THE IMPACT OF UNCERTAINTY ON SUBSIDENCE AND COMPACTION PREDICTION

Abstract

This paper presents the stochastic approach using Monte Carlo simulation as applied to compaction and subsidence estimation in an offshore oil and gas deep-water field in the Gulf of Mexico. The results reveal both the impact of using probability distributions to estimate compaction and subsidence for a disk shaped-homogenous reservoir as well as taking into account Young's modulus, Poisson's ratio and the reduction of pore fluid pressure. The uncertainty reservoir model is also compared with numerical simulation commercial software - Eclipse 300. The stochastic-based simulation results confirm that the deterministic results obtained from the coupled geomechanical - fluid flow model are in the range of acceptable distribution for stochastic simulation. The sensitive analysis shown that Young's modulus has more impact on compaction than Poisson's ratio. The results also presented that values of Young's modulus in this deep-water field in Gulf of Mexico lying beyond 140,000psi are insignificant to compaction and subsidence. Based on output results of compaction and subsidence with the stochastic model, potential reservoirs presenting subsidence and compaction are described as an uncertainty range within distribution of Young's modulus, Poisson's ratio and the reduction of pore fluid pressure in large-scale regional model.