Method for fracturing coalbed methane reservoir by using nitrogen foam fracturing fluid

Abstract

The invention relates to a method for fracturing a coalbed methane reservoir by using nitrogen foam fracturing fluid. A coalbed methane well is fractured, and the coal-bed methane well comprises a fracturing operation pipe column, a well completion casing pipe, a packer, a hydraulic anchor and a sliding sleeve; nitrogen foam fracturing equipment comprises a sand tank, a sand mixing truck, a liquidpreparation tank, a liquid preparation pump, a liquid nitrogen truck, a liquid nitrogen pump, a foam fluid generator, a fracturing pump truck and a high-pressure tee joint; and the method for fracturing the coalbed methane reservoir by using the nitrogen foam fracturing fluid comprises the following steps of S1, preparation before nitrogen foam fracturing construction, S2, nitrogen foam fracturing fluid pumping, S3, fracturing crack control, S4, fracturing construction parameter monitoring and regulation, S5, fracturing fluid flowback, and S6, evaluation after fracturing. Compared with the prior art, the method has the advantages that the leakage of the fracturing fluid in the fracturing process of the coal-bed methane reservoir can be obviously reduced, the reservoir pollution is small,the construction safety is high, the flowback speed of the fracturing fluid is high, and the construction period is short; and operation steps are simple, construction parameters are clear, and operability is high.

Description

technical field [0001] The invention belongs to the field of oil and gas resource development, and in particular relates to a method for fracturing coalbed gas reservoirs by using nitrogen foam fracturing fluid. Background technique [0002] As a clean energy source, coalbed methane is an important part of unconventional natural gas in my country. It is a self-generated and self-storage gas in coal seams, and its main component is methane. Coalbed methane exists in two states of adsorption and dissociation in coal seams. Due to the lack of free coalbed methane, the production of coalbed methane wells is generally low, which cannot reach the economic mass production index. Therefore, it is necessary to perform fracturing stimulation operations on coalbed methane reservoirs. At present, the main methods of fracturing and stimulating CBM wells include: water-based fracturing (active water, jelly fracturing fluid, clean fracturing fluid), oil-based fracturing and CO2 fracturing...

AI Technical Summary

Problems solved by technology

[0004] (2) In the jelly fracturing method, a large amount of jelly residue remains in the reservoir during the fracturing process, resulting in serious reservoir pollution

After the fracturing is completed, it is not easy to break the gel, which blocks the flowback channel of the reservoir water and significantly reduces the gas production capacity of the coalbed methane well

[0005] (3) Oil-based and clean fracturing fluid methods have high construction costs, low safety, and difficult control of gel breaking, resulting in their low application in coalbed methane well fracturing

[0006] (4) CO 2 The dry fracturing method requires high equipment and poor sanding capacity (CO 2 There is no way to add a large amount of sand in the sealed tank), and it is impossible to effectively control the size and shape of the fracture during the fracturing process

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