Misplaced pride in complexity
Tony Duncan considers smaller, simpler and more cost-effective options for age old industry problems
The oil and gas business has, is, and will probably continue to be, conservative in its approach to engineering. If it develops a product or system that works on one project, its variant will likely be used again on the next project and so on, project after project. Operators tend to repeat what has been done before, because it is tried and tested.
For example, the development of floating production storage and offloading (FPSO) vessels found their original use in the UK North Sea. Since then, they have been adopted and adapted globally and the system designers have incrementally modified the designs, because of increases in top tension, water depth, environmental conditions and so on. However, these developments have driven the technology towards a trend of making everything larger, more complicated and more expensive. The flexible pipes used have become more complex, the vessels utilised to install the FPSOs have become larger, the buoy systems used to support the riser system have been made bigger, and the result is a FPSO that has a large turret or porch system that can, in some cases, break project economics or introduce a too high a level of project risk.
Engineers in oil companies, design houses and engineering, procurement, construction and installation (EPCI) contractors, use past project experience when they look to a new project or tender. Take, for example, a mid-water arch, commonly used for supporting risers. When engineers start a new project, what is the first thing they look to? Past examples of mid-water arch design or design bases are a natural starting point. Then, they add in the new conditions such as water depths, environmental load, sour service and CO2 requirements, temperature, etc. Factoring in these new conditions often adds in more complexity, more weight and more risk, all without challenging why a mid-water arch is being used in the first place. Some of the early mid-water arches used in the UK sector weighed about 150 t. Offshore Brazil, projects such as Guará-Lula use a form of the mid-water arch that weighs in excess of 2000 t. The spiral is in train: larger projects mean more and larger installation vessels, and more commercial and technical risk.