Experience in using seismic data when setting reservoir pressure in a hydrodynamic model

Setting up the reservoir pressure is an important stage of hydrodynamic modelling. This procedure is related to both validity of legacy production data and correctness of drained reserves assessment, including the accounting for impermeable boundaries, faults, and reservoir limits. When setting the reservoir pressure, there are problems associated with the convergence of calculated and actual reservoir pressure. The paper presents an example of practical approval of the method of seismic data and well testing results application to solve the problem of reservoir pressure setting up in hydrodynamic modelling. The initial geological and hydrodynamic models did not provide for impermeable boundaries because of their ambiguous delineation within all the beds. Coherence maps were used to determine the zones limiting the extent of fluid movement (presumably) showing not only fracture zones but also replacement zones and changes in reservoir properties. The results of interpretation of well testing data confirmed these boundaries. In the well testing under consideration, in addition to the model of infinite layer, the following models were used to take into account the flow unit boundaries and interpret the pressure derivative behaviour: model of a single impermeable fault; model of two parallel boundaries; and model of two impermeable boundaries intersecting at certain angle. Evidences of the presence of the boundaries were determined on the basis of well testing, wells interference, as well as these data consistency with the impermeable boundaries identified in seismic attributes. Following the analysis, faults were introduced to the full-field model as impermeable boundaries. After the calculation, convergence with the respect to reservoir pressure increased from 27 to 67 %, and estimated values reached the acceptable deviations in most wells