Oil and gas producers in the Permian Basin of West Texas will have to drill substantially more wells just to maintain current production levels and even more to expand production, analytics and data provider IHS Markit said in a report on Dec. 12.

The analysis showed the base decline rate, or the rate at which production will fall through the year, has "increased dramatically" for more than 150,000 producing oil and gas wells in the Permian Basin, the largest U.S. oil patch.

A boom in U.S. shale output over the past decade from seven major shale formations, particularly the Permian Basin of Texas and New Mexico, has made the U.S. the biggest crude oil producer in the world, ahead of Saudi Arabia and Russia.

However, production from shale wells decline faster than traditional oil wells in general. On top of that, producers have in the last couple of year tried to eke out as much oil as possible to stem a fall in revenue amid weak crude prices.

Production from the Permian Basin was at 3.8 million barrels per day at the start of the year, a million barrels per day higher than the year before, IHS said.

However, the base production is expected to decline by 40%, or about 1.5 million barrels of oil per day, by the end of 2019, according to the report.

IHS expects these declines to continue to accelerate which will be a "challenge" especially for some companies with cash constraints, just to keep production flat, said Raoul LeBlanc, vice president of unconventional oil and gas at IHS.

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