Francesca Verga, Politecnico diTorinoThis issue of SPE Res Eval & Eng brings readers eight papers that reflect areas of current activity and interest within the industry. The first paperfocuses on rock-fluid properties. The following four papers dwell on the always open-for-debate improved oil recovery (IOR)/enhanced oil recovery (EOR) topic. Next, readers will find two papers dealing with heterogeneous reservoirs. And,the final paper tackles the still hot topic of unconventional reservoirs.
Rock-Fluid PropertiesIn the opening paper, entitled Factors That Affect Gas-Condensate Relative Permeability, authors measured relative permeability on reservoir rock at different conditions to determine the sensitivity to interfacial tension and fluid type. One of their main conclusions is that laboratory tests should usereservoir fluids to obtain data that are applicable to a specific reservoir,whereas results from alternative fluid pairs might be misleading.
Improved and Enhanced Oil RecoveryThe first paper in the IOR/EOR section, Polymer-Flooding-Pilot Learning Curve: Five-Plus Years’ Experience To Reduce Cost per Incremental Barrel of Oil, describes the learning curve rather than the reservoir response to polymer flooding; in order to ponder the possibility of extending the project to other areas of the oil field under consideration.Authors of the subsequent paper, OptimalApplication Conditions for Steam/Solvent Coinjection, provide someguidelines for selecting an optimum solvent and its concentration incoinjection of a single-component solvent with steam. Their results showed thatcontrolling the concentration of a given coinjection solvent can maximize oilrecovery and minimize solvent retention in situ. The next study, Pore-Scale Investigation of Phase Distribution and Residual-Oil Development During Secondary and Tertiary Solvent Injection,revolves around microscale-experimental investigations on flow process andprovides a parametric analysis on the microscopic displacement efficiency ofoil recovery using miscible solvents. Authors employed micromodels created byuse of a replica of sandstones. Experiment results showed that injection ofsolvent before the introduction of any water to the reservoir can increase therecovery factor. Closing the IOR/EOR section is a paper, Optimizing Well Trajectories in Steam-Assisted-Gravity-Drainage Reservoir Development, in which an approximate physics simulator is applied to optimize well trajectory (of both producer and injector locations). Authors used two methods to accomplish this: the undulate trajectory and the double spline.
Heterogeneous ReservoirsAuthors of the paper Closed-Loop Feedback Control in Intelligent Wells: Application to a Heterogeneous,Thin Oil-Rim Reservoir in the North Sea evaluated the benefit of using closed-loop control strategies on the basis of direct feedback between reservoir monitoring and inflow-valve settings, within a geologically heterogeneous, thin oil-rim reservoir. Authors compared an open-loop control strategy against a closed-loop one. They found that the latter yields positive gains in net present value for the majority of reservoir behaviors investigated, and higher gains than the open-loop strategy. The second paper in this section, Diagenetic Geobodies: Fracture-Controlled Burial Dolomite in OutcropsFrom Northern Oman, presents an overview of the learning outcomes gained bystudying fracture-related dolomite in outcrops of Oman and subsequentlaboratory analyses. Authors highlight the need to understand timing and structural setting of dolomite bodies in the subsurface to improve reservoir management.
Co-Executive Editorof SPE Res Eval & Eng