Reviewing the effectiveness of Plug and Abandonment (P&A) work for an aged subsea well by utilization of jack-up rig in oil fields in the Natuna Sea block. Evaluation of various methods in dealing with operational challenges and well integrity issues in order to comply with the standards. S-14 is a horizontal well that been drilled in 1996. The well have to be decommissioned in complying with Oil & Gas UK guidelines and Standard Nasional Indonesia (SNI) requirements. Strategy of this project was dividing the P&A project into two phases: Pre-Abandonment and Main Abandonment. If compared to semi-sub rig and multipurpose drilling vessel; a jack-up rig was selected by considering the reasonable rate during that period. In the other hand, it also considered of having the capability to encounter any contingency works with limited well construction information and lack of downhole conditions. The other benefit is its capability to hold 13-5/8" wellhead loads on the paramount Natuna sea climate. Two intervention hoses were deployed by Diving Support Vessel (DSV) during P&A Phase-1. These hoses will be utilized at P&A Phase-2 for killing purposes in the case of well control occurred. The main productive zone was successfully isolated as a suspension barrier prior nipple down the conventional subsea tree. Production tubing was pulled out to allow the integrity verification for cement above an expected hydrocarbon bearings with reliable cement evaluation tool prior to set the primary barrier. The 2,052 feet of 9-5/8" casing was pulled and the secondary barrier set above the 9-5/8" casing stub. Surface plug then set after wellhead, 20" and 30" casings were successfully cut. Total cost for main P&A phase was US$ 9.5 million with 38 operation days, including 40% of days to execute the contingency due to resolving tubing parted case. At the current economic and for the trouble free case, this P&A project cost is approximately US$ 7.0 - 8.0 million.
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