For the first time, PDVSA was planned to evaluate Lago Cinco cretaceous formation logs for 9 wells. The Lago Cinco is located in the Maracibo Lake, West of Venezuela. There is no core and additional data included NMR, ECS and MDT data. The available SPE papers related to the Northern Colombia near Venezuela border show these unconventional reservoirs richness in organic matters with production history.

A petrophysical methodology for evaluation of unconventional deposits has to be founded on approaches that sit outside the conventional range of thinking and the wrong petrophysical model produce silly results. The generated petrophysical model was used for old raw log data without calibration with core and TOC analysis data. The high GR values in 9 wells and low thorium from spectral GR in one of the wells confirmed presence of organic carbon at the top of La Luna Formation. Also overlaying deep resistivity curve with sonic and density logs show unconventional hydrocarbon (Kerogen) in the La Luna Formation. The estimated effective porosity varies between 5 to 10 percent and average minimum water saturation is about 10 percent. The La Luna Formation has very low permeability. The calculated lithology from porosity logs (neutron, density, sonic and Pe) show a mudstone and mudstone-wackstone limestone with minor amount of shale at the top of La Luna, high shale volume at the middle and lower parts. The generated variable m from logs in some wells which Rxo curve was available are confirming possibility of some fractures m<2 and vugs m>2. Generally vuggs are isolated m>2.5. The La Luna Formation must be developed with horizontal wells and multi stages hydraulic fracturing technology to let flow hydrocarbon into the wellbore.

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