Unconventional shale gas drilling comparison in Sichuan Basin, China different approaches aim for same target

Low cost, high technology and fast rate of penetration (ROP) are three main factors which related to successful development of unconventional shale gas all over the world^[1]. Local operator and international operator use different approaches to develop shale gas in Sichuan basin, where is a hot place for shale gas chasers in China. Both operators have had some field application lessons learnt to improve drilling efficiency and save cost in past 3 years. • Flexible local well structure optimization design reduces loss risk. • Local batch drilling is proven to improve working efficiency and reduce cost per well. • Local service providers help to reduce cost, especially, local DD/MWD/LWD service. • Local well placement concept reduces downhole collapse issue through field application lessons learnt. • New rotary steerable system (RSS) tool has high efficiency to improve ROP, especially, in curve section. • Near bit gamma ray/gamma image is a useful tool for high dip angle / multi-faults formation for horizontal section well placement while avoiding geological sidetrack. • Bit optimization helps to improve ROP and extend downhole working life. Through above field applications, average cost of international operator is 2.4 times of local operator, but on bottom ROP is 2.1 times faster than local operator. Both operators' drilling efficiency improved 55% - 70% based on learning curves of previous 3 years. Local operator tries 6 wells per pad with 300 meters well spacing and 8 wells per pad with 400/500 meters well spacing batch drilling separately, then tries to find the best well spacing to improve shale gas production in Sichuan basin.