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An advanced downhole sub-surface safety valve (SSSV) has been developed to create an improved well control solution for slim-line, cable deployed Electric Submersible Pump (ESP) applications. The new SSSV enables all safety regulations to be met whilst simplifying deployment and retrieval. During traditional ESP deployments the production tubing is replaced, allowing power cables and control lines to run outside the tubing. However, slim-line cable deployed ESPs are retrofitted through existing tubing, which means the ESP cable and SSSV control lines can cause an obstruction to the existing SSSV. To maintain a functioning SSSV a modified valve can be retrofitted into an existing safety valve profile nipple and is designed to seal around the ESP cable. However, this option is limited to wells with existing wireline retrievable SSSV profile nipples and associated control lines that are in acceptable condition. The new advanced SSSV does not require a control line and functions based on the ESP intake to discharge differential pressure signal. The valve is installed at the ESP depth and opens when the ESP is pumping, with a fail-safe closing mechanism when the ESP is switched off. The deployment configuration can be varied to suit the application, either as an ingrated part of the cable deployed ESP assembly, or separately. As sealing around the ESP cable is not required, the new technology significantly reduces cost and complexity of cable deployed ESP installations where a SSSV is required. The new technology can also be used in other artificial lift systems. |
