Publications

In 2018, ConocoPhillips Grissik Limited (CPGL) completed a reprocessing project of the 3D seismic data over Suban field. The primary objectives of the reprocessing were to improve the seismic imaging of previous data which has abundant noise, low resolution and a lack of reflector continuity at the reservoir level. Improvements in seismic quality will improve the detailed structural and stratigraphic interpretation which will support further field development efforts for the lower Talang Akar Formation and basement reservoirs. The processing started with the raw field data and was conducted in two phases: a pre-processing and pre-stack time migration phase followed by pre-stack depth migration phase. It incorporates thorough noise attenuation and detailed velocity analysis. Major differences with the previous pre-processing workflow include the application of adaptive ground roll and guided waves attenuation, and curvelet-domain de-noise to attenuate random noise while increasing the signal-to-noise ratio. In addition, 5D interpolation was performed in common offset vector domain to achieve higher stacking fold as well as a broader seismic frequency. The final velocity model generated from the initial pre-stack time migration velocity model was then refined with five iterations of wide-azimuth tomography and a basement velocity sweep. In the model building process, the velocity profile progressively converged to the trend of the available well data. The overpressure zone in the Telisa Formation and velocity of an overhang structure were also built in to capture details in the velocity model. Finally, control beam migration technology was utilized for depth imaging since it is able to handle multiple arrivals, imaging around complex geological structures, such as steep dips and reverse faults, and it can provide higher signal to noise ratio. Compared to the previous processing data, the newly reprocessed 3D pre-stack depth migration stack shows major improvements in frequency content, higher signal to noise ratio and continuity and in steep dip imaging. Detailed stratigraphic and structural interpretation of the lower Talang Akar Formation and basement events can now be performed with greater confidence to identify future opportunities in Suban Field.