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Calgary, Canada

Vestrum R.,Thrust Belt Imaging | Lawton D.,University of Calgary
Geophysical Prospecting | Year: 2010

Dipping anisotropic clastic strata are ubiquitous in fold and thrust belts. Geological structures below these strata will be mispositioned laterally and vertically on seismic images if we do not properly correct for seismic anisotropy during migration. The magnitude of this lateral mispositioning of a target structure varies with source-receiver offset, so reflection points will be smeared in the final stacked image. Raytracing demonstrates the lateral-position and smear phenomena when imaging structures below tilted transversely isotropic media. Analysis of the raytracing results predicts the quantity of lateral-position error and reflection-point smear on a seismic image. We created numerical-model seismic data to show reflection-point smear on synthetic seismic images and to evaluate the accuracy of the predictions from raytracing. © 2009 European Association of Geoscientists & Engineers. Source


Vestrum R.,Thrust Belt Imaging | Florez I.C.,Hocol S.A.
72nd European Association of Geoscientists and Engineers Conference and Exhibition Incorporating SPE EUROPEC 2010, Workshops | Year: 2010

The objective of the anisotropic depth imaging was to obtain a more accurate positioning of the events for an appropriate well trajectory. The original well location was determined from the isotropic depth migration, and it was clear from early in the drilling cycle that there were lateral-position errors on the seismic image. The TTI anisotropic depth migration project ran during drilling to refine the well trajectory. We used a collaborative, geologically constrained approach that integrates all available geologic information into the interpretation of the seismic velocity model. This area has interbedded siliciclastic rocks with high dips and vertical and lateral velocity contrasts, giving a considerable lateral movement in the images in depth when we correct for seismic anisotropy and lateral-velocity heterogeneity. The position of the structure and dips on the final depth image were confirmed by two wells drilled in the area. Source


Vestrum R.W.,Thrust Belt Imaging | Rojas N.A.,Ecopetrol SA | Brouwer F.G.C.,DGB Earth science | Rincon C.O.,Ecopetrol SA | Dolgov V.S.,Thrust Belt Imaging
1st EAGE/ACGGP Latin American Geophysics Workshop | Year: 2012

The Rio Zulia oil field in the Catatumbo Basin has a 3D seismic survey for further field development and to identify additional prospective zones. Reprocessing of this volume included additional prestack-time migration and TTI anisotropic depth migration. Low signal-to-noise on the volume over complex geologic structures led the team to employ an interpretive model-building methodology for the depth-migration velocity model. The dipping anisotropy around the edges of the anticlinal structure resulted in lateral shifts in imaging of the subthrust reflectors. Source


Dolgov V.,Thrust Belt Imaging | Vestrum R.W.,Thrust Belt Imaging | Wittmann G.,MOL Hungarian Oil and Gas | Gittins J.M.,Thrust Belt Imaging
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010

In a tectonically complex area of northwest Pakistan, MOL Pakistan and its partners acquired two 3D seismic surveys. Extreme topography led to irregular shooting geometry. Varied surface access over this terrain required a mix of vibroseis and dynamite source types to maximize subsurface coverage. With the combination of difficult surface conditions over a structurally complex subsurface, the data processing and merging of these two surveys required close attention to detail throughout the processing sequence, and we had to rely on the most robust algorithms in the data-processing toolkit. There was no single technology that stood out in the processing, but careful attention to details in the application of the fundamental processes created a readily interpretable seismic volume © 2010, European Association of Geoscientists and Engineers. Source


Gittins J.M.,Thrust Belt Imaging | Wittman G.,MOL | Vestrum R.W.,Thrust Belt Imaging | Csontos L.,MOL | Dolgov V.,Thrust Belt Imaging
1st EAGE/ACGGP Latin American Geophysics Workshop | Year: 2012

The transpressional geologic setting of northwest Pakistan is at the boundary of three continental tectonic plates. MOL Pakistan and its partners acquired two 3D seismic surveys over highly complex structures in this area. Extreme topography led to irregular shooting geometry. Varied surface access over this terrain required a mix of Vibroseis and dynamite source types to maximize subsurface coverage. With the combination of difficult surface conditions over a structurally complex subsurface, the data processing and merging of these two surveys required close attention to detail throughout the processing sequence, and we had to rely on the most robust algorithms in the data processing toolkit. There was no single technology that stood out in the processing, but by taking care at every stage in the processing sequence we were able to produce a readily interpretable seismic volume. Source

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