This excerpt taken from the PBR 6-K filed Nov 19, 2009.
Due to the average inventory period of 60 days, international oil and oil product prices, as well as the impact of the exchange rate on imports and government take are not fully reflected in the cost of goods sold in the actual period, but in the subsequent period.
The chart below shows the estimated impact on COGS:
(*)The impact of selling inventories formed at a lower unit cost in previous periods was greater in the 3Q-2009 than in the 2Q-2009, generating a positive effect when comparing COGS in the two quarters, partially offset by the period increase in COGS. Besides the behavior of international oil and oil products prices and FX rate, the effects above were also due to other factors such as the concentration of operations throughout the quarters (production, imports, sales), inventory volumes and other expenses evolution (personnel, material, services, depletion of oil fields, depreciation of equipments, etc.)
A R$ 2,520 million increase in the following operating expenses:
√ General and administrative expenses (R$ 132 million), due to the increase in expenses related to engineering services, given the expansion of the Companys operations, and personnel training and development expenses; and
√ Other operating expenses (R$ 2,394 million), due to the recognition, in September/2009, of the special take from the Marlim field, pursuant to the agreement between Petrobras and the ANP (R$ 2,048 million).