Establishment And Application Of Fine Velocity Field In North Troywa Oilfield

The Caspian Basin has experienced four stages of sedimentary tectonic evolution,and the Lower Permian Konggu is a set of high-speed salt rock formations.The study area is located in the eastern part of the basin.The salt dome is 2600 m thick in the west of the work area and 400m-500 m in the east of the work area.The existence of high-speed salt domes makes the seismic data of salt subsoil poor.In addition,the large velocity difference between salt rock and surrounding rock causes the structural uplifting illusion of the seismic section,which makes the T0 structural form under the salt and the real structural form of the underground stratum inconsistent.There are more false structural traps.How to obtain the appropriate layer velocity of the salt paste layer by fine velocity research,establish the velocity field of the whole zone,eliminate the influence of salt dome on the underlying stratum,and implement the true structural form of the subsalt stratum,which becomes the key to the velocity field research.The results of previous studies have confirmed that in addition to the influence of salt domes in the work area,there is also the impact of high-speed anomalous body in the east,which also causes the up-down axis of the time domain below the high-speed anomalous body to pull up,creating structural artifacts.Eliminating the effects of high-speed anomalous body is also critical to implementing the construct.In this study,the average velocity field is established by horizon-controlling.By replacing the salt dome and limestone anomaly with layer velocity,and the average velocity field is established to eliminate the structural artifacts caused by the influence of salt domes and limestone,and restore the true structural form.