Integrated Top Seal Evaluation for Robust Solutions
J.S. Davis, S.A. Barboza and X. Liu
Event name: 2nd EAGE International Conference on Fault and Top Seals - From Pore to Basin Scale 2009
Session: Fault and Top Seals in Exploration
Publication date: 21 September 2009
Info: Abstract, PDF ( 209.98Kb )
Prediction of hydrocarbon column heights and contacts requires simultaneous evaluation of capillary and mechanical bed seal properties together with trap geometry (crest, spill), estimation and quantification of uncertainties, and propagation of these uncertainties through the analysis. We developed a method for making a probabilistic determination of total seal capacity for a hydrocarbon trap, simultaneously considering both bed seal leak mechanisms (capillary entry pressure and hydraulic fracture pressure), and accounting for trap geometry. Assuming unlimited gas and oil charge and uniform seal properties, simultaneous evaluation of top seal capacity and geometric controls on hydrocarbon fill, leads to recognition of only six possible combinations of hydrocarbon fill control in two-phase (gas and oil) systems. Single phase systems are controlled by only one of the three leak mechanisms. Different combinations of top seal and geometric spill controls can achieve very similar final hydrocarbon distributions in hydrocarbon traps. Without investigating all possible controls it is easy to draw incorrect conclusions about controls on hydrocarbon fill in any single accumulation, promoting incorrect prognostications about undrilled traps. When considering field development plans that include pressure support, misunderstanding actual controls on fluid distributions could lead to unanticipated outcomes, such as leakage through the top seal.