UPDATE 2-Halliburton says Pemex slowdown to hit Q4 profit

* Halliburton sees 2 cent hit to Q4 EPS on Mexico slowdown

* Halliburton shares down more than 2 pct after-hours

* Weatherford, Noble Corp both down 1 pct (Adds detail on Mexico natural gas demand, Pemex spending)

SAN FRANCISCO, Nov 24 (Reuters) - Halliburton Co (HAL.N: Quote, Profile, Research), the world's second-largest oilfield services company, said it expects that reduced activity in Mexico will weigh on its fourth-quarter profit, and its shares fell 2 percent.

Halliburton said on Tuesday that work in Burgos, Veracruz and southern areas was hit by the decision of state-owned oil company Pemex [PEMX.UL] to reduce activity because of low natural gas prices and other constraints.

Halliburton said it expected its fourth-quarter earnings would be reduced by 2 cents per share as a result. Analysts had been expecting earnings per share of 28 cents for the quarter, according to the average on Thomson Reuters I/B/E/S.

Pemex was not immediately able to comment.

Mexican natural gas demand has grown in the last year as the power sector has switched to burning more gas as it has fallen in price relative to other fuels.

However Pemex is under government pressure to reduce wasteful and polluting gas flaring at its Cantarell oil field which is expected to add substantially to domestic gas supplies in the new year once new gas compression and treatment equipment is installed.