Optimization of Perforation in CBM Horizontal Wells in Southern Qinshui Basin
To enhance the fracturing performance of coalbed methane(CBM)horizontal wells in the Qinshui basin,by analyzing the data of distributed optical fiber monitoring of water and gas production profiles,mud log,and well logging,the key factors influencing the fractur-ing performance were identified.These factors include coal quality,coal structure,drilling position,and perforation method.The middle to upper part of coal seam No.3 in the Qinshui basin,characterized by low GR values,high coal quality,and intact coal structure,is identified as the optimal interval for fracturing stimulation.Based on the double GR curves,the drilling position of horizontal wellbore trajectory in the coal seam can be accurately determined,aiding in the selection of optimal fracturing interval and perforation method.When the drilling position is located in the middle part of the coal seam,conventional perforation method can be efficient.When the drilling position ap-proaches the roof or is beyond the seam,downward directional perforation is preferred to effectively stimulate the high-quality upper part of the coal seam.When the drilling position is near the lower dirt band,upward directional perforation is advisable to target the high-quality middle part of the coal seam.Field application to 46 horizontal wells demonstrated that the single well production exceeded 2.5×104 m3/d and was stabilized at 2×104 m3/d,and the reservoir fracturing efficiency increased by 10%to 50%,recording a satisfactory development ef-fect of the horizontal wells.
NETL
NSTL
万方数据
