| CPC E21B 43/261 (2013.01) | 8 Claims |

|
1. A multi-stage temporary plugging fracturing method based on a stress cage effect, comprising:
injecting a preset amount of acid liquid into a wellbore at a preset injection speed to a stratum, so as to reduce a rock fracture pressure around the wellbore;
injecting a preset amount of fracturing fluid into the wellbore at a preset injection speed to the stratum, and forming a first major fracture with an injection point in the stratum as a starting point;
acquiring a position where a principal stress of the first major fracture is minimum, in which the magnitude of the principal stress at the position is denoted as σmin;
according to the minimum principal stress σmin, acquiring an increase value Δp of a net pressure in a fracture needed to generate a branch deflection fracture at the position where the principal stress is minimum;
according to the increase value Δp of the net pressure in the fracture, acquiring a volume of temporary plugging deflection fluid needed to generate the branch deflection fracture at the position where the principal stress is minimum;
injecting the acquired volume of temporary plugging deflection fluid into the first major fracture, and plugging the position where the principal stress of the first major fracture is minimum;
injecting fracturing fluid into the first major fracture at a preset first injection speed until a deflection branch fracture is generated at the position where the principal stress of the first major fracture is minimum;
repeating the above steps to form a plurality of deflection branch fractures in the first major fracture until the distance between the position where the principal stress of the first major fracture is minimum and the position of the injection point is less than a preset distance threshold, and completing multistage temporary plugging deflection fracturing of the first major fracture.
|