Fault and Fracture Study using Multiple Seismic Attributes in Mississippian Carbonate Reservoirs of the Dickman Field, Ness County, Kansas.

Jianjun Zeng and Christopher L. Liner
Department of Earth & Atmospheric Sciences, University of Houston, Houston, TX

Possible fault and fracture zones were identified from 3D seismic patterns of discontinuity extracted from six geometry attributes. These patterns were displayed in their original geological occurrence and tied to stratigraphic units at the reservoir-scale through depth conversion by a stratigraphic-controlled velocity model. This helped to identify discontinuity patterns in two geometric categories: unconfined features penetrating at least two litho-zones up to the entire stratigraphic window, and confined features mostly within individual stratigraphic units. Unconfined features are best seen on 2D vertical SPICE profiles and 3D plane-extraction from the ANT attribute. Confined features are easiest to identify by plan-extraction from aggressive ANT volume, and by varying density patterns while marching depth slices of Chaos and Variance. The geological integrity of discontinuity patterns were evaluated based on the understanding of regional deformation history, the distribution pattern of fault/fracture zones predicted by carbonate deformation models, the structural-controlled maturity of karst topography, and the fault and fracture indicators from sparse well logs, and core description. Unconfined features are mostly structural and their style and occurrence reflects motion of the latest structural deformation episode. A multiple-episode faulting history was determined by strata thickness and lithology data, and by indirect indicators of differential up-lifting including relative roughness of karst-topography. The study of confined features is preliminary. They are mostly non-structural and may represent post-depositional changes. Some can be related to intra-strata features observed in Middle Mississippian cores from the nearby Schaben Field.

AAPG Search and Discovery Article #90152©2012 AAPG Southwest Section Meeting, Fort Worth, Texas, 19-22 May 2012