To recover heavy oil and bitumen from the highly unconsolidated reservoirs of the Western Canada oilsands fields using the horizontal well method, and in particular the thermal in situ method of Steam Assisted Gravity Drainage (SAGD), some forms of sand control, such as slotted liners and wire-wrapped screens (WWS), are generally required to limit sand production and maintain well productivity. Over the past two decades, a number experimental and analytical studies have been performed for developing industry guidelines and best practices for the structural and hydraulic design and evaluation of sand control liners under the challenging conditions of SAGD steam injection and production wells. The vast majority of SAGD applications, estimated at about 90% (RPS 2009), employ slotted liners as the sand control method. Design efforts to address the structural and serviceability requirements, however, often oppose one other, presenting significant challenges to the design of slotted liners. For example, in order to maintain sufficient torque, collapse and strain-absorbing capacities, traditional slotted liners are often designed to have low Open Flow Areas (OFA) around 1%, although a larger OFA is desired for production efficiency.
This paper reviews current design requirements for SAGD wells, as well as puts forward a new slotted liner design consideration for the optimized performance under installation and operational loads. Using Finite Element Analysis (FEA) modeling, the effect of key design parameters, such as slot length and slot pattern, are studied. This paper focuses on the feasibility study of achieving higher OFA than the currently-used limit, while maintaining sufficient torque, collapse and strain-absorbing capacities under thermal well load conditions.