Addressing Complex Structural Imaging Challenges in Southern Caspian Sea Through Modern OBN Acquisition and Processing

Summary The Greater Cheleken Area (GCA) developed by Dragon Oil, is situated on a complex NW-SE dextral transcurrent zone which separates the Northern from the Southern Caspian Basin (SCB). Complex fault systems such as highly faulted Pliocene-Pleistocene flower structures and various mud volcanoes creating slow-velocity and high-absorption dimming zone, which bring huge difficulties and challenges in seismic imaging. In 2022, an OBN seismic acquisition survey was carried out aiming to resolve the imaging problems that exist in a legacy dataset. The main objectives for the 3D OBN seismic survey are: proper imaging of structures, faults and fractures characterization, stratigraphy, petrophysical properties, gas columns and clouds mitigation and fluid contacts in clastic reservoirs cited between1500-4700m depth. The implementation of the seismic acquisition is successful, and a fast-track 3D data cube has been produced showing good results. The meticulous processing sequence has been completed and the results of the 3D seismic data processing and interpretation are very encouraging, showing a clear improvement compared to the legacy 3D seismic data set. This processing workflow and key techniques used in the project are presented in this manuscript.