Real-time Optimization Of Drilling Parameters Of PDC Bit In Fuling Shale Gas Field

The problem of low drilling rate,serious bit wear and high construction cost in the second stage of Fuling shale gas severely limited the exploitation of shale gas.Therefore,this paper carries out the research on real-time optimization of DDC bit drilling parameters in Fuling shale gas field to achieve cost reduction and efficiency improvement.According to the experimental data of the core grinding of the Fuling stratum in the predecessor,combined with the logging data,the multi-regression model was used to establish the evaluation model of the formation grinding log.Based on the predecessor PDC bit wear equation,combined with the formation grinding log evaluation model,the PDC bit wear equation in this area is established.According to the PDC bit rock breaking method,shear fracture is the main method.Combined with the predecessor PDC bit rock breaking torque model,the cutting depth and threshold torque coefficient are introduced.Considering the hydraulic energy of the screw drilling tool,a new model for calculating the rock breaking torque of the PDC bit is established.Using the bit wear equation,the new model for calculating the rock breaking torque of the PDC bit is modified to optimize the torque required to crush the unit volume rock and the shear strength of the drilled formation.A new method for optimizing the drilling parameters of the PDC bit is established.Many wells in Fuling Jiaozhou have been successfully applied.The results show that the average mechanical drilling speed of the optimized well section is increased by 10-15% compared with the adjacent well,and the energy utilization efficiency of rock breaking is greatly improved,which can guide the optimization of drilling parameters in real time.Using the drill wear equation,the previous hydraulic-mechanical specific energy model was modified to establish a new hydraulic-mechanical specific energy model.Based on the optimization of the hydraulic-mechanical specific energy and the shear strength of the stratum,the PDC bit drilling parameters optimization method was established.This method has been successfully applied in Fuling area.The results show that the average mechanical drilling speed of the optimized well section is increased by about 10% compared with the adjacent well,which verifies the rationality of the optimization method for the optimization of drilling parameters in this area.