Deposition and evolution of V oilfield in Magdalena Basin, Columbia

After analyzing the coring, cuttings and well logging data, it can be concluded that V oilfield belongs to braided river delta facies with braided river delta front as its main subfacies and braided river delta plain deposited only in the north.After two periods of up and down cycles, the lake level became the highest during Guad-Ⅳ and Guad-Ⅱ.The frequent river diversions, widespread interlayers formed by flood plain and underwater distributary interchannel deposition and poor reservoir connectivity have resulted in a very complex oil-water system.And the underwater distributary channel and mouth bar are the main reservoirs.As controlled by sedimentary microfacies, the reservoir property of mouth bar is the best, followed by underwater distributary channel, and braided river is the worst.