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US 7,507,952 B2Granted
Apparatus and method for fluid density determination
AssigneeSchlumberger Technology Corporation
InventorsJoel Lee Groves, Etienne Vallee, Peter Wraight
Life of this patent
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Abstract
A fluid density determination apparatus and method comprising an X-ray generator emitting a high energy radiation signal and a low energy radiation signal; a sample cell housing a sample of interest and at least one of the high energy and low energy radiation signals being directed through the sample cell; and a radiation detector measuring the output radiation from the sample cell. Data gathered at the radiation detector using the high and low energy signals are used to calculate the density of the fluid sample of interest.
Claims33
A tool for downhole analysis comprising:
- an X-ray generator configured to emit a high energy radiation signal and a low energy radiation signal;
- a sample cell operably connected to said x-ray generator and configured to house a sample of interest and to direct at least one of said high energy and said low energy radiation signals through said sample cell;
- and
- a radiation detector operably connected to said sample cell being configured to measure the output radiation from said sample cell,
- wherein said radiation detector is operable to provide an output signal for determination of mass density of said sample of interest using:
- ρ=C3ρe2+C4ρe
- where ρ is mass density, ρe is electron density index, and C3 and C4 are calibration coefficients relating the electron density index of the material to the mass density.
4 more elements
A method for determining density of a fluid in a high temperature environment comprising:
- (a) producing radiation in response to an input voltage using an X-ray generator;
- (b) filtering said radiation at an output of said X-ray generator using at least two filters that are alternately disposed at said output to produce a filtered radiation signal;
- (c) channeling said filtered radiation signal through an analysis cell comprising a first channel and a second channel wherein a test material is inserted into said first channel;
- (d) detecting radiation at an output of said first channel using a measurement radiation detector wherein the radiation detected by said measurement radiation detector has passed through said test material;
- (e) detecting radiation at an output of said second channel using a reference radiation detector wherein the radiation detected by said reference radiation detector has not passed through said test material;
- and
- (f) calculating a mass density of said test material based on information gathered by said reference radiation detector and said measurement radiation detector including calculating an electron density index of said test material and further comprising a set of calibration steps to determine said electron density index, said calibration steps comprising;
- using a calibration material with a known electron density index as said test material;
- determining an attenuation due to said calibration material at a high energy and a low energy;
- plotting said high energy attenuation and said low energy attenuation against said known electron density index to create two points;
- drawing a high energy calibration curve and a low energy calibration curve from an origin (0,0) to said high energy attenuation and said low energy attenuation points;
- inserting a plurality of known mixtures with known electron density indexes;
- determining an apparent electron density index at a high energy and at a low energy for each of said plurality of known mixtures by utilizing said calibration curves;
- plotting a plurality of correlation points representing the difference between the low energy and high energy apparent electron density indexes against the difference between the high energy apparent electron density index and the true electron density index for each of the known mixtures;
- and
- generating a correlation equation for the curve extending through said correlation points, wherein said correlation equation is of the form:
- ρe,app,high−ρe,actual=C1(Δρe,app)2+C2(Δρe,app)
- where C1 and C2 are correlation coefficients.
15 more elements
A method for determining density of a fluid in a high temperature environment comprising:
- (a) producing radiation in response to an input voltage using an X-ray generator;
- (b) filtering said radiation at an output of said X-ray generator using at least two filters that are alternately disposed at said output to produce a filtered radiation signal;
- (c) channeling said filtered radiation signal through an analysis cell comprising a first channel and a second channel wherein a test material is inserted into said first channel;
- (d) detecting radiation at an output of said first channel using a measurement radiation detector;
- (e) detecting radiation at an output of said second channel using a reference radiation detector;
- and
- (f) calculating a mass density of said test material based on information gathered by said reference radiation detector and said measurement radiation detector,
- wherein calculating a mass density of said test material comprises calculating an electron density index of said test material.
5 more elements
A method for determining density of a fluid in a high temperature environment comprising:
- (a) producing radiation in response to an input voltage using an X-ray generator;
- (b) filtering said radiation at an output of said X-ray generator using at least two filters that are alternately disposed at said output to produce a filtered radiation signal;
- (c) channeling said filtered radiation signal through an analysis cell comprising a first channel and a second channel wherein a test material is inserted into said first channel;
- (d) detecting radiation at an output of said first channel using a measurement radiation detector;
- (e) detecting radiation at an output of said second channel using a reference radiation detector;
- and
- (f) calculating a mass density of said test material based on information gathered by said reference radiation detector and said measurement radiation detector, wherein said mass density is calculated using an electron density index according to the following formula:
- ρ=C3ρe2+C4ρe
- where C3 and C4 are calibration coefficients relating the electron density index of the material to the mass density.
6 more elements
Dependencies are inferred from the claim text.