Novel supercritical CO2 fracturing process

Abstract

The invention relates to a novel supercritical CO2 fracturing process and belongs to the technical field of petroleum exploitation. The provided novel supercritical CO2 fracturing process mainly overcomes the defects in the prior art and comprises the following steps of (1) well cleaning, (2) perforation, (3) fracturing treatment, (4) proppant injection, (5) sectional fracturing, (6) isolation treatment, (7) well closing treatment and (8) blowout and flowback after pressing. According to an adopted method, a supercritical CO2 fracturing fluid and a conventional fracturing fluid sand-carrying fluid are simultaneously pumped, the effect of supplementing formation energy of the supercritical CO2 fracturing fluid is fully exerted, and complex cracks are more likely to be generated at the sametime; a method for conventional fracturing combined with mixed injection is utilized; under the condition that a closed system is not needed, the advantages of supercritical CO2 fracturing are fully exerted, and the defects of conventional fracturing are avoided.

Description

technical field [0001] The present invention relates to a kind of supercritical CO 2 The invention relates to a new technique of fracturing, which belongs to the technical field of petroleum exploitation. Background technique [0002] With the increasing demand for oil and gas resources and the deepening of exploration and development, fracturing is the key to the economic development of low-permeability and ultra-low-permeability reservoirs, and has attracted more and more attention. For the development of shale gas reservoirs, coalbed methane reservoirs, and low-permeability and ultra-low-permeability oil and gas reservoirs, fracturing is a necessary means. Disadvantages such as related pollution caused by cracking. [0003] Hydraulic fracturing technology was first proposed in the 1940s. At that time, it was mainly used in the reconstruction of old wells and enhanced oil recovery. At present, hydraulic fracturing technology has become an unconventional technology for lo...

AI Technical Summary

Problems solved by technology

[0009] The present invention mainly overcomes the deficiencies in the prior art and proposes a supercritical CO 2 A new process for fracturing, this invention uses supercritical CO 2 Simultaneous pumping of fracturing fluid and conventional fracturing fluid with sand-carrying fluid can give full play to supercritical supercritical CO 2 The fracturing fluid supplements the formation energy and is more likely to generate complex fractures. At the same time, the conventional fracturing method is also mixed with it, and the supercritical CO can be fully utilized without the need for a closed system. 2 The advantages of fracturing, while avoiding the disadvantages of conventional fracturing

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