Seismic Facies Study of 3D Seismic Data, Northern Louisiana, Wilcox Formation Kaare Egedahl 1 , Gary L. Kinsland 1 , and Dan Han 2 1 Department of Geology, University of Louisiana at Lafayette, P.O. Box 44530, Lafayette, Louisiana 70504 2 Berger Geosciences, LLC., 13100 Northwest Frwy., Ste. 600, Houston, Texas 77040 ABSTRACT The lower Wilcox of northern Louisiana is a known producer of coalbed natural gas (CBNG). The difficulty with identifying coals within a fluvial-deltaic clastic sequence lies in the horizontal heterogeneity and complexity of the depositional environments in which coals are formed. The lateral extents of known coalbeds were constrained within a seismic data volume made available by Devon Energy, covering all of Township 8N– 3W and portions of 8N–2W and 8N–4W, located in northern Grant Parish. Coalbed extent was determined by utilizing the combination of well log’s high vertical resolution and conventional 3D seismic data’s relatively high horizontal resolution. By utilizing TerraSpark’s Insight Earth software, paleo-geomorphology was more accurately imaged through proportional flattening the 3D seismic volume and the crea- tion of “stratal” slices. Well log facies were correlated with their equivalent seismic fa- cies visible on stratal slices and provide an analog with which to further explore the CBNG potential within northern Louisiana. INTRODUCTION The purpose of this study was to define more clearly the lateral extents of coals previously identified within a conventional 3D seismic volume. The technique of stratal slicing of the seismic data volume allowed better interpretation of environments of deposition from the improved delineation of seismic facies. Combining inter- pretation of seismic facies from stratal slices with analysis of well log facies provided improved control of the lateral extents of coal facies and will decrease the risk of drilling for coals. The University of Louisiana at Lafayette’s (UL) Coalbed Natural Gas (CBNG) Research Group has been actively researching the lower Wilcox in northern Louisiana primarily through the use of wireline logs downloaded from the Louisiana Strategic Online Natural Resources Information System (SONRIS) (Fig. 1). Devon Energy recently made available to the university a conventional 3D seismic amplitude volume, allowing for a greater understanding of the lateral facies changes and occurrences of coals to use as an analog throughout the lower Wilcox of northern Louisiana. The study area was limited by the extent of the 3D seismic volume. This included all of Township 8N–3W and portions of 8N–2W and 8N–4W in Grant Parish, and a very small portion of two townships in southern Winn Parish, in northern Louisiana. The 3D seismic volume comprised the first 2 s of two-way travel time (TWT) data of an area of roughly 80 square mi, with a bin size of 110 ft. Egedahl, K., G. L. Kinsland, and D. Han, 2012, Seismic facies study of 3D seismic data, northern Louisiana, Wilcox For- mation: Gulf Coast Association of Geological Societies Transactions, v. 62, p. 73–91. 73