Horizontal well supercritical co 2 Method and system for fracturing enhanced geothermal development

Abstract

The invention provides a horizontal well supercritical CO 2 Method and system for enhanced geothermal development by fracturing, the method comprising liquid CO 2 After being fully mixed with abrasives, the resulting mixture is lowered into the position to be perforated, and the obtained supercritical CO 2 The mixed liquid with the abrasive passes through the hydraulic jet nozzle to form a high-pressure jet, which destroys the casing, cement sheath, and hot dry rock to form perforations; the pure liquid CO 2 pumped to the perforation site to create artificial fractures; proppant mixed with supercritical CO 2 Fully stir in the sand mixing truck, and pump the mixed fracturing fluid into the well through the fracturing truck, and pass the supercritical CO 2 Carry the proppant into the fracture to complete the first stage of fracturing; move the hydraulic jet nozzle to the next position to be stimulated, pump spacer fluid to protect the fractured well section, and repeat the above operations in sequence until all horizontal wells are fractured and stimulated Completed; continue to convert supercritical CO 2 It is used as a circulating working medium for heat exchange production of dry hot rocks to realize repeated heat extraction and power generation.

Description

Horizontal well supercritical CO 2 Method and system for fracturing development of enhanced geothermal technical field The present invention relates to a kind of horizontal well supercritical CO 2 Method and system for fracturing development of enhanced geothermal Type geothermal efficient development technology field. Background technique Geothermal resource is a kind of clean, efficient, stable, renewable energy that is not affected by seasonal climate change. Thermal resources are an important part of realizing the transformation of the national energy structure and building a low-carbon green society. my country is rich in geothermal resources, especially It is Enhanced Geothermal Systems (EGS) with a resource of 850 trillion tons of standard coal. with beauty Compared with the 40-year history of enhanced geothermal development in China, Japan, Europe and other countries, the research on enhanced geothermal development in my country is still in its infan...

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Problems solved by technology

At present, the enhanced geothermal is mainly developed by the method of "vertical well hydraulic fracturing + clear water circulation heat exchange". This development method has the following problems in the process of hot dry rock reconstruction: (1) The fracturing fluid mainly uses clear water or slippery water. The leakage in the natural fractures of hot dry rocks is serious, resulting in limited pressure transmission distance, resulting in waste of water resources, especially in arid areas, resulting in greater economic losses; Relatively single, the communication between the two symmetrical main fractures formed and the natural fractures in the hot dry rock is not sufficient, and the heat exchange channels are very limited; Mineral components in the hot dry rock undergo incompatibility reactions, and the reactants block the pore throats and heat exchange channels of the hot dry rock, causing thermal reservoir pollution; (4) The minerals in the hot dry rock are dissolved in water, which will damage the pipelines and equipment Cause chemical corrosion and scaling damage, reduce development efficiency and increase operating costs; (5) The circulating working fluid needs to do work on clean water during the injection and extraction process, consuming a lot of energy

The above problems seriously restrict the efficient development and commercial process of enhanced geothermal resources. In order to overcome the above problems, it is urgent to propose a new enhanced geothermal efficient development system.

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