The write down is the result of the bad "macro outlook," Shell said in a press release, which refers to the slowdown in the global economy, weak demand growth and relatively low prices for gas, oil and for refining margins. "Additional well write-offs in the range of $100-200 million are expected compared to the fourth quarter 2018. No cash impact is expected," Shell said in a statement. The company's share price in London fell 1 percent on the news.

Shell didn't offer a lot of details, but hinted that several of its segments would be impacted by a deterioration in the outlook. "Chemicals cracker and intermediate margins are expected to be materially lower than the third quarter 2019 due to the continued weak macro environment," Shell said, for example.

Shell also said that it would keep its fully-year capex for 2019 at the low end of its original guidance of $24-29 billion.