During a tubing depressurizing operation in a sour gas producer, the Sub-Surface Safety Valve dislodged from the nipple profile, broke and stuck inside the tubing hanger, restricting accessibility to the well. Multiple attempts to recover the stuck fish via slick line in combination with a permanent magnet resulted in recovering a few broken pieces and revealed a limited clearance of 1.85" through the fish.
The well was killed and attempts to secure the well by installing through tubing inflatable bridge plugs using coil tubing were unsuccessful. It was then decided to exclude the coiled tubing operation for well integrity purposes due to limited clearance as the coil tubing had to pass through broken fish and could get stuck compromising the X-tree valves operation and it was decided to carry out work over operation to recover the broken fish. The cost for well work over was estimated at $ 3.0 MM.
An innovative approach to secure this gas well riglessly using through Inflatable bridge plugs setting with electric line was introduced and the job was conducted successfully after completing all the risk assessments saving the significant costs associated with rig intervention. Two 1-11/16" through tubing inflatable retrievable bridge plugs (TTIRBP) were set with electric line passing thru the limited access hole of the broken fish. Plugs were set inside 4-1/2" and 3-1/2" tubing and pressure tested to 3000 PSI.
The well was secured and the fish was successfully retrieved. Both bridge plugs were retrieved using 0.108 inches slickline and the well was put back into production.
This great achievement was recognized as a 1st trial to carry out securing a sour gas well in the Middle East using a combination of electric line and slick line for setting and retrieving TTRPB
Inflatable packers and plugs run on coiled tubing and wireline through production tubing for water & gas shut-off applications were introduced in late 1980s. This has brought substantial cost savings by eliminating the workover rig and all ancillary operations required by conventional workover in additional to bringing wells back to production in significantly less time.
Expanding the use of thru-tubing retrievable beyond their usual scope, to secure wells where maintenance work was required on x-mas trees, tubing hangers and in this example to retrieve and replace the sub surface safety valve stuck in the tubing hanger in a rigless environment sheds light on a whole new range of applications. The rigless program designed and executed successfully to secure the sour gas well utilizing through tubing retrievable bridge plugs.