Cesar PATINO, Maria del Pilar Martin TRUJILLO, Hans MORALES; ECOPETROL
Dariusz STRAPOC, Ulises BUSTOS, Oliver MULLINS; SLB
Elkin COLORADO, Dora PIEDRAHITA, EXPRO
In a Colombia field, an interesting system of Paleozoic basement overlain by potential H2-trapping reservoir has been identified below the petroleum targets. As drilling continued, H2 was found on a mud logging mass spectrometer; however, at greater depths, the drilling conditions became harsh, and the risk of degrading the oil-based mud increased, causing generation of artificial H2. A detailed study allowed for differentiating those intervals with significant fractions of natural occurring H2. This condition in combination with nuclear magnetic resonance and resistivity measurements served as a base for downhole sampling decisions. A sophisticated strategy of sampling was designed by the service company personnel and the operator. In the first ever operation of its type, H2reservoir sampling was successfully completed at reservoir pressure. Despite different levels of drilling mud contamination, samples of mud only at the same depths were obtained to correct for any residual drilling derived H2present in the mud. During transfer of fluid to transportation bottles at pressures above reservoir pressure, an H2 indication was observed, confirming the successful operation. Detailed analyses of the fluid are currently underway, and the results will be hopefully available to present at the conference in late November.