Seismic attribute-based characterization of coalbed methane reservoirs: An example from the Fruitland Formation, San Juan basin, New Mexico

Abstract

The Fruitland Formation of the San Juan basin is the largest producer of coalbed methane in the world. Production patterns vary from one well to another throughout the basin, reflecting factors such as coal thickness and fracture and cleat density. In this study, we integrated conventional P-wave three-dimensional (3-D) seismic and well data to investigate geological controls on production from a thick, continuous coal seam in the lower part of the Fruitland Formation. Our objective was to show the potential of using 3-D seismic data to predict coal thickness, as well as the distribution and orientation of subtle structures that may be associated with enhanced permeability zones. To do this, we first derived a seismic attribute-based model that predicts coal thickness. We then used curvature attributes derived from seismic horizons to detect subtle structural features that might be associated with zones of enhanced permeability. Production data show that the best producing wells are associated with seismically definable structural features and thick coal. Although other factors (e.g., completion practices and coal type) affect coalbed methane production, our results suggest that conventional 3-D seismic data, integrated with wire-line logs and production data, are useful for characterizing coalbed methane reservoirs.