Screen repair to eliminate sand production with Saltel Patch, set on Coiled Tubing – Offshore Caspian sea
In an open-hole gravel pack completion (5in #18), two sand producing zones were localized thanks to permanently installed optical fiber.
48 (157ft) and 24m (79ft) needed to be sealed, but the riser length limited the maximum possible patch length to 14m (46ft). It was decided to overlap the Patches to provide an effective solution over the entire length.
Solution: Casing patches overlapped, covering the bottom zone of the sand screen
The patches overlapped covered the whole length of the damaged sand screen section
- Inflatable packer qualification
Saltel Industries Expandable Steel Patch Technology is a unique solution which uses an inflatable Packer to expand the steel patch. This gives a high expansion ratio and means Patches can be overlapped (or Patch run through a previous Patch) to mold to the exact ID of the damaged screen.
- Patches set on Coiled Tubing
The patches and setting BHA were conveyed on intelligent Coiled Tubing, to provide pressure from surface. The behavior of the CT at this depth in a horizontal well was the main uncertainty of this job (stick and slip, downhole movements,…). In order to monitor downhole movements and the forces applied on the patch and the BHA during the setting, the CT supplier developed a tension compression sub.
The CT MHA also included a CCL module (for positioning), and pressure and temperature sensors.
Result: 4 casing patches set overlapped
A test run (consisting in running in the BHA without patch and inflating an inflatable packer) was performed to:
- Confirm possibility of progressive pick up of the CT to compensate for its elongation under pressure, and validate calculated values
- Measure the transition between up and down movements downhole
Then four patches were set overlapped to cover the bottom zone, and two patches overlapped for the top zone; 150 pressure cycles were performed in a total of 12 days offshore (including mob./demobilization) without issue.
Start-up of the well was performed.
There were several World Wide Firsts on this sand screen repair operation
- A 4-1/2in Patch was successfully set in 5in 18ppft casing, showing the versatility and expansion capacity of the Expandable Steel Technology
- 6 Patches of 14m (46ft) were set in the same well, with 4 overlaps
- Screen repairs at over 4,000m (13,300ft) on CT (horizontal well)