Sealing Properties of Thrust Faults

Kostenko, Olga V.¹; Naruk, Steve ¹; Solum, John G.¹; Mora-Glukstad, Miguel ²; Brandenburg, John Paul ^1
1 Shell International Exploration and Production Inc, Houston, TX.
² Shell International Exploration and Production B.V., The Hague, Netherlands.

Quantification of risk associated with fault seals for fault-bounded traps is a critical success factor in the petroleum exploration industry. Studies of known sealing and leaking faults have shown that maximum pressures and column heights trapped by the faults are linearly proportional to the shale gouge ratio (SGR). The predictions of sealing capacity of the faults are based on empirically derived and carefully calibrated databases that relate the properties of the fault gouge (SGR) to the observed hydrocarbon column.

Most of the calibration points in the existing databases are from normal fault environments. Little direct information is available on the sealing potential of thrust faults. We present a recently compiled empirical database of sealing properties of thrust fault rocks. The data are from numerous thrust fault outcrops in McKinleyville, California, Buckskin Gulch, Utah, Miri, Malaysia, the Colorado Front Range, and the Wyoming foldbelt. The data indicate that the relationships between the different petrophysical properties of the thrust faults (i.e., permeability, capillary entry pressure etc) are similar to those observed in normal faults. This indicates that sealing capacities of the thrust faults are similar to the normal faults.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009