A method for plugging multi-stage fractures in horizontal wells combined with particles and gel

Abstract

The invention discloses a method for plugging multiple sections of cracks in a horizontal well by combining particles and gel. The method comprises the steps that a horizontal well shaft is processed,the shaft is ensured to be unblocked, a plugging agent slug mixed by the chemical particles and gel liquid is subjected to pump injection through wellhead displacement, multiple times of pump injecting of the plugging agent slug is conducted, the working pressure is gradually increased to the casing limit pressure or the highest breaking pressure value of primary fracturing formation, and the well is closed to wait for solidification; and after the gel liquid is solidified, the particle plugging form is maintained, whole reverse pressure bearing of the plugging agent is achieved, the horizontal well shaft is subjected to secondary processing, the residual particles and the solidified gel in the horizontal well shaft are removed, and the shaft is ensured to be unblocked. The method for plugging the multiple sections of cracks in the horizontal well by combining the particles and the gel greatly improves the construction efficiency of repeated fracturing and the construction scale, andhas wide application prospects in the aspect of repeated fracturing of the low-yield horizontal wells with tight reservoirs.

Description

technical field [0001] The invention belongs to the field of oil production engineering, and in particular relates to a method for plugging multi-stage fractures of a horizontal well by combining particles and gel. Background technique [0002] In recent years, horizontal well drilling and staged fracturing have become effective ways to increase single well production in tight reservoirs. With the gradual deepening of development, some low-yield horizontal wells appear, and repeated fracturing is required to restore the single-well production and improve the development effect. Affected by factors such as multi-stage perforation in primary fracturing, uneven recovery between stages, and large differences in cementing quality in horizontal sections, horizontal well refracturing technology is difficult, and its targeted technology is still in the exploratory and experimental stage. At present, there are mainly two types of refracturing technology for horizontal wells at home ...

AI Technical Summary

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, there are mainly two types of refracturing technology for horizontal wells at home and abroad: the first is the mechanical isolation refracturing technology, which has the advantage of using the pipe string and packer to seal the fractured well section, and achieve fixed-point stimulation through tubing injection. , the disadvantage is that the dragging operation of running the pipe string has high requirements on the wellbore conditions, and is affected by the inner diameter of the pipe string, and the scale of fracturing is limited

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 injected into the wellhead to realize inter-stage diversion fracturing, and the construction efficiency is high. The disadvantage is that it cannot be fixed. There are uncertainties in stimulation and reservoir stimulation, that is, the existing two main horizontal well refracturing methods have the disadvantages of small fracturing scale and poor partial pressure effectiveness