is 15MPa, wellhead oil and casing pressure are 6MPa, 7″casing and 2 7 / 8″ tubing combination as an example, calculate the required amount of elastic gel temporary plugging and killing fluid, and then perform elastic gel temporary plugging and killing fluid synthesis and workover operations.

[0069] 1) Prepare 2 5m with agitator 3 Clean the liquid distribution tank;

[0070] 2) First add 4m to the 1# liquid distribution tank 3 Clear water, then add 20kg of stabilizer (thiourea), and stir evenly. Then add 200kg of inorganic toughening agent (montmorillonite), and stir evenly. Add 100kg of temperature-resistant and salt-resistant polymer (polyacrylamide) while stirring, and finally add 50kg of organic cross-linking agent (acrylic acid).

[0071] 3) First add 4m to the 2# liquid distribution t...

Embodiment 2

[0080] According to the formation pressure coefficient and wellbore structure of Well B, the artificial bottom hole is 3200m, the tubing depth is 3080m, the predicted formation pressure is 15MPa, the wellhead oil and casing pressure are 6MPa, 7″casing and 2 7 / 8″ tubing combination as an example, calculate the required amount of elastic gel temporary plugging and killing fluid, and then perform elastic gel temporary plugging and killing fluid synthesis and workover operations.

[0081] 1) Prepare 2 5m with agitator 3 Clean the liquid distribution tank;

[0082] 2) First add 2.4m 3 Clear water, add 12kg stabilizer (thiourea), stir evenly. Then add 120kg of inorganic toughening agent (nano silicon dioxide) and keep stirring. Add 48kg of temperature-resistant and salt-resistant polymer (polyacrylamide) while stirring, and finally add 24kg of organic cross-linking agent (acrylic acid).

[0083] 3) First add 2m to the 2# liquid distribution tank 3 Add 10kg of stabilizer (thiou...

Embodiment 3

[0092] 1# elastic gel includes, in parts by weight: 1.5 parts of temperature-resistant and salt-resistant polymer, 1.5 parts of organic crosslinking agent, 6 parts of inorganic toughening agent, 0.3 part of stabilizer and 100 parts of water;

[0093] 2# elastic gel includes, in parts by weight: 2 parts of temperature-resistant and salt-resistant polymer, 1.0 part of organic crosslinking agent, 0.5 part of stabilizer and 100 parts of water.

[0094] Wherein, the temperature-resistant and salt-resistant polymers are all polyacrylamide and 2-acrylamide-2-methylpropanesulfonic acid.

[0095] The organic crosslinking agents are all acrylic acid.

[0096] The inorganic toughening agent is montmorillonite.

[0097] Described stabilizing agent is all thiourea.

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Abstract

The invention relates to an elastic gel temporary plugging and killing fluid used in combination with gas wells and a construction process, including 1# elastic gel and 2# elastic gel; the 1# elastic gel includes: temperature and salt resistance in parts by weight 1.5-3 parts of polymer, 1.0-1.5 parts of organic cross-linking agent, 4-6 parts of inorganic toughening agent, 0.2-0.5 parts of stabilizer and 100 parts of water; 2# elastic gel includes: temperature-resistant 2-5 parts of salt-resistant polymer, 1.0-1.5 parts of organic cross-linking agent, 0.2-0.5 parts of stabilizer and 100 parts of water. The combined elastic gel of the present invention can resist pressure ≥ 20MPa after the temporary plugging and killing fluid is gelled, the theoretical fluid loss is less than 200mL / h, and the performance stability time is more than 30 days. , wellbore and other places to meet the technical requirements of temporary plugging and leakage prevention and reservoir protection of gas wells with relatively low formation pressure coefficients.

Description

technical field [0001] The invention relates to the technical field of natural gas development, in particular to an elastic gel temporary plugging and killing fluid used in combination for gas well workover and a construction process. Background technique [0002] Workover operation is one of the important means to maintain the normal production of gas wells. During the production process of gas wells, sand production in the formation, dirt precipitation, blow-by of production strings, tubing breakage, water flooding of gas wells, etc. will lead to abnormal production of gas wells. In addition, casing deformation, corrosion, rupture, tubing corrosion and perforation, breakage, tubing blockage and other reasons will also cause gas wells to stop production or even be scrapped. In order to keep these gas wells in a good production state, it is necessary to carry out workover operations on them to restore normal production. [0003] There are two main methods of workover for g...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/512C09K8/516E21B33/13
CPCC09K8/512C09K8/5083C09K8/516E21B33/13
Inventor 刘伟朱方辉李明星李琼玮董晓焕张振云郭钢于淑珍程碧海谷成义
Owner PETROCHINA CO LTD
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