- Home
- Conferences
- Conference Proceedings
- Conferences
First EAGE/ACGGP Latin American Geophysics Workshop
- Conference date: 07 Mar 2012 - 09 Mar 2012
- Location: Cartagena, Colombia
- ISBN: 978-94-6282-049-4
- Published: 07 March 2012
21 - 26 of 26 results
-
-
Interpretive Model Building for TTI Anisotropic Depth Migration over the Rio Zulia Field, Colombia
Authors R.W. Vestrum, N.A. Rojas, F.G.C. Brouwer, C.O. Rincón and V.S. DolgovThe 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.
-
-
-
Seismic Modeling for Structural Interpretation Verification and PSDM Workflow Design - A Case Study
Authors Q. Liao, M. La Cruz, L. Benkovics and F. OrtigosaIn this study, Seismic modeling was used as an effective tool to verify structural interpretation of a seismic section from onshore Venezuela. The structure/velocity model was derived based on analysis of PSTM image and information from the well. Finite difference modeling was applied to the model and the resultant shot gathers have been migrated using PSTM method. The comparison of PSTM image of synthetic data with PSTM image of real data verifies the new interpretation concept and confirms that the target event was distorted by the overriding thrust fault in the PSTM image and PSDM has to be adopted to produce accurate structure image. To select adequate PSDM velocity model building workflow for the specific imaging target the same synthetic dataset collected from the modeling process has been used to evaluate different PSDM model building methods. Both grid and model based tomography workflows have been fully tested with multiple velocity update iterations. The PSDM results from both methods have been compared and the one produces accurate image has been recommended. In addition, the tests reveal many specific issues associated with selected workflow and unique geological structure, which allow us to fine tune the workflow before applying to real data.
-
-
-
Resolving Complex Overthrust Features Using Magnetotellurics - The Bolivian Foothills Case Study
Authors A. Zerilli, A. Lovatini, A. Battaglini and P.D.L. MenezesThe sub-Andean foothills are an area of increasing interest for oil and gas exploration. Exploration in these areas however is challenged by several factors. Their accessibility due to thick forest coverage and steep terrains is not straightforward, thus making exploration and development plans more complex and far more expensive. Targeting the most promising areas is of paramount importance to reduce the footprint of any exploration and production activity. A reliable understanding of the subsurface is fundamental, so is also choosing the best geophysical tools to achieve these objectives. Satellite and airborne techniques are utilized, since they cover large areas in time and economical effective manners. However they lack the resolution to infer the geology at depth. Seismic imaging is the principal tool to infer the earth geometries from their elastic properties. However in these areas reflection signal to noise ratio is severely reduced by steep topography and almost vertical bedding, thus making its use for imaging limited. The Magnetotelluric (MT) method has been successfully used as a complementary tool in the sub-Andean environment. In this paper we show how MT can be used to enhance depth imaging and help understand the structures and their potential for exploration.
-
-
-
3D Seismic Imaging over Two Structurally Complex Surveys in the Foothills of Pakistan
Authors J.M. Gittins, G. Wittman, R.W. Vestrum, L. Csontos and V. DolgovThe 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.
-
-
-
Unconventional Statics for Unconventional Exploration: An Integrated Approach
Authors C.F. Diggins, R.D. Wisecup and M. DuikerOften unconventional shale plays underlay areas where conventional refraction statics cannot always be applied because near-surface high velocity layers may obscure underlying slow-velocity layers.
-
-
-
Deterministic and Stochastic Seismic Inversion Methods for Gas Discrimination at La Creciente Field, Colombia
Authors M.E. Bosch, G. Bertorelli, G. Alvarez, A. Moreno, R. Colmenares and E. GarciaAt La Creciente Field, which produces gas from depths of around 3 km, we applied deterministic and stochastic techniques of seismic and petrophysical inversion, with the objective of estimating the lithology and fluids. With the techniques applied and adequate calibration, we succeeded to discriminate the gas bearing sands of Ciénaga de Oro formation from the non reservoir surrounding rocks like the shale seal, shaly sands and brine bearing sands, supporting the discovery of new gas compartments in the area. The gas bearing sands exhibit a Type II seismic response, and are characterized by low density, high shear velocity and low compresional velocity compared with shaly sands and brine sands. The stochastic inversion method provides estimation of marginal probabilities in reservoir parameters, for description of uncertainties related with the deviations of the petrophysical model predictions and errors of the acquisition, modeling and processing of the seismic data. Also probabilities for the total and extractable gas volume at interpreted compartments can be calculated, providing relevant information for the definition of drilling priorities.
-