Evaluating Fault and Cap Rock Seals
This volume constitutes the proceedings of the AAPG Hedberg conference on seals held in Barossa Valley, South Australia, in 2002. The key driver for both the Hedberg conference and this publication was the recognition that knowledge of risk in the estimation of sealing capacity and fault-seal potential is important in making judgments at the exploration, appraisal, and development stages of the petroleum business. In addition, incorporating seal risk in the overall assessment of hydrocarbons in place can affect decisions to drill prospects and the location of appraisal and development wells, as well as reserve estimation. Improved methods to estimate seal capacity and fault integrity can lead to savings in well costs, improved recoveries through optimum placement of wells, and improved estimates of hydrocarbon in place. This volume contains 18 chapters that reflect the spectrum of presentations at the conference. The knowledge imparted by these chapters will be a window on the state of seal knowledge at this juncture of time and includes topics such as seal failure related to basin-scale processes, the role of geomechanics in seals, and the economic evaluation of prospects with a top seal risk.
Using Buoyancy Pressure Profiles to Assess Uncertainty in Fault Seal Calibration
Published:January 01, 2005
Effective fault seal model calibration is dependent on the quality of the available data. Buoyancy pressure profiles provide a method to assess the potential uncertainty involved in deriving key input data, such as Vclay (volumetric clay fraction), and in the empirical equations used to derive seal-failure criteria. For a membrane-sealing fault, seal failure occurs when the buoyancy pressure exerted by the hydrocarbon column is equal to the minimum capillary entry pressure of the fault zone. If the seal is intact, the predicted fault zone capillary entry pressure value must be higher than the buoyancy pressure and, on a...