--> Abstract: Use of Computer-Aided Cross-Section Construction to Validate Seismic Interpretations: An Example from the Turner Valley-Quirk Creek Area of the Canadian Rocky Mountain Foothills, by A. Morris, N. R. Watts, and J. E. Wojhan; #91012 (1992).
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ABSTRACT: Use of Computer-Aided Cross-Section Construction to Validate Seismic Interpretations: An Example from the Turner Valley-Quirk Creek Area of the Canadian Rocky Mountain Foothills

MORRIS, ALAN, University of Texas, San Antonio, TX, and NIGEL R. WATTS, and JEFF E. WOJHAN, AEC Oil and Gas Company, Calgary, Alberta, Canada

Exploration for thrust antiformal structures has been the main industry focus in the Southern Canadian Cordillera for the past 70 years. Structural interpretations of the classic Turner Valley field were first published in 1951, and this structure is now a well-known example of hydrocarbon accumulation within a fold-thrust terrain. Over time, exploration has concentrated on the more subtle imbricates that ride "piggy-back" upon the main Turner Valley structure. However, although there has been intense exploration in this fold and thrust belt, few published studies have used modern structural geological techniques to illustrate the geometry of the imbricates.

In the present study, we illustrate the structural style, geometry, and position of these imbricate structures. Three Previous HitbalancedNext Hit seismic and structural cross sections have been constructed using GEOSEC, a section construction and balancing program that permits integration of time-seismic data with a geological model. Subsurface control from reflection seismic profiles, data from wells located near these profiles, and surface map information were combined to constrain the subsurface interpretation.

Time to depth conversion: (1) Original time-seismic interpretations were depth-converted in the GEOSEC package using a vertical ray-path method; initial velocities for the depth-conversion were estimated from the time-seismic sections and well logs. (2) Iterative time-depth and depth-time conversions were performed for seismic picks in key wells using slightly modified velocities, until internal consistency between seismic, velocity model, and well data was achieved.

GEOSEC provides forward-modeling tools that permit the rapid construction of geologic sections that obey current analytical models of thrust-related folding and flexural-slip/flexural flow kinematics. Cross sections were constructed using the (modified velocity model) depth-converted seismic profiles, and projected well and surface data. An iterative, trial-and-error approach was once again used to ensure that all available data were honored. The final revised interpretations are restorable, Previous HitbalancedTop, and kinematically viable.

Finally, using the revised velocity and geologic models, the original time-seismic data were reprocessed. The resulting seismic profiles revealed details of the imbricates' leading edges that were predicted by the geological modeling but had not been visible on the original seismic sections.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)