Publications

Produced water always accompanies production from oil/gas wells as an unwanted by-product, various methods have been employed to control water production, one of them being what is known as Relative Permeability Modifier (RPM). The objective of this technique is to create water oil separation in reservoirs and to prevent water flow, without adversely affecting oil production. This paper describes a successful polymer RPM pilot trial to stimulate Bekasap Formation, where characteristic high porosity, high permeability sand presents a challenge. A candidacy process base on the remaining reserve, well integrity and relatively attic location overlaid with geological data are factors which come into play. Non singlehomogeneous and continuous sand with steeply declining production is the main consideration. This paper includes the pre-job design, detailed execution, technique of placement, challenges encountered during execution and limitations of this technology. To evaluate stimulation results and as reservoir surveillance, a time lapse pressure transient testing and step rate test was also executed, to address any anomaly or change in reservoir characteristics. First data (set before stimulation as a baseline) and second, third and fourth acquisitions served to verify divergence in reservoir character, especially permeability and observed shifting on near well bore parameters. This pilot project yielded very interesting results, with reduced water flow at 47% and incremental oil gain at 48%. Additional recovery is 10.7 MBO, with total reduced water of 120 MBW and predicted additional reserves at 22 MBO from baseline, over six months of production. Following stimulation, declining production could be improved, from 10.3% to 7.1% decline rate. The limitation we face is to justify a realistic expectation of RPM treatment, to monetize its benefits (not only with more oil recovery but also with less water produced) signifying an extension of the wells lifetime. Basically, this signifies incremental oil recovered from improved water-oil fractional flow and additional drawdown created in the bore hole. Above all, this method has succeeded in arresting a decline in production.