Technologies and prospect of full-cycle development of low-permeability tight gas reservoirs with horizontal wells，Ordos Basin

Abstract

The geological characteristics of low-permeability tight gas reservoirs（developed mostly with horizontal wells）in the Ordos Basin are systematically described based on previous gas development experiences. A successful development of these reservoirs with horizontal wells usually comprises four stages based on a study of the targets，technical parameters，and performance indicators of the wells：exploring all possibilities，tackling technical problems，scaling up of technology implementation as well as optimization and improvement. The technical connotation of horizontal well development in Ordos Basin is elaborated and represented by a series of development technologies including multidisciplinary sweet spot optimization technology，overall deployment technology of multi-layer large well cluster，multidisciplinary integrated geosteering technology，and fine fracturing technology with a full life cycle production management. A comprehensive evaluation of gas development through horizontal wells from different types of gas reservoirs indicates that horizontal wells perform better in tight gas reservoirs，that strengthening the joint efforts on multi-disciplinary research for the whole process is the main direction of horizontal well technology development as well as the key to a large-scale development of low-grade natural gas resources with profit. For developing reservoirs with more complex conditions such as those buried deep in thin layers with low abundance of gas，horizontal wells will be further improved to deal with the challenges in the brown Sulige gas field where targeted optimization of the technology will be carried out，the green gas fields such as Qingyang and Yichuan where supporting technology will be developed，and the new forms of gas resources such as shale gas，coal-bed methane，etc，that require effective development technologies，thus ensuring a steady increasing gas production in the Ordos Basin.