Facies and Cycle Architecture in the Gulf PDB-04 Core: Integration of Outcrop Derived Models Into the Subsurface

Abstract

The Artesia Group (Seven Rivers, Yates, and Tansill Formations) form significant oil and gas fields particularly along the western margin of the Central Basin Platform. In 1984, Gulf Research and Development Company drilled the PDB-04 stratigraphic research well in Eddy County, New Mexico, and recovered approximately 4,800 feet of continuous core, the focal point of extensive studies carried out thereafter. Since then, numerous outcrop and reservoir studies have resulted in significant advancements in the structural and stratigraphic framework in the Guadalupe Mountains. A new look at the classic PDB-04 provides a key tie-point and illustrates how the outcrop-based high-frequency sequence framework from core/log patterns can be brought into the subsurface. High resolution core descriptions allowed for detailed facies tracking and the interpretation of the 1D sequence architecture and stacking patterns of complex reservoirs in the Capitan Reef equivalent shelf. Core plugs and a conventional suite of wireline tools from the PDB-04 provide the ability to link the stacking patterns observed in the core to their respective log signatures. Upon building log-facies models, it will be possible to extrapolate the platforms geometric architecture from wells in the nearby subsurface allowing for the generation of an accurate large scale 3-D stratigraphic framework extending from the Guadalupe Mountains to the Central Basin Platform. 111 high frequency cycles (HFC) were interpreted in the core and the range of HFC per high frequency sequence (HFS) ranged from 4-14. The wide range was attributed to syndepositional faulting and missing section near the shelf margin, and a better record of sea level change preserved in the facies in close proximity to the shelf crest, a proxy for the paleoshoreline. HFC patterns tend to be incongruous due to varying positions on the shelf profile between core and outcrop and local controls on sedimentation rate and subsidence. However, cycle sets exhibit strong similarities indicating broad scale mechanisms of accommodation were operating simultaneously across the 70 km area between the outcrop analogs and the core, and the delineation of this trends continuity will be discernable post construction of a log-core facies models.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016