The Perla World-Class Giant Gas Field, Gulf of Venezuela: An Overview on a Successful Case History in a Virtually Unexplored Basin

Fioretta, Alberto ¹; Schiroli, Antonio ¹; Barletta, Vincenzo ¹
(1)ESAM, ENI E&P Division, San Donato Mi. (MI), Italy.

The Perla gas field was discovered in late 2009. It is operated by the Cardon-IV consortium which runs the exploration activities in the homonymous block, equally participated by Eni and Repsol.

The field is located in the shallow water of the eastern part of Gulf of Venezuela (GoV), 30 km west to the Paraguanà Peninsula. The prompt and successful appraisal drilling campaign, with four wells spudded in less than one year, conclusively confirmed its world-class giant rank.

The block was awarded in early 2006 as outcome of the 2005 International Bid Round. Until 2005 the Gulf of Venezuela offshore represented an area virtually devoid of any significant hydrocarbon exploration drilling activity, being the shallow-TD Lamparosa-1X dry hole the sole borehole drilled in the 20,000 km² GoV waters.

In the GoV mportant dextral stike-slip movements were active since the Latest Cretaceous and the complex geodynamic history played a fundamental role in the final setting of different hydrocarbon-prone domains in the GoV offshore. At the Paleo-Neogene boundary the presence of deeply-rooted structural reliefs created favourable conditions for the development of shallow-water carbonate depositional systems, with good to excellent primary reservoir properties.

The exploration/appraisal wells result shows that the Perla reservoir system consists of a calcareous carbonate of Early Miocene age, reaching 300 m in thickness. The Perla carbonate system displays an overall transgressive vertical facies stacking pattern, and consists of three main units, a thinner basal one compensating the morphology of the uplifted substratum, a thickest middle unit showing an excellent lateral continuity in the well record over 5 km, and an upper and more variable unit testifying an abrupt deepening of depositional conditions.

The diagenetic overprinting is vertically selective and rules the ultimate reservoir production behaviour, which is excellent over most of the vertical section, with average porosity around 20%.

The best well flowed 68 million scf/d of gas and 1,350 bpd of condensates.

Geochemical analyses indicate that most of the gas was of thermogenic origin and was probably sourced by Early Tertiary rocks.

The trap shows a strong structural print, but a clear stratigraphic component is locally recognizable. The proved hydrocarbon column exceeds 350 m, in complete hydraulic continuity, and the proved closed surface is larger than 100 km². The trap houses OHIP in excess to 2000 MBOE.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.