Patent ID: 8441269
Filing Date: 2013-05-14
Classification: G01V

Abstract:
1. A method to determine the salinity of connate water in a subsurface formation using a downhole logging tool or assembly, comprising: providing a downhole logging tool or assembly having the ability to make substantially concurrent disparate measurements on the subsurface formation; making substantially concurrent disparate measurements on the formation using the downhole logging tool or assembly; defining a range of salinity values; computing a water capture cross section value and a water resistivity value for each salinity value in the range of salinity values; computing a first water saturation value using the computed water resistivity value, for each computed water resistivity value; computing a second water saturation value using the computed water capture cross section value, for each computed water capture cross section value; computing the square of the norm of the difference between the first water saturation value and the second water saturation value, for each pair of computed water saturation values corresponding to a salinity value; and selecting the salinity value that corresponds to the minimum computed squared norm as the determined salinity of the connate water.