Deep Shelf Gulf of Mexico Regional Study 

Operators in the Gulf of Mexico are directing their efforts toward the exploration and exploitation of deep reservoirs in the shelf area of the Gulf of Mexico. These reservoirs range in depth from 15,000 to 30,000 feet and are primarily Pliocene, Miocene, and Oligocene in age. These reservoirs present a challenge to operators and have an inherently high risk and cost. Traditional AVO seismic methods have yielded mixed results for identifying prospective target reservoirs. Explorationists must currently rely on identifying and evaluating prospects by projecting sand distribution from regional well control, identifying structural traps seismically, assessing the risk of reservoir quality, and evaluating the risk of seal integrity. All are challenging and aid significantly to the risk in drilling these wells.

Our project focus is on three key areas to help reduce operator risk and increase success rates.

• Characterize the reservoir quality and petrophysical properties of deep shelf reservoirs: As geological characterization of deep shelf reservoirs is critical to effective exploration, exploitation and reservoir quality prediction. Data on depositional facies, environment, rock types, mineralogy, pore structure, clay types, and petrophysical properties will be determined on conventional, rotary and percussion sidewall cores and/or cuttings as applicable.
• Seal rock evaluation: Seal and potential seal rock material from conventional cores, rotary sidewall cores, percussion sidewall cores, and drill cutting samples will be evaluated in terms of seal rock properties. Methods used to determine seal capacity are mercury injection capillary pressure, thin section, x-ray diffraction, and SEM analysis. An evaluation of seals in terms of lithology, log response, pressure regime, thickness, facies, areal extent, etc. from multiple wells and horizons will provide critical information needed to evaluate seal risk.
• Predict reservoir quality of deep shelf reservoirs in prospective (undrilled) areas: Geocosm will work with the Integrated Reservoir Solutions Division to provide reservoir quality predictions using the Touchstone reservoir quality analysis and prediction system. Touchstone incorporates an integrated suite of diagenetic and petrophysical models that simulate sandstone reservoir properties through geologic time and can be used to predict reservoir quality away from well control. Important controls on model results include sandstone depositional texture and composition and subsequent temperature, depth, and fluid overpressure histories. Touchstone incorporates process models that are calibrated using petrographic, core analysis, and burial history data for analog samples. Calibration model development will be included as part of the project and will be performed by Core Laboratories.
• Available in RAPIDLink™