Finite element simulation of Wilmington oil field subsidence: I. Linear modelling

The Wilmington oil field in Long Beach California has been a site of large ground subsidence since the onset of production. The cause of the subsidence has been attributed to the lowering of pore fluid pressures in the formations of the field. In this study the subsidence in the Wilmington field is simulated numerically by solving the equilibrium equations for a region of the earth's crust containing the oil field. The input parameters for the calculation include a linearly elastic rheological mode for the formations of the field and pore pressure values at the producing zones at specified times. It is found that the numerical simulations can reproduce reasonably well most field observations. There remain however a few observations which the present model cannot explain, a fact which suggests that the material response of the field is more complicated than that of the linearly elastic model adopted in the present study