Processing method for controlling abnormal pressure rise in shale fracturing process

Abstract

The invention discloses a processing method for controlling abnormal pressure rise in the shale fracturing process. The processing method comprises the following steps that in the middle and later periods of fracturing, a critical sand ratio method is adopted for construction when abnormal pressure rise occurs and comprises the specific steps that 1, the critical sand ratio is determined, wherein a critical sand ratio range is determined as the sand ratio subtracted by 2%-5% at the moment when pressure rises at the slope greater than 1 / 2 in the sand adding process, sand adding is stopped immediately, fracturing fluid injection continues, the injection amount is 1-1.5 times of shaft volume, sand adding is stopped but fluid injection is not stopped; 2, abnormal pressure rise is processed, wherein the point not exceeding the critical sand ratio serves as a starting point to perform pressurized fracturing again after the injection of a fracturing fluid 1-1.5 times of shaft volume is completed, and a sand ratio value in fracturing sand is gradually increased till designed sand adding amount is completed. By adopting the critical sand ratio method, a sandy dyke formation speed can be reduced, the rapid rise situation of construction pressure is effectively controlled, and the method has the advantages that operation is simple and convenient, an existing fracturing process is not changed, the fracturing construction quality can be improved, and a reconstruction effect is ensured.

Description

technical field [0001] The invention relates to a fracturing treatment method, in particular to a treatment method for controlling abnormal pressure rise during shale fracturing. Background technique [0002] Abnormal increase in shale fracturing pressure refers to a stepwise increase in construction pressure higher than the normal fluctuation range under the condition of basically stable displacement, which usually occurs in the middle and late stages of construction. The ultra-low porosity and permeability characteristics of shale reservoirs determine that in order to obtain high-yield industrial gas flow through fracturing, a complex fracture network different from conventional reservoirs must be formed. Low, low-viscosity liquids are mostly used in fracturing construction, and the sand-carrying performance is poor, and the fracturing sand is easy to settle during the migration process. The above factors make the shale fracturing process very risky, and it is prone to dif...

AI Technical Summary

Problems solved by technology

The ultra-low porosity and permeability characteristics of shale reservoirs determine that in order to obtain high-yield industrial gas flow through fracturing, a complex fracture network different from conventional reservoirs must be formed. Low, low-viscosity liquids are mostly used in fracturing construction, and the sand-carrying performance is poor, and the fracturing sand is easy to settle during the migration process. The above factors make the shale fracturing process very risky, and it is prone to difficulty in adding sand or even sanding due to abnormal pressure rise. Blockage, unable to achieve the purpose of transformation, thus affecting the final transformation effect

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