Geochemical Software Technology to Characterize Reservoir Systems in the Llanos Basin: Cutting Costs and Learning More

Geochemical indicators of petroleum composition provide especially useful and 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 in a field and to determine how many wells should be drilled, where wells should be drilled, and how to maximize the production.

Results of a case study of a well in the Llanos Basin in Colombia are presented to demonstrate how the gas-chromatographic (GC) fingerprints of oils from the well were evaluated using InfoLogic's ReserView™ and OilUnmixer™ programs to successfully delineate the producing reservoir intervals, identify vertical reservoir fluid compartments, as well as estimate and monitor the production allocation of a 2-zone completion over a seven-month period. The reliable results from the unbiased 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 why 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 employed.