Ensuring zonal isolation and optimizing data acquisition in the Mediterranean

Challenge
Zonal isolation
Sub Standard Graphics 3D JIL182762 00000
  • Development Well
  • Deviation 21°
  • Open Hole

Background

An offshore client in the Levant Basin of the Mediterranean Sea was planning a pilot hole as part of a wider field development campaign. The upper and lower sands needed to be isolated and monitored to evaluate pressure communication from a deeper sand during production from the main bore. The client needed reliable open-hole isolation with a simple setting mechanism.

This job required critical open-hole isolation to evaluate pressure communication via the sands, so the client needed to ensure that the zones would be properly isolated. Welltec® offered a dual-zone, open-hole straddle consisting of the Welltec Annular Barrier (WAB®) and the Welltec Isolation Valve (WIV) as a solution for compatibility with the hydraulic running system while also providing the required zonal isolation performance. The client pursued this solution because of Welltec’s long track record of demonstrated success with open-hole isolation and the company’s willingness to collaborate with third parties to ensure seamless integration with the deployment system.

Operation

Welltec delivered a single-trip, dual-zone, open-hole straddle consisting of three 1214WABs and one WIV for the operation.

After drilling the 12-1/4” section of the pilot hole to target depth (TD), the straddle assembly was run in hole on a hydraulic-release tool deployed on drill pipe with wireless pressure-temperature gauges in each zone. At TD, a setting ball was circulated down to activate the WIV and initiate WAB expansion. All three WABs were set simultaneously within 10 minutes. After WAB expansion, a frac sleeve at the top of the straddle was opened, followed by cementing 90 m to the top of the assembly. The running tool was then released. Data verified gauge communication, and the operation moved to drilling the main bore for flow back.

Achievements

The client was quite pleased with Welltec’s tool performance in the field, as well as the collaboration with third-party service providers during make-up and load out.

The operation was being performed on a high OPEX offshore drillship. The rapid setting of the WABs delivered great value to the client by enabling swift continuation for the rest of the operation. The seamless integration with the hydraulic-release tool meant the operation was completed with no costly delays due to challenges in setting and releasing.
The WAB ensured critical isolation between the zones, giving the high CAPEX monitoring system the best chance of success in delivering reliable data and enabling the client to confidently plan field development.

Challenge
Zonal isolation
JIL182762 00000