Preliminary Study On The Relationship Between Hydraulic Fracturing,Seism And Casing Deformation

The exploration and development of shale gas in China is at an important stage.However,the failure of casing deformation during hydraulic fracturing has seriously affected the development process and greatly limited the application and popularization of volume fracturing technology.However,the research on this kind of “quick” casing deformation mechanism is still not deep enough.Therefore,it is urgent to strengthen the communication between research units and field,and to sort out the main factors of casing deformation as soon as possible,in order to propose feasible solutions.Based on extensive research of domestic and international institutions,this paper used field data and finite element theory to clarify the main factors that caused casing deformation failure during hydraulic fracturing,and concluded that natural fractures / faults is the most important factor of the failure of casing deformation in the process of hydraulic fracturing in Changning-Weiyuan block.According to this,the relationship of hydraulic fracturing,seismic and casing deformation are explained with the source mechanism theory in classical seismology in recent decades.The relationship equations among fault slip,moment magnitudes and fault scales for different fault models are deduced,and the magnitude of moment magnitudes and fault scales for failure of casing deformation in the Changning-Weiyuan area are given;To analyze the thinking route and feasibility of measures to solve casing deformation during hydraulic fracturing and provide guidance to the field.The research results show that natural fracture/fault slipping prediction technology is the most important means to solve the problem of casing deformation during hydraulic fracturing.Before the technology has become mature,seismic interpretation and faults identifying should be strengthened,and faults with a radius of 100-400 m should be prevented from during the wellbore trajectory design.During the hydraulic fracturing operation,the microseismic signals should be monitored in real time.When a microseismic event with a magnitude of 2.0-3.5 occurs,the fracturing operations should be suspended,and the wellbore abnormalities should be checked out before next stage fracturing.The research content of this paper has important guiding significance for field application and has a positive effect on the shale gas exploration and development process.