RIASSUNTO
Abstract
An integrated study was carried out on the region of Bolivia called the Boomerang Hills. The purpose was to determine the oil and gas reserves and to design an integrated system which could produce the oil and gas. One goal of the design was to provide gas produce the oil and gas. One goal of the design was to provide gas sufficient to meet the requirements of the contract between Brazil and Bolivia for delivery of gas.
The study integrated the disciplines of geophysics, geology, petrophysics, reservoir engineering, production engineering, and petrophysics, reservoir engineering, production engineering, and surface facilities design. Black oil simulation models were built, history matched, and used for predictions of four oil fields. A compositional model was built of one representative gas predicted using traditional volumetric methods. The results of the predicted using traditional volumetric methods. The results of the study showed a total oil and condensate in place of 295 million barrels and a total gas in place of more than 1.8 TCF. The recoverable oil was estimated at 38 million barrels and the recoverable gas was estimated at 1.4 TCF.
Introduction
Yacimientos Petroliferos Fiscales Bolivianos has discovered a series of new fields in the area north of Santa Cruz known as the Boomerang Hills (Figure 1). These new fields are currently under development for potential production of liquid and gas hydrocarbon reserves. Plans are currently underway to develop the fields and to sell a certain amount of the gas to Brazil. Because the fields occur near one another, integrated development is practical. Six fields were included in the analysis: Yapacani, Sirari, Humberto Suarez Roca, Vibora, Cascabel, and Boqueron.
GEOLOGY
Structural Geology
The Boomerang Hills area is situated in the morpho-structural area of Bolivia known as the ""Pie de Monte Andino,"" or Andean Foothills. Topographically this is a zone of generally low relief; the area exhibits various types of fold structures that lie parallel or sub-parallel to the general tectonic grain of the region. In the case of the Boomerang Hills area, the trends are nearly due east-west. Folds in the study area range from rather symmetrical gentle anticlines, such as Sirari, to complexly faulted and thrusted structures, such as Humberto Suarez Roca culmination along the Santa Rosa trend. Horizontal displacement along the tectonic front is considered to be modest, probably no more than a few kilometers in rare instances. Compressional forces from at least three major orogenic periods, the last of which may still be in progress, have thus created a complex frontal folded/faulted zone that has formed the present traps for hydrocarbons in the Boomerang Hills area.
Local Geology
A number of zones in each field were correlated, studied, and mapped. The stratigraphic column which is characteristic of the entire area is shown in Figure 2. In general the Pataca Zone, Yantata Zone, Ichoa Zone, and Robore Zone may contain gas or gas condensate. The Sari Zone contains oil, usually with a gas cap.
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