Field Results for Recovering Oil From a Steam-Project Pressure-Isolation Wall

Abstract

Summary The Lloydminster, Saskatchewan, area Pikes Peak steam project has been onproduction since 1982. A key part of the development strategy was use of anundeveloped pressure-isolation wall to allow the two halves of the pool to bedeveloped with different time schedules and exploitation processes. Use of thepressure-isolation wall allowed different exploitation options to be used, butduring late project life the oil left in the wall needed to be recovered toenhance project economics. A significant challenge in recovering the oil in thewall was the lack of pressure containment or oil saturation on both flanks,resulting in the need for a gentle recovery process to avoid pushing the oiloutside the wall. On the basis of numerical-simulation results, the recoveryprocess selected for the wall was use of two cyclic-steam-stimulation (CSS)horizontal wells operated in a gentle manner. After the horizontal wells weredrilled, however, temperature logs showed the reservoir surrounding one of thehorizontal wells had already been heated by offsetting steam injection, andthat well has been continually produced at good rates without the need forsteam stimulation. The second new horizontal wall well was initially operatedsuccessfully using the CSS process designed using numerical simulation, butthat well is now also being operated in an external drive mode. The results ofthis field study show that the oil in a wall used to pressure isolate sectionsof a steam-project pool can be recovered economically without pushing the oilinto the adjacent depleted areas by use of processes designed to account forlocal wall conditions.