Interpretation of dilatometer tests in a heavy oil reservoir

This paper presents a prospective study for identifying selected parameters of the modified Cam-Clay model representing the behaviour of heavy oil reservoirs. The first part shows that the plastic compressibility, which controls the main recovery mechanism of such reservoirs, can be accurately determined, simultaneously with other parameters, by an inverse analysis of pressure-strain curves. The conditions of the identification procedure mainly involve two tests conducted under different drainage conditions or at different strain rates. The numerical study also establishes the sequence of an original in situ experimental program, in which three dilatometer tests at a relatively great depth (several hundreds of metres) were carried out. The comparison of the experimental data with the numerical computations reveals a significant over-consolidation ratio which does not allow the plastic compressibility to be determined but supports the findings regarding the geological erosion of the site. Copyright (C) 2006 John Wiley & Sons, Ltd.