Seismic reprocessing, interpretation and petroleum prospectivity of the East Cano Rondon Area, Llanos Basin, Colombia

Abstract

The Llanos Basin, in Eastern Colombia, is the major oil-producing province in the country. In recent years, exploration in this basin has been focused towards plays in the Llanos foothills, where proven thrust traps present the possibility of large discoveries. However, the Llanos foreland still remains an attractive exploration target due to lower risk plays linked to proven production mechanisms. One giant field and over 51 smaller fields have been discovered. The basin, with an exploration well density of 1:500 1=2, can hardly be considered mature. Improvements in seismic data processing, sequence stratigraphic analysis and a better understanding of the petroleum systems have led to a renewed interest in the Llanos foreland in an attempt to identify new plays and prospects. An integrated geophysical and geological study was done to evaluate the petroleum prospectivity of the East Cano Rondon Area, located 35-km southwest of the giant Cano Limon Field. The purpose of the project was to reprocess approximately 200 km of mid 1980s seismic, integrate the interpretation of the seismic data with the available well and geologic data, create a sequence stratigraphic framework and describe the hydrocarbon potential of the area. Reprocessing the seismic data gave an improved image of the subsurface from previous processing. The implementations of techniques like refraction statics, pre-stack linear noise attenuation (FK Filter), surface consistent residual statics, dip moveout (DMO), post stack signal enhancement (FK Weighting) and finite difference migration improved the static solutions, signal noise to ratio and imaging of the fault planes. The interpretation of the seismic data led to the dentition of the structural styles, deformation history, paleotopography and identification of seismic facies. The sequence stratigraphic framework was built from the integration of the seismic, well and regional data. 5 transgressive-regressive sequences were identified in the Upper Cretaceous to Early Oligocene rocks. Two prospective areas were identified within the East Cano Rondon Area. One of them is related to the proven play of fault bounded anticlinal structures. Three gelds in the vicinity of the study area have proven reserves in this play. The second prospect is based on a new play that is being proposed. The play involves the stratigraphic pinchout of basal transgressive sands deposited in the topographic lows created by wrench fault tectonics. The two prospects could have up to an estimated 759 MMBO.