Positioning requirements. The NORSOK Standard D-10 provides specific well abandonment regulations. This document requires xxxxx to be plugged and maintain their integrity over geological time scales. At least one well barrier is required between a potential source of inflow and the surface, unless a reservoir contains hydrocarbons in which case two well barriers are required. Well barriers should be installed as close to the potential source of inflow as technically possible, sealing all possible leak paths. The primary and secondary well barriers shall be placed at a depth where the estimated formation fracture pressure at the base of the plug is in excess of the potential internal pressure (NORSOK D-10). The final location of the well barrier/WBEs has to be verified. Where casing is part of the permanent barrier, a column of intact cement in the annulus is required as a permanent barrier. A cement plug must be set along the same interval. An open-hole cement plug can be considered a proper well barrier between reservoirs. It should also be used as a primary well barrier, if technically feasible, see Table A 2 in the Appendix. These practices and well configurations are in line with the methodology recommended in UKOOA (2009). When well completion tubulars are left in hole and permanent plugs are installed through and around the tubular, appropriate practices to install and verify the position and quality of the plug inside the tubular, and between the tubular and the casing shall be used. Multiple reservoir zones/perforations within the same pressure regime, isolated with a well barrier placed in between them, can be considered as one reservoir for which a primary and secondary well barrier shall be installed as shown in Figure 2.
Positioning requirements. For all monitoring activities, navigational instruments shall be correctly calibrated before each sampling event.
