Seal and Reservoir Pressures Analysis for E&P Prospects Risk Assessment

• Subsurface Compartmentalization:
  • The integrated process of prospect generation
  • The four geopressure zones and their models
  • Vertical and lateral subsurface compartments
  • Pressure gradient in seals vs. reservoirs calculations
  • Causes of pressure transgression and regression across seals
• Reservoirs:
  • Direct and pertinent measurements of pore pressure
  • QC, calibrate and validate measured data for analysis
  • Graphic representations (PSI and PPG MWE), including some of their pitfalls
  • Calculation of hydrocarbon fluids and gas densities (types) and the water-oil-gas contacts
  • Predicting production driving mechanisms type (water or depletion drive)
  • Estimating hydraulic head for production forecast (initial natural and secondary)
  • Monitoring reservoir pressure (BHP) for production forecast and recharge
• Cap Seals (four ways):
  • Lithology, age and pressure decay
  • Seismic velocity – Well logs and calibration of prediction model
  • Sealing capacity vs. hydrocarbon retention capacity calculations
• Fault Seals (faulted three ways):
  • Fault types: their rock mechanics and pressure yield
  • Crossing fault, beds-juxtaposition, fault geometry and hydrocarbon spills
  • Shale smear potential seal: calculations and uncertainty
  • Counter – regional dip and fault seal
  • Pulse sealed fault leakage
• Salt Basins in Deppwater:
  • Salt’s stresses and PPP models (above/within/below the salt)
  • Trapping integrity of sediment’s closures in salt environments
  • Dirty vs. Clean drilling challenges
  • Salt displacement to emplacement and the impact on supra-sub salt prospects
  • Rocking Salt Basins and their impact on prospect’s risk
• Prospect Evaluation
  • Pre-Drilling
    • Strat-Geopressure Fairways
    • Predict sealing capacity from seismic and offset wells
    • Velocity crossover vs. seismic attributes
  • While Drilling
    • Pre-drilling PP- FP Model calibration
    • Adjust the drilling tolerance window (DTW) for prospective hydrocarbon column
    • Adjust MW for under and over balance to avoid BH and Formation Damages
    • Check for the optimum casing shoes depth positioning
  • Post-Drilling
    • Appraise of success and/or failure
    • Define hydrocarbon, type, thickness, lateral extension and down-dip limits
    • Calculate excess pressure, communication and reservoir initial pressure
    • Identify bypass pay zone
    • QC and assess the predicted pre-drill DHI, AVO indicators
    • Identify additional sealed structural closures in the same prospect for future E&P

Analog and digital data (in excel format) will be utilized to assess and evaluate a prospect risk. Before drilling risk evaluation and post drilling appraisal methods will be clarified, as well as how to salvage a prospect that was tested by a dry hole wildcat.

Participants in this course should have minor knowledge of subsurface formation pressures.