A Refracturing Method for Wellbore Reconstruction and Refracturing in Cased Horizontal Wells

Abstract

The invention discloses a casing pipe horizontal well shaft reconstruction repetitive fracturing method. The method comprises the steps that an oil pipe or drill pipe string with a drift size gauge tool is lowered into a casing pipe of a casing pipe horizontal well and leads to an artificial well bottom; an oil pipe or drill pipe string with a scraper is lowered into the casing pipe of the casingpipe horizontal well and repeatedly passes through the position of a perforation cluster for multiple times, and chippings are circulated by adopting water-based fracturing fluid base fluid; an oil pipe or drill pipe string with an upper Y341 packer, a lower Y341 packer, a safety connector, a hydraulic anchor, a flow guide centralizer, a dead plug and a pressure guide sand blower is lowered into the casing pipe of the casing pipe horizontal well, the pressure guide sand blower is placed between the two Y341 packers, the position of the pressure guide sand blower is aligned to the position of the perforation cluster, the packers are sealed, and sealing slurry is squeezed and injected into the perforation cluster, and after the sealing slurry is solidified, multistage fracturing operations of conventional multi-cluster perforation volume fracturing and high-density perforation seam volume-controlled fracturing are carried out. According to the method, fixed-point transformation can be achieved, and the beneficial effect of being high in construction efficiency is achieved.

Description

Technical field [0001] The invention relates to the technical field of oil and gas exploitation, in particular to a re-fracturing method for casing horizontal well borehole reconstruction. Background technique [0002] Staged fracturing of horizontal wells is an effective way to increase single well production of oil and gas reservoirs. However, with the gradual deepening of development, affected by factors such as the low degree of initial fracturing and the reduced conductivity of the fracture system, some low-yield horizontal wells have appeared. Repeated fracturing is required to restore single well production and improve development effects. Affected by factors such as multi-stage perforation in the first fracturing, uneven production between intervals, and large differences in cementing quality in horizontal sections, horizontal well repeated fracturing technology is difficult, and its targeted process technology is still in the exploratory test stage. At present, there ar...

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Problems solved by technology

Affected by factors such as multi-stage perforation in primary fracturing, uneven recovery between stages, and large differences in cementing quality in horizontal sections, it is difficult to refracture horizontal wells, and its targeted technology is still in the exploratory stage.

At present, horizontal well refracturing technology at home and abroad mainly includes two types: the first is mechanical isolation refracturing technology, which has the advantage of using the pipe string and packer to seal the target well section, and achieves fixed-point stimulation through tubing injection. It is a pipe string drag operation, which has high requirements on wellbore conditions, and is affected by the inner diameter of the pipe string, so the efficiency of large-scale fracturing operation is low (only one section of the pipe string is constructed in a single trip)

The second is the dynamic multi-stage temporary plugging repeated fracturing process, which has the advantage of bare casing operation and lower requirements on the wellbore. The temporary plugging agent is pumped into the wellhead to realize inter-stage diversion fracturing, and the construction efficiency is high. The disadvantage is that it cannot be fixed. Restructuring, and the controllability of multi-stage temporary plugging and boosting is poor (the boosting range of the first stage is >5MPa, and the subsequent boosting range is smaller), resulting in uncertainty in reservoir stimulation

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