Clean fracturing fluid for low-temperature coal-bed gas reservoirs and application thereof

Abstract

The invention relates to a clean fracturing fluid for low-temperature coal-bed gas reservoirs and application thereof. The clean fracturing fluid for low-temperature coal-bed gas reservoirs is composed of 0.2-0.4% of cationic surfactant, 0.10-0.15% of salicylate, 1.0-1.5% of potassium chloride, 0.06% of pH regulator, 0.06-0.08% of residue preventer and the balance of water. The cationic surfactant is selected from cetyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride or cetrimide. The preparation method comprises the following steps: adding the water into a large fluid preparation tank, sequentially adding the salicylate, potassium chloride, pH regulator and residue preventer under stirring conditions, adding the cationic surfactant after the previous components are completely dissolved, and stirring until the concentration or viscosity of the fluid in the big tank is uniform, thereby obtaining the clean fracturing fluid, wherein the application temperature for the fractured coal-bed gas reservoir is 15-30 DEG C.

Description

technical field [0001] The invention relates to the technical field of coalbed methane gas recovery, in particular to a fracturing fluid for coalbed gas fracturing reconstruction, which is a clean fracturing fluid suitable for low-temperature coalbed methane reservoirs. Background technique [0002] The permeability of coalbed methane reservoirs in my country is low, and the fracturing fluids used are mainly active water fracturing fluids and jelly fracturing fluids. Activated water fracturing fluid has been widely used in coal seam fracturing because of its simple preparation and less damage to coal seams. However, the scale of fracturing reconstruction is limited due to the influence of active water on its own rheology. At the same time, in order to ensure smooth sand addition, the construction displacement of active water fracturing fluid is usually high. In this way, the longitudinal extension of fractures is difficult to control, and it is difficult to form long propped...

AI Technical Summary

Problems solved by technology

The disadvantage of this fracturing fluid is: there is no potassium chloride in the formula; the thickener is a mixture of quaternary ammonium salts with 12 to 18 carbon alkyls, which has poor thickening ability than octadecyltrimethylammonium chloride. Poor temperature resistance

The disadvantage of this fracturing fluid is: there is no potassium chloride in the formula, and the thickener is cetyltrimethylammonium bromide, which has poorer thickening ability and temperature resistance than octadecyltrimethylammonium chloride. Disadvantages such as poor performance and high price

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