Structural interpretation and restoration of Rocky Mountain Brazeau zone

Abstract

The Rocky Mountain Foothills lie along the eastern margin of the Rocky Mountain fold-thrust belt. The area has been the focus of extensive research aimed at locating oil and gas fields with the potential to be used as CO₂ storage traps. In this study, we use a seismic line from the Canadian Rockies to interpret the geologic structures along a cross-section parallel to the tectonic transport direction. We then compare our results with those of previous studies. The section was restored using the MOVE software (manufactured by Midland Valley Exploration Ltd.). The primary objectives of this work are: (1) to conduct a stratigraphic and structural interpretation of a 2D seismic profile; and (2) to conduct a cross-sectional restoration of the structures in order to validate the seismic interpretation in terms of CO₂ storage candidates. Additional data sources include maps of the surface geology, which show that the age of horizons decrease from west to east, and stratigraphic and structural profiles derived from well logs. The results of our structural restoration indicate a detachment fault between the foreland and hinterland. This fault is responsible for the cutting and subsequent upwards and eastwards movement of a stratum located between the basement and the Late Devonian formation. Large thrust faults are responsible for the deformation of strata (through both folding and faulting) in the foreland basin. As a result of continuous eastward tectonic stress, the strata from Jurassic have deformed, forming a duplex system in the middle of the section and resulting in the uplift of the upper part of the section. Following surface erosion, this uplifted area became exposed during the Tertiary Period. The high shortening rate (53%) detected through structural restoration is consistent with the thin-skinned tectonic model.

Keywords

Rocky Mountain Foothills / fold-thrust belt / stratigraphic and structural interpretation / structural restoration

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