5 May 2024
During routine slickline operations the slickline became stuck in the Stuffing Box during pull out of hole. Due to work hours being limited by Helicopter schedule and the unavailability of a nightshift crew, the decision was made to close the BOP and leave the Lubricator standing over night for the operation to continue in the morning. To maintain platform safety the fusible cap was removed and the Hydraulic Master Valve was switch back to platform control, bringing it back into the safety shut down system.
Unfortunately during the night the platform safety shut down activated and all the hydraulic safety valves on the platform shut.
The slickline was cut by the Hydraulic Master Valve causing a Slickline toolstring and 2500m of 0.125” slickline to be lost and fell to HUD.
First step in the operation was to develop a work program identifying primary equipment and contingency equipment, so that equipment can be prepared and shipped internationally to location.
Due to Pressure Control Equipment limitations, it was required to use an undersized Wire Finder. To reduce the risks of passing the top of the slickline with the Wire Finder we decided to utilize a Down Hole Camera to accurately locate the top of the slickline and minimize these risks.
Crane height severely limited the length of lubricator that could be utilized. Again our working relationship with Limar Oil Tools was critical to the operation, they were able to quickly prepare and mobilize a 2.800” Limar Compact Toolstring maintaining the schedule requested by our client.
7/32” Dyform cable was selected, this would allow us to activate the Spring Jars on the lost toolstring if it was stuck on HUD, highly likely after falling over 1200m. The Limar Compact Toolstring is also the only tool of its kind on the market capable of jar settings up to 3000lbs.
Maximum of 7 hour work days was addressed and consideration made during planning.
The first step of the operation was for the wireline crew to run a down hole camera and locate the top of the wire.
The operation was a success and the top of the wire was located at 1305mWL, 210m above the calculated top of wire at 1515mKB, again proving the safest method to fish Slickline or Wireline includes utilizing a Downhole Camera.
The Limar Compact Toolstring was utilized in conjunction with a 2.720” UniTool for the safety release and a Limar nom 4.500” Wire Finder/Grab system. Already knowing the exact location of the top of the broken Slickline, the tools were ran to the top of slickline depth mitigating the need to sweep the well looking for the top. Saving valuable time in an extremely limited work day.
The Slickline was located and grabbed at 1305m WL. The spring jars on the lost toolstring were activated once to free the complete fish and the tools were recovered to surface.
The BOP’s were closed and inflow tested as per the wireline companies procedures.
Again the Compact toolstring was critical in saving time. The LS Well Interventions supervisor found that there was sufficient Slickline at surface to back feed the stuffing box. This not only saved time but increased safety limiting the time spent using the BOP as the primary barrier.
The lost toolstring was recovered to 150mWL and operations were suspended for the day. A nightshift crew was brought to the platform to monitor the well status.
When operations commenced in the morning the BOP’s were again closed and inflow tested as per procedure.
70m of slickline was spooled off the slickline unit and back feed through a 30ft lubricator and stuffing box. The lubricator was installed on top of the BOP and a pressure test to tubing head pressure conducted.
The fish and complete length of slickline was recovered to surface and the well secured.
Meticulous planning, attention to detail and access to the correct equipment were critical in this operation. Due to the limited work hours of 6 to 7 hours available per day, this operation would have highlighted poor planning. Completing this fishing operation in just 2 shifts safely and efficiently, highlighted the attention to detail in the entire crew.
The Compact toolstring was not only a good operational decision but also increased safety by limiting well control risks and additional manual handling.
SITE INSPECTION SAFETY
Extra Care should be taken while changing tools. Minimizing body parts & time spent close to a suspended load.
While it is impossible to completely remove working in proximity to suspended loads during wireline operations exposure should be limited as much as possible. Minimum number of personal required for the operation should be in the red zone (no spectators), where ever possible suspended loads should be kept below head height.
The operation was conducted on a remote unmanned platform.
Weather conditions can changing rapidly, be prepared for unexpected changes & monitor wind speeds.
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