Oil prices extended their decline on Wednesday, deepening a selloff that pushed both major benchmarks to three-week lows. Brent crude futures fell 92 cents, or 1.2%, to $78.44 a barrel by 3:30 a.m. GMT. U.S. West Texas Intermediate futures dropped $1.07, or 1.4%, to $74.70. Brent had fallen more than 12% for the week. WTI had lost more than 11% over the same period.