Flow Control Hanger
Optimal distribution of steam can significantly improve the recovery factor of a heavy oil or bitumen reservoir. Thermal recovery utilizing steam has been extensively and successfully used, but thermal liner hanger failures are common due to thermal expansion and contraction.
The steam heat injected provides for thermal expansion of the liner system, therefore subsequent movement of the liner hanger and corresponding common element/seal failure can allow for steam bypass at the hanger – located in the heel of the well – thus affecting uniform steam distribution into the formation. This results in costly work-overs associated with down hole equipment malfunctions and failures and reduced recovery. The liner system has a tendency to expand upwards into the intermediate casing.
A specifically designed and engineered Polished Bore Receptacle (PBR), set directly above the float equipment in the intermediate casing string, provides for proper seal ability of the thermal liner hanger against the intermediate casing. The thermal liner hanger is positioned inside this PBR to provide a pressure and debris seal, coupled with unrestricted thermal expansion/movement of the liner system without compromising the main function of the thermal liner hanger – pressure seal and expansion relief of stress-strain due to steam injection. The PBR has a “no-go” step at the bottom of the five and a half (5 ½) meter PBR length.
The new advanced casing hanger, named Flow Control Hanger (FCH), manufactured from hardened steel material, will not wash or fail under high steam temperatures and pressures during movement inside the PBR. The FCH steel seals are engineered and manufactured to have a positive-seal-memory when set and installed inside the PBR. There is no need for hydraulic or mechanical movement to set or inflate seals on the FCH, only string weight is required to set the steel seals of the FCH and to seat within its matched and specifically honed PBR. The FCH steel seals are engineered to permit movements within the PBR while providing for continual seal. This provides for an option for further assistance to installing the liner to total depth (TD) by rotation of the FCH within the PBR. The FCH steel seals will not collapse smaller than the “no-go” located at the bottom of the PBR, which is also used to ensure proper placement of the FCH inside the PBR.