A Judgment Method for Temporary Plugging and Fracture Initiation in Refracturing Well Fractures

Abstract

The invention discloses a method for judging temporary plugging and fracture initiation in a repeated fracturing well crack. The method specifically comprises the following steps that basic parameters are collected; a hydraulic fracture filled with temporary plugging agents is divided into two hydraulic fractures, and the stress of all points on the fracture face is calculated; a judging criterion of the temporary plugging, fracture initiation and diversion the fracture wall face after the temporary plugging agents are added into the hydraulic fractures is established by the force analysis of the fracture wall face; and the effects of different fracture length, net fluid pressure in the fracture, the temporary plugging agents, the pressure and the sealing blocking length of the temporary plugging agents on the temporary plugging and fracture initiation of the fracture wall face are analyzed quantitatively. According to the method for judging temporary plugging and fracture initiation in the repeated fracturing well crack, the organic combination of the parameters of induced stress fields produced by the extension of the hydraulic fractures and pressure changing of stratum hole fluid, the performance parameters of the temporary plugging agents, the sealing blocking length of the temporary plugging agents and the like is fully considered, the location and orientation of the fracture initiation of the temporary plugging fracture in the repeated fracturing well fracture can be effectively predicted, and the effect of repeated fracturing temporary plugging diversion transforming can be effectively improved.

Description

technical field [0001] The invention relates to measures for increasing production by hydraulic fracturing of oil and gas reservoirs, in particular to a method for judging temporary plugging and crack initiation in repeated fracturing well fractures. Background technique [0002] Low-permeability oil and gas reservoirs generally have the characteristics of low porosity, low permeability, low natural productivity, and poor conditions for stable production. Hydraulic fracturing is a key technology for the development of such reservoirs. Affected by various factors such as engineering geology and construction parameters, after long-term production of fracturing wells, the conductivity of hydraulic fractures gradually decreases until they fail, which seriously affects the normal production of oil and gas wells. For this type of wells, since the oil and gas controlled by the primary fractures have basically been produced, new fractures are usually formed by implementing repeated ...

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Problems solved by technology

[0007] The above-mentioned methods (1) and (3) for judging the fracture initiation of temporarily plugged and diverted fractures only consider the influence of the performance parameters (plugging pressure) of the temporary plugging agent on fracture initiation, but ignore the induced stress generated by hydraulic fracture extension, Influenced by factors such as induced stress produced by formation pore fluid pressure changes, and the direction of initiation of new fractures cannot be judged; method (2) can be used to judge the initiation mode of new fractures: opening or shearing, but formation pores are ignored Fluid pressure changes and the impact of temporary plugging agent performance parameters, etc.

[0008] None of the above methods for judging the initiation of fractures from temporary plugging in refracturing fractures can analyze the influence of the position of temporary plugging agent on the initiation of new fractures, nor can it take into account the induced stress of hydraulic fractures and the pressure drop of formation pore fluid due to production. Organic combination of stress and plugging capacity parameters of temporary plugging agent

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