Scott:

My interpretation is the specified dates represent an increases in money paid per barrel and not QTY.

Tranche. Certain securities, such as collateralized mortgage obligations (CMOs), are made up of a number of classes, called tranches, that differ from each other because they pay different interest rates, mature on different dates, carry different levels of risk, or differ in some other way.

When the security is offered for sale, each of these tranches is sold separately.

I read it as 1 tranche of 2500 bbl/d for $46 another Tranche of 2500bbl/d for $49.50.. Each tranhce has the same qty but different price.

"two attractive WTI hedges for average prices of US$46.00/bbl and US$49.50/bbl, on two tranches of 2,500 bbl/d of notional production taggered August 2009 and December 2009 maturities.