Upper Cretaceous Tocito Sandstone Lentil of Mancos Shale, San Juan Basin, New Mexico--Is There Any Oil Left?: ABSTRACT

Abstract

The Upper Cretaceous Sandstone Lentil of the Mancos Shale consists of a series of northwest-trending linear sandstone bodies in the San Juan basin of New Mexico. This sandstone unit, which has produced most of the basin's crude oil (more than 125 million bbl to date), was referred to as the Sandstone for many years. Recent stratigraphic studies of the by several authors clearly demonstrated that the Sandstone Lentil is a totally different stratigraphic unit from the Gallup; thus, the name was reinstated as a lentil of the Mancos Shale. (Actually, the Tocito was thought to be part of the Gallup years ago and the name was dropped in favor of the name.) Even though hundreds of holes drilled to produce natural gas from th deeper Dakota Sandstone have penetrated the Tocito, these holes cannot be thought of as dry holes because, for many of them, no attempt was made to test the for its possible oil potential. There is still a good chance that significant amounts of oil remain to be found in the Tocito. End_of_Article - Last_Page 559------------