Live Well SSSV Installation



The gas well was located onshore in Germany. Gas production had ceased due to liquid loading. The well was completed with a 4.5" production tubing complete with a Wireline Retrievable Surface Controlled Sub Surface Safety valve (WR-SCSSSV). In general, liquid loading can be mitigated by increasing the gas velocity allowing water to be produced instead of accumulating at the bottom of the well. The gas velocity can be increased by decreasing the inner diameter of the production tubing. Common practices are to snub in velocity - or siphon strings. Local well standards require to have a tested sub-surface safety valve installed in the production tubing. To prevent reservoir damage and to prevent well productivity loss the well may not be killed with heavy fluids.


The objective was to; remove the existing WR-SCSSSV with Slickline, using a HWU to snub in a 2-3/8"X 2-7/8" tapered velocity string directly into the live gas well to a depth of 5000m MDAH, and install a smaller WR-SCSSSV into the new velocity string on Slickkline. The smaller WL-SCSSSV was to be hooked up to the existing control line of the 4.5" tubing.


A 600K Snubbing unit was selected to snub in the velocity string into the pressurized well. Two independent pressure barriers were installed inside the well. The X-mass tree was removed to be able to install a new hanger spool to support the new velocity string. The velocity string was equipped with a Wellbore Damage Tool (WDB-tool). This WDB tool was spaced out such that after the velocity string was installed inside the well and landed inside the new hanger spool, the WDB tool fitted in the old WR-SCSSSV nipple profile of 4,5" completion. Packing elements of the WDB-tool were set, creating a new but smaller WR-SCSSSV nipple profile inside the 2-7/8" velocity string. The old safety valve control line could now be used to control the new but smaller WR-SCSSSV. After the Snubbing operation the new WR-SCSSSV was installed on Wireline.


The velocity string and the WR-SCSSV were successfully installed. The WDB tool performed well. The new WR-SCSSSV was tested successfully during all tests. The whole operation was carried out with Zero incidents and accidents.