Method and application of secondary fracturing of compact oil and gas reservoir

Abstract

The invention provides a method and an application of the secondary fracturing of a compact oil and gas reservoir. The invention is mainly applied to the secondary fracturing field of shale gas and shale oil reservoirs. The method comprises the steps of injecting micro-nano-sized and energy-contained blasting material particles in the graded manner on the basis of primary hydraulic fracturing, transmitting blasting material particles to the wall surface of a primary fracture, and realizing the secondary fracturing by using the pulse current detonation mode. According to the method, a dense seam network capable of communicating matrix pores with one another can be formed. Based on the dense seam network, the exposed area of the pore walls of matrix pores is greatly increased. The total discharge area of an oil-gas desorption and migration pathway is increased and the recovery efficiency is further improved. Selectable energy-contained materials are rich in variety, wherein the materialregulation and material combination are carried out through the physical and chemical means. A secondary fracturing scheme is designed according to the characteristics of different reservoir lithology, physical properties and the like. Adopted energy-contained blasting materials can be compounded with high-strength and micro-size propping agents, and the injection of a fracturing agent and a propping agent can be realized at one time. The invention provides a new idea for further improving the shale gas and shale oil yield.

Description

technical field [0001] The invention belongs to the technical field of fracturing engineering of tight oil and gas and shale oil and gas reservoirs, and relates to a method and application of secondary fracturing of tight oil and gas reservoirs. Background technique [0002] The proven geological reserves of shale gas in my country are as high as 544.129 billion cubic meters, ranking first in the world in terms of recoverable reserves. my country is rich in shale oil resources, with technically recoverable resources of 4.352 billion tons (EIA. Sep 24, 2015), ranking third in the world. Due to the low porosity and low permeability of shale reservoirs, horizontal wells plus multi-stage fracturing are currently the most widely used method for shale gas development in the United States. North American shale gas mainly adopts horizontal well casing completion, cluster perforation, rapid drillable bridge plug isolation, large-scale slick water or "slick water plus linear glue" st...

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Problems solved by technology

[0004] Due to the limited energy provided by the above-mentioned hydraulic fracturing, the fractures formed each time are mostly generated and extended along the mechanically weak area of ​​the rock formation, and most of them are horizontal fractures parallel to the shale sedimentary bedding, which cannot form a large number of matrix pores. network of cracks

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