John V Leone¹, Steven L Dorobek¹

(1) Texas A&M University, College Station, TX

ABSTRACT: Enhanced Interpretation of Structural and Depositional Features Using Variance Seismic Attributes, Halley and Emperor Fields, West Texas

The imaging of subsurface structural and depositional features can be greatly enhanced using variance volume attributes derived from 3D seismic data. Variance is a direct measurement of the dissimilarity within a 3D seismic volume. Specific input parameters used in this technology depend on local geology (e.g. fault orientations, facies geometries).

Variance attributes were analyzed within a 3D seismic data set from Winkler County, Texas. The main objective of the variance attribute analysis was to image oilfield-scale structures along the western margin of the Central Basin Platform (CBP) of the Permian Basin. The CBP is a fault-bounded, late Paleozoic basement uplift in the Marathon-Ouachita foreland. The major boundary faults of the CBP trend NNW-SSE and are generally characterized as steeply dipping reverse faults with a component of right-lateral strike-slip offset. The CBP can be partitioned into two major basement-scale blocks, the Andector Block to the north and the Fort Stockton Block to the south. These blocks rotated in a clockwise sense during late Paleozoic time and had an E-W trending left-lateral strike-slip shear zone along their shared boundary. 3D seismic data from Emperor and Halley fields, which are located at the southwestern corner of the Andector Block, provide important constraints on the styles and timing of deformation at this critical location. Structural relief generated during late Paleozoic deformation was also a dominant factor on the development of carbonate systems in the study area. Faults, stratigraphic relationships, and depositional features that are only marginally imaged on traditional seismic profiles can be better imaged in profiles derived from the variance cube volume.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado