Selecting Drilling Technologies and Methods for Tight Gas Sand Reservoirs

Abstract

Abstract As compared to a well in a conventional gas reservoir, a well in a tight gas sand (TGS) reservoir will have a lower productivity index and a small drainage area. The economic risk involved in developing a TGS reservoir is much higher than the development of a conventional gas reservoir as the economics of developing most tight gas reservoirs borders on the margin of profitability. Therefore, it is important to select the appropriate drilling method and technology to drill a given TGS reservoir condition. In our review of the petroleum literature, we have found few papers that provide a logical method for selecting the best drilling method and technology for a given set of reservoir conditions. There are individual papers that discuss individual, successful field cases where specific drilling methods and technology seem to work for specific reservoirs. We have used many of these SPE papers to help define "best-practices" concerning the selection of drilling technologies and methods. We then developed logic to provide advice on the best drilling technologies and methods for specific reservoir conditions. In this paper, we will explain the logic we have developed for choosing drilling technologies and methods for drilling a TGS reservoir. For several years, we have been working on software we call TGS Advisor. TGS Advisor can be used to provide advice to engineers developing TGS reservoirs. The program can be described as an ‘Advisory System’. The user enters the known reservoir data and the program provides advice on how to drill, complete and stimulate the reservoir. We have combined knowledge from the petroleum literature and interviews with experts to build the TGS Advisory system. We evaluated the results of the advisory system with published case histories in the SPE literature. In this paper, we will describe how we have included the selection of appropriate drilling technologies and methods used to develop TGS Reservoirs.