SAGD Startup: Leaving the Heat in the Reservoir

Abstract

Abstract Successfully starting up Steam Assisted Gravity Drainage (SAGD) well pairs is crucial in achieving good wellbore temperature conformance and rapid production ramp-up. Performing a SAGD startup effectively and economically is a significant challenge in the industry and reservoirs with mobile water offer an opportunity to optimize and accelerate this process. A traditional SAGD startup involves steam circulation, where steam is injected into a well down the long tubing string to the toe and fluids are produced back to surface at the heel. Steam circulates across the full horizontal length of the well and conductively heats the near reservoir. In reservoirs with mobile water, there can be fluid losses to the reservoir during circulation, allowing for convective heating of the reservoir. In a bullheading startup, return fluids are not produced and all injected steam is forced to leak off into the reservoir. By avoiding fluid returns, bullheading offers significant advantages over circulation in terms of thermal efficiency, steam demand, operational simplicity and facility requirements. This paper examines the effectiveness of a bullheading startup compared to a circulation startup through a simulation study and field trials at Suncor Energy Inc’s Firebag in-situ project.