Well Life Increased by a Projected 2 Years
Published: 01/01/2008
Well Life Increased by a Projected 2 Years
Published: 01/01/2008
High gas/oil ratio causes ESP shutdowns and unstable production
Profound Energy, Inc., of Calgary completed a well using a conventional electric submersible pump (ESP) with a gas separator. In a 2-month period, the ESP system experienced a number of shutdowns caused by high free gas content. ESP ingestion of free gas causes gas pockets to form on the low-pressure side of the impeller. The gas bubble continues to grow until it prevents the passage of fluid—a phenomenon called gas locking. When gas locking occurs, the ESP will shut down owing to the reduced load on the motor. However, sometimes the current drop is not sufficient to trip the motor controller shutdown. With the Profound Energy well, the ESP was replaced twice solely because of gas-locking problems. The operator asked Schlumberger to recommend a product that would impede gas lock and lengthen ESP run life.
Poseidon technology remedies production and ESP issues
Schlumberger experts analyzed data from the well and found that the ESP was not maintaining a balanced mixture between gas and liquid. The engineers recommended installation of a high-capacity gas handling device, the Poseidon multiphase helicoaxial pump, between the intake and the pump to homogenize the fluid and charge the ESP. The Poseidon pump is capable of handling up to 75% free gas, enabling the ESP to pump the mixture. This installation increased the pressure in the produced fluid to reduce the gas volume and significantly decreased the possibility of gas lock by priming the main production pump and pushing the gas/liquid mixture through the production pump stages. In addition, the espWatcher surveillance and control system was installed to monitor the well, alert the owner to possible problems, and allow operational adjustments remotely.
Oil production and ESP run life increases
The Poseidon technology not only enabled the operator to produce oil with a free gas content of 75%—increased from 20%—but because of its hydraulic design, the pump also stabilized the ESP system operation and eliminated pump shutdowns caused by gas locking. This substantially improved the ESP system run life.
Because the initial material balance calculations indicated that the well would be depleted in 4 months, Profound Energy, Inc., had decided to rent the ESP equipment. However, after 2 months of using the Poseidon gas handling pump, no further operational issues occurred. The operator opted to purchase the equipment based on the combination of extended ESP life and improved well performance. The operator now believes the well will produce for another 2 years.
Challenge: Eliminate or decrease the number of well shutdowns and prolong ESP life.
Solution: Installed the Poseidon gas handling pump to avoid gas lock.
Results: Boosted well-life estimates by 2 years, increased production of oil threefold and free gas handling capability by 55%, prevented ESP shutdowns caused by gas locking, eliminated the need for ESP replacements, and stabilized production.
