Technology Focus: Offshore Facilities (September 2023)
Authors: Collier Graham 
Published: September 2023

Today, if one looks out at the vast offshore oil fields of the Gulf of Mexico, Venezuela, Brazil, the North Sea, West Africa, and the Arabian Gulf, it is hard to imagine that, at some point, all that mass oil and gas production for our energy and transport needs will come to an end.
So, what will take its place? We have dabbled with nuclear power, but that is potentially more harmful than a carbon-based energy source and, in most quarters, definitely less popular. Hydroelectric power stations were once the darling of the alternative energy brigade of the mid-20th century, but flooding fertile valleys, displacing whole populations, and adversely affecting fauna and flora has cost that option its environmentally friendly status. Besides, demands on fresh water in many parts of the world have added another dimension to the issue. As we moved into the 21st century, the landscape began to fill with wind farms and fields full of solar panels; significant gains in green energy were being made. But did that satisfy everyone? No, of course not. The Not In My Back Yard culture took effect, and protests against solar farms and wind turbines on land and near shore became as vociferous as those of the anti-nuclear and anti-oil groups.
Does this mean that we have run out of alternatives? No, not yet, because there is still an abundant energy source all around us that does not necessarily need carbon in the equation. Green hydrogen (i.e., hydrogen produced through electrolysis using electricity generated from the likes of wind turbines and solar panels) is growing rapidly in popularity as a successor to hydrocarbon fuel. Hydrogen can be used in a fuel cell or burned in a turbine or internal combustion engine with the resulting exhaust being water vapor. Energy can be stored in the form of liquid hydrogen or piped from the source to the place of use. It is worth noting that hydrogen does have some issues, which, to be fair, have yet to be overcome. Hydrogen does have to be chilled significantly to be stored in liquid form and does have a tendency to permeate carbon steel. It is highly likely that, in the future, we will see a derivative of hydrogen in the form of ammonia that will become more prominent. Ammonia also can be used in a fuel cell to generate electricity and also can be used in a turbine or combustion engine. Ammonia has very similar physical properties to propane and is significantly easier to store and transport than hydrogen.
On our route to Green Utopia, there are still some significant hurdles to overcome. Installing new offshore wind farms and laying new electricity cables to shore is expensive. There still must be improvement in green hydrogen storage and transport technology, and, if we are to branch down the ammonia path, there definitely has to be significant improvement in green ammonia production rates.
Coming back to offshore oil and gas, much of the massive infrastructure of offshore platforms and pipelines is nearing the end of its production life. The original plan for the myriad of platforms and pipelines is to decommission, remove, and scrap. This original plan is flawed. Removal of platforms has the most negative environmental impact. The successful Rigs to Reefs plan in the US Gulf of Mexico offers a viable alternative, but full repurposing of platforms and pipelines is probably the best solution—a solution that could have a positive effect on the fledgling offshore wind-to-hydrogen (ammonia) industry. If we are to achieve the goals of significant carbon reduction this century, then a holistic approach to the environment must be considered.
I hope that you enjoy this month’s selection of technical papers.
Recommended additional reading at OnePetro: www.onepetro.org.
OTC 30993 The Use of Offshore Wind To Reduce Greenhouse Gas Emissions in Offshore Hydrocarbon Production—A Case Study by David McLaurin, Intecsea, et al.
SPE 205446 Feasibility of Repurposing Offshore Decommissioned Gas Rigs Into Fish Farms by Saptarshi Pal, University of Strathclyde, et al.
SPE 205439 Initiatives in UK Offshore Decommissioning Following the Wood Review: Applicability for Decommissioning in Norway by Rune Vikane, University of Stavanger, et al.