Browsing by Subject "Barnett shale"
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Item Evidence of Reopened Microfractures in Production Data of Hydraulically Fractured Shale Gas Wells(2012-10-19) Apiwathanasorn, SippakornFrequently a discrepancy is found between the stimulated shale volume (SSV) estimated from production data and the SSV expected from injected water and proppant volume. One possible explanation is the presence of a fracture network, often termed fracture complexity, that may have been opened or reopened during the hydraulic fracturing operation. The main objective of this work is to investigate the role of fracture complexity in resolving the apparent SSV discrepancy and to illustrate whether the presence of reopened natural fracture network can be observed in pressure and production data of shale gas wells producing from two shale formations with different well and reservoir properties. Homogeneous, dual porosity and triple porosity models are investigated. Sensitivity runs based on typical parameters of the Barnett and the Horn River shale are performed. Then the field data from the two shales are matched. Homogeneous models for the two shale formations indicate effective infinite conductivity fractures in the Barnett well and only moderate conductivity fractures in the Horn River shale. Dual porosity models can support effectively infinite conductivity fractures in both shale formations. Dual porosity models indicate that the behavior of the Barnett and Horn River shale formations are different. Even though both shales exhibit apparent bilinear flow behavior the flow behaviors during this trend are different. Evidence of this difference comes from comparing the storativity ratio observed in each case to the storativity ratio estimated from injected fluid volumes during hydraulic fracturing. In the Barnett shale case similar storativity ratios suggest fracture complexity can account for the dual porosity behavior. In the Horn River case, the model based storativity ratio is too large to represent only fluids from hydraulic fracturing and suggests presence of existing shale formation microfractures.Item Industry evolution : applications to the U.S. shale gas industry(2014-05) Grote, Carl August; Tinker, Scott W. (Scott Wheeler); Ikonnikova, SvetlanaThe present study applies evolutionary and resource-based firm theories to three of the most prominent U.S. shale gas basins – the Barnett, Fayetteville, and Haynesville plays. Rather than broadly considering a host of factors that enabled what has often been labelled a shale gas revolution, an evolutionary approach recognizes the internal agents that have long been in place, but were triggered by technical and economic developments. As geologic understanding, along with innovation and competitive environments, evolves in each play so too does the entire shale gas industry. Building upon the Bureau of Economic Geology shale gas study funded by the Sloan Foundation, this study offers data-driven analyses to test theories of industrial evolution as applied to shale gas plays. Each of the three focus plays has undergone introductory and growth phases as well as a maturation phase in which there is an evident shakeout of operators. Industries are theorized to enter decline phases, yet none of the plays here have definitively declined. Certain economic signals, however, indicate that a decline is imminent, albeit variable in timing and pace. Conceptualizing the entire shale gas industry as an amalgamation of individual and evolving plays correctly describes how the industry is able to rejuvenate its growth trajectory through investment in emerging plays. Although heterogeneous geology, engineering capabilities, and economic environment, particularly natural gas prices, complicate the economics of shale gas extraction, an evolutionary approach proves to be a useful tool in describing the historical development of individual plays as well as the entire shale industry. Importantly, this application sheds light on the future development of valuable shale resources.