Method for improving complexity index of deep shale gas fracture

Abstract

The invention relates to a method for improving the complexity index of a deep shale gas fracture. The method is characterized in that when a fracturing design of the a deep shale gas well is performed, selection and an injection manner of a fracturing fluid, selection of a supporting agent, and the number of perforations are optimized and controlled, and an artificial main fracture can be opened and communicate with a natural fracture as much as possible in an extending process; extension of a single fracture is longer, expansion of the single fracture is wider, and finally the complexity of the deep shale gas fracture can be improved to the greatest extent. The method can be used for deep shale gas reservoirs having the depth of more than 3500 meters and in which the natural fractures containing carbonate minerals are distributed in a reconstruction range of the artificial main fracture, and a certain included angle is formed between the fracturing main fracture and the natural fractures. The method is reasonable in design, is simple in process, is easy to operate, is high in fracturing construction successful rate, can effectively increase the volume of deep shale gas segment fracturing fractures, can remarkably improve the fracturing construction effect, and can acquire more economic benefits.

Description

technical field [0001] The invention belongs to the field of petroleum exploitation, and relates to a method for increasing the complexity of deep shale gas fractures. Background technique [0002] With the continuous improvement of the exploration and development technology of medium and shallow shale gas reservoirs, North America, led by the United States, has begun large-scale exploration and development of deep shale gas resources, and in some shale gas blocks, the deep shale gas Rock gas has achieved certain development results. As we all know, shale gas reservoirs are characterized by low porosity, low permeability, and high formation pressure. For deep shale gas reservoirs with a burial depth greater than 3500 m, as the burial depth increases, the formation temperature, horizontal stress difference, closure Various parameters such as pressure and rock plasticity will be greatly increased compared with the middle and shallow shale gas reservoirs. In the fracturing ope...

AI Technical Summary

Problems solved by technology

As we all know, shale gas reservoirs are characterized by low porosity, low permeability, and high formation pressure. For deep shale gas reservoirs with a burial depth greater than 3500 m, as the burial depth increases, the formation temperature, horizontal stress difference, closure Various parameters such as pressure and rock plasticity will be greatly increased compared with the middle and shallow shale gas reservoirs. In the fracturing operation, affected by the above parameters, the net pressure in the artificial fractures will decrease, and a large number of natural fractures will be opened and connected. It is difficult to achieve fracture diversion, resulting in low complexity of fractures, which affects the development effect of deep shale gas wells