Reservoir Modeling for Horizontal-Well Exploitation of a Giant Heavy-Oil Field

Abstract

Summary The Hamaca field, located in Venezuela's Orinoco heavy-oil belt, is a giant extra heavy-oil accumulation operated by Ameriven, an operating agent company for PDVSA, ConocoPhillips, and ChevronTexaco. Over the 35-year life of the field, more than 1,000 horizontal laterals are planned to deliver 190,000 BOPD to a heavy-oil upgrader facility. Reservoir models are built to support a broad continuum of activities to meet this objective. This paper will review the Hamaca reservoir-modeling process, the challenge of integrating many sources of geologic and geophysical constraints (including horizontal-well information), the focus on continuous model improvement, and issues unique to Hamaca rock and fluid properties. We will show that efficiently evolving a very large geocellular model in an active project like Hamaca can be accomplished through the use of object-oriented process automation. In addition, the paper will illustrate that careful consideration should be paid to issues related to horizontal-well sampling bias and positional uncertainty before constraining a geocellular model with horizontal-well data. The paper will discuss the multiple sophisticated modeling techniques that were used to address the objectives of the Hamaca modeling program.