The decision to drill new expensive offshore wells is made because of the availability of information that proves the profitability of these new wells and the possibility that these wells can be drilled faster and more efficiently due to experience that has been gathered from drilling older wells under similar conditions. The cost of drilling new offshore wells has not reduced in recent times and drilling new wells to meet production targets has become more challenging while well trajectories have become increasingly more complex thereby increasing the associated costs of delivering such wells. However, new technologies combined with experience have improved the efficacy of operations when drilling relatively challenging wells.
Addax Petroleum Nigeria in its offshore OML-126 operations has been able to overcome technical, logistical and organizational challenges by effectively applying lessons learned from previous operations in its on going operations there by improving drilling performance – reducing time spent drilling and operational costs.
Simple modifications such as using a 36″ bit instead of a hole opener to drill the top hole section improved cementing, setting the seal assembly after cementing operations rather than before cementing to prevent the accumulation of debris around the seal assembly area improved the efficiency of setting the seal assembly, optimizing the screen sizes while drilling the reservoir section reduced the time spent conditioning the mud to Production Screen Testing (PST) quality for completion operations (running Expandable Sand Screens (ESS) and Stand Alone Screens (SAS)), and has also considerably reduced the time for completion operations, other factors like continuity, in-house competition, improved communication and knowledge management has helped increase the efficiency of operations and saved cost».
This paper expounds on these and other changes that were carried out during the Phase I development of the Okwori field and how they reduced costs and saved time while achieving the goals that were set prior to commencing the drilling campaign.