Bitumen production from the Grosmont formation is enabled by bitumen-viscosity reduction caused by heating with steam, and is driven by three processes: thermal expansion, gravity drainage, and spontaneous imbibition. Gravity drainage is the dominant recovery mechanism. Maintaining a balance of injected and produced fluid is indicative of good performance. The projected steam/oil ratio (SOR) for the carbonate Grosmont formation is comparable to that of the clastic Clearwater formation; the impact of lower porosity is compensated by lower water saturation.On the basis of the experience from the pilot project, a followup development of the Grosmont formation relies on cyclic operation of injection and production. Saleski Phase 1, approved by the Alberta Energy Regulator, is designed for 1700-m 3 /d oil capacity from the Grosmont formation. For the first time, probable undeveloped reserves have been assigned to a fractured-carbonate bitumen reservoir. The cyclic-to-continuous steam-assisted-gravity-drainage drainage (C2C-SAGD) concept, where initial cyclic operation of individual wells is converted into continuous injection and production with well pairs as the reservoir depletion matures, intends to maximize recovery in future exploitation projects.Spontaneous Imbibition. In general, fractured carbonate reservoirs are initially oil-wet (Al-Hadhrami and Blunt 2001). Specific to the Saleski Grosmont, laboratory experiments are currently being executed to confirm the wettability. Assuming bitumen is the wetting phase (Fig. 2, left), capillary pressure in the matrix is low at high bitumen saturations. Fluid movements into or from

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SAGD (Steam Assisted Gravity Drainage) thermal production of heavy oil in the area surrounding Lloydminster involves the injection of steam and subsequent pressurization of the reservoir. As fluid enters the horizontal producer, the pressure drop results in the deposition of calcium carbonate scale. Scale deposition eventually begins to have a detrimental effect on fluid inflow into the wellbore. In addition to the calcium carbonate scale, the high ashphaltene content of the oil results in a hydrocarbon coating being deposited on the scale. Many options exist to remove the scale/ashphaltene deposit and return the well to prior oil production rates. This paper will review the mechanism believed to cause scale deposition, available chemical and mechanical methods to remove the scale and Husky’s recent successes from treatment of SAGD wells in a sandstone reservoir in the Lloydminster heavy oil area.

Type curves that are developed for bitumen recovery from the Grosmont carbonate reservoir by cyclic operation of steam injection and production through a single horizontal well, consistently match field data, thereby confirming the validity of two key simplifying assumptions:1. heat flow is conductive; the heat capacity of the rock dominates: This is consistent with the low porosity and high heat capacity of dolomite. As a result, heat retention in the reservoir is efficient. 2. gravity drainage dominates the recovery mechanisms: Thermal Assisted Gas-Oil Gravity Drainage (TA-GOGD) is the dominant recovery mechanism.The type curve method is used to evaluate unrestricted reservoir performance by quantifying operational constraints and to forecast new cycles in the pilot operations.