Patent ID: 7558716

Claim:
A method for estimating the amount of supercharging in a formation penetrated by a wellbore, the method comprising the steps of: obtaining measurements of pressure fluctuations at a position in the formation accessible from the well bore and at an adjacent position in the wellbore; in a computer, providing a formation flow model which relates variations in pressure with time at said positions to one or more adjustable parameters from which the amount of supercharging can be estimated, at least one of the one or more adjustable parameters accounting for the influence on fluid flow of a wellbore filter cake layer and/or the influence on fluid flow of the formation, wherein the model is a forward model accounting for the drilling history of the wellbore; adjusting the one or more adjustable parameters to provide a best fit between the pressure variations predicted by the model and the measured pressure fluctuations; and estimating the amount of supercharging from the one or more adjustable parameters thus-adjusted.