EP 1511979 A1 20050309 - METHOD AND APPARATUS FOR A DERIVATIVE SPECTROMETER
Title (en)
METHOD AND APPARATUS FOR A DERIVATIVE SPECTROMETER
Title (de)
VERFAHREN UND VORRICHTUNG FÜR EINEN DERIVATIV-SPEKTROMETER
Title (fr)
PROCEDE ET APPAREIL POUR UN SPECTROMETRE PAR DERIVATION
Publication
Application
Priority
- US 0317648 W 20030604
- US 16203002 A 20020604
Abstract (en)
[origin: WO03102520A1] The invention comprises a method of adapting derivative spectrometry for use in a downhole environment and addresses problems that are inherent in this environment. Such problems include, but are not limited to, elevated temperatures and scattering from particles residing within dirty fluid samples. Under such conditions, the photometric resolution of a spectrometer decreases at the same time that the need for better resolution increases. The invention improves the resolution by measuring the first derivative of the spectrum. The derivative spectrometer of this invention operates by vibrating a linear variable interference filter back and forth along the plane of the filter or by oscillating a circular variable filter about some angle. The effect is to oscillate the wavelength of light that is received by each photodetector. The photodetector signal can be electronically filtered to reject signals that are not at the oscillation frequency and which do not have a fixed phase relative to it. In a preferred embodiment, a vibrating actuator is the means to achieve the required oscillations about a given wavelength. Derivative spectrometry gives a higher resolution than normal methods of spectrometry. Through improved resolution, it is possible to estimate the contamination percentage of the crude oil in real time. Furthermore, it is possible to determine whether a contamination percentage is leveling off over time. It is expected that high-resolution spectra enable an improved estimation of the percentages of methane (natural gas), aromatic, olefins, saturates, and other crude oil properties.
IPC 1-7
IPC 8 full level
G01J 3/26 (2006.01); G01J 3/433 (2006.01)
CPC (source: EP)
G01J 3/26 (2013.01); G01J 3/433 (2013.01)
Citation (search report)
See references of WO 03102520A1
Citation (examination)
US 2001030288 A1 20011018 - WILKS PAUL A [US], et al
Designated contracting state (EPC)
DE DK FR GB
DOCDB simple family (publication)
WO 03102520 A1 20031211; AU 2003245395 A1 20031219; EP 1511979 A1 20050309
DOCDB simple family (application)
US 0317648 W 20030604; AU 2003245395 A 20030604; EP 03739037 A 20030604