Occidental Petroleum is aiming to extend its position as the number one producer in the Permian basin through its attempt to take over Anadarko Petroleum, but the combined company would significantly pare back the number of operated rigs in the core US shale play, writes Eoin O'Cinneide.

Should Oxy’s $57 billion proposal to acquire US independent Anadarko succeed, combined net Permian production would be 533,000 barrels of oil equivalent per day out of total global output of more than 1.4