Oil & Gas Saturation of Upper Cretaceous Sediments in Southern Part of Orinoco Heavy Oil Belt (OHOB)

Bochkarev, Vitaly A.¹, Eurídice J. Solórzano Sanchez², Alexander I. Grigorev³, Raul Gataulin¹ (1) N/A, Caracas, Venezuela (2) PDVSA Intevep, Caracas, Venezuela (3) N/A, Caracas, Venezuela

The oil deposits in the Oligocene (Merecure Formation) and lower Miocene (Oficina Formation) of the OHOB have been formed by processes of remote migration (several hundreds kilometers) of hydrocarbons from upper cretaceous oil source rock contained in Querecual and San-Antonio Formations and to lesser extent the subject migration processes was facilitated by the Lower Miocene Oficina Formation as well.

Oil-and-gas content in Cretaceous sediments for this area have been confirmed by log but it hasnxt been confirmed by tests and core analyses. According to log interpretation of Junín block, we have detected oil content of Upper Cretaceous sediments of the southern part of the block (wells # IZZ0034, IZZ0036, IZZ0091). According to 2D seismic interpretation, the general tendency of increasing of Upper Cretaceous and Oligocene-Miocene thicknesses from the south to the north are observed. In the northern part of the block the Cretaceous Unconformity was detected by biostratigraphics studies, in the southern part of the block the Cretaceous is eroded and in the middle part was estimated by correlation.

Considering а huge area of Upper Cretaceous sediments extension in the southern part of the block it is possible to estimate their oil resources as hundreds millions barrels. For confirmation oil saturation and resources estimations of Upper Cretaceous sandstones in the southern part of OHOB it is necessary to select core and to make tests of these sediments in new wells.