MEXICO CITY, May 8 (Reuters) -

Mexican state energy company Pemex plans to reopen old wells

in a bid to squeeze more barrels out of them to boost declining

production, according to two documents and four sources, as it

struggles to reach an ambitious government target.

Earlier this week, Pemex said in a filing to the United

States Securities and Exchange Commission that it expects

production to fall to 1.58 million barrels per day (bpd) this

year rather than the 1.8 million bpd officials have consistently

touted.