A practical 4D seismic attribute to estimate saturation and pressure changes arising from reservoir production and injection

One of the main objectives of 4D seismic interpretations is to estimate pressure and saturation change caused by reservoir production and injection. Estimation of these changes would assist to update the simulation and geomechanical models of our hydrocarbon reservoirs. Different techniques have been recently proposed to estimate the pressure and saturation changes using 4D seismic data. Typically, these methods linearly decompose the effect of pressure and saturation changes. For calibration of the proposed equations, laboratory measurements, rock physics relationships or even reservoir scale simulation model and well production data have been employed. Although, they work reasonably well in the given datasets, there is a need for extensive pre-setting steps to calibrate these equations which in turns requires time and cost. In this paper, Rock Physics and Petrophysics principles are utilised in order to develop two independent attributes which can calculate the pressure and saturation changes, separately. Both equations are easy to apply and interpret, and require not more than a few hours for their parameters calibration. Although, these two independent attributes were successfully implemented in one of the North Sea complex oil reservoir, but both attributes are qualitative indication of pressure and saturation changes.