Shares in some of the world’s biggest energy groups tumbled on Friday as the collapse in oil prices battered the profits of ExxonMobil and Chevron, capping a week in which European rivals announced thousands of job losses and slashed spending by billions of dollars.As Exxon, the US giant seen as best insulated from the crude price crash, reported its worst quarterly profits since 2009, its main US competitor Chevron suffered a huge $2.2bn loss in exploration and production in the three months to June 30. For the first time, the biggest and strongest industry operators are feeling the full effect of a plunge in Brent crude since last summer that has led to an estimated 70,000 job losses worldwide and caused some $200bn of spending on major new oil and gas projects to be shelved. The slide in the oil price, which began around this time last year, accelerated in November when Opec, the producers’ cartel, decided not to cut output in the face of a US supply glut.