Print this pageS. A. Tavernier1, R. T. Williams2, R. D. Hatcher3
(1) University of Tennessee, Knoxville, Knoxville, TN
(2) University of Tennesse, Knoxville, Knoxville, TN
(3) University of Tennessee, Knoxville, TN
ABSTRACT: Shallow Fractures and Basement Faulting in the Swan Creek Field, Tennessee
The Swan Creek field in Hancock County, TN, contains substantial oil and gas reserves, which continue to increase as new seismic reflection and geologic data are acquired and more is learned about the structure. Production in the field is strongly influenced by fault-related fracture systems. USGS geologic maps for the Swan Island and Howard Quarter quadrangles, show northwest-oriented strike-slip faults with as much as 100 meters of displacement. Well data from the Swan Creek field also suggest the presence of northwest trending faults. Seismic reflection profiles indicate that some of these faults may cut the entire Paleozoic sedimentary section. Based on cross-cutting relationships, the mapped strike-slip faults would therefore be late Alleghanian faults. The Swan Creek field is located within a zone of concentrated seismic activity, the East Tennessee Seismic Zone (ETSZ). The earthquake foci are in Grenville-age metamorphic basement rocks beneath the Alleghanian thrust sheets. Recent first motion studies have identified 4 well-constrained events clustered in this region, for which one of the nodal planes is northwest trending. Coincidence between the northwest orientations of shallow strike-slip faults, and northwest nodal planes for earthquakes in basement, raises numerous questions. This paper examines the possible influence of ancient basement faults, still active in the modern stress field, on the development of fractures in the overlying sedimentary section. Better understanding the role of basement tectonics during the development of fractures in the reservoir rocks will lead to improved strategies for the future development of the Swan Creek field.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado