ABSTRACT: Hydrocarbon Distribution in Tertiary Sandstones as a Function of Formation Pressure and Temperature

W. G. Leach, Walter H. Fertl

Hydrocarbon distribution is related to formation pressure and temperature, with the highest concentrations of all hydrocarbons encountered near the onset of abnormal pressure regimes. A thorough understanding of the interactive relationship between lithology, pressure, temperature, and hydrocarbon distribution is essential for the efficient exploration and development of oil and gas accumulations. All information, such as lithology, pore pressure, and temperature, can be obtained from geophysical well logs.

The primary purpose of this presentation is to discuss distribution and redistribution of hydrocarbons in Tertiary sandstones of southern Louisiana with respect to the depth, pressure, and temperature at which these oil and gas accumulations are predominantly encountered. Also discussed are the thermodynamics of ascending fluid movement and the sourcing of these hydrocarbons. Production data from approximately 33,000 well completions and pressure/temperature data from over 20,000 wells provide the database used in this analysis.

In addition, similar findings are presented for clastic overpressured reservoirs in the Baram Delta, located offshore in Sarawak, Malaysia, and the hydrocarbon resources being developed in the West Turkmen depression of the Soviet Union.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990