A Comparative Simulation Study of Chemical EOR Methods Applied to the Norne E-Segment Using Eclipse 100
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Secondary recovery techniques such as waterflooding are often used to maintain pressure during depletion. Still, unfavorable mobility ratios, reservoir heterogeneity and strong capillary forces may cause a waterflood alone to only recover 20-40% of the oil in place. This thesis is a comparative study of chemical EOR methods such as surfactant flooding, polymer flooding and surfactant-polymer flooding applied on the Norne E-Segment, using Eclipse 100. The objective of this study is to find out if the Norne E-Segment is a good candidate for these EOR methods. The study will focus on testing different injection scenarios and polymer/surfactant concentrations to find the best solution in terms of net present values (NPVs). A test case simulation on a synthetic reservoir indicated that the combined increased water viscosity from the polymers and the decreased interfacial tension from the surfactants gave the highest incremental oil recovery. This was also the case in the Norne E-Segment, where continuous polymer injection for 16 years together with surfactant slugs at 6 month intervals for 3 years gave an incremental oil recovery of 9.9 million barrels and a NPV of 753.2 million USD. The concentration used in this surfactant-polymer flood was 1 kg/m3 for the surfactants as well as the polymers. The Norne E-Segment is a good candidate for chemical EOR methods. Best out of the different EOR methods was surfactant-polymer flooding which gave an estimated recovery factor of 0.68. The success of a surfactant-polymer flooding project in the Norne E-Segment is dependent on the operational costs being lower than the NPV of 753.2 million, as operational costs were excluded from the NPV calculations. It is also dependent on the input values from the polymer and surfactant keywords used in the simulations to be compatible with the reservoir and fluid properties of the Norne E-segment.