Improved Reservoir Characterization with Lower Risk and Higher Efficiency Using a New Wireline Formation Tester Module in a Giant UAE Offshore Field

摘要

One of the giant mature carbonate offshore field with multilayer hydrocarbon reservoirs in Abu Dhabi, United Arab Emirates is undergoing further development in its deeper, heterogeneous and more structurally complex carbonate sub-zones. The reservoirs in this field have a range of low to high permeabilities, several oil-water contacts and relatively big transition zones. There has been extensive water and gas injection operations in this field, which changed the fluid saturations with varying amounts in some of the zones. The main challenges in the current development wells are to have an extensive data gathering program to recover representative fluid samples, to identify altered fluid saturations and contacts and decide on the optimum completion intervals of the work-over and/or new wells. One of the most important requirement at offshore fields obtaining pressure measurements and samples efficiently with minimum risk while maintaining the quality at the highest level due to offshore operational risk. Historically, a large number of formation testing and sampling operations with wireline formation tester (WFT) tools were conducted in this field using straddle dual-packer and single-probe type inlets. A recently introduced new inlet module shows a significant improvement in risk minimization and increased operational efficiency over the dual-packer and single-probe inlets by reducing the sampling durations while maintaining high quality fluid sample recovery even in low mobility formations. High efficiency and low risk operations offered by the new WFT inlet has enabled the operator to include extensive formation testing and sampling operations in their drilling programs that resulted in better reservoir characterization especially in the deeper, undeveloped and less developed carbonate sub-layers even in difficult borehole conditions where the data gathering program was difficult to tackle. This paper demonstrates the benefits of the new WFT module, which achieves operational efficiency and obtains quality PVT samples and accurate downhole data for the reservoir characterization. In addition, this paper shows the differences between the new WFT inlet and the previous WFT inlets, such as the dual packer and the single probes.