A Comprehensive Scheme for Application of Low Salinity Waterflooding Technique in Mature Fields

Abstract

The main seek for the whole oil industry is to find a way to prolong the economic life of the existing mature fields, as a result of the difficulty of finding new big assets. The waterflooding efficiency can be dramatically enhanced by the application of new technologies with the target of sweeping higher amounts of unswept oil. IOR/EOR methods are investigated to improve the oil production from the giant Belayim Onshore mature field located in Gulf of Suez, Egypt. The field was previously developed by using sea water peripheral injection. The existing water injection strategy is found not be the optimum strategy to increase the sweep efficiency and the recovery factor as a result of the huge lateral heterogeneity and different mobility ratio. This paper describes the work done to improve the efficiency of water injection by the application of different IOR/EOR technologies specifically Low Salinity water. First, Coreflooding experiments on porous medium have been performed in the tertiary mood to detect the effect of IOR compared to the sea water injection. It was found that LS can increase oil recovery nearly to 7% more. After finishing the lab phase, simulation runs have been performed to predict the enhancement on field scale. The coreflooding experiments have been simulated using a wettability alteration model to determine the LS parameters and the new relative permeability curves. These parameter were the input into a sector model of fine gridding. The model was history matched using the wells production and injection data for the LS pilot area under study. Different forecast scenarios have been run and the incremental increase in oil recovery was reported against the current water injection scheme A number of Single Well Tracer Tests have been performed to detect the effect of Low Salinity water flooding on well scale. The test was designed to incorporate a number of injection, production and shut in cycles in the pilot well with the aim determining the residual oil saturation with the current scheme of sea water injection and after switching into low salinity water. It was found that Low salinity water has achieved very promising results that produced a remarkable reduction in Sor at the range of (5-11) saturation units. In order to estimate the full-field effect of the LS waterflooding as a promising EOR method, all the major aspects have been taken into account including the expected reduction in residual oil saturation, permeability alteration as a result of possible fine migration or clay swell and the possible change in the sweeping efficiency. Finally, all the produced results from the experimental and simulation work have been incorporated into an economic study to determine the feasibility of constructing a desalination plant for the full-field application phase