Compositional changes resulting from the water-washing of a petroleum fluid

Several mechanisms can be responsible for the compositional modification of a hydrocarbon fluid in a reservoir. One of them is related to its contact with a large amount of connate water. This water-washing phenomenon has been simulated in model laboratory conditions. A compositional analysis of both water and hydrocarbon phases at every stage allows for a direct visualisation of the effect of water-washing. Volumetric measurements have been performed simultaneously. Henry's law is used to describe the hydrocarbon solubility in water. This approach is validated with a global mass balance. (C) 2001 Elsevier Science B.V. All rights reserved.