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Casing damage well chemical leaking stoppage prepad fluid and preparing method thereof

A pre-fluid, chemical technology, applied in the direction of chemical instruments and methods, drilling composition, etc., can solve the problems of casing outer wall corrosion, short validity period, low leakage plugging success rate, etc., and achieve the effect of improving cementation quality

Inactive Publication Date: 2016-07-13
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Casing damaged wells without a cement sheath between the formation and the casing, because the outer wall of the casing is soaked by crude oil and formation water for a long time, the outer wall of the casing is corroded
Due to the presence of oil stains attached to the outer wall of the casing and corrosion products, the cement cannot form a good cemented interface with the casing during chemical plugging, resulting in a low plugging success rate and a short validity period

Method used

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  • Casing damage well chemical leaking stoppage prepad fluid and preparing method thereof
  • Casing damage well chemical leaking stoppage prepad fluid and preparing method thereof

Examples

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Effect test

Embodiment 1

[0021] This embodiment provides a chemical plugging fluid for old wells with casing damage, which includes water, and also includes the following raw materials in terms of weight percentage of water, 0.5%-3% of tackifier, and 0.5-1mm in diameter with corners Stone particles 5%-8%, surfactant 1%, co-solvent 0%-0.25%, potassium chloride 1%, sodium carbonate 0.1%-0.3%.

[0022] Principle of the present invention:

[0023] The viscosifier can effectively replace the oil and formation water in the formation and the casing annulus. When the formation leaks, it will form a blocking slug to seal the lost layer; the stone particles with a diameter of 0.5-1mm When the pipe gap moves, the edges and corners of the particles can scrape the oil and corrosion products on the outer wall of the casing. Wet" becomes "water-wet" to improve the bonding quality of cement and casing; potassium chloride (KCl) can prevent clay from swelling, and sodium carbonate (Na 2 CO 3 ) Adjust the pH value be...

Embodiment 2

[0025] On the basis of Example 1, this example provides a method for preparing a chemical plugging fluid in an old well with casing damage:

[0026] (1) Take 1000Kg of water, add 10Kg of KCl and stir evenly, and add 1Kg of Na 2 CO 3 , stirring to adjust the pH value at 7.5-8.5;

[0027] (2) Add 10Kg isomeric decanol ether (industrial product), stir evenly, and measure the surface tension to below 1.0mN / m;

[0028] (3) Add 5Kg of ZND-2 gel under uniform stirring to make it fully swell for more than 0.5h, requiring 7S -1 The lower viscosity is 1800-2000mPa·s;

[0029] (4) Add 0.5-1mm in diameter, 50Kg of angular quartz, calcite or marble particles, stir to suspend evenly in the solution, and then get the chemical plugging pre-fluid for old wells with casing damage.

[0030] In this example, the surfactant is isomeric decanol ether, and the tackifier is ZND-2 gel, purchased from Sichuan Guangya Company.

Embodiment 3

[0032] Preparation of a chemical plugging fluid in an old well with casing damage:

[0033] (1) Take 1000Kg of water, add 10Kg of KCl and stir evenly, and add 2Kg of Na 2 CO 3 , adjust the pH value at 7.5-8.5;

[0034] (2) Add 10Kg sodium heavy alkylbenzene sulfonate (industrial product) and 2.5Kg isopropanol (industrial product), stir evenly, and the surface tension reaches below 1.0mN / m;

[0035] (3) Add 7.5Kg of ZND-2 gel under uniform stirring to make it fully swell for more than 0.5h, requiring 7S -1 The lower viscosity is 1800-2000mPa·s;

[0036] (4) Add 0.5-1mm in diameter, 65Kg of angular quartz, calcite or marble particles, stir to suspend evenly in the solution.

[0037] In this embodiment, the surfactant is sodium heavy alkylbenzene sulfonate, the tackifier is ZND-2 gel, purchased from Sichuan Guangya Company, and isopropanol is used as a cosolvent.

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Abstract

The invention provides casing damage well chemical leaking stoppage prepad fluid.The casing damage well chemical leaking stoppage prepad fluid comprises water and further comprises, by weight, 0.5-3% of tackifier, 5-8% of stone particle with the corner diameter being 0.5-1 mm, 1% of surfactant, 0-0.25% of cosolvent, 1% of potassium chloride and 0.1-0.3% of sodium carbonate.The chemical leaking stoppage prepad fluid has the functions of efficiently replacing oil contamination in a stratum and in an annular space of a casing pipe of mud flushing liquid and conducting wettability alteration on the wall of the casing pipe, and also has the functions of scrapping oil contamination and corrosion products on the outer wall of the casing pipe.When the stratum leaks, the chemical leaking stoppage prepad fluid has the function of partitioning, bridging and plugging the leakage layer to achieve the purpose of improving the adhesion quality of cement and the casing pipe.

Description

technical field [0001] The invention belongs to the technical field of treatment of casing damaged wells in oil and gas fields, and in particular relates to a chemical plugging fluid for old casing damaged wells and a preparation method thereof. Background technique [0002] For casing damaged wells without a cement sheath between the formation and the casing, the outer wall of the casing is soaked by crude oil and formation water for a long time, causing the outer wall of the casing to corrode. Due to the presence of oil stains attached to the outer wall of the casing and corrosion products, the cement cannot form a good cemented interface with the casing during chemical plugging, resulting in a low plugging success rate and a short validity period. Therefore, before chemical plugging, it is necessary to add a cleaning slug to efficiently replace the oil and formation water in the formation and casing annulus, and effectively clean the oil and corrosion products on the oute...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/524
CPCC09K8/524
Inventor 王小勇李琼玮杨立华奚运涛黄战卫饶辰威张育超邱家友刘爱华付彩利
Owner PETROCHINA CO LTD