Horizontal well supercritical CO2 fracture development enhanced geothermal method and system

Abstract

The invention provides a horizontal well supercritical CO2 fracture development enhanced geothermal method and system. The method comprises the steps that after liquid CO2 and a grinding material aresufficiently mixed, the obtained mixture is placed down to the position to be perforated, the mixed solution of the grinding material and the supercritical CO2 forms high-pressure jet after passing through a hydraulic injection nozzle, and a sleeve, a cement sheath and a hot dry rock are broken to form a perforated hole; the pure-liquid CO2 is pumped to the position to be perforated to form a manual crack; a propping agent and the supercritical CO2 are sufficiently stirred inside a sand mixing vehicle, the mixed fracture liquid is pumped into a well through a fracturing truck, the propping agent is carried into the crack through the supercritical CO2 to complete first-section fracturing; the hydraulic injection nozzle is moved to the next position to be modified, a spacer fluid is pumped in to protect a fractured well section, the operations are sequentially executed repeatedly till the horizontal well is completely fractured and modified; after modification, the supercritical CO2 continues to be adopted as a circulating working medium to perform hot dry rock heat exchange production to achieve repeated heating and power generation.

Description

technical field [0001] The invention relates to a horizontal well supercritical CO 2 The invention discloses a method and system for developing enhanced geothermal energy through fracturing, and belongs to the technical field of enhanced geothermal efficient development. Background technique [0002] Geothermal resources are clean, efficient, stable and renewable energy that is not affected by seasonal climate changes. The development of geothermal resources is 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 enhanced Geothermal (Enhanced Geothermal Systems, EGS), its resources reached 850 trillion tons of standard coal. Compared with the 40-year history of enhanced geothermal development in the United States, Japan, Europe and other countries, my country's enhanced geothermal development research is still in the initial stage of research and deve...

AI Technical Summary

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 dry hot rock reconstruction: (1) The fracturing fluid mainly uses clear water or slick 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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