Steam Still Chromatography--New Application for Old Technology

Dan E. Burnham, W. T. Deubel

The use of a steam still to enhance the efficiency of gas chromatography from drilling mud has been available since the 1960s. The steam still is a device that boils water to create steam, which is kept under pressure. The steam is allowed to mix with samples of the drilling mud, and the entrained gasses are liberated and removed for analysis with a gas chromatograph. The steam still improves the hydrocarbon detection by reducing the variable effects of drilling mud and equipment factors (e.g., mud weight, mud viscosity, trap efficiency, detector performance, etc). Steam still chromatography is successfully used today in offshore and Gulf Coast sandstone reservoirs. The use of this technology in evaluating Permian basin carbonates is in its infancy; preliminary results ar impressive.

Steam still chromatography was used on two wells in the Indian Mesa field and one well in the Coyanosa field, Pecos County, Texas. The objective of using steam still chromatography was to determine the gas-oil and oil-water contacts in a fractured dolomite at the Indian Mesa field and to determine the dry gas vs. rich condensate zones in a chert conglomerate at the Coyanosa field.

In the Indian Mesa field, preliminary data indicate an oil-water contact at -5,360 ft. The Coyanosa well is clearly zoned with very lean gas, predominately C₁, at the top of the reservoir and a rich condensate zone higher in C₃-C₅ nearer the bottom.

Clearly, steam still chromatography is an old technology that deserves a second look in evaluating carbonate reservoirs in the Permian basin.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.