NUMERICAL SIMULATION OF HYDROCARBON SYSTEMS WITH VISCOSITY GRADIENT

Methods for simulation of hydrocarbon systems having a sharply varying viscosity gradient include receiving, by a computer system, Neutron Magnetic Resonance (NMR) logs for hydrocarbon wells in an oilfield. The computer system identifies viscosity regions of hydrocarbons present within the hydrocarbon wells based on the NMR logs. The computer system determines equation of state (EOS) parameters based on compositional analysis of pressure-volume-temperature (PVT) samples obtained from the hydrocarbon wells. The computer system generates a three-dimensional (3D) model of the oilfield, using as inputs, the viscosity regions, the EOS parameters, and a fluid composition gradient with respect to a depth within each viscosity region. The computer system determines a landing depth from the surface of the Earth for operation of peripheral water injectors based on simulating the 3D viscosity model.