Advances in the Key Technologies of Drilling and Completion for Tight Sand-stone Gas Reservoirs
CHEN Zhixue1,2, FENG Xiaowei1, CUI Longlian2, DAI Wei3, LIU Li2, BI Wenxin2
1. School of Petroleum Engineering, China University of Petroleum, Beijing 102249, China;2. CNPC Drilling Research Institute, Beijing 100195, China;3. Chuanqing Drilling Engineering Company Limited, CNPC, Chengdu 610051, China
Abstract：Since 1970s, the wide development of American tight sandstone gas reservoirs have reveived the widespread attention. In the way of driling and completion for the tight sandstone gas reservoirs, a series of mature advanced matching technologies have formed. Well design has witnessed a process of development from the initial single vertical wells to horizontal wells and cluster horizontal wells, and the longest horizontal segment is more than 3000m. The way of well spacing has been changed from single well drilling into the factory drilling to improve the operation efficiency. Many advanced technologies have been utilized for ROP improvement, such as unbalanced drilling, MPD and high quality drilling fluid to realize safe and fast drilling during the long lateral section. Well completion has a development from conventional acidizing technology to large-scale multi-stage fracturing, whose stimulation stage is more than 60, and the individual well production has increased by more than 45%, making low cost and high efficiency come true during the development of tight sandstone gas reservoirs. According to tight sandstone gas reservoir features in China, cluster horizontal wells factory drilling and long horizontal-section with staged fracturing transformative technology have been carried out in Changqing and Jilin Oilfield. The longest horizontal segment is 2800 m, and remoulding stage numbers are more than 25. Single well cost savings are about more than one million yuan, and the output is 3-10 times as the vertical wells. Finally remarkable application results have been achieved. The formation of these supporting technologies gradually improve drilling and completion technologies of the tight sandstone gas reservoirs in China, and it has important guiding significance to accelerating the development pace of tight sandstone gas reservoirs.