An Integrated Approach to Shale Gas Evaluation
With shale plays gaining importance in the North American market, the need for an integrated analysis to help operators better understand and produce this complex reservoir has become obvious. Gas shales are unlike conventional reservoirs in that they serve as the reservoir rock, source rock and seal. They also require extensive hydraulic stimulation and quite often horizontal wells to produce economically. Because of this complexity, a through understanding of the geology, petrophysics, and geomechanics of the formation are required to ensure success of a well.
Proposed integrated interpretation methodology, developed specifically to evaluate shale gas reservoirs, is focused on the use of conventional resistivity, neutron, density, advanced acoustic, magnetic resonance, geochemical, geomechanics, and borehole image logs (acoustic and/or resistivity) to determine the lithology, mineralogy, rock mechanical properties, total organic carbon, and gas in place in the formation.
Integrated approach of a variety of formation evaluation techniques (including geochemical logging data), along with detailed geological studies from borehole image logs and geomechanics allows for better understanding of the many geological factors that can potentially affect the successful exploitation of a shale gas reservoir. Moreover, results of an integrated study can be used to pick the best intervals for perforations (or to kick off a lateral) and to design the optimum hydraulic stimulation treatment.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009