SPWLA Twenty-First Annual Logging Symposium, JULY 8-11, 1980        PAPER BB

PAPER BB

 

NATURAL GAMMA RAY SPECTRAL LOGGING AIDS GRANITE WASH RESERVOIR EVALUATION

 

Philip A. Schenewerk

Enserch Exploration, Inc., Oklahoma City, Oklahoma

 

Darshan K. Sethi and Walter H. Fertl

Dresser Atlas, Houston, Texas

 

M. Lochmann

Dresser Atlas, Oklahoma City, Oklahoma

 

ABSTRACT

 

Granite wash reservoirs in the Texas Panhandle, in New Mexico and in parts of southern Oklahoma and Colorado have produced substantial quantities of oil and gas. By the drilling of new wells, these reservoirs continue to be actively explored. Furthermore, many old and already cased boreholes are being re-evaluated and recompleted.

 

In this complex reservoir rock, application of natural gamma ray spectral logging has been found to successfully evaluate reservoir shaliness despite the presence of other radioactive minerals.

 

The present discussion describes reservoir characteristics of the granite wash, presents novel interpretive concepts, and illustrates the latter on several field case studies.