Fiber composite hydraulic fracturing fluid for shale volume fracturing

Abstract

The invention relates to a fiber composite hydraulic fracturing fluid for shale volume fracturing. The hydraulic fracturing fluid comprises the following components in percentage by weight: 0.1% of drag reducer, 1% of antiswelling agent, 1% of long-acting clay stabilizer, 0.06% of compound bactericide, 0.005% of scale inhibitor, 0.3% of surfactant and the balance of water. The fiber is nano SiO2 composite fiber with favorable thermodynamic and chemical stability, and the fiber concentration (fiber / proppant mass ratio) is 0.5-1%. The hydraulic fracturing fluid system has the advantages of complete formula, low friction resistance, favorable antiswelling and clay stabilization effects, favorable sterilizing and antibacterial effects, favorable antiscale performance, favorable discharge aiding effect and low surface / interfacial tension, and can effectively protect the shale reservoir. The added fiber obviously enhances the sand suspension property of the hydraulic fracturing fluid, effectively lowers the string friction resistance of the hydraulic fracturing fluid, can prevent the proppant from back flow, and is especially suitable for volume fracturing development of the shale reservoir.

Description

technical field [0001] The invention relates to a shale gas reservoir volume fracturing stimulation technology, in particular to a fiber composite clear water fracturing fluid technology for shale volume fracturing. Background technique [0002] At present, the recoverable amount of conventional oil and gas resources in the world is decreasing year by year, while the demand for oil and gas resources is increasing day by day. Unconventional natural gas accounts for an increasing proportion of energy supply, and shale gas occupies an important position in unconventional natural gas resources. The United States is in the leading position in the world in terms of exploration and development technology and production of shale gas resources. In 2012, the annual production of shale gas in the United States reached 2653×10 8 m 3 About 37% of its total natural gas production, more than China's total annual conventional natural gas production. my country's shale gas reserves are ver...

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Problems solved by technology

[0007] At present, the fracturing of shale gas wells in my country basically uses clean water fracturing fluid system, but there are often problems of damage to the formation and poor compatibility with the formation

One of the reasons is that foreign fracturing fluids are not directly used in a targeted manner. my country's reservoirs contain not only abundant marine shale gas, but also a large number of continental and marine transitional shale gas blocks. The physical properties of shale in different regions Widely variable and often high clay mineral content (>35%) leading to adverse effects

The second reason is that since the development of shale gas in my country has just started, the research and evaluation system for shale gas reservoirs has not been fully established. Many indicators for evaluating conventional oil and gas reservoirs are no longer applicable to this type of gas reservoirs. Some indoor experiments in the fracturing design of gas reservoirs are quite different from the conventional evaluation standards commonly used in China

[0008] Another problem that needs to be paid attention to is that due to the low viscosity of clear water fracturing fluid, the sand-carrying ability is weak, and it is usually used to increase the construction displacement (>12m 3 / min) to improve the sand-carrying capacity, but the high-displacement construction not only sets high standards for the ground fracturing crew, but also increases the friction of the pipe string, resulting in a great waste of equipment power, and also affects the fracture. The size of the net extension

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