Carbon dioxide-slickwater intermittent mixed-fracturing design method

Abstract

The invention provides a carbon dioxide-slickwater intermittent mixed-fracturing design method. The carbon dioxide-slickwater intermittent mixed-fracturing design method comprises the following stepsthat 1, at a first injection stage, a first slickwater fracturing fluid is injected into a target reservoir; 2, at a second injection stage, a liquid carbon dioxide fracturing fluid is injected into the target reservoir; 3, at a third stage, a second slickwater fracturing fluid is injected into the target reservoir; 4, at a fourth injection stage, the liquid carbon dioxide fracturing fluid is injected into the target reservoir; 5, after the fourth injection stage finishes, well soaking is performed; 6, at a fifth injection stage, the second slickwater fracturing fluid is injected into the target reservoir; 7, at a sixth injection stage, the first slickwater fracturing fluid is injected into the target reservoir, wherein the second slickwater fracturing fluid is prepared from the first slickwater fracturing fluid and a supporting agent. By adopting the method, fracturing fluids of different properties are injected at different stages, the chemical and physical properties of carbon dioxide are reasonably utilized, and the purposes of improving hydraulic fracturing complexity, the reverse discharging rate of the fracturing fluids and oil gas yield are achieved.

Description

technical field [0001] The invention relates to a fracturing technology for an unconventional reservoir, in particular to a carbon dioxide-slick water intermittent mixed fracturing design method, which belongs to the research field of reservoir production stimulation and transformation technology. Background technique [0002] my country is rich in unconventional oil and gas resources, and the preliminary evaluation of the recoverable resources of unconventional oil and gas resources in China is (890~1260)×10 8 t oil and gas equivalent, about three times that of conventional oil and gas resources. Unconventional oil and gas reservoirs have the characteristics of large continuous distribution of oil and gas, low porosity and low permeability, and rapid production decline. Forming a complex fracture network in the reservoir through hydraulic fracturing technology to improve the migration conditions of oil and gas is a key link in the efficient development of unconventional oi...

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Problems solved by technology

However, there are few related studies on carbon dioxide composite fracturing.

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