Practical aspects of commingled IOR operations

Decisions to implement commingled improved oil recovery (IOR) techniques are informed by a variety of economic and technical considerations. Many reservoirs have dissimilar qualities and extents of oil saturation depletion and pressurization, which can lead to different resistance levels in IOR operations. This paper presented an outline of critical screening considerations in the implementation of IOR. Issues concerning hydraulic continuity, infilling, solvent washing and lift optimization were examined. Controlled fracturing and the compatibility of different fluids and potential interactions with reservoir rocks were discussed. Various stages in the planning of commingled projects were reviewed. It was noted that IOR and enhanced oil recovery (EOR) in commingled operations can be infeasible if all the participating intervals are not compatible in terms of fluids, production mechanisms, controls, pressures and injectivity. Prospects for commingled IOR are further diminished when options for well interventions or data for individual zones are limited, as well as if the indicated injection pressure exceeds fracture pressure of any of the target reservoirs. It was concluded that successful commingled IOR and enhanced oil recovery (EOR) practices require a thorough understanding of reservoir architecture, fluid and pressure distributions as well as clear insights into the reservoir mechanisms involved. 9 refs., 5 figs