LONDON: The UK North Sea has been in a state of perpetual transformation in recent years. As oil majors left the aging basin for less expensive and larger fields across the globe it has been forced to sharply cut costs to compete for investment. Then the US fracking boom upset global prices. If that wasn’t enough, investment, which has fallen by more than a third, is also under threat from lukewarm support from the UK government amid the global transition to greener energy. Oil major Shell last week pulled out of a large-scale development in the aging basin amid accusations that government pandering to environmentalists was behind delays in formally licensing the scheme and had made it uneconomical. Now it appears the very definition of the black gold extracted from the forbidding waters of the North Sea is also under threat with the news that UK oil major BP is backing calls to add US West Texas Intermediate Midland crude to the global Brent benchmark index. Brent is the benchmark for almost two thirds of the world’s oil — around 100 million barrels per day (bpd) — including African, European, and Middle Eastern crude. These days it is based on five North Sea crudes — Forties, Brent, Osebe Ekofisk and Troll — all of which are in long-term decline. However, now BP, one of the UK’s biggest companies and an oil major with a long and profitable North Sea history, believes Brent should now include WTI. BP discovered the Forties field in 1970. The Brent field was discovered by Royal Dutch Shell a year later. In an internal document quoted by Reuters news agency this week BP said it “strongly believes that the inclusion of WTI Midland, properly executed, is the best solution to improve liquidity and retain Brent as a well-supplied and reliable sweet and light benchmark”. BP declined to comment. Adding WTI to Brent poses a problem in that their prices are based on two different markets, with different price drivers. However, the move, which was first put forward by S&P Global Platts — the energy prices agency which first established the Brent benchmark — is becoming widely seen necessary because falling North Sea supplies have made it difficult to rely on the benchmark as a reliable indicator of the price of light, sweet crude oil preferred by refiners. WTI, the benchmark used in much of North America, refers to the gathering point in West Texas where pipelines from fields in the American interior converge. Like North Sea oil, WTI is defined as light sweet, which is low in sulphur. While quality and the location of where oil is drilled are key factors in valuations, there are essentially just three types of oil in terms of global prices. Brent, the most heavily traded, WTI, and Dubai/Oman. The percentage of sulfur in crude determines the amount of processing needed to refine the oil into energy products. Brent and WTI sweet crude both contain less than 1 percent sulfur making them easier to refine, particularly for diesel and gasoline. Dubai/Oman has a much higher sulfur content but is the main benchmark reference for Persian Gulf oil delivered to the Asian market. However, analysis carried out by S&P Global Platts indicates North Sea crude is getting heavier and more sulfurous. It adds medium sour crude will make up around 30 percent of the basin’s volumes by 2040 compared to just over 2 percent in 2010. Thus another solution to declining production of North Sea light sweet crude is to include heavier oil from Norway’s massive North Sea Johan Sverdrup field, oil which is in demand in Asia. However, BP states in the leaked document that it does not support the idea of adding the Sverdrup field to Brent because it’s a too sour grade of crude and it wants to maintain the lighter, easier to refine market. Thus, the momentum to include WTI to keep Brent sweet and provide liquidity to the market is growing and is likely to prevail. And in words that show sentiment plays no part in business, the BP document added: “BP also believes that in the medium term, Forties and Brent (the two cornerstones of North Sea development) should be removed from the benchmark, as their values are becoming increasingly difficult to assess due to declining volumes.”