UPPER GUADALUPIAN HIGH-FREQUENCY SUBSURFACE SEQUENCE STRATIGRAPHY BASED ON WIRELINE WELL LOG DATA IN THE NORTHWEST DELAWARE BASIN AREA, SOUTHEASTERN NEW MEXICO

The world type section for the Middle Permian (Guadalupian) is in the Guadalupe Mountains, located in the northwest Delaware Basin of southeastern New Mexico and west Texas. Even though the Permian Reef Complex has been studied for many years, stratigraphic controversies remain, some of which are addressed in this study. Sequence stratigraphy of the shallow-water shelfal, reefal and deep-water basinal environments of the Capitan reef complex (Late Guadalupian) is based on the concept of “reciprocal sedimentation” where stratal units deposited at highstands and lowstands are distinct. In the basin, very fine-grained sands and silts from the exposed shelf were deposited during lowstands whereas carbonate deposition occurred during highstands. On the shelf, aeolian siliciclastics formed during lowstands whereas carbonates and evaporites formed during highstands. Using “reciprocal sedimentation” three composite sequences and 12 high frequency sequences were recognized in outcrops of the Upper Guadalupian (Kerans and Tinker, 1999). In this study, “reciprocal sedimentation” is used to correlate and map subsurface defined high frequency sequences in approximately 100 wireline logged wells throughout a four township area where recognizing the gamma-ray and porosity signatures of the stratal units are key. The high frequency sequences in the subsurface are largely in agreement with the surface-defined sequence stratigraphy of the Capitan reef complex. This data confirms the outcrop-based model for reef progradation (Kerans and Tinker, 1999; Kerans and Kempter, 2002).