SCA2003-49: SENSITIVITY STUDIES OF FLUID FLOW ACROSS WATER-SATURATED FAULTS WITH HIGH ENTRY PRESSURE

摘要

Water-saturated faults with high oil entry pressure and very low permeability may hinder the flow of hydrocarbons in reservoirs due to formation of traps or fault-related compartments.This compartmentalisation can lead to lower than expected reservoir performance as has been observed in several oilfields in the Brent Province in the North Sea.This paper presents numerical simulations(using an Eclipse Simulator)of two-phase(oil/water)flow in models that mimic reservoir/fault situations.The fault rock is initially 100% water saturated and is expected to continue acting as a sealing fault/barrier to oil flow until its capillary entry pressure for oil is exceeded.A ceramic material has been selected to represent the fault while the reservoir zone is Berea sandstone-both rocks were characterised by special core analyses.The ceramic material can be viewed as a porous membrane across which transport is obtained by a potential difference,which was achieved by pressure drawdown due to production.Relative permeability and capillary pressure data were derived from established correlations and mercury porosimetry data.The results show that fluid conductivity in the fault varies with initial water saturation in the reservoir zone.Also,the oil breakthrough and recovery are highly controlled by the fault properties(permeability,entry pressure and thickness).