Abstract
The NY structure located in the South Oman Salt Basin (SOSB), Sultanate of Oman. This structure was newly discovered and produced oil from the Ara-Birba Dolomite reservoir, which is a deep target and relatively underexplored play in the area. 3D wide azimuth (WAZ) seismic data that was processed through Pre-Stack Depth Migration (PSDM), 3D Planar Event Filtering (EVPFI) mild volume was used for the seismic interpretation due to having better seismic image continuity however too smooth for the fault identification, in this study TMA 3D was used as the input seismic volume.
Current understanding from the existing wells showing that the well that penetrates faults (indicated with losses) in the Ara-Birba Dolomite NY structure will produce better oil rate, therefore seismic fracture characterization is required for the next well placement and orientation. In this paper we will present seismic-based fracture characterization workflow based on vector high fidelity (VHF) signal enhancement technique and machine learning fault prediction.
VHF uses a Tau-p modelling /noise suppression methodology to enhance both frequency and signal within user defined frequency parameters. Machine Learning (ML) used input data label fault interpretation and used algorithm deep convolution neural network (CNN) to convert the seismic into images and look for discontinuities based on images it has seen before from the labels provided. Seismic attributes such as variance and ant-track are also used for the fault QC and visualization tools of the output fault extraction from the ML.
In conclusion, seismic conditioning and filtering with VHF 12-45Hz on the TMA3D seismic volume shows better seismic image for the fault displacement indication. ML together with the seismic attributes variance and ant-track indicate fault prediction that Ara-Birba Dolomite in the NY structure has three fault orientation groups. There are W-E faults (Tectonic Event T1), NNE-SSW fault (Tectonic Event T2) and SW-NE fault (Tectonic Event T3). The NY structure is bounded by W-E fault in the North and in the South. The NNE-SSW fault is bounding the NY structure in the East and appears in the crestal area of the structure which is a consistent result with the borehole image data in the well. Therefore, it is recommended that the next well to be drilled deviated/horizontal, perpendicular/oblique to this fault orientation result.
