Reducing oil prices, wellhead system performance and regulatory testing requirements are driving the need for efficiencies in the installation, testing and support of well operations worldwide. Wellhead equipment manufacturers provide a critical role in maximizing these efficiencies by supplying installation and test tools with increased functionality, versatility, performance and reliability. Many operators provide minimum commercial bid specifications for subsea wellhead tools, but these may fall short of addressing the actual operating expense (OPEX) time savings certain tools provide. Likewise, in scenarios where operators are defining their wellhead system based upon these capital expense (CAPX) specifications, the realistic OPEX benefit of the tools provided by different suppliers may be overlooked. The goal of this paper is to expound upon the benefits and complexities of subsea wellhead tooling for the practical benefit of increased operational efficiency and reduced personnel risk exposure. Saving a trip may cover the cost of the subsea wellhead tool many times over.
In recent years subsea wellhead suppliers have focused on increasing bending capacity, increasing pressure ratings, casing carrying capacity, lockdown capacity and temperature ratings. At the same time considerable effort has been applied to reducing the number of trips into the well and accomplishing more activities with each trip. Saving just one trip into the well can save up to 24 hours of rig time thus saving USD 500,000 million of non-productive drilling cost. To achieve these trip savings, the running and testing tools will become more complex and therefore more costly. Additional purpose built tools may have to be added to the running and testing tool package to support the new trip saving equipment. At the same time operators and drilling contractors are demanding lower costs, more reliability, simple running procedures, fewer tools and less rig down time. This paper will strive to find the balance that meets the customer requirements and minimize the number of tools while saving as many trips into the well as possible. Tools with increased complexity will increase down time risk and cost but the reward in trip savings will make the risk manageable. Cost comparisons and trip comparisons between conventional and latest generation subsea wellhead systems will be presented.