Mexico racing against time at Cantarell oil field

MEXICO CITY (Reuters) – Mexico’s state energy company Pemex is scrambling to extract what oil it can from its key Cantarell deposit as growing water and natural gas levels in the giant field depress yields of crude.

Cantarell produced more than 2 million barrels per day as recently as 2004, but yield has plunged as the aging field enters its natural decline phase, sending Mexican oil production tumbling to its lowest level since the mid-1990s.

The giant offshore Akal field and several nearby deposits that Pemex groups as Cantarell produced only 713,000 bpd in April, below Pemex’s forecast of 756,000 bpd for 2009. Yields from the area have fallen at annualized rates of more than 35 percent in recent months.

Pemex engineers said at a conference last week that the oil layer of the Akal field is shrinking by at least 4 meters (13 feet) a month as gas moves downward and water moves upward in the rock formation.

Contraction of the oil layer means many of the traditional vertical wells Pemex has used to drain Cantarell since the late 1970s are getting flooded by gas or water, which forces their closure.

To prolong the field’s life, Pemex is drilling horizontal wells costing more than $20 million each. These extend hundreds of meters (feet) along the middle of the shrinking oil layer.

Reuters