Dense oil well carbon dioxide front energy storage composite sand adding fracturing method

Abstract

The invention discloses a dense oil well carbon dioxide front energy storage composite sand adding fracturing method. The dense oil well carbon dioxide front energy storage composite sand adding fracturing method comprises the following steps that (1) a ground surface flow is connected, and pressure testing is conducted on the ground surface flow; (2) liquid carbon dioxide is subjected to pump injecting, and circulating cooling is conducted on the ground surface flow; (3) pump injection construction is conducted on a mixture of slickwater and the liquid carbon dioxide, a pure liquid carbon dioxide, cross-linked fracturing fluid and cross-linked fracturing fluid with sand in sequence; (4) fracturing liquid flowback is conducted; (5) well shut-in is conducted; and (6) blowout testing is conducted. According to the dense oil well carbon dioxide front energy storage composite sand adding fracturing method, the liquid carbon dioxide is combined with the conventional fracturing liquid whilea construction requirement for dense oil fracturing transformation is met and the construction safety is guaranteed, the productivity effect after pressure is effectively improved, and the target of afracturing technology is achieved.

Description

technical field [0001] The invention relates to a method or equipment for extracting oil, gas, water, soluble or meltable substances or mineral mud from wells by forming cracks or fractures, in particular to a carbon dioxide pre-storage composite sand fracturing method for tight oil wells. Background technique [0002] my country has abundant tight oil resource reserves, but due to tight reservoirs and low natural production capacity, it is necessary to release the production capacity of oil wells through fracturing and obtain industrial production. However, conventional large-scale water-based fracturing, temporary plugging diversion fracturing and other technologies have not achieved obvious results in fracturing and stimulation of tight oil wells. damage, difficulty in flowback of fracturing fluids, and insufficient crude oil flow capacity underground. [0003] Compared with conventional water-based fracturing technology, carbon dioxide fracturing technology has the foll...

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Problems solved by technology

However, pure carbon dioxide fracturing also faces the following problems: first, carbon dioxide has high frictional resistance, low viscosity, and relatively poor fracture creation ability, which easily leads to insufficient fracture space; second, low viscosity of carbon dioxide leads to poor sand suspension ability, It is impossible to achieve high-sand ratio sand-adding construction, which may easily lead to low fracture conductivity, and then cause construction sand plugging accidents; thirdly, carbon dioxide-sand adding construction requires an expensive and difficult-to-control airtight sand mixing device

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