BHP Billiton has announced that the Mad Dog South (826-5) appraisal well and sidetrack, drilled and operated by BHP Billiton, had encountered a significant hydrocarbon bearing reservoir. The 826-5 well is located on Gulf of Mexico Green Canyon block 826 approximately 100mi south of Grand Isle, Louisiana, in 5100ft of water. The well encountered 280 net feet of hydrocarbons in the objective, Miocene hydrocarbon bearing sands. The subsequent sidetrack reached a total measured depth of 27,143ft and discovered an oil column of more than 2200ft. The results from this well continue the successful phased development of the Mad Dog field and build upon the success of the A-7 well which came online in February 2008 in the western part of the field and encountered more than 2500ft hydrocarbon column, and 275ft of net pay.