Large Diameter Hole Steering Drilling Technology for Three-Dimensional Horizontal Well in the Fuling Shale Gas Field

The Fuling shale gas three-dimensional horizontal well featuring with the second spud deviated section with a large hole diameter, long tangent section, frequent interbedded sandstone and mudstone, presented issues like large azimuth adjustment, a lower unstable build-up rate of BHA and a low rate of penetration. Therefore, directional drilling technology for three-dimensional horizontal well with large diameter hole was studied. The well trajectory was optimized considering the natural build-up rate of formations to reduce build-up rates, shorten the tangent section, and reduce the wellbore trajectory adjustment and wellbore trajectory control difficulty. The "single PDM and dual stabilizer" BHA were alternated by "single PDM and single stabilizer" BHA combined with WOB, so that to improve the composite drilling footage in tangent section and reduce friction and torque. A hydraulic oscillator was applied to reduce friction and torque in azimuth change section in order to improve ROP. The steering drilling technology was applied in 34 horizontal wells in the Fuling Area with a deviated second spud average directional drilling time of 15.30 d, which was 37.63% short compared to the wells in the same block. The average drilling cycle was 58.45 d, which was 21.01% shorter than the wells in same block. The wellbore quality passing rate was 100%. Application results showed that the steering drilling technology for a three-dimensional horizontal well with large hole diameter could increase ROP in deviated section with large hole diameter and could shorten the drilling cycle.