Abstract

Steam Assisted Gravity Drainage process has been done and successfully implemented for the producing of the Canadian heavy oils and bitumen. Although it is commercially proven, but it still uses high energy intensity and has high environmental impact. To reduce those side effects, hybrid steam-solvent is proposed as one of the alternative processes in order to reduce the problems.

There are some challenges in reservoir heterogeneity correlated with steam-solvent injection. In conventional process, spreading of steam-solvent is able to be controlled using bottom-hole pressure injection and liquid production rate. In heterogeneous reservoirs however, each part of the horizontal well will have different optimum operation conditions.

This paper presents a strategy for hybrid steam-solvent optimization using ICVs (interval control valves) to maximize energy efficiency. To provide an overview of this phenomenon, the synthetic reservoir model is built from McMurray Formation. Bitumen saturation distribution and rock properties are created using geostatistic method and validated using several wells. The reservoir models were run using several operating conditions to achieve the most realistic interpretation. Sensitive variables are steam injection pressure, length grouping of perforations, managing of perforation openings, and solvent concentration. Afterwards, steam efficiency and solvent affectivities are evaluated during 15 years of project life.

Simulation results show that the managing of steam injection will increase heat efficiency up to 7.4% compared with conventional perforations. Furthermore, in the hybrid steam-solvent injection, the recovery factor will be better 8% compared to without adjustment in solvent concentration of 10% volume. Finally, retention of solvent injection can also reduce until 30% by this managing of processes.

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