Optimized and Fast Drilling Technology for Horizontal Shale Gas Wells in Pingqiao and Jiangdong Blocks of Fuling Area

Downhole problems and failures are often encountered while drilling the shale gas horizontal wells in Pingqiao and Jiangdong blocks of Fuling Area,which result in low ROP and long drilling cycles.Consequently,we studied the latest technologies for optimizing drilling and increasing the rate of penetration in shale gas wells.We focused first on conductive and technical casing,which could be optimized to the point that it turned into a double conductor program.We could also optimize the wellbore trajectory using incrementally variable curvature.In addition,the trajectory control technology of vertical well section and small build-up section was developed for drilling high-steep structures according to the requirement of well quality on different well sections.The relationship between ROP and drilling method is analyzed and the drilling methods was optimized according to the characteristics of different formations in different sections.Furthermore anti-shock roller bit,axe tooth PDC bit,and hybrid drill bit are studied and developed to meet requirement from bit performance on lithology,drillability,and abrasiveness of drilled formation.The ϕ285.8 mm low-speed and high-torque motor and ϕ171.5 mm all-metal hydraulic oscillator are optimized for ROP enhancment.BT-100 low-density and high inhibiting drilling fluid and oil-based gel plugging materials are selected to solve the problem of circulation loss.Hence,the guidelines for optimized and fast directional drilling technology for shale gas wells in Pingqiao and Jiangdong blocks could be established through those studies.The technology was applied in 32 wells in Pingqiao and Jiangdong blocks of Fuling Area.By using this technology,the average drilling cycle was decreased from the previous 128.00 days to 76.25 days with excellent ROP increasing effect,which provided reference to enhance ROP in Pingqiao and Jiangdong blocks well drilling.