Investors’s fears that Royal Dutch Shell will fail to complete its planned £43bn acquisition of BG Group have been exaggerated, Shell’s chief executive has said.

With U.S. crude oil prices 47% lower in first-half 2015 compared to first-half 2014, U.S. onshore companies experienced a significant reduction in cash flow from operations. Most companies responded by reducing capital expenditures.

“Russia and OPEC have talked about cooperation in cutting production many times in the past, but the results of that were always dismal and disappointing,” said Nordine Ait-Laoussine, president of Geneva-based consultant Nalcosa and former energy minister of Algeria. “Russia has assumed that when oil prices go down, OPEC countries are in a weaker position and are more likely to be the first to cut its production, and they always did.”

Top oil exporter Saudi Arabia sees no need to hold a summit of producing countries' heads of state if such discussions would fail to produce concrete action toward defending oil prices, sources familiar with the matter said on Thursday.

Brent crude oil prices will average $54/b in 2015 and $59/b in 2016. Forecast West Texas Intermediate (WTI) crude oil prices in 2015 and 2016 average $5/b lower than the Brent price. The current values of futures and options contracts for December 2015 delivery suggest the market expects WTI prices to range from $32/b to $73/b (at the 95% confidence interval) in December 2015.

Russia is overhauling its approach to crafting the budget next year to safeguard reserves, highlighting the challenges it faces in steering the recession-hit economy through a downturn in oil prices.

Low oil prices risk causing a lack of investment in conventional oil supply in non-OPEC countries, strengthening OPEC market power and creating additional uncertainty, the IEA's director for energy markets and security, Keisuke Sadamori, said Tuesday.

Britain's North Sea oil and gas sector has shed more than 5,000 jobs since late last year, the country's new Oil and Gas Authority said on Monday, putting an official figure on job losses resulting from a year-long decline in oil prices.

Energy companies have been hurt by the swoon in crude prices this year, but Canadian Oil Sands is among the worst performing. The company’s stock has lost almost 40% of its value so far this year, compared with a 22% decline in the Toronto Stock Exchange energy index.

U.S. crude-oil futures remained in negative territory Tuesday in Asian trade, tracking the previous day’s drop in Brent crude when U.S. markets were shut for a holiday.