ABSTRACT

The whole industry seeks to extend the economic life of existing brown fields, due to the difficulty of discovering new giant assets. The efficiency of mature waterfloods may be drastically improved by means of new technologies in order to recover a significant amount of unswept oil. IOR and EOR processes were investigated to increase oil production in the giant brown field of Belayim Land in Egypt, developed by means of peripheral sea water injection. Current water injection scheme shows not optimal sweep efficiency and moderate recovery factor due to geological heterogeneity and unfavorable mobility ratio.

This work describes the efforts to maximize water injection efficiency by means of the combination of different IOR and EOR techniques with focus on low salinity water LS water benefits were investigated within a comprehensive EOR study. First, tertiary corefloods on porous media were performed, showing an evident EOR effect compared with sea water, in increasing the oil recovery up to 7%. Simulation work to predict the benefits in the field was executed. Core experiments were reproduced using a wettability change model to obtain low salinity water parameters, the salt-dependent relative permeability curves. The process was scaled up to a fine sector model, calibrated on historical production data, representing the area of interest for low salinity water pilot. Simulations of low salinity water injection were run in different forecast scenarios and additional recovery was compared with sea water injection. A sequence of Single Well Chemical Tracer Tests (SWCTTs) was performed to evaluate LS performance at the well scale resolution. Cycles of injection, shut-in and production periods were performed on a selected well to measure the residual oil saturation (Sor) after sea water and LS water. Promising results were achieved for LS, showing a considerable reduction in residual oil, of about 5-11 saturation units compared to sea water. The SWCTTs were used as a powerful tool to achieve a quick EOR response and confirmed low salinity potential. In order to evaluate the global effect of low salinity water injection as EOR process, all the aspects were taken into consideration, decrease in residual oil saturation, permeability reduction, expected sweep efficiency on effective reservoir matrix volume.

The experimental and simulation results were used for an economic feasibility study for a desalination plant in the field to reduce the salinity of current injected sea water.

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