Salt-tolerant resistance-reducing agent applied for shale gas reservoir

A shale gas reservoir and drag-reducing agent technology, which is applied in the direction of drilling compositions, chemical instruments and methods, etc., can solve the problems not mentioned, achieve good salt tolerance, and overcome the effect of insufficient salt tolerance

Inactive Publication Date: 2013-10-02
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The average usage concentration of this anionic polyacrylamide drag-reducing agent is lower than 0.15%, and the molecular weight is above 2.5 mi...

Method used

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  • Salt-tolerant resistance-reducing agent applied for shale gas reservoir

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Take 500g of the flowback liquid (the main ion content in the flowback liquid is shown in Table 1) and place it in a mixer with a volume of 1000ml, and slowly add 4.875g of the drag reducing agent (the mass percentage concentration of the drag reducing agent is 0.975%), Among them, the drag reducing agent is a binary copolymer composed of 70% acrylamide units and 30% acryltrimethylammonium chloride units, with a molecular weight of 1.6×10 6 , stirred for 10 minutes, and made into a uniform solution. The measured kinematic viscosity of the solution was 1.7mPa.s, and the resistance reduction rate was 68%.

[0019] Table 1 Main ion content in flowback liquid

[0020] Ca 2+ (mg / L)

Embodiment 2

[0022] Take 500g of the flowback liquid (the main ion content in the flowback liquid is shown in Table 2) and place it in a mixer with a volume of 1000ml, slowly add 0.375g of the drag reducer (the mass percentage concentration of the drag reducer is 0.075%), Among them, the drag reducing agent is a binary copolymer composed of 70% acrylamide units and 30% acryltrimethylammonium chloride units, with a molecular weight of 1.6×10 6 , stirred for 10 minutes, and made into a uniform solution. The kinematic viscosity of the solution was measured to be 1.7mPa.s, and the resistance reduction rate was 67%.

[0023] Table 2 Contents of main ions in flowback liquid

[0024] Ca 2+ (mg / L)

Embodiment 3

[0026] Take 500g of the flowback liquid (the content of main ions in the flowback liquid is shown in Table 3) and place it in a mixer with a volume of 1000ml, and slowly add 0.25g of the drag reducing agent (the mass percentage concentration of the drag reducing agent is 0.05%), Among them, the drag reducing agent is a binary copolymer composed of 75% acrylamide units and 25% acrylamidopropyltrimethylammonium chloride units, and its molecular weight is 1.7×10 6 , stirred for 10 minutes, and made into a uniform solution. The kinematic viscosity of the solution was measured to be 1.7mPa.s, and the resistance reduction rate was 66%.

[0027] Table 3 Contents of main ions in flowback liquid

[0028] Ca 2+ (mg / L)

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Abstract

The invention relates to a salt-tolerant resistance-reducing agent applied for a shale gas reservoir. The resistance-reducing agent is a biopolymer comprising an acrylamide unit and a propenyl quaternary ammonium salt unit. The weight percent of the acrylamide in the biopolymer is 10%-80%. The propenyl quaternary ammonium salt is one of a propenyl trialkyl ammonium chloride, an alkyl acrylamido propyl trialkyl ammonium chloride or a dialkyl diallyl ammonium chloride. The weight percent of the propenyl quaternary ammonium salt in the biopolymer is 20%-90%, and the molecular weight of the propenyl quaternary ammonium salt is 1*10<6> to 2*10<6>. The resistance-reducing agent provided by the invention can be used as resistance-reducing agents for fracturing flow-back fluid, cavern water and underground produced water, wherein the fracturing flow-back fluid, the cavern water and the underground produced water contain divalent metal ions, and the weight percent resistance-reducing agent provided by the invention for using is 0.05%-0.1%. The resistance-reducing agent provided by the invention has good salt tolerance and resistance-reducing properties, and overcomes problems, of other polypropanamide resistance-reducing agents at present, comprising salt tolerance deficiency in using processes and incapability of being applied for hypersalinity water that comprises Ca<2+> and Mg<2+> at the same time.

Description

technical field [0001] The invention relates to the application of a low molecular weight cationic polyacrylamide drag reducer in high salinity water of shale gas reservoirs. Background technique [0002] Polyacrylamide polymers have been widely used as drag reducing agents at home and abroad, and many patents have widely reported their applications. The current polyacrylamide drag reducer is mainly due to insufficient salt resistance during use, especially it cannot be applied to Ca 2+ , Mg 2+ At the same time, high salinity water exists. [0003] U.S. Patent US3943060 and US6787506 then reported respectively by acrylamide and 2-acrylamide-2-methylsulfonic acid, methacrylic acid ester, acrylic acid, dimethylaminomethyl chloride quaternary ammonium salt, dimethylaminomethylacrylic acid benzyl chloride Anionic and cationic polyacrylamide drag reducers synthesized by copolymerization of monomers such as quaternary salts. US Patent US4152274 reports a cationic polyacrylamid...

Claims

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Application Information

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IPC IPC(8): C09K8/68C08F226/02C08F220/60C08F220/56
Inventor 刘友权陈鹏飞金洪吴文刚孙川龙顺敏陈楠
Owner PETROCHINA CO LTD
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