Radiant energy – Geological testing or irradiation – Well testing apparatus and methods
Reexamination Certificate
2006-02-21
2006-02-21
Porta, David (Department: 2878)
Radiant energy
Geological testing or irradiation
Well testing apparatus and methods
C356S128000
Reexamination Certificate
active
07002142
ABSTRACT:
A method and apparatus detects dew precipitation and determines dew precipitation onset pressure in a sample of formation fluid located downhole in an oilfield reservoir. In a preferred embodiment, the method includes (a) isolating a sample of formation fluid downhole; (b) illuminating the sample downhole with fluorescence excitation light; (c) measuring at least one characteristic of fluorescence short from the sample; (d) reducing pressure on the sample; (e) repeating steps (b) to (d); (f) detecting dew precipitation when a change is detected in a parameter that is a function of the at least one characteristic of fluorescence emission; and (g) setting dew precipitation onset pressure equal to pressure on the sample when the change in the parameter is detected. The parameter preferably is a function of fluorescence intensity and fluorescence red shift, and the change is an increase in fluorescence intensity and detection of fluorescence red shift. Also, the function includes a ratio of a measured intensity at a first wavelength to a reference intensity, and the reference intensity is a function of a measured intensity at a second wavelength.
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Dong Chengli
Fujisawa Go
Groenzin Henning
Kinjo Hideki
Kurkjian Andrew
DeStefanis Jody Lynn
Gaudier Dale
Lee John L.
Lee Shun
Schlumberger Technology Corporation
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