3D Basin and Petroleum Systems Remodeling of San Joaquin Basin, California

摘要

California has long been one of the USA’s most important oil-producing states, and the San Joaquin Basin has long since eclipsed as the country primary oil production basin. San Joaquin Basin is also home to 21 giant oil fields that have produced over 100 million barrels of oil each, with four "super giants" that have produced over 1 billion barrels of oil. Among these "super giants" are Midway-Sunset (the largest oil field in the lower 49 United States), and Elk Hills (the former U.S. Naval Petroleum Reservoirs). In 2007, the U.S. Geological Survey (USGS) published a complete assessment of the oil and gas resource potential of the San Joaquin Basin Province of California. With respect to technically recoverable undiscovered conventional hydrocarbon resources in the San Joaquin Basin Province, the USGS assessment team1 estimated means of 1.8 trillion cubic feet of gas (TCFG), 393 million barrels of oil (MMBO), and 86 million barrels of total natural gas liquids (MMBNGL) for five total petroleum systems (TPS), Winters-Domengine TPS, Eocene-Miocene Composite TPS, Eocene Composite TPS, Miocene TPS and Neogene Non-associated Gas TPS. A 4-D Petroleum Systems Model was build and published by the USGS assessment team in 2007 (Used in this re-modelling project as base case model), but due to limited Rock-Eval/total organic carbon data, the Tumey formation was modelled using constant values of original total organic carbon and original hydrogen index (Values used by the modelling team were, 2% TOC and HI equal to 550 mg hydrocarbon/g total organic carbon). Maps of original total organic carbon and original hydrogen index were created for the other three source rocks. In this re-modelling effort, 6 wells were found to have Rock-Eval data for Tumey Formation that would be suitable to create original total organic carbon and hydrogen index distribution maps for Tumey Formation. The maps were used in remodelling the San Joaquin Basin Petroleum systems and results for Tumey Formation were compared to the earlier results. Petrel?/PetroMod? Workflow was used for re-building the BPS model Heatflow was a challenging and important parameter for the model calibration. The 2007 published model results didn’t achieve the best vitrinite reflectance and temperature calibration with selected calibration wells. In this project, the published San Joaquin heatflow information by Colin Williams (Colin F. Williams’s presentation, USGS, Menlo Park, CA, 2008) was used to create new basin surface heatflow trends and maps used for re-modelling sensitivity and calibration runs. It was found that lower surface heatflow values from what was applied during the 2003 assessment model gave better calibration with well data.