Fault Seal Prediction and Uncertainty Estimation of a Water Wet Fault

Chun Hock, Tan¹; Schulte, Lothar²
¹Exploration, Talisman Energy, Kuala Lumpur, Malaysia.
²Schlumberger Information Solutions, Schlumberger, Kuala Lumpur, Malaysia.

Recent advance on computing power has led to vast improvement on static modeling for both fault modeling and fault seal prediction. Nevertheless, there are still many uncertainty factors that are being built into the seal models and need to be addressed in order to come up with a reliable risking. This poster is dealing with a major water wet fault of a clastic oil reservoir. Consequently its possible sealing is based on capillary entry pressure. The first part of the poster discusses the estimation of the shale/clay content of the fault. Based on the upscaled well data the shale distribution is modeled using multiple stochastic realization as well as different interpolation algorithm. This approach tries addressing fundamental issues of juxtaposition uncertainty. The shale/clay contents of the fault is estimated based on different algorithm (e.g. Vshale cutoff, Shale Gauge Ratio, Shale Smear Factor etc). The impact of each approach is assessed and reviewed. The results are compared to the simplistic approach of triangulating the Vshale/Vclay of the wells to the fault.

The second part of the poster discusses the estimation of the permeability and the capillary entry pressure using different published empirical algorithm . Again emphasis is laid on the attempt to estimate the uncertainty range of the properties. The final result is presented by three scenarios representing the low, base and high case. Based on the limited pressure data the pressure difference across the fault resulting from the oil buoyancy is estimated and the sealing likelihood of the fault evaluated.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012