New Geochemical Techniques Used to Characterize Reservoir Systems in the Llanos Basin: Cutting Costs and Learning More

Geochemical indicators of petroleum composition provide cost-effective tools for evaluating reservoir continuity and allocating commingled production. These geochemical tools are highly complementary to engineering methods for deriving reservoir continuity information, and can effectively replace engineering methods for allocating commingled production. Using geochemistry to better understand the characteristics of reservoirs and reservoir fluids allows engineers to maximize the recovery of hydrocarbon fluids and to determine how many wells should be drilled, where wells should be drilled, and how to maximize the production. This case study of a well in the Llanos Basin in Colombia is presented to demonstrate how the gas-chromatographic (GC) fingerprints of oils were evaluated using InfoLogic's ReserView™ and OilUnmixer™ programs to delineate the producing reservoir intervals, identify vertical reservoir fluid compartments, and estimate and monitor the production allocation of a 2-zone completion. The results from the comparison of the oils using the programs identified the reason for a reduction in production, why the API gravity of the commingled oil decreased, and the Gas-Oil Ratio (GOR) increased over the seven-month period. The geochemical approach cost approximately 95% percent less than if three production logging tool (PLT) events had been used instead.