Shrouded ESPs to Abate Non-Condensable Gas Interference in SAGD Wells - Successful Surmont Implementation

Non-condensable gas (NCG) is co-injected along with steam to help reallocate steam to new pads, decrease steam oil ratio (SOR) in late life wells and improve overall field economics. Some of the injected gas is produced back, leading to gas interference in pumps, reduced lifting efficiency and lower production rates. NCG is a widely used pressure compensation process in Steam-Assisted Gravity Drainage (SAGD), typically performed during late life. While it can be economically successful, unintended NCG returns lead to pump gas interference that can reduce total production capability by 40% to 50%. This paper presents a large-scale field evaluation of shrouded ESP systems to prevent NCG gas slugs from entering the ESP and reducing lifting efficiency. Specially designed "canned" ESP systems and "inverted shrouds" for SAGD conditions were installed in over 35 wells impacted by gas interference along with measurable hindered well performance. Results with both canned ESPs and inverted shroud designs were successful in restoring lifting efficiency and liquid production in most wells. Most canned systems showed shorter runtimes (due to motor overheating) while inverted shrouds showed a tendency to plug with solids which is addressed through shroud design changes, appropriate wellbore cleaning and installation procedures.