Field Results for Recovering Oil from A Steam Project Pressure Isolation Wall

摘要

The Lloydminster Saskatchewan area Pikes Peak steam project has been on production since 1982. A key part of the development strategy was use of an undeveloped pressure isolation wall to allow the two halves of the pool to be developed using different time schedules and exploitation processes. Use of the pressure isolation wall allowed different exploitation options to be used, but during late project life the oil left in the wall needed to be recovered to enhance project economics. A significant challenge to recovery of the oil in the wall was the lack of pressure containment or oil saturation on both flanks, resulting in the need for a very gentle recovery process to avoid pushing the oil outside the wall. On the basis of numerical simulation results the recovery process selected for the wall was use of two CSS horizontal wells operated in a gentle manner. After the horizontal wells were drilled, however, temperature logs showed the reservoir surrounding one of the horizontal wells had already been heated by offsetting steam injection, and that well has been continually produced at good rates without the need for steam stimulation. The second new horizontal wall well has been successfully operated using the CSS process designed using numerical simulation. The results of this field study show that the oil in a wall used to pressure isolate sections of a steam project pool can be economically recovered without pushing the oil into the adjacent depleted areas by use of processes designed to account for local wall conditions.