Shelf Sand-Ridge Core Studies
The Solar Petroleum Navajo F-151 (NW Sec. 10 T31N R17W), which is the subject of this discussion, is located in Horseshoe Field in the San Juan Basin in San Juan County, New Mexico (Fig. 1). It produces from the Tocito Sandstone Lentil of the Mancos Shale which has been incorrectly included by many workers in the Gallup Sandstone of Turonian and Coniacian (Upper Cretaceous) age (Fig. 2 and 3). The Tocito Sandstone Lentil is typically inter-bedded with or lies at the base of the upper Mancos (Niobrara) Shale in the western and central parts of the San Juan Basin (Molenaar, 1973, 1983a).
Substantial amounts of the production attributed to the Gallup Sandstone should probably now be attributed to the Tocito Sandstone Lentil (125 million barrels, to date, Fassett, 1981). The most conclusive evidence for differentiating the Tocito Sandstone from the Gallup Sandstone is obtained from outcrop studies and from cores such as the Solar Petroleum Navajo F-151.
Figures & Tables
Shelf Sands and Sandstone Reservoirs
Shelf sandstone reservoirs are becoming a more and more common exploration target. What they are, how they may be characterized, and how they differ from shoreline and deep-water deposits in the subject of this publication. Shelf sands and sandstone reservoirs are among the more poorly understood types of sandstones. Continental, shoreline and deep water sandstones have all been studied in much more depth than have shelf sands and sandstones. However, during the last fifteen years significant progress has been made in understanding shelf sands and sandstones. Studies of modern sediments have allowed us to understand many of the depositional processes active on the shelf. This book is intended to be an up-to-date summary of shelf processes and products. The papers are intended for those new to shelf sands and sandstones as well as the shelf specialist.