A staged fracturing method of cryogenic fluid for upward drilling

Abstract

The invention discloses a method for grading fracturing by low-temperature fluid in upward drilling. Firstly, three fracture areas are prefabricated by using a perforating gun, and then water is injected through a water pipe to fill up a hydraulic occluder, thereby forming three sealed fracturing chambers. ; Fill the three sealed fracturing chambers with supercooled water in turn, and finally the low-temperature fluid flows through the internal threaded heat exchange tubes and external threaded heat exchange tubes in the three sealed fracturing chambers in turn, and the low temperature fluid flows through each sealed fracturing chamber At this time, the supercooled water in each sealed fracturing chamber exchanges heat with the low-temperature fluid. At this time, the temperature of the supercooled water drops rapidly, making the water phase change into ice and increasing in volume, so that the ice expansion force is used to compress each sealed fracturing chamber. After a certain period of time, stop and cycle multiple times to complete the process of supercooled water ice swelling and fracturing; not only can effectively ensure the fracturing effect of coal and rock mass and reduce the high pressure required for hydraulic fracturing, but also because the supercooled water has no chemical agents Added, so there will be no pollution to the surrounding environment after leakage.

Description

technical field [0001] The invention relates to a low-temperature fluid classification fracturing method for upward drilling, and belongs to the technical field of anti-reflection of coal rock mass. Background technique [0002] China is rich in CBM resources and has great development potential, with recoverable resources of about 10.87×10 12 m 3 In the next 10 to 20 years, China's coalbed methane production will increase significantly, playing an increasingly important role in making up for the shortage of conventional oil and gas production. With the increase of mining depth, the content and pressure of coalbed methane in the coal seam gradually increase, the permeability of coal seam gradually decreases, and gas disasters such as coalbed methane explosion, coal and gas outburst are also becoming more and more serious, and coalbed methane extraction is indispensable. Through investigation, it is found that the current coalbed methane extraction generally has the problems...

AI Technical Summary

Problems solved by technology

Through investigation, it is found that the current coalbed methane drainage generally has the problems of low drainage concentration and small drainage volume. Traditional anti-permeability measures are mostly hydraulic measures, such as hydraulic fracturing, water jet slotting, etc., which cannot form complex drainage. Fracture network and huge water consumption. Due to the addition of special chemical reagents in the fracturing fluid, once it leaks, it will pollute the groundwater body, and hydraulic fracturing has high start-up pressure in hard formations, and a lot of water resources are wasted.

[0003] In addition, the existing hydraulic fracturing all uses high-pressure water to fracture the coal rock formation, so continuous high pressure is required to ensure the continuous fracturing of the water to the coal rock formation, which leads to large energy consumption and serious waste of water resources; therefore How to effectively reduce energy consumption during hydraulic fracturing and prevent groundwater pollution after leakage is the research direction of this industry

Images