Research on Architecture Pattern of Deepwater Turbidity Channel in X oilfield of Neogene, West Africa

Lin, Yu; Wu, Shenghe; Lu, Yao; Wan, QIonghua; Zhang, Jiajia

Turbidity channel is an important reservoir style of submarine fan. Although Studies on the architectures of turbidity channels have been largely carried out by many researchers, the morphology, scale and superimposed style of low-graded architecture units have not been deeply understood. Taking X oilfield of Neogene in West Africa as an example, architecture patterns of turbidity channels from three hierarchies (channel complex set, channel complex, elementary channel) are studied and the 3-D reservoir architecture models of turbidity channels are built. The results depend on variety high-quality data of the study area. There are 34 wells altogether (the minimum well space is 200m) and 500m systematic core data. It also has high resolution 3-D seismic data (dominant frequency is 65HZ). The methods such as core observation and description, well logging analysis, seismic spectral decomposition and seismic strata slicing are utilized in the analysis procedure. Finally, four conclusions are obtained from this project. (1).Elementary channels are 300-600m wide and 10-30m deep. When the bend curvature reaches 1.6, the channel is defined as high-sinuosity channel. The Cut-off happens for the channel interval when its bend curvature reaches 6. (2).Elementary channel, based on internal filling characteristics, can be grouped as slump-filling channel, high-density sandy channel, low-density sandy channel(internal beddings are evident)and mud abandoned channel. In view of the intensity and direction of erosion process, elementary channel can be classified as longitudinal erosion-dominant channel, lateral erosion-dominant channel and weakly erosional channel. (3).Channel complex manifests various superimposed styles, including disordered style (a), lateral amalgamated style(b),inclined en echelon style(c), vertical swinging style(d) and solitary style(e). Vertically, the channel complexes have a rule of evolution from (a) to (e) upwards. (4).Along the source direction, the confined degree of Channel complex set varies in a character of decreased-increased-decreased. The bend curvature of channel complex set has a logarithmic relation with aspect ratio and a power relation with slope gradient.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013