Oil field services company Schlumberger and tool-maker Cameron International said their proposed $12.7 billion merger was cleared by U.S. regulators.

"The U.S. Department of Justice has cleared their proposed merger without any conditions," the companies said in a joint statement.

Schlumberger made the offer for the Houston-based maker of tools for oil field development in August, saying the combined entity would have a "pore-to-pipeline" footprint in the industry.

When announcing the deal, Schlumberger Chief Executive Officer Paal Kibsgaard said innovation and integration would help companies like his survive the market downturn.

In a September report, the U.S. Energy Information Administration said total upstream investments could stay below the 10-year average if crude oil prices remain depressed. West Texas Intermediate, the U.S. benchmark for crude oil prices, closed trading Tuesday at $40.67 per barrel, down about 7 percent from last week.

Schlumberger counterpart Halliburton last year made a move to acquire rival Baker Hughes. Each company has cut staff and spending in an effort to survive in the weak oil economy. Both companies said they were unloading several business units as they prepare for their eventual $35 billion merger.

Cameron stockholders are scheduled to hold a special meeting Dec. 17 to consider a vote on the merger with Schlumberger.