Fayetteville-Shale Production: Seismic-to- Simulation Reservoir Characterization

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 147226, ’Understanding and Predicting Fayetteville-Shale Gas Production Through Integrated Seismic-to-Simulation Reservoir-Characterization Workflow,’ by Hariharan Ramakrishnan, SPE, Eva Peza, Shekhar Sinha, SPE, and Miriam Woods, Schlumberger, and Christopher Ikeocha, Flemming Mengel, Yves Simon, Paul Pearce, Jeff Kiester, Steven McKetta, SPE, and John Jeffers, SPE, Southwestern Energy, prepared for the 2011 SPE Annual Technical Conference and Exhibition, Denver, 30 October-2 November. The paper has not been peer reviewed. A comprehensive workflow was developed that incorporates geologic, seismic, and production data in an effort to understand and predict the performance of gas wells in the Fayetteville shale play. A reservoir model was developed by integrating all available well, log, petrophysical, sonic, image, core, stimulation, production, microseismic, and processed surface-seismic data. This static reservoir model was used to history match the short- and long-term production performance and its variations across the exploration area. The reservoir characterization and the dual-porosity simulation model were used to predict production performance of future wells in the Fayetteville shale formation. Introduction Significant technological advances have been made toward identifying shale-gas resources and developing those resources economically. Acquiring (and use of the correct combination) of information and measurements to understand production capabilities early in the life of a large play remains a critical challenge. An integrated seismic-to-simulation workflow was developed to understand and predict the production performance of Fayetteville shale-gas wells. The Fayetteville shale-gas play extends across northern Arkansas, USA, from the state’s western edge through-out north-central Arkansas. Ranging in thickness from 50 to 550 ft and varying in depth from 1,500 to 6,500 ft, this Mississippian shale is the geologic equivalent of the Barnett shale in north Texas and the Caney shale in Oklahoma. Currently, this operator controls approximately 916,000 acres, which produced 350 Bcf of gas in 2010. Between the start of the project in 2004 and 31 December 2010, the company had spudded 2,445 wells. Geological Setting The structures in this area are the result of Precambrian-to-Cambrian rifting that generated the Reelfoot rift, also called the Mississippi Valley graben, and subsequent compressional tectonics of the Ouachita orogeny. The rifting event generated large normal northeast-striking faults, whereas the tectonics related to the development of the Ouachita orogeny is characterized by generally north-directed thrusting as a result of continent-to-continent collision along the southern margin of North America. The current orientation of maximum horizontal stress is northeast/southwest. In the study area, the Fayetteville shale is 250 to 300 ft thick and at a depth of 2,500 to 3,000 ft.