Salt: ESCO – Frisia BAS-3O Workover operation 2016

Well engineering partners completed successfully a Hydraulic Workover Snubbing Operation. Within 20 days access of the production tubing was fully restored and the well was brought back into production again. All operations were done under approximately 150 bar wellhead pressure. The workover operation was carried out with a Hydraulic Workover Unit of Wellgear.

BAS-3O well has been leaching and producing from the salt cavern without problems since it was set in production in March 2015. The direct production mechanism relies on the injection of fresh water into the 5 ½“ which dissolves the salt and production of brine via the 5 ½” x 9 5/8” annulus. The diesel in the 9 5/8” x 11 ¾” annulus provides the control on the shape of the cavern.

Recently when attempting to perform echo wire-line operations for cavern measurement it was found that a HUD in the inner leaching string prevented access to the cavern, not allowing passing beyond 4632mAH. Production has continued without problems but a repair of the well is planned to regain access to the cavern and to reconfigure the leaching strings.

With the wireline operations, a permanent bridge plug is placed at the bottom of the 5 ½” inner string and tested for inflow. Secondly, a plug, with pump through capability, is set in the R-nipple profile. With the pump through option (BPV) the plug can be inflow tested by pressuring up the 5 ½” inner string to 100 bar and bleeding off above.

The objective of the workover is to run the inner leaching string to a new depth. The wireline works pre and post workover will shoot-off the inner leaching string above the HUD, perform a sonar echo log, shoot off the inner and outer leaching strings, and restore full access to BAS-3O.

All operations were performed accordingly without any incidents/accidents. The operation was finished within 20 days and the access of the 5 ½” leaching string was fully restored.