Abstract
The Tena Sandstone, a small horizon belonging to the Tena formation, is presented regionally in the Oriente basin, but has high variability in its productive characteristics, to the point that oil reserves have been recovered from this horizon only in the Blanca-1 well. The information available from the Putumayo, Oriente, and Marañon basins in the upper Cretaceous to Paleogene periods was revised, and a summary table of correlation was performed. Based on the information from the Blanca-1well, and other nearby wells, the stratigraphic features of the Tena Sandstone have been defined. Using 3D seismic data and petrophysical information obtained from wells drilled in the area, the structural and the static models have been elaborated. Considering the production history and the behavior of fluid pressure, material balance was applied in order to estimate the original oil in place. A dynamic model was initialized and a history matching process was performed. Finally production forecasts were made considering three scenarios: a single production well, the drilling of another production well, and the implementation of a small waterflooding project.
The Blanca field is located in the lower part of the main fault Tipishca-Huaico-Blanca. Structurally it is presented as a series of nodes with a stratigraphic component and a soft structural component. The Blanca-1 well has a ten years production history, with an oil production that goes from 600 to190 oil barrels per day. The original oil in place of the Tena Sandstone, estimated by reservoir simulation, is 14.2 million barrels, and primary recovery with one well reaches 1.9 million barrels. With the drilling of an additional production well and the implementation of waterflooding, the recovery would reach 3.7 million barrels. It is considered that this reservoir may be present and be productive in other wells in this area of the Amazon basin.
The information obtained from the Blanca-1 well, and simulation models performed for the Tena Sandstone at the Blanca field, allows to recommend oil operators to investigate the characteristics of small sandy horizons presented in wells that have been already drilled and in other wells to be drilled in the future in the Oriente basin. This will provide a productive alternative in areas where traditional reservoirs have lost their initial production levels.
