Assessing Hydrocarbon Prospectivity of Krishna Godavari Basin through 3D Petroleum System(s) Modeling

Abstract

Krishna Godavari Basin, located in East coast of India is a polyhistory basin trending NE–SW characteristically defined by en-echelon system of horsts and grabens, with commercial accumulation of hydrocarbons hosted by all formations. To gain an understanding of time-space dynamics of source, reservoirs, seals, formation of traps and generation, migration and entrapment of hydrocarbons. To understand various elements of petroleum system(s) with respect to hydrocarbon charging and identify the YTF locales, is through 3D Petroleum System Modelling. Study area comprises both onland and offshore, a total area of 1,90,000 km2. Based on Source Rock tracking, Multiple Petroleum Systems (!) are observed ranging from Permian to Pliocene. PROCEDURE: Integration of seismic, GM, well data including sedimentological and biostratigraphic data, Source rock data accomplished to bring out an understanding of facies distribution and depositional architecture of various sequences / hydrocarbon plays. Conceptual depositional model was prepared which depict 3 different depositional setups: Intracratonic Gondwana, Synrift & the Passive margin. Calibration data is available for ~300 wells.Geochemical and maturity related data and various other individual source rock logging reports were accesed to delineate the known petroleum systems. Multiple source sequences have been identified for source input e.g., organic matter richness (TOC, Total organic Carbon, wt. %), source potentials (S2, mg HC/g rock), Type of organic matter, thermal maturity (VRo, Tmax) and thickness of source rock layers in respective formations. Combination of ‘Heat Flow Calibration’ tool and traditional 1D extractions were used to arrive at the calibrated heat flow in the basin. Maturity calibration data ,Generated HF trends are calibrated for present day with help of VRo and BHT data. RESULTS : Mature source rocks are present within the Cretaceous interval over a large geographical area in onshore as well as offshore. Hybrid (Darcy plus Flow path) migration simulation runs were performed. CONCLUSIONS : Broadly hydrocarbons occur in outer shelf / slope setting except the Pliocene plays which occur mainly in slope/basin floor fans of deep water setting.Modeling elucidates the charging type to be both thermogenic and biogenic corroborating the known discoveries.The study also identifies areas of YTF potential for future exploration activity, from onland to shallow offshore to Deep/Ultradeep waters.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018