Abstract

Direct hydrocarbon indicators are the measurements by which presence and absence of a hydrocarbon accumulation can be predicted. These indicators include local amplitude increase (bright spot), decrease (dim spot), phase change, lowering of impedance due to presence of gas and flattening of seismic events due to gas-water contact. All these seismic attributes are directly related to the presence of hydrocarbons in a known field. These attribute changes can as well be due to lithological variations. A bright spot identified on a seismic section passing through a gas well, in Kosamba field, South Cambay Basin, led to the analysis of seismic attributes and resulted in identification of a shallow gas prospect. Usually bright spots can be authentically identified at shallow depths and are helpful in delineation of gas fields. Even though shallow gas fields may not be commercial, these observations help to ward off the drilling hazards. This paper deals with the analysis of seismic attributes to delineate the shallow gas pool in Kosamba field, South Cambay Basin.