Variation in reservoir connectivity in vertically stacked deepwater turbidite channels: impacts on oil recovery

Abstract

The study demonstrates the influence of variable reservoir connectivity on oil recovery from turbidite reservoir marked by stacked channel architecture. The considerable variability in facies types and distribution affects the geometry and dimensions of sand bodies that make up individual channel forms. The results from the application of attribute indices approach to estimate connectivity of the reservoir facies are pretty consistent with the conceptualised facies distribution across the reservoir system. The vertical stacking pattern of channel-fill facies enables a levee complex to develop. This complex bound up with slope sediments improving lateral connectivity between channel-fill and overbank facies for effective communication between injection well (16/07a-B14) that penetrates the slope facies and production well (16/07a-B1) that penetrates the channel-fill facies. The occurrence of mudstone at the base of individual channel forms reduces vertical connectivity at channel margins. The mudstone distribution constitutes a major risk to vertical oil sweep, particularly in channel-axis, channeloff-axis and channel-margin sequences. In order to optimise oil recovery from deepwater turbidite reservoirs with similar reservoir architecture, it is therefore crucial to consider a depletion strategy that will reduce the risk of differential waterflood performance and improve oil sweep, particularly in the vicinity of production wells.