Detecting Hydrocarbon Microseepage Using Remotely Sensed Data

Ira S. Merin, Donald B. Segal, Ronald J. Staskowski, John R. Everett

Many petroleum reservoirs leak, and the upwardly migrating hydrocarbons and associated fluids can produce a series of chemical changes that may affect plant physiology and the mineralogical and physical attributes of the overlying strata. Alterations manifested the surface depend on the composition of both the upwardly migrating fluid and the strata overlying the leaking reservoir. These alterations may appear on airborne spectroradiometric or satellite multispectral data as tonal (mineral or plant spectral) or textural (geomorphic or plant ecological) anomalies, or both. Examples include: (1) bleaching of red beds due to loss of hematite and/or anomalous clay mineral distributions in strata overlying petroleum accumulations at Lisbon Valley, Utah, and at Cement and Velma fields, Oklahoma; (2) mineral alterations such as replacement of calcium sulfates by calcite at Cement, Oklahoma, and Limestone Buttes, Gypsum Plain, Texas, resulting in anomalous geomorphology; and (3) geobotanical manifestations caused by soil chemistry variations resulting in anomalous plant communities above Lost River gas field, West Virginia, or physiological alteration (stunting) of plant communities such as at Patrick Draw field, Wyoming. The diagnostic visible and near-infrared absorption features exhibited by iron oxides, clay minerals, and botanical assemblages permit airborne and satellite-borne sensors to be used to distinguish and map spatial patterns of these materials, and form the basis for remote detection of surficial phenomena that may indicate hydrocarbon microseepag . The ability to detect these anomalies using remotely sensed data depends on the susceptibility of the surface to alteration, the inherent heterogeneity of the surface, and the degree of exposure.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.