SAGD Circulation Phase: Thermal Efficiency Evaluation of Five Wellbore Completion Designs in Lloydminster Reservoir

摘要

The main objective during the circulation phase (start-up) of Steam Assisted Gravity Drainage (SAGD) is to lower the heavy oil or bitumen viscosity, to create inter-well fluid communication between the injector and producer well and to uniformly warm-up the lateral section of the well pair to achieve uniform steam chamber growth during the life of the SAGD well pair. Typically, the circulation phase (start-up) lasts between three and six months and it is completed when the temperature between the producer and injector is high enough, generally greater than 80°C. It has been proven that during the circulation phase (start-up) of a SAGD well pair, the variations in thermal efficiency result from factors such as tubing size, well trajectory, well length, completion configuration, reservoir properties, and operating parameters.