Sequencing technologies to maximize recovery

The deliberate sequencing of extraction technologies for viscous oil may optimize financial returns. Sequencing is based on an understanding that some technologies improve reservoir transport parameters through phenomena such as shear dilation; fracturing of shales through high pressure injection; thermal consolidation; shear rupture of clay dustings and shale laminae; and the dislodging of pore blocking agents. Cold heavy oil production with sand (CHOPS) increases reservoir permeability, porosity and compressibility, and can alter stress fields and flow paths, which can in turn lead to more effective subsequent thermal or gravity methods of extraction. High pressure thermal extraction processes such as steam flood (SF) and cyclic steam stimulation (CSS) generate reservoir dilation and viscosity reduction which mean that subsequent gravity methods such as VAPEX will achieve increased extraction efficiency. Massive dilation during cyclic injection phases means that recompaction drive mechanisms will improve recovery rates and recovery factors. Successful planning means that the physics and impacts on the reservoir of all commercial technologies must be understood, and initial systems of exploitation should be designed to minimize future well needs. It was concluded that if implemented correctly, the impact of sequencing on technically recoverable reserves estimates in heavy oil will be considerable. Recoverable reserves increases exceeding a trillion barrels are anticipated. 12 refs., 8 figs