AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Petroleum Systems Analysis in the Gulf of Mexico – From Regional Framework to Predicting Fluid and Rock Properties
(1) Shell International Exploration and Production Company, Houston, TX.
The deepwater Gulf of Mexico has been one of the major deepwater exploration provinces during the last 25 years. In the beginning, the shallower plays of Pleistocene to Pliocene age have been explored very successfully. This success was mainly related to the rather strong seismic response of the hydrocarbon fill. During the last 5-8 years, large volumes of hydrocarbons have been discovered in the ultra-deepwater and related deeper plays, which show no clear response on seismic. The oil quality and rock properties in these deeper plays are of rather poor quality, however, and this leads to a significant challenge to produce these oils at economic rates.
In order to address these challenges and identify potential production sweet-spots in the various plays, SHELL carried out a re-assessment of the petroleum potential of the entire deepwater area.
A regional framework has been established, which incorporates regional depth grids, structural (palinspastic) reconstructions, petrophysical, geological and geochemical data, to create a large 3D basin model, which was used to derive key variables, controlling fluid and rock properties.
Shell's in-house basin modeling software CAULDRON was used to model these variables, including uncertainties. The basin model is used to generate regional maturity maps, pressure-, VES- and temperature volumes. The hydrocarbon generation and expulsion module in CAULDRON is based on a multi-component reaction scheme, which allows to model bulk fluid properties rather accurately. The detailed petrographic work carried out in-house is used as input to the Touchstone module linked to CAULDRON, which is used to generate regional porosity and permeability maps. The workflow and some example ouputs will be presented.
The basin model results helped to understand the spatial and temporal variability of these critical parameters, and therefore helped to target exploration wells more effectively and optimize the exploration success. The output of the models is used as input to a thorough Volume to Value (V2V) analysis, which forms the basis for the pre-drill economic evaluation of the opportunities.