Decommissioning: Challenges to access the wells on shallow water

Hey Folks,

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Let’s talk about the challenges for Decommissioning for mature oil fields in Brazil.

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Sometimes 50% of success of the decom campaign is to have access of the XT/Well, but in this case below was 60% due all limitations :

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• XT CBV from 80’s installed at 101m water depth.
• Low bending moment of the re-entrance XT hub with flange 7-1/16”.
• Agnostic TRT w/o access of the function lines of the XT.
• Light Well Intervention Vessel with DP system. ( Another operator ,below 300m, only moored rigs)
• EDP and LRP Workover package with 70 tons and 5.7m high.
• Riser analysis of XT and workover System with 0,5m.

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This well was big milestone for the decom campaign and after a lot of brainstorms and meetings with suppliers we took the decision to use the Tethering System to increase the red watch circle and perform the access.

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After spent five months for engineering analysis, developed Gravity Bases Anchor locally and performed some FEA’s finally we got a good result to proceed with DP vessel increasing the red witch circle above 6m, but inside of the vessel limits.

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Spent 30 days on this well , one disconnection due the weather condiction however the barriers were installed and the well decommissioned.?First time in Brazil a well access with 101m water depth , workover package and DP vessel to decom the well.

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We are changing the way to perform Decom in shallow waters here in Brazil.

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“Challenges are an opportunity to test you and rise for the next level”.