The Central Segment of The Eastern Cordillera (Colombia): Rejuvenating an "Old" Exploration Frontier
Gyorfi, Istvan1; Passos Giraldo, Sandra; and Gonzalez, Alejando
The Eastern Cordillera (EC) of Colombia is bounded to the West by the Magdalena Valley and to the East by the Llanos Basin - the two most prolific hydrocarbon provinces of Colombia. The EC has been the subject of extensive regional-scale structural studies. Some of the models depict the EC as the result of "rift inversion", dominated by thick-skinned tectonics, while others emphasize the thin-skinned nature of the deformation. Recent thermo-chronological studies suggest that the first phases of compressional deformation of the EC could be as old as Paleogene, which would have important consequences on hydrocarbon exploration. Within the study area ten wells have been drilled, without economic success. There have been shows reported in the wells and on surface but these were regarded as the "remnants" of a once active and prolific hydrocarbon system. It was not until 2010 when the Corrales-1D, a re-entry of a previously drilled well, demonstrated that commercial hydrocarbon accumulations do exist here.
The main focus of this study is to establish a workflow to re-evaluate the prospectivity of the region. In the first step, six regional lines were constructed using legacy seismic and surface geology. Thorough seismic reprocessing and interpretation of these transects was followed by structural balancing to validate the interpretation. These transects have been integrated with potential field (gravity and magnetic) data, and calibrated with available well data. Subsequently, they were the input to a regional study addressing burial history, and hydrocarbon generation / expulsion. Areas with the highest exploration potential were selected for two 3D surveys. Simultaneously with the 3D seismic acquisition, detailed geological mapping was performed, and integrated in seismic processing and interpretation.
The complex structural play requires high-quality imaging techniques, which involve both time (PSTM) and depth (PSDM) domains. Examples will be presented, to show the integration, and the complementary nature of 2D (PSTM) and 3D (PSTM and PSDM) datasets in defining prospects. The results of the presented workflow highlight the need for continuous integration of all geological and geophysical disciplines. In general, fold-and-thrust belts and specifically the Eastern Cordillera offer unique possibilities for such an approach. Otherwise, they will remain expensive and high-risk exploration regions, which will offer limited success to explorers.
AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013