Shale gas reservoir pre-fracture composite acid solution, preparation method and application thereof

A compound acid liquid and shale gas reservoir technology, which is applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve the problems of poor adaptability of acid liquid, fast dissolution of acid and reservoir minerals, poor pertinence of acid liquid formula, etc. problem, to achieve fast dissolution, good clay stabilization effect, and strong decontamination ability

Inactive Publication Date: 2015-11-25
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The current problems are that the conventional acid solution has poor adaptability to shale gas reservoirs, the acid dissolves quickly with reservoir minerals, and the acid solution formulation is poorly targeted

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] The composition of the compound acid solution is 15% HCl+1%AI-810+0.3%BZP-3+0.5%NTA+0.3%BFC-03, and the rest is water.

[0057] The composite acid solution of this embodiment is suitable for shale reservoirs with a temperature lower than 100°C and a carbonate mass content higher than 20%, and the core dissolution rate at 80°C is about 25%.

Embodiment 2

[0059] The composition of the compound acid solution is 12% HCl+1.5% HF+1% AI-810+0.3% BZP-3+0.5% NTA+0.3% BFC-03, and the rest is water.

[0060] The composite acid solution of this embodiment is suitable for shale reservoirs with a temperature lower than 100°C and a carbonate mass content lower than 20%, and the core dissolution rate at 80°C is about 25%.

Embodiment 3

[0062] The composition of the compound acid is 12% HCl+5% CH 3 COOH+1%AI-811+0.3%BZP-3+0.5%TCB-05+0.3%BFC-03, the rest is water.

[0063] The composite acid solution of this embodiment is suitable for shale reservoirs with a temperature higher than 100°C and a carbonate mass content higher than 25%, and the core dissolution rate at 90°C is about 30%.

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Abstract

The invention belongs to the field of petroleum engineering and relates to a shale gas reservoir pre-fracture composite acid solution and its preparation method and application. The composite acid solution comprises the following components: Component a) at least one component of hydrochloric acid, hydrofluoric acid, fluorboric acid, phosphoric acid, formic acid and acetic acid; and Component b) a corrosion inhibitor, a discharge aiding agent, a ferric iron stabilizer and a clay stabilizer. The composite acid solution containing different acids is selected for different reservoirs. Rock core corrosion ratio is 25-30%. A certain rock core corrosion ratio is maintained, and borehole wall collapse caused by too high corrosion ratio is also prevented. The corrosion inhibitor, the discharge aiding agent, the ferric iron stabilizer and the clay stabilizer which are used as additives have good compatibility with acid. The composite acid solution provided by the invention has advantages of fast dissolving speed, uniform mixing, high corrosion inhibition efficiency, high surface activity, good clay stabilizing effect and wide range. Applicable temperature of the composite acid solution is 20-180 DEG C. by the use of the composite acid solution, normal construction of large-scale fracturing of long horizontal-section shale gas wells can be guaranteed under the condition of existing equipment capacity.

Description

technical field [0001] The invention belongs to the field of petroleum engineering, and relates to a composite acid liquid before fracturing of shale gas reservoirs, a preparation method and application thereof. Background technique [0002] Shale gas reservoirs are typical ultra-low permeability unconventional natural gas reservoirs, which exist in shale reservoirs in an adsorbed state (about 50%) or in a free state (about 50%). The special geological conditions determine the conventional development technology It cannot be directly applied to the production of shale gas reservoirs. To develop such reservoirs, it is necessary to use enhanced means—reservoir fracturing technology to improve the seepage conditions of oil and gas flow, so as to achieve the purpose of effective exploitation. At present, the main fracturing technology in the development of shale gas reservoirs is the high-displacement and large-fluid-volume slickwater fracturing technology. Through multi-stage ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/74
Inventor 王宝峰蒋廷学贾长贵王海涛李双明李奎为卫然
Owner CHINA PETROLEUM & CHEM CORP
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