M.E. Eck, ARCO Oil and Gas & D.E. Powell, Schlumberger Well Services
A method has recently been developed for evaluating the Delaware Mountain group of West Texas by using electromagnetic propagation, photoelectric effect, and neutron density measurements. The Delaware Mountain group is a series of sand-shale sequences deposited in the Delaware Basin of West Texas and Southeastern New Mexico during the Guadalupian Age. For a variety of reasons, conventional interpretation methods based on resistivity measurements have not always been definitive in these formations for distinguishing between oil and water. An interpretation technique using electromagnetic propagation data, specifically porosity derived by comparing electromagnetic propagation measurements to porosity from neutron-density logs, has been used with considerable success in identifying traditional pay zones and locating new pay zones in the Bell Canyon and Cherry Canyon formations of the Delaware Mountain group.