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Deterministic and Stochastic Seismic Inversion Methods for Gas Discrimination at La Creciente Field, Colombia
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, First EAGE/ACGGP Latin American Geophysics Workshop, Mar 2012, cp-278-00026
- ISBN: 978-94-6282-049-4
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Abstract
At 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.