Coiled tubing supercritical CO2 jet fracturing method

Abstract

The invention relates to a coiled tubing supercritical CO2 jet fracturing method. The method is used for performing jet fracturing on oil well reservoirs by taking supercritical CO2 as fracturing fluid. By the method, a supercritical CO2 fluid is used as the fracturing fluid to perform the jet fracturing; a supercritical CO2 sand jet perforating hole can reduce system pressure; the pressure needed by fissure extension can be further reduced by the characteristics of low viscosity and high dispersion performance of the supercritical CO2 fluid; most importantly, the supercritical CO2 jet fracturing does not pollute the reservoirs, but the supercritical CO2 can further improve the oil and gas recovery ratio after entering the reservoirs; the return discharge is not needed after the fracturing is completed; when the stage-by-stage jet fracturing is performed by using the coiled tubing, a tube pillar can be lifted or put down without mineshaft pressure relieving, the operation process is reduced and the operation cost is reduced, so that the method is extremely suitable for fracturing modification of unconventional oil-gas reservoirs such as thick oil reservoirs, low permeability and super-low permeability oil-gas reservoirs, shale gas reservoirs, coal bed methane reservoirs and the like of which the effects are low by using the conventional water-based fracturing fluid.

Description

technical field [0001] The invention relates to a jet fracturing method for an oil well, in particular to a coiled tubing supercritical CO 2 A jet fracturing method belongs to the field of oil drilling. Background technique [0002] 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 low-permeability and ultra-low-permeability oil fields, shale gas reservoirs, and coalbed methane reservoirs. One of the main measures to increase production of oil and gas reservoirs. It uses surface high-pressure pumps to inject fracturing fluid into the wellbore with a displacement exceeding the absorption capacity of the formation (reservoir), and generates high pressure near the bottom of the well. When the pressure overcomes the in-situ stress near the well wall and the tensile strength of the ro...

AI Technical Summary

Problems solved by technology

However, for the above-mentioned traditional fracturing, it is necessary to inject a large amount of high-viscosity fracturing fluid, then pump the gel breaker, and then flow back the fracturing fluid. This is not only costly, but also complicated. The most important thing is that a large amount of water After entering the reservoir, it will cause secondary damage to the reservoir, reduce the permeability of the reservoir, and thus reduce the fracturing effect

Although a variety of clean fracturing fluids have appeared to reduce the reservoir pollution, it is still impossible to completely eliminate the secondary pollution of the reservoir during fracturing.

Images