Enhancing Downhole Density: Traditional vs Modern Gas Trap Comparison

🎙 Enhancing Downhole Hydrocarbon Density Estimates: A Comparative Study of Traditional and Modern Gas Traps Using Established Calculation Methods

Accurate determination of hydrocarbon density from surface gas data remains a vital tool in formation evaluation. While the underlying calculation methods have stood the test of time, the accuracy and consistency of the input data—particularly from gas traps—can vary significantly with trap design. Tom Selman evaluates a modern, redesigned gas trap against a traditional setup by applying a proven density calculation method to both data sets. Field results are shown side by side, highlighting differences in gas ratios and resulting density estimates. He explores potential causes of the discrepancies (fluid dynamics, trap geometry, gas liberation efficiency) and examines their implications for interpreting downhole hydrocarbon properties—especially in complex or subtle fluid systems. The talk demonstrates how an improved gas trap design can yield more reliable density estimates—without altering established interpretation workflows—and offers both practical field guidance and deeper insight into surface gas behavior.

About the Speaker

Tom Selman, BS Geology (UGA 1980)

Wyoming PG-3030 | Texas PG-6785

45 years in mudlogging; founder, Selman & Associates (est. 1983)

Author/co-author of 40 mudlogging patents

Host or Publisher The Permian Basin Chapter of the Society of Petrophysicists and Well Log Analysts (SPWLA)