--> --> Exxon Entry into the Guyana‐Suriname Basin: A Historical Look Back into Genetic Basin Analysis and its Application

2019 AAPG Latin America & Caribbean Region Geosciences Technology Workshop:
Recent Discoveries and Exploration and Development Opportunities in the Guiana Basin

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Exxon Entry into the Guyana‐Suriname Basin: A Historical Look Back into Genetic Basin Analysis and its Application

Abstract

The exploration activities by Exxon and ExxonMobil in the Guyana-Suriname basin that led to the recent exploration successes started over 50 years ago. Early participation by Esso in offshore drilling in the 1970's, including operation of the first deep water well in the basin (Suriname Demerara A2-1 well in 1978) led to the assimilation of early observations that indicated a basin with excellent source rock potential but with dubious reservoir quality and scarce structural traps above the known source. After disappointing results in the Demerara A2-1 well, Esso relinquished its licenses in Suriname and no significant studies were performed until the early 1990's. At that time, Exxon conducted a series of regional studies in Northern South America, Mexico and the Caribbean that utilized genetic basin analysis to identify the key play elements needed for working hydrocarbon systems. The culmination of this effort was a short focus study in 1995 in Northeast South America (Guyana and Suriname) which utilized legacy Exxon data which included sparse proprietary deep water seismic and well data from the 1970’s and newly-available global satellite gravity data. These data were viewed in light of old and new concepts with additional information provided by biomarker technology and a proprietary plate tectonic reconstruction to question long-standing dogma and provide new regional geologic and deepwater exploration models. The results of this project indicated that that 1) Jurassic oceanic crust, pre-dating the known Ceno-Turonian source rocks could be postulated; 2) coincident free-air and isostatic residual gravity highs were hypothesized to have resulted from recent, rapid deposition of Neogene sediments; 3) a new sequence stratigraphic model based on the sparse 2D deep water lines supported the concepts of reciprocal sedimentation between shelf and basin, evidence of Ceno-Turonian source facies, and Cretaceous deep water reservoir systems, 4) low heat flow in the Jurassic-aged basin would allow for high quality clastic reservoirs and 5) sufficient load of Tertiary sediments to push the source rocks into the oil window. The integration of these key play components led to the decision to pursue re-entry into the Guyana-Suriname basin in the late 1990's.