Well completion device and method for horizontal well re-fracturing

Abstract

The invention provides a well completion device and method for horizontal well re-fracturing. The well completion device for horizontal well re-fracturing comprises a sleeve, a suspension tail pipe and a plugging head, wherein one end of the suspension tail pipe is suspended at the heel part of a horizontal section in the sleeve, the plugging head is arranged at the other end of the suspension tail pipe to plug the suspension tail pipe, and in the well completion operation, a perforating device is lowered into the suspension tail pipe to perforate the sleeve and/or the suspension tail pipe. According to the well completion device, the suspension tail pipe is lowered into the sleeve, repeated fracturing can be carried out on an interval already having a perforation hole but not transformed,the problem that an existing horizontal well faces staged repeated fracturing is solved, repeated fracturing with the large displacement volume is achieved, the single-well yield is increased, the measure cost is reduced, and the repeated fracturing effect and the final oilfield recovery ratio are improved.

Description

technical field [0001] The invention relates to the field of oil and gas field development, in particular to a well completion device and method for repeated fracturing of horizontal wells. Background technique [0002] Today, most horizontal wells have taken stimulation measures in the early stage to increase the single well production. However, affected by factors such as the development of well completion technology at that time, some intervals of horizontal wells remained unstimulated, and oil and gas were only produced from the stimulated intervals. , the recovery degree of the unmodified interval may be significantly lower than that of the transformed interval. Therefore, after the initial fracturing and acidizing, after a period of production, the production gradually decreases, and it may be necessary to repeat the reconstruction of the unfractured and acidized layers, or the layers with insufficient initial fracturing and acidizing, so as to increase the production ...

AI Technical Summary

Problems solved by technology

[0003] At present, there are mainly four methods for refracturing completion of horizontal wells in China: one is to adopt the method of dynamic multi-stage temporary plugging. Opening new fractures, this method has been used in refracturing of unconventional horizontal wells, but in the actual construction process, there are widespread cases of plugging failure or unsuccessful plugging, resulting in the failure of the refracturing process

The second is the double-seal and single-card technology. By running the tubing with a packer, it can be accurately targeted at the unreformed target layer for reformation measures. However, the process is relatively complicated, and the displacement is limited due to the impact of the construction string, and the operation time is long. Supporting operations are time-consuming and costly

The third is to introduce foreign liquid rubber plug technology, that is, to run the oil pipe into the horizontal well casing, inject the liquid rubber plug into the oil pipe, and make the liquid rubber plug fill the annulus and solidify through the circulation of the oil pipe and the casing annulus. In order to effectively seal the entire well section, it is convenient to repeat fracturing, but this method forces the oil pipe injection method to carry out repeated fracturing measures in the whole well section, and the construction displacement is limited; the fourth is to introduce foreign expansion pipe technology, that is, down When the well section needs to be plugged, the expansion tube is forced to expand and fit tightly on the casing by hydraulic pressure to achieve effective plugging. However, this method is not conducive to economical and effective refracturing in low-permeability old areas or tight oil areas.

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