Method of forming fractures by means of hydrofracturing assisted by alternate spraying of high- and low-temperature fluids in deep hot dry rock

A hot dry rock, high and low temperature technology, applied in the direction of mining fluid, earthwork drilling, wellbore/well components, etc., can solve the problems of inability to penetrate deep into the thermal reservoir, chemical stimulation and rapid reaction speed of rock mass minerals, etc. Achieve significant heat transfer efficiency, strong thermal stress, large permeation area and heat transfer area

Active Publication Date: 2018-12-11
CHINA UNIV OF PETROLEUM (BEIJING)
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  • Abstract
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Problems solved by technology

However, in the high-temperature environment of thermal reservoirs, the reaction speed of chemical stimuli and rock mass minerals is fast, and it disappears in the near-wellbore area, making it impossible to penetrate deep into thermal reservoirs

Method used

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  • Method of forming fractures by means of hydrofracturing assisted by alternate spraying of high- and low-temperature fluids in deep hot dry rock
  • Method of forming fractures by means of hydrofracturing assisted by alternate spraying of high- and low-temperature fluids in deep hot dry rock
  • Method of forming fractures by means of hydrofracturing assisted by alternate spraying of high- and low-temperature fluids in deep hot dry rock

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Embodiment

[0055] in such as figure 1 and figure 2 For the hot dry rock reservoir in the geothermal anomaly area shown, using the method provided by the present invention to assist hydraulic fracturing with alternate injection of high and low temperature fluids in deep hot dry rock, it is expected to establish a fracture network at a depth of 3000m to form a good high-efficiency heat exchange reservoir layers, the layout of injection wells and production wells is as follows figure 1 and figure 2 As shown, the distance from the injection well to the production well does not exceed 1500 meters.

[0056] Such as figure 1 As shown, hydraulic fracturing is performed on the hot dry rock reservoir below the upper formation 2 with normal geothermal gradient. The layout of the hydraulic fracturing process device is as follows: production wells 1 and 9 are arranged and distributed on both sides of injection well 27, and the well spacing is 500 -1000 meters is appropriate; the lower end of th...

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Abstract

The invention provides a method of forming fractures by means of hydrofracturing assisted by alternate spraying of high- and low-temperature fluids in deep hot dry rock. The method herein includes: setting out a well network, and performing primary hydrofracturing to form main fractures; injecting a high-temperature high-pressure fluid and low-temperature water alternately into the main fractureswithin short alternate time; forming micro fractures in the rock at the surface of the main fractures under the thermodynamic action of a great temperature difference and the impact action of a jet; allowing multilevel fracturing to enable the micro fractures to further expand and form more micro fractures under the action of a low-temperature waterborne fracturing fluid and the action of high pressure; repeating until the main fractures and the micro fractures are in mutual lap joint and communication so that a fracture cluster and/or a fracture belt is formed between injection wells and production wells; injecting a sand-carrying fluid, a proppant and a displacing fluid, and closing the wells to complete fracture forming so as to construct an efficient heat exchange reservoir. The methodenables the quantity of the fractures to be significantly increased via the thermal stress action of the temperature difference, so that a fracture network is formed; heat exchange efficiency of a heat storage space is improved.

Description

technical field [0001] The invention belongs to the technical field of energy exploitation, and relates to a method for alternately jetting high and low temperature fluids in deep dry hot rocks to assist hydraulic fracturing to create fractures. Background technique [0002] Geothermal resources have become a renewable and clean energy that is mainly researched and developed by countries all over the world due to their clean renewability and wide spatial distribution. According to the existing form of geothermal heat, it is mainly divided into two types: hydrothermal type and dry hot rock type. Among them, the hydrothermal type is mainly steam and liquid water, which is currently the main geothermal resource developed and utilized in the world. Hot dry rock is a body of hot rock without water or steam. [0003] The enhanced geothermal system is an artificial geothermal system that uses the method of artificially forming geothermal reservoirs to economically extract deep he...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26
CPCE21B43/26
Inventor 宋先知李根生黄中伟田守嶒史怀忠王海柱盛茂张逸群杨睿月谢昕陈畅畅
Owner CHINA UNIV OF PETROLEUM (BEIJING)
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