Abstract: Exploration of the Late Cretaceous and the Oligocene Sequences Underneath the Pirital Allochthonous Block, Northern Monagas Area, Eastern Venezuela Basin

R. Lander, A. Gonzalez, J. Fuentes, J. Daal

The search for prospective formations underneath the Pirital allochthonous block began in the 50th decade, when the Mene Grande Oil Company drilled seven exploratory wells. These penetrated the Pirital allochthonous block, but due to mechanical problems they did not reach the programmed objectives. At that time, the proposed exploratory model suggested a high-angle reverse fault as the base of the allochthonous block, which restricted the prospective section towards the north.

Since 1989, after the drilling of 11 exploratory wells along the El Furrial-El Tejero trend, a new exploratory model is proposed: the base of the Pirital block is a sub-horizontal plane, and the Upper Cretaceous and Oligocene-lower Miocene sediments are extended northward, beneath it.

The SBC-3E well was drilled in order to test the new model. It was completed in December 1989, with a production of 6100 BOPD (35 degree API) and 47 MMCFGD.

A second well, PIC-1E, located 7.5 km northwest of the SBC-3E well, was drilled in order to investigate the quality of the reservoir rocks underneath the Pirital block. This well was completed in April 1992, with a production of 4500 BOPD (36 degree API) and 37 MMCFGD.

The successful results of these two wells drilled north of the Pirital thrust suggest an exploratory area as big as the El Furrial-El Tejero trend, but two geological risks must be taken into account: the allochthonous block's thickness and the depth of the prospective sequences.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994