July 30, 2012. Asian refiners will boost imports of Angolan crude in August to the highest level in six months while purchases from Nigeria will drop to a new low. Refiners bought 1.31 million barrels a day from Angola, the highest since February, and oil from Nigeria will be reduced to 154,032 barrels a day, the lowest since at least August 2011. In total, 59 cargoes amounting to 1.76 million barrels a day will be shipped from Angola, Nigeria, Republic of Congo, Equatorial Guinea, Democratic Republic of Congo and Gabon. Buyers in Asia can opt between Middle Eastern crude or Atlantic Basin grades, and their choice normally depends on the value of the lighter, sweet blends from the North Sea and West Africa versus heavier, sour grades from Saudi Arabia and Iran. Lighter crude yields more lucrative products such as diesel and gasoline. Sweet grades contain less sulfur than sour.