Probabilistic Analysis of Fault Seal Capacity in Compressional Settings: Risking Prospects and Fields in Exploration and Production

David Richards¹, Titus Murray², Maren Kleven², and Greg Christie^2
1FaultSeal Americas, Englewood, CO
²FaultSeal, Sydney, NSW, Australia

Fault seal capacity is well-studied in extensional terrains, but publications concerning compressional terrains are scarce. We present selected analyses from compressional settings here.

Analysis of fault seal capacity and its impact on potential hydrocarbon columns is affected significantly by uncertainties of reservoir geometry, fault position, orientation and throw as well as stratigraphic changes and uncertainties along and across faults. A new technique for stochastic analysis provides probability of leakage, ranked leak points and ranges of potential hydrocarbon columns. In production settings, compartmentalization effects of faults are also modeled with statistical distributions.

Basic data inputs are a key 3d surface intersection with a fault, fault parameters for orientation and displacement profile with estimated uncertainty ranges. For the stratigraphic sequence of interest, the reservoir-seal stratigraphy and Vshale from nearby wells or regional estimates is also input, with variations along and across the fault as well as ranges of uncertainty on thickness. A workflow interface allows rapid input of parameters. The calculations are in full 3d.

Results to date indicate a good match between predicted hydrocarbon-water contacts and observed contacts. Examples from a variety of settings show the applicability and effectiveness of the technique in compressional settings. As the results of the analysis are probability of seal and distributions of fluid contacts, they aid understanding of risk on prospects and field development.

AAPG Search and Discovery Article #90092©2009 AAPG Rocky Mountain Section, July 9-11, 2008, Denver, Colorado