A kind of acid slick water composite fracturing method for shale gas horizontal well

Abstract

The invention discloses an acid slick water composite fracturing method for a shale gas horizontal well. Including: (1) reservoir evaluation before fracturing; (2) perforation scheme optimization; (3) acidic slick water injection; (4) addition of 70-140 mesh proppant; (5) injection of iso-viscosity conventional slick water; (6) Injection of high-viscosity conventional glue; (7) Injection of 40-70 mesh and 30-50 mesh proppants. The method of the present invention improves the complexity of the fracturing fractures of deep normal pressure shale gas, and the filling rate of fracture systems of different scales, thereby increasing the effective volume of deep normal pressure shale gas stimulation, and improving the effect of increasing production and stabilizing production after fracturing .

Description

technical field [0001] The invention relates to the field of oil and gas exploitation, in particular to an acidic slick water composite fracturing method for shale gas horizontal wells. Background technique [0002] At present, the horizontal well staged fracturing technology has been successfully practiced in the marine high-pressure Longmaxi shale gas formation and achieved good results. However, with the advancement of shale gas exploration and development, shale gas is gradually moving towards deep layers and atmospheric pressure. At present, neither deep shale gas nor normal pressure shale gas fracturing has achieved demonstration breakthroughs. The main reason is that the complexity of fractures formed by fracturing of deep shale gas and normal pressure shale gas and the insufficient volume of effective stimulation. [0003] Generally speaking, the current shale gas horizontal well staged fracturing technology has poor adaptability to deep shale gas and normal pressu...

AI Technical Summary

Problems solved by technology

[0004] (1) As the burial depth increases in deep shale gas, the horizontal stress difference increases, the plasticity of the rock becomes stronger, the induced stress effect is weakened, and the scale of micro-fractures becomes smaller. These factors are not conducive to increasing the volume of fracture reconstruction and the complexity of fractures;

[0005] (2) The reduction in the pressure coefficient of atmospheric shale gas may be the result of the escape of original shale gas, which also leads to the reduction of internal micro-cracks and bedding / texture scales

[0006] (3) For many current deep shale gases, they often have the characteristics of atmospheric shale gas at the same time. Therefore, the combination of the above two difficulties makes fracturing more difficult;

[0007] (4) The injection method of slick water + glue + 100-mesh proppant + 40 / 70-mesh proppant + 30 / 50-mesh proppant used in the conventional fracturing mode has a better effect on high-pressure medium-shallow shale gas However, it is not necessarily suitable for deep formation and normal pressure shale gas fracturing, especially under the premise that the above-mentioned micro-fractures and horizontal bedding / texture scales are generally reduced, the particle size selection and corresponding addition of small particle size proppant Therefore, the result may be that the 100-mesh proppant may not fill and support effectively in small-scale fractures, but may be mixed with large-scale proppant in large-scale fractures to block large-scale fractures. cracks, resulting in a reduction in the conductivity of the cracks