Genetic Mechanism Of Overpressure And Pressure Prediction In Turkmenabat Terrace In Turkmenistan

Due to the harm of abnormal pressure to drilling, it’s important to do the pore pressure prediction study. Because of the far-ranging overpressure in Turkmenabat terrace in Turkmenistan, this dissertation gave a research of pressure prediction by combination of logging and seismic method by mean of 3D seismic data, relative logging and geological data.On the basis of seismic data processing method, the original data from 3 aspects containing signal to noise ratio, vertical resolution and migration have been analyzed and studied. By all kinds of tests, the reasonable parameters are defined. Finally it has improved the processing quality, and prepared a good base for the precision of velocity picking.The building method of interval velocity field is the necessary path to improve the precision of interval velocity. By studying and utilizing 6 aspects including the seismic semblance optimization, velocity on the well location setting up, floating datum definition, lateral extrapolation along the layer and velocity picking method, it optimized the building method of interval velocity field, and improved its precision by seismic data.By studying the genetic mechanism of overpressure, it can grasp the basic distribution of abnormal pore pressure, and carry out the pressure prediction by considering all factors caused from abnormal pressure. On the basis of the genetic mechanism of overpressure study, the cause of overpressure in the studying zone from 6 aspects has been comprehensively analyzed, which contains undercompaction, territorial salt sediment, tectonic extrusion, hydrocarbon creation, water heated expanding and hydrocarbon migration, it found out the genetic mechanism of overpressure in Turkmenabat terrace.By analyzing and studying the VSP, seismic data and geological structure in studying zone, combining the calculation method of stratum pore pressure prediction, it puts forward the experience formula in Turkmenabat terrace. The pressure prediction was carried out in the studying zone and got a good validating result. It provided the theoretical foundation for stratum overpressure prediction.