A method for hydraulic fracturing of coalbed methane

Abstract

The invention relates to a hydraulic fracturing method for coal bed gas. Active water fracturing fluid is used as the front fluid and the displacement fluid, and carboxymethyl guaridine fracturing fluid is used as the sand-carrying fluid; four kinds of quartz sands with different particle size ranges are selected as the proppant 100-70 mesh silt sand and 70-40 mesh fine sand are used as proppant in the pre-fluid, and 40-20 mesh medium sand and 20-14 mesh coarse sand are used as proppant in the sand-carrying liquid; the proppant selection is different The ratio of the amount of sand added to the particle size sand; the concentration of the clay stabilizer KCl in the active water fracturing fluid and the carboxymethyl guar gum fracturing fluid is based on the natural gamma ray log expressed in API units of the logging data of the fracturing target interval Intensity GR averages are determined. The invention greatly improves the effect of coal bed methane recovery increase, effectively prevents swelling and at the same time reduces the configuration cost of fracturing fluid to the greatest extent.

Description

Technical field [0001] The invention relates to a hydraulic fracturing method for coalbed methane exploitation, and belongs to the technical field of hydraulic fracturing for coalbed methane wells. Background technique [0002] Coal bed methane is an unconventional natural gas resource with great resource potential and low development level in my country. The total coal-bed methane resources of the country with a buried depth of more than 2000m are 32.86×10 12 m 3 . The low-cost and high-efficiency mining of coal-bed methane can not only solve the pollution and safety problems caused by coal mine production, but also make up for the shortage of conventional energy development and utilization. However, due to the characteristics of low saturation, low permeability, and low pressure in my country's CBM reservoirs, certain enhanced production enhancement measures are needed to realize the commercial development of CBM, and the most commonly used enhancement method is hydraulic frac...

AI Technical Summary

Problems solved by technology

However, there are also deficiencies in actual construction: ①The sand-carrying capacity is poor, especially when it is used as a sand-carrying liquid to carry medium-coarse sand and other large-grained sand; ②High friction limits the construction displacement and construction scale, affecting the overall Fracturing effect

However, there are also disadvantages in actual construction and application: ①The cost is relatively high; ②When used as pre-fluid for joint creation, the joint height is not easy to control, and the joint height will be greatly expanded during large-displacement construction

[0015] In the actual construction process, the application concentration of the clay stabilizer KCL is usually an empirical value, which cannot achieve an economical and effective anti-swelling effect

If the applied concentration is low, the stabilization effect will be poor; if the concentration is too high, the overall fracturing cost will increase accordingly

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