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

The development of shale oil with horizontal wells in Jimsar Sag of Junggar Basin has entered the stage of large-scale productivity construction. The fine description of faults is very important to improve the effective producing degree of shale oil resources in Jimsar Sag and provide in advance warning for drilling and fracturing of horizontal wells. According to the results of the drilled wells and fault identification from new acquisition 3D seismic with broadband azimuth and high density, fault in the shale oil reservoir of Jimsar Sag is generally developed. The source and reservoir integration, high abundance of organic matter and strong plasticity for shale oil resources lead to various types of faults and different faults generating different effects to horizontal wells. In this paper, the maximum positive and negative curvature attributes with high signal-to-noise ratio are firstly obtained by 3D seismic Kalman filter method for space-time combination. This method proposes alternate iterative optimization model in space and after time and obtains the formula of space and time combined kalman filtering for seismic data. Then, the faults being open or not are studied by combining the information of lost circulation and fracturing crosstalk of the drilled wells and formation dip angle. It is found that the open faults, semi-open faults and sealed faults have their own characteristics in the maximum positive curvature, negative curvature attributes and seismic profiles, respectively. Simultaneously, that the faults are open or not can be effectively identified by their respective characteristics.