Energy complementing and fracturing stimulation integrated repeated transformation method of dense oil reservoir old well

Abstract

The invention provides an energy complementing and fracturing stimulation integrated repeated transformation method of a dense oil reservoir old well. The method comprises the following steps: S1, analyzing according to an early stage reservoir scaling type, using an optimized blockage relieving fluid formula to squeeze small-displacement blockage relieving fluid into an old well original perforation interval, removing formation wax and inorganic scale; S2, according to reservoir refracturing static pressure requirement, injecting a low-viscosity oil displacement fracturing fluid in medium displacement to an objective interval; S3, in an injection last phase of the objective interval, performing volume fracturing repeated transformation construction with low sand proportion, large displacement, and low-viscosity fluid as a main method, to further expand reservoir transformation volume and recover main fracture conductivity near a shaft; S4, after construction of the objective interval, shutting the well in to diffuse pressure, until wellhead pressure is reduced to 0MPa; S5, removing sand to complete the well, and putting the well into production . For a reservoir which is insufficient in initial stage transformation or an oil well whose fracture conductivity reduces obviously, the method further expands reservoir transformation volume, and realizes objectives of oil well production enhancement and natural decline reduction.

Description

technical field [0001] The invention relates to the field of oil recovery engineering, in particular to a repeated transformation method for integrating energy replenishment and fracturing stimulation for an old well in a tight oil reservoir. Background technique [0002] Tight oil reservoirs in the Ordos Basin generally have reservoir characteristics of poor permeability and developed natural micro-fractures, which usually need to be effectively developed by the stimulation method of "volume fracturing", and the initial single well production can usually reach more than 2.0t / d. However, with the prolongation of time, the single well production gradually decreased. The initial single well production capacity decreased by 20% to 30% in half a year, and decreased by 30% to 50% in one year. After one year, the natural decline of the reservoir was still as high as 40%. The pressure maintenance level is less than 80%, which is comprehensively manifested as the development charact...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the problem that the existing late-stage treatment is more difficult and seriously affects the improvement of the overall recovery of the reservoir, the present invention provides a method for the repeated transformation and stimulation of old wells in tight oil reservoirs that integrates energy replenishment and fracturing stimulation. The oil displacement fracturing fluid is directly injected into the format