Patent ID: 7920970

Claim:
A method for characterizing one or more properties of a multi-component petroleum fluid comprising: (a) measuring downhole with a downhole fluid analysis tool data representing at least one property for a group of components of the multi-component petroleum fluid and storing the data in a non-transitory, computer-readable memory, said at least one property for the group of components comprising weight percentage of the group of components; (b) using a computer processor and software stored in the computer-readable memory to derive at least one property for the respective components of the group of components based on the data stored in (a), wherein said at least one property comprises weight percentages for the respective components of the group, and an empirical relation derived from analysis of a pressure-volume-temperature (PVT) database, wherein said empirical relation follows a linear function of carbon number for the respective components of the group and is based on weighing factors calculated according to the equation, ψ i =A*CN i +β, where i varies over a range of integers corresponding to the group of single carbon number components of the group of components, ψ i is the weighing factor for the i th single carbon number component in the group of components, A and B are determined by a regression analysis of the PVT database, and CN i is the carbon number for the i th single carbon number component in the group of components; (c) using the computer processor and software and the at least one property for the respective components of the group derived in (b) to estimate or predict one or more properties of said multi-component fluid; and (d) outputting the results obtained in (c) for presentation to a user.