The operator of this Christina Lake SAGD producer well confirmed a liner failure. The instrumentation string needed to be pulled to run in with an inflow control device (ICD) and prepare for the repair. A service rig was on site, but they were unable to circulate with jointed pipe or by bailing. The operator called in Quantum Downhole. Quantum advised a JetVak™ cleanout.
Quantum’s JetVak is a patented system that simultaneously vacuums away fluidized wellbore materials, with guaranteed circulation, while gathering continuous inflow data. The JetVak is a concentric coiled tubing assembly that includes an engineered jet pump and jetting head. The rotating jetting head is speed governed to maximize energy to the jetting force. A recorder installed in the BHA logs downhole BHP and BHT during the operation while a Quantum technician at surface gathers oil, water and solids cuts for reporting.
In a cleanout intended to prepare for liner repair in a SAGD producer, the operation needs to accommodate for the viscosity of bitumen and the risk of solids inflow during the operation. Quantum’s chemical injection program is carefully selected to suit the downhole environment and then optimized during the operation to limit chemical usage and enhance effectiveness. Quantum’s technical program specifies that the JetVak lifting rate be higher than the fluid jetting rate to keep the operation underbalanced. This is particularly important to maintain positive pressure on the failure region with make-up fluid to mitigate the potential for solids inflow. The jetting rate is regulated during the operation to ensure effective fluidizing of wellbore materials while maintaining suitable pressure to keep reservoir fluids out of the wellbore.
Initially, the operator requested two runs—the first to remove solids to the toe so the instrumentation string could be removed, the second to clear the liner for ICD installation. Due to excessive temperatures recorders were not installed on the first run. After the instrumentation string was pulled, recorders were installed for the second run to liner depth. Chemical concentrations were adjusted, and jetting rate lowered resulting in an even and consistent return rate.
About one month later, after the installation of the ICD, the operator discovered an intermediate casing failure. The operator requested Quantum be on site during the casing repair in the event of tagging solids. The casing repair was successful. The operator capitalized on Quantum’s presence and requested a third JetVak cleanout of the full length to optimize start-up and production.
Quantum retrieved 7 m3 of solids in 61 hours of operating time across all three cleanouts.
The operator had a better than expected start up.
|First Run||Second Run||Third Run|
|Maximum depth||1391 m||588 m||1381 m|
|Average jetting rates||49.9 L/min||39.2 L/min||38.9 L/min|
|Average gross lifting rates||50.2 L/min||56.7 L/min||77.9 L/min|
|Average underbalanced lifting rates||0.3 L/min||17.5 L/min||39.0 L/min|
|Confirmed volume of solids||4.0 m3||1.5 m3||1.5 m3|
|Maximum gross solids cut||14.5%||2.0%||6.0%|
|Maximum gross oil cut||30%||15%||20%|
|BHA operating time||25.5 hrs||14.0 hrs||21.5 hrs|
|BHT from recorder||n/a||100°C||n/a|
|BHP from recorder||n/a||2.7 MPa||n/a|
“Never had a liner repair go so well”