Technologies for Fast Drilling Ultra-Deep Wells in the HLHT Block, Tarim Oilfield

Reservoirs in the HLHT Block, Tarim Oilfield contain soft formations in upper parts and rocks with poor drilling performances in lower parts. Consequently, these formations are characterized by a low rate of penetration (ROP) and longer time required for drilling operations. With the original casing program optimized to casing program with three intervals up to requirements specified in Standard III of the Tarim Oilfield, research has been conducted to accelerate the ROP in the second interval. By analyzing the drilling performance of relevant formations, selecting optimal bits and other drilling tools, and with consideration to available data, technical programs for EOP acceleration in the second interval were developed: PDM with long service time and high torque/domestically produced high-efficiency PDM+Model STS915K or Model MS1952SS high-efficiency PDC bits could be used to enhance ROPs in formations above the Permian; Torkbuster torsion impinger+Model U513M or Model U613M designated PDC bits could be used to enhance ROPs in the Permian and formations below. On-site application results showed that the application of relevant technologies to enhance ROPs in ultra-deep wells of the HLHT Block could effectively enhance ROPs from 5.55 m/h to 8.82 m/h while the average required drilling time decreased from 131.0 d to 86.1 d. Relevant research results showed that the technologies to enhance ROPs in ultra-deep wells of the HLHT Block had outstanding performances and could effectively satisfy demands related to safe and fast drilling of ultra-deep wells in the target block.