Curvature attributes with the 3D seismic Kalman filter for fault opening description — An application to a shale oil reservoir in the Jimsar sag, Junggar Basin, Xinjiang

Abstract

The large-scale shale-oil production in the Jimsar sag of the Junggar Basin is being aggressively developed. To improve unconventional production and make precise suggestions for horizontal well developments, fault interpretations using seismic data play an important role. The target reservoir in the Jimsar sag of the Junggar Basin has a comprehensive network of faults, according to the drilled wells and fault identification from the broadband azimuth and high-density 3D seismic data. Several reasons such as the integration between source and reservoir, the substantial abundance of organic matter, and the major reservoir plasticity result in different fault types, which then create different impacts on horizontal wells. We have developed a fault-type identification tool using the curvature attributes via the 3D seismic Kalman filter to provide a more accurate description of fault types. In contrast with previous studies, we derive the Kalman-curvature formulation in terms of space and time, by using a dynamically iterative optimization model. Our strategy reveals that various fault types (open faults, semiopen faults, and sealed faults) represent their characteristics associated with the 3D Kalman-curvature attributes. The resultant fault divisions are valid by combining the drilled information of lost circulation and fracturing crosstalk of the horizontal wells. High-quality field results validate the robustness of our algorithms.