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Prioritization of Seismic Prospects Through Geo-microbial Grading Technique - A Case Study in Panidihing Area

D.Elizabeth Nathaniel
ONGC, Mumbai, INDIA [email protected]

Exploration in Panidihing area of Upper Assam basin attained importance due to its proximity to Moran field lying in ESE and Rudra Sager field in SW directions. Geo-microbial prospecting crew was pressed in to the area much before (1997) the well results of panidihing-2 to understand the tantalizing exploration results observed in Panidihing area of Upper Assam basin.

This surface exploration method based on the presumption that the hydrocarbon accumulations leak minute quantities to the surface. The geomicrobial method locates the blooms of the microbial proliferations at near surface. The methodology is reliable, effective and environmentally friendly to detect the micro seeps quickly and economically. This paper presents the results of the survey done along with the 3D seismic campaign in the area.

The interpretation of 3D seismic data of Panidihing area brought out several structural prospects both at Sylhet and Barail stratigraphic levels viz. Bejpathar, Naojan, Duigingiagoan, apart from delineating Panidihing prospect more precisely. The drilled wells Panidihing -1 & 2 are falling in the comparatively lower range of microbial values. However, Naojan prospect in the NNW appears to be better charged with hydrocarbons in view of the excellent microbial proliferations observed near it. In the same way north eastern prospect (Duigingiagoan) also attains importance in view of very good microbial expression which needs delineation possibly with the help of available 2D/3D seismic data. In Panidihing area the closure between two faults systems is perhaps better charged than the area where the two wells were drilled. The southern part of the study area indicates modest prospectivity. In essence, the Naojan is ranked as excellent and Duigingiagoan is very good to excellent prospect and appears to be better charged with hydrocarbons and thus attains immediate exploration attention.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery