SPWLA. A society of 3800 persons (as of 1984) in over 60 countries which was organized to advance the science of [[formation evaluation]] through [[well log|well-logging]] techniques. It was organized on January 29, 1959 at Tulsa, Oklahoma; incorporated December 14, 1959 in the State of Oklahoma; and has its business office in Houston, Texas. The SPWLA conducts annual symposia and publishes "The Log Analyst."