So the $9.1bn stumped up by CEFC China Energy this month for a 14.16 per cent stake in Russian oil producer Rosneft was a welcome surprise for those keen for China to become a big investor in Russia.

Oil major Chevron Corp will next year invest around $4 billion to ramp up its crude production in the Permian Basin area of the United States, a company executive said on Monday.

Second-quarter 2017 financial statements for 55 U.S. oil companies indicate that aggregate liquids production grew year over year for the first time since the fourth quarter of 2015. Cash flow from operating activities also increased year over year, the third consecutive quarter of year-over-year growth, reaching the highest level in nearly two years.

Instead, with the planned referendum just days away, Russian state oil giant Rosneft announced its latest investment last week, to help Iraqi Kurdistan develop its natural gas industry, for domestic supplies and eventual export.

“We welcome the President’s commitment to pro-growth tax reform, and look forward to working with the administration and Congress on continuing our nation’s energy leadership. Pro-growth tax reform and economic policies can further strengthen our energy infrastructure and benefit consumers. As an industry that invests billions in the U.S. economy each year, pro-growth policies would allow us to accelerate these economic investments while keeping energy affordable. Private investment in our nation’s energy infrastructure could exceed $1.3 trillion and support 1 million jobs annually through 2035.”

Norway’s $970-billion sovereign wealth fund, the world’s largest, should allocate a bigger share of its investments to renewable energy to boost returns, a U.S. energy policy think-tank said

Iran, Russia and Turkey signed agreement on maintaining trilateral cooperation in developing oil and gas fields.

"Russia is among the leading energy countries today. We see colossal unrealized potential for cooperation, for investment -- we will continue working on implementing it with all the interested parties," Novak said.

Total energy investment worldwide in 2016 was just over $1.7 trillion, accounting for 2.2% of global GDP. Investment was down by 12% compared to IEA’s revised 2015 energy investment estimate of $1.9 trillion.

“Saudi Aramco plans to invest more than $300 billion over the coming decade to reinforce our preeminent position in oil, maintain our spare oil production capacity and pursue a large exploration and production program centered on conventional and unconventional gas resources.”