The effective basin model concept and fast 3-D overpressure modelling in basin time scale

The approaches and background Earth model applicable for overpressure phenomenon investigation have been reviewed and systemised in the context of their applicability for pre-drill and while-drill prediction. An Effective Basin Model (EBM) concept has been introduced basing on the successive assumption simplifying full-scale basin modelling solutions. The EBM concept allows to incorporate 1-D and 2-D approaches to overpressure modelling in basin time scale. The relevant combine 3-D overpressure modelling operator has been designed. The operator has been capable to account for the main overpressuring mechanisms including 3-D pressure communication phenomena (centroid effect, dipping aquifer beds, pressure drop across the sealing faults, etc.). A stable implicit scheme has been developed for numerical pressure solutions. The scheme reveals absolute numerical stability within the practically important range of model parameters and combined grid properties. The benefits of the developed combined 3-D HD approach versus full scale 3-D regular grid solution in computing speed is estimated to be about N⋅(105-106) times for the Earth model cube based on about 109 cells. The applicability of the new fast 3-D modelling scheme has been tested on real geology settings and has been checked against real data. The Gulf of Mexico basin has been used for prototyping of the centroid effect on salt induced positive Cainozoic structures. The North Sea tectonics has been used for simulating overpressured fault sealed compartments.