SHALLOW RESERVOIRS AND THE “GAS-EFFECT”, TINTA 3 WELL, AN OLIGOCENE AND EOCENE CASE IN BURGOS BASIN, MEXICO

摘要

This paper shows the shallowest gas reservoirs in the Burgos Basin. These kind of reservoirs have thicknesses from 3 up to 16 meters, and are located in Eocene and Oligocene siliciclastic sediments, in Jackson, Frio Marino and No Marino, having excellent permeability (1.6 to 825 mD) and porosity (18 to 34%). The NPHI and DPHI curves of the lithodensity (LDL) and compensated neutron (CNL), show an overcrossing called “gas effect” in producing sands. The relevance on these reservoirs penetrated for the Tinta 3 well is the depth: 125, 170, 205, 239, 283, 305, 336 and 645 meters. The description of “gas effect”, rock quality index and mineralogy, based upon sidewall cores, cross-plots, petrography images and scanner electronic microscope (SEM). The gas rates for these sands varied from 0.3 to 1.67 mmcfd with pressures ranges between 400 to 900 psi.