High pressure nitrogen-low temperature liquid nitrogen composite fracturing method for oil and gas production increasing

Abstract

The invention discloses a high pressure nitrogen-low temperature liquid nitrogen composite fracturing method for oil and gas production increasing. Formation rock is fractured through high pressure nitrogen to form large-scale artificial fractures, then ultralow temperature liquid nitrogen is injected into main fractures, the ultralow temperature characteristic of the liquid nitrogen is utilized to assist in fracturing rock on the wall faces of the main fractures, thus the rock generates secondary fractures which are perpendicular to the main fractures, the self-supporting capacity of the mainfractures is improved, the fracturing degree of a reservoir is increased, closing of the fractured main fracture is prevented, and thus efficient development of the reservoir is achieved. In the whole fracturing process, the high temperature and high pressure nitrogen and the low temperature liquid nitrogen are alternately injected for multiple times, the disadvantage that during conventional fracturing, the reservoir mainly generates a single main fracture is overcome, large-volume network fractures are formed in the reservoir advantageously, and the fracturing production increasing effect of the oil and gas reservoir is improved effectively.

Description

technical field [0001] The invention relates to a waterless fracturing method, in particular to a high-pressure nitrogen-low temperature liquid nitrogen composite fracturing method for oil and gas stimulation, and belongs to the technical field of oil and gas stimulation. Background technique [0002] Currently, unconventional natural gas resources such as shale gas have become an important part of the world's energy supply. The natural production capacity of unconventional reservoirs is extremely low, and generally requires hydraulic fracturing to realize industrial exploitation. However, the quality of this type of reservoir is poor, and it is easily damaged by foreign fluids. For example, water retention and swelling of clay minerals can impede gas flow after fracturing is complete. The development of unconventional natural gas will also involve problems such as excessive consumption of water resources and pollution. For example, the water consumption of a single well f...

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Problems solved by technology

Due to the low viscosity of nitrogen, it cannot carry a large amount of proppant into the formation like water-based fracturing fluid to form effective propped fractures

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