A fracturing method for enhanced heat transfer with low-temperature fluid in horizontal wells

Abstract

The invention discloses a method for intensifying heat exchange and fracturing of horizontal wells with low temperature fluid. A perforating gun is used to set up multiple fracture areas, and water is injected through a water injection pipe to fill up a hydraulic plug to form a sealed fracturing chamber. The room is filled with supercooled water, and then low-temperature fluid is injected into the heat exchange section in the sealed fracturing chamber. The supercooled water exchanges heat with the low-temperature fluid through the heat exchange fins. Ice, after the phase change, the volume increases to use its ice expansion force to fracturing the sealed fracturing chamber. At the same time, after heat exchange, the low-temperature fluid will phase change to form gas, and the gas will pass through the gas discharge pipe and the well in turn under the influence of negative pressure. The annulus and the exhaust pipe are discharged, and the ice swelling and cracking process is completed after a period of time. Not only can it effectively ensure the fracturing effect of coal and rock mass and reduce the high pressure required for hydraulic fracturing, but also because no chemicals are added to the supercooled water, it will not pollute the surrounding environment after leakage.

Description

technical field [0001] The invention relates to a fracturing method for enhanced heat transfer of low-temperature fluid in a horizontal well, belonging to the technical field of anti-permeability of coal and rock mass. Background technique [0002] China is rich in unconventional natural gas resources and has great potential for development, among which the recoverable resources of coalbed methane are about 10.87×10 12 m 3 , the recoverable resources of shale gas are 15×10 12 ~25×10 12 m 3 In the next 10 to 20 years, China's unconventional natural gas production will increase significantly, and it will play an increasingly important role in making up for the shortage of conventional oil and gas production. Although the reserves of unconventional natural gas resources in my country are large, the reservoirs are complex and dense, and the main part of the reservoir space is a nanoscale pore-throat system, with micron-millimeter-scale pores locally developed. Therefore, en...

AI Technical Summary

Problems solved by technology

The success of large-scale development of shale gas in foreign countries is inseparable from hydraulic fracturing anti-permeability technology, but at the same time, problems have also emerged, such as: adding special chemical reagents to fracturing fluid, once leaked, it will pollute the groundwater body, and hydraulic fracturing is difficult. High start-up pressure in the formation, a lot of waste of water resources, etc.

[0003] In addition, the existing hydraulic fracturing is to use high-pressure water to fracture the coal rock formation, so a relatively high pressure is required to ensure the continuous fracturing of the water on the coal rock formation, which leads to a large energy consumption; therefore, how to effectively reduce the hydraulic pressure The energy consumption in the cracking process and the prevention of groundwater pollution after leakage make the research direction of this industry

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