Method of analyzing oil and water fractions in a flow stream

US5331156A · kind A · utility

Assignee

• SCHLUMBERGER TECHNOLOGY CORPORATION · US

Inventors

• Daniel R. Hines · Lawrenceville, US
• Noboru Wada · Tokyo, JP
• Stephen Garoff · Pittsburgh, US
• Oliver C. Mullins · Ridgefield, US
• Paul Hammond · Bourn, GB
• Jeffrey A. Tarvin · Brookfield, US
• Stephen P. Cramer · Palo Alto, US
• Ralphe Wiggins · Stamford, US

Key dates

• Filing date: Feb 9, 1993
• Grant date: Jul 19, 1994
• Expiry date: Feb 9, 2013

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N33/2823
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Methods for quantifying the oil and water fractions of a fluid stream. A first method broadly includes making optical density (OD) measurements of the fluid stream by detecting photons of a first predetermined energy where the oil and water absorption characteristics are substantially identical (e.g., 1710 nm wavelength), and determining the oil and water fractions f.sub.o and f.sub.w according to OD.perspectiveto.f.sub.w .alpha..sub.w l+f.sub.o .alpha..sub.o l where .alpha..sub.w and .alpha..sub.o are related to the absorption coefficients of the oil and water at the predetermined energy, l is the path width of the fluid stream, and f.sub.w +f.sub.o =1. A second method which eliminates scattering effects utilizes the photons at the first predetermined energy and further utilizes photons of a second predetermined energy which is sufficiently close to the first predetermined energy such that the oil fraction is a linear function of the OD over the energy range. The oil and water fractions are then determined from the difference in optical density values (.DELTA.OD) according to .DELTA.OD=f.sub.o [(OD.sub.o,a -OD.sub.o,b)- (OD.sub.w,a -OD.sub.w,b)]+(OD.sub.w,a -OD.sub.w,b), where OD.…