Key Technologies for ROP Improvement in Exploratory Well Yangliu-1

Well Yangliu-1 is an exploratory well in the surrounding blocks of Puguang Gas Field, with a design well depth of 5 850.00 m. Problems such as interlaced soft and hard continental strata, large dip angles, strong abrasiveness of the Xujiahe Formation, fractured strata were encountered, leading to difficulties in improving the ROP(rate of penetration), hard quality control of the casing program, and serious lost circulation during the drilling process. According to the lithological characteristics of strata in the well area, the air/foam drilling technology was selected to improve the ROP of upper continental strata; the PDM(positive displacement motor) + compound bit technology was employed to improve the ROP in the highly abrasive strata of the Xujiahe Formation; the pre-bending dynamic inclining prevention and fast drilling technology was adopted to enhance casing program quality; the lost circulation prevention and control technology was applied in fractured strata for a higher success rate of lost circulation control. As a result, the well was successfully drilled to the depth of 5 890.00 m, with an average ROP of 2.77 m/h, which was greatly enhanced compared with that of adjoining wells. This process had no serious downhole failures, which reduced the bit usage, shortened the time for lost circulation control, and thus achieved good economic benefits. The drilling goal has been achieved in Well Yangliu-1, which enriches the geological data of this block and provides ROP improvement experience for the drilling in this block in the future.