Fluid flow pipes triggered by lateral pressure transfer in the deepwater western Niger Delta

Abstract

Using three-dimensional (3D) seismic data, we establish a simple model for the development of vertical fluid flow pipes in the deepwater western Niger Delta. We analyse two examples of fluid flow pipes that form vertical seismic chimneys that are 400–600 m wide and ∼2000–2500 m in height, terminate at the current seabed and have bases located at the crest of rollover anticlines. In both cases we identify buried deepwater channels-complexes located below the pipes that formed prior to the growth of the rollover anticlines. The development of the anticlines caused tilting of these channel complexes and differential loading. We propose the channel complexes represent connected permeable reservoir intervals and that lateral pressure transfer caused the pore pressure at the crest of the structures to reach critical levels, leading to hydraulic fracturing of the overburden. Although hydrocarbons may migrate upwards through the chimney systems, they are not necessarily indicators that the channel complexes were gas or oil charged.