Norwegian oil and gas company Statoil needed advice on a planned project to divide oil and gas mixtures gathered from North Sea wells to two separate destinations.
The company had devised a system, and approached Professor Barry Azzopardi of The University of Nottingham for a second, expert opinion.
Professor Azzopardi used his experience in the field to analyse the proposed project and advised Statoil on the best course of action.
Statoil have now installed the device, known as a flow splitter, into the North Sea, which became operational in the summer of 2007.
Oil is an important topic that’s rarely out of the news. We feel the effect of oil price variations whenever we put fuel into our cars. There is much worry about those, thankfully rare, event when oil spillages cause environmental damage. What is rarely considered are the actual logistics of getting the oil from its source to its destination. But it’s a subject close to the heart of Statoil, a Norwegian oil and gas company which ranks as one of the world’s largest crude oil traders.
“Most people think of oil as something that’s simply extracted from the ground, but it’s not really as simple as that,” explains Professor Azzopardi, from the School of Chemical and Environmental Engineering. “Oil rarely emerges alone – what comes out is a mixture gas, with water, sand or gas and sometimes sand. In particular, the flow of gas and liquid is difficult to design for as there are some unusual behaviours. If you’re trying to send a liquid (say a mixture of oil and water) to two destinations it’s relatively simple. But with a mix of oil and gas where there are a number of ways in which the liquid and gas are distributed within a pipe – it all starts to get complicated.”
This was exactly the problem that Statoil wanted to address. They needed to find a way that their oil which has been extracted from its source under the bed of the North Sea in to a pipeline could be sent to two separate locations. One way to do this is by having a side branch off the inlet pipe - a simple T junction. However, for a mixture of gas and oil meant that the gas went one way, the oil the other, when they wanted an equal quantity of both to go in each direction.
That’s where Professor Azzopardi came in. As one of the few experts in the world dealing with T junctions in the oil industry, he was the perfect choice to act as a consultant for the project.
“The University of Nottingham is part of a consortium with three other universities which does research work for companies in the oil industry – which is where we formed our connection with Statoil,” he explains. “This particular area of T junctions is such a specialised, and rare, form of expertise that it was natural for them to approach me to give them reassurance that their project would be successful.”
Professor Azzopardi, who has published a book and a large number of papers and spoken at conferences on the subject, was given a set of plans for the flow splitter which Statoil were hoping to implement. He then used his experience to assess what would happen in the specific geometry based on the results of his own experiments and with published in the engineering literature. He carried out some appropriate calculations to support his assessment. From this, he was able to give Statoil the guidance they needed.
“Statoil knew that my experience in this field meant that I could use my knowledge of the available body of knowledge relevant to this type of design. As the flow splitter is designed to be placed right at the bottom of the seabed it’s vital to get it right first time – replacing it is a very difficult task. Statoil have now installed the flow splitter at the Tordis Field in the North Sea (about 200m deep) and it should start operating later this summer.”