--> --> Holistic Approach in Integrating Multiple Datasets When Building Geological Models of Complex Reservoir Sand Bodies in the South Coast Gas Field in Bredasdorp Basin, South Africa

2018 AAPG International Conference and Exhibition

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Holistic Approach in Integrating Multiple Datasets When Building Geological Models of Complex Reservoir Sand Bodies in the South Coast Gas Field in Bredasdorp Basin, South Africa

Abstract

The Field was discovered by the wellbore A in 1983 and further appraised by 5 more wells. In 2007, a development wellbore was drilled to further harvest the gas within one of the fault blocks identified in the Field from the synrift reservoirs. The Field is highly faulted causing a major uncertainty with respect to the connectivity of the upper shallow marine and fluvial reservoirs within the different fault blocks. Tectonics have played a major role in the current faulted nature of the field and the existing geological setting. This study focuses on the modelling of the entire Field to capture the complexity related to the reservoir heterogeneity specifically the fluvial channels of which their channel width, depth, wavelength and amplitude character lack vivid clarity on the available 3D seismic data. Channel analogues from various fluvial environments around the world were used to define the above mentioned channel parameters, in addition to seismic anomalies and dip meter data which were integrated in finding the channel orientations. Connectivity across the fault blocks was also investigated using fault seal analysis in order to decipher whether any cross flow from adjacent fault blocks could be detected to aid in the optimal placement of the proposed development well.