Orinoco Belt, Cerro Negro Area: Horizontal Well Evaluation

摘要

The horizontal drilling activity in Venezuela started in 1989 with two (2) wells, CI-87 and CI-97, which were completed in the Orinoco Belt, one of the largest bitumen reservoir in the world. The objective was to find the best exploitation scheme and alternatives to increase the recovery factor. Reservoir criteria to select the position of these wells was focused on the petrophysical and reservoir characteristics like sand quality, porosity, permeability, net bitumen sand, pressure and water-bitumen contact depth. Actually there are eight (8) horizontal wells drilled with 8 1/2 inch diameter production hole and completed open hole with 7 inch slotted liner (0.020-0.030 inch slot size) in a horizontal length between, 1,000-2,722 feet. The artificial lift systems used on these wells are rod pumping and electric submersible pumps, with initial production rates between 800-2,000 BPD and productivity indexes in the range of 2.0-6.0 BPD/PSI. The objective of these paper is to show the preliminary production results obtained with horizontal wells compared to traditional wells (vertical, deviated and slant), as the first step to look for a better exploitation scheme for the development of the total remaining reserves. Considering drilling and operating cost reduction and reservoir recovery factor improvement.