13 April 2009
At $40 per barrel, it is impossible for oil companies to continue to find, develop, and maintain new sources. At these prices many countries don’t have the resources to continue production development. OPEC is working day and night to reduce production to drive the price back up, and of course depleting the world’s oil resources by 4 million barrels a day will help in the long run to increase scarcity. Projects like the Canadian Tar Sands, for example, need at least $60 per barrel (some estimate more than that) to keep going. OPEC producer Indonesia may even become a net importer of oil, simply because it can’t afford to continue production development. You can’t turn oil production on and off like an automobile plant; it has to keep flowing. Brazil and Mexico are facing similar problems with their deepwater projects. OPEC wants to achieve a goal of $75 per barrel and they’ll likely get what they want, sooner than later.POLITICS IS BORINGLeaving world politics behind, we come into the much more exciting realm of control and instrumentation technology. What is interesting here is what companies are doing to squeeze more oil from existing wells. Pure economics is forcing them to do it. The North Sea oil field is close to us, so we find out more about what they’re doing up there than anywhere else. We hear that off the coast of Norway, a new oil and gas field called ‘Tyrihans’ is due to start production this year. It is one of the biggest developments on Norwegian continental shelf in recent years, holding 176 million barrels of oil and 30 billion cubic meters of gas. To move things along StatoilHydro is positioning five subsea skids 300m underwater. Four of the skids are for production and gas injection. The fifth skid has a special design: it has a 2.5 mW pump motor on it for the sole purpose of injecting raw seawater into the undersea oil reservoir. Each day pumps will suck in 14,000 cubic metres of untreated seawater and inject this and gas into the reservoir. This raises the pressure in the field and facilitates oil extraction. WHERE DOES IT GO?After the oil comes up, where does it go? The five skids are out in the middle of nowhere. The nearest oil platform, called Kristin, (love these Norwegian names) is 31 kilometres away, as the seagull flies. So StatoilHydro has built an electrically heated pipeline—freezing temperatures out there, you know—to connect the Tyrihans field with Kristin. The pipeline itself is actually 43 kilometres long.There are several challenges involved in controlling heavy production equipment 300m below the surface, from a distance of 31 km across the open sea, but let’s just look at one of them: Where do you put the motor drive for the 2.5 mW pump? As you know, in most manufacturing plants, the motors and drives are in the same room, or at least not too far away. But there’s nothing out there on the surface in the Tyrihans field. Nowhere to put it.So, StatoilHydro ordered an ABB ACS1000 medium voltage frequency converter and politely asked the company: would you please install it on the Kristin platform, and come up with some fancy—and very long—undersea cabling to do the job? We’re not going to build a platform in the Tyrihans field, so you figure out how to do it.ABB had to carry out dynamic simulations to determine how the electrical system would behave, but it was possible to meet the technical requirements, after stretching the technology to its limits. ‘We were really challenged,’ commented ABB project manager Ole Meyer in Bergen. ‘It's a world record, as far as we know.’In addition to the unusual pump motor-converter connection, ABB is also supplying the biggest subsea transformer it has ever delivered for the injection skid on the sea floor. For the Kristin platform, ABB will supply specially designed transformers, frequency converters and a controller with newly developed software to power subsea motors, and ensure optimal operation of the injection pumps. The subsea cable and platform equipment will be installed in 2009-2010.
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