Scattering Detection from Downhole Optical Spectra

摘要

Obtaining in-situ, at a first time, first optical spectral data associated with a formation fluid flowing through a downhole formation fluid sampling apparatus, and then obtaining in-situ, at a second time after the first time, second optical spectral data associated with the formation fluid flowing through the downhole formation fluid sampling apparatus. A wavelength-independent scattering intensity within the formation fluid flowing through the downhole formation fluid sampling apparatus is then determined based on the first and second optical spectral data, and a wavelength-dependent scattering intensity within the formation fluid flowing through the downhole formation fluid sampling apparatus is determined based on the first and second optical spectral data.

主权项

1. A method comprising:
operating a downhole acquisition tool in a wellbore in a geological formation, wherein the wellbore or the geological formation, or both contain a fluid that comprises a native reservoir fluid of the geological formation and a contaminant; receiving a portion of the fluid into the downhole acquisition tool; measuring a fluid property of the fluid using the downhole acquisition tool, wherein the fluid property includes a first optical density of a first portion of the fluid at a first wavelength and a second optical density of a second portion of the fluid at a second wavelength, wherein the first and second optical densities are measured at successive times; and using one or more processors to:
determine a scattering intensity of the first and second portions of the fluid using the first and second optical densities;estimate a saturation pressure of the fluid using the scattering intensity; andadjust an operational parameter of the downhole acquisition tool based on a relationship between the operational parameter and the saturation pressure.