Look behind the scenes
Immense effort is required to access new deposits, as boreholes have to be prepared and created. It can take years of preparation before a new oil field comes online. For offshore wells, oil producers now frequently are opting for a Floating Production, Storage and Offloading Unit (FPSO). The FPSO is flexible and can be used to store, process and load the extracted crude oil or natural gas, as well as for pumping. Particularly for offshore operations, using FPSOs means that expensive pipelines at the point of production are no longer necessary. That means even fields with a short life span or far from the coast can be developed cost-effectively.
In January 2018, one of the world's largest oil companies decided to deploy just such a flexible production unit off the coast of Great Britain. Once the planned eight boreholes have been drilled, the FPSO will be one of the largest investments the group has made in the British North Sea for decades. Up to 45,000 barrels per day will be produced at the new site in the future. Efficient operation is important to the company, especially in view of volatile oil prices, so the company wanted the system to be profitable even at world market prices of less than 40 US dollars per barrel. Efficiency is therefore also a priority for the technology used on the platform, both for the primary tasks associated with oil production and for secondary processes such as crude oil processing. The oil company's partner in charge of engineering and construction therefore turned to NETZSCH Pumps & Systems for the pumping technology. NETZSCH not only has a comprehensive portfolio of technology for pumping liquid media, it also has the required expertise in the oil and gas industry. NETZSCH is familiar with the challenges involved in pumping a wide range of media for the industry and offers the right solution for every application. The portfolio includes special technologies for extending the life of oil wells that are drying up, for increasing the efficiency of existing oil fields, and for the safe and efficient production of low-quality or high-viscosity crude oil. "We do especially well in the offshore sector– not least because NETZSCH concentrates its combined knowledge of the industry and its applications in a specialised business field with a global presence," says Ulrich Eibl, Head of the Oil & Gas Mid-/Downstream global business field at NETZSCH Pumpen & Systeme in Germany. Eibl also knows that, on the high seas especially where every repair job comes with enormous costs, customers need very low-maintenance technology that functions simply, is reliable and has long life cycles. "After all, downtime on an FPSO quickly adds up to several million US dollars in losses per day", the pump expert explains. Eibl is also familiar with the dimensioning requirements, as every inch of space is used to operate platforms as efficiently as possible. The pumping system must therefore also have as space-saving a design as possible.
Three different types of pumps will operate off the English coast: a rotary lobe, a multi screw and a progressing cavity pump. Each model has been developed perfectly for its specific application.
The TORNADO T2 T.Proc rotary lobe pump is used to clean the marine diesel oil. "Since maintaining and cleaning all the components at a remote site such as an FPSO is expensive and time-consuming, the fuel used for the power supply is cleaned in a separator," Eibl explains. This keeps engines and tanks clean and makes sure that the fuel is of a consistently high quality – an approach that has proven to be valuable and that also ensures a longer service life for the engines.
NOTOS multi screw pumps are used around the FPSO ship's storage tanks. "Safety is of course the top priority for our customers," says Eibl. "To prevent even the possibility of an explosive atmosphere developing in the storage tanks for crude oil from the outset, an inert gas is produced from some of the ship's diesel fuel, which floats on top of the oil in the tanks". The 3-spindle multi screw pumps, which convey the diesel used to produce the inert gas, therefore have an essential task. Finally, several NEMO progressing cavity pumps are used in a completely different part of the floating platform. As it is the American Petroleum Institute (API) design, the pump is an extremely robust all-rounder that can be used universally. On the FPSO, the pumps take care of the produced water. "This is not waste water in the traditional sense," Eibl explains. "This is in fact reservoir water at a temperature of 50 - 60°C that comes to the surface together with the crude oil". The NEMO units pump about 2m³ per hour against 15 bar pressure at 240 revolutions per minute. Besides oil droplets, the water contains minute rock particles from the formation deep in the seabed, as well as hydrogen sulphide (H2S) and chlorides. For the pump, that means a risk of abrasion and corrosion and, in the event of a leak, it can even mean toxic H2S could be released. The NEMO comes out top again with its unique wear-resistant design, which ensures a long service life even when media is loaded with rock particles.