Completion system for CCS monitoring

A completion system for CO2 storage monitoring in a reservoir in a formation, the completion system being arranged in a borehole having a top and extending towards the reservoir, the completion system comprising:

• a first well tubular metal structure having a first inner diameter,
• a second well tubular metal structure having a first part arranged within the first inner diameter of the first well tubular metal structure and a second part extending below the first well tubular metal structure into the borehole,
• a monitoring line extending from the top along both the first and second part of the second well tubular metal structure and into cement, and
• a production packer assembly providing a seal between the first well tubular metal structure and the first part of the second well tubular metal structure, the production packer assembly comprising:
• an anchoring unit, and
• an annular barrier unit,
• wherein the annular barrier unit comprises:
• a tubular metal part configured to be mounted as part of the first part of the second well tubular metal structure, the tubular metal part having an outer face, and an axial extension along the second well tubular metal structure, and
• an expandable metal sleeve surrounding the tubular metal part, the expandable metal sleeve having a circumferential groove, a first end and a second end, each end of the expandable metal sleeve being connected with the outer face of the tubular metal part, the tubular metal part comprising an opening through which fluid passes to expand the expandable metal sleeve,
• wherein the anchoring unit further comprises an anchoring element arranged in the circumferential groove, the anchoring element comprising a first anchoring part at least partly overlapping a second anchoring part in a radial direction perpendicular to the axial extension so that an inner face of the first anchoring part at least partly abuts an outer face of the second anchoring part,
• wherein the annular barrier unit further comprises a sealing element arranged in the circumferential groove, and
• wherein the monitoring line extends through both the anchoring unit and the annular barrier unit between the tubular metal part and the expandable metal sleeve.