The purpose of this paper is to review the status of a 13 well pilot program to utilize cyclic steam stimulation as a commercially applicable process for the Athabasca Oil Sands deposits in Alberta, Canada.

In the Athabasca deposit, bitumen bearing sands are contained in the lower Cretaceous McMurray formation, which is a clastic sequence deposited in a predominantly fluvial environment. The reservoir consists of a series of stacked channel sands. These sand bodies can be divided into distinct units based on stratigraphy and ichnology. These channel sands vary both laterally and vertically and correlation of individual sands is quite difficult. The bitumen is very viscous 1,000,000 cp (1000 Pa.s) at original reservoir temperature with an API gravity of 8. The effective permeability of the reservoir at original conditions is very low because of high bitumen viscosity and low connate water mobility. Therefore, to inject steam at commercial rates, artificial fractures are induced.

Prior to the 13 well Pilot, Three Single Well Tests (SWT) were conducted in the nearby area, between 1985 and 1990. During this period operating problems related to completion, sand handling, fluid production have been overcome and considerable progress was made towards optimizing operating strategies such as fracture configuration and cycle steam slug sizes using the field data and a thermal simulator.

In view of the encouraging performance of the single well tests and simulation results construction of a thirteen well pilot started in 1989.

To date, 9 wells have completed 2 cycles and one well in the center of the pilot 3 cycles of cyclic steam operation.

The results of these ten injector/producer wells will be summarized together with five observation wells and alternate strategies to improve the performance will be discussed.

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