Royal Dutch Shell ( RDSa.L ) said on Friday it expects to write down up to $2.3 billion in the fourth quarter, the latest major energy company forced to shrink estimates for sector values due to a weaker economic outlook. FILE PHOTO: A guard stands outside Anglo-Dutch oil major Royal Dutch Shell’s first gas station in Mexico City, Mexico September 5, 2017. REUTERS/Ginnette Riquelme/File Photo In a trading update ahead of full year results, Shell also said it expected weaker margins in its refining, trading and marketing division while maintaining spending on the lower end of forecasts amid slowing demand for oil and gas. The Anglo-Dutch company warned in October that trade tensions between the United States and China, the world’s two largest energy consumers, could hurt demand and take a toll on its performance. Shell said it expects to take post-tax impairment charges in a range […]