1. A method for determining viscosity, \u03b7, of a fluid downhole, the method comprising:
performing a nuclear magnetic resonance (NMR) survey of the fluid;
determining a longitudinal relaxation time, T1, and an apparent transverse relaxation time, T2app, for the fluid;
forming a ratio R of T1T2app for the fluid;
determining the viscosity, \u03b7, according to the ratio, R.
2. The method as in claim 1, wherein T2app is approximately equal to an intrinsic transverse relaxation time, T2intrinsic, when a radiofrequency field gradient strength, G, is about equal to zero.
3. The method as in claim 1, wherein obtaining a magnetization decay of multiple NMR echo trains provides for determining T1 and T2app.
4. The method as in claim 3, wherein determining T1 and T2app comprises solving the relationship:
M(t,Tw)=\u222b\u222bf(T2app,T1)1\u2212eTwT1)e\u2212tT2appdT1dT2pp
where
Tw represents a wait time;
t represents a duration of an echo train; and
f represents a two dimensional porosity distribution function.
5. The method as in claim 4, wherein the following relationship is substituted for the longitudinal relaxation time, T1:
T1=R*T2app.
6. The method as in claim 5, wherein the substitution provides the relationship:
E(t,Tw)=\u222b\u222bg(T2pp,R)(1\u2212eTwR*T2app)e\u2212tT2appdR dT2app
where
g represents an acquisition parameter.
7. The method as in claim 1, wherein the survey is performed using a magnetic field frequency of about 0.5 MHz to about 100 MHz.
8. The method as in claim 1, wherein the wait time, TW, is between about 5 milliseconds (ms) and about 10,000 ms.
9. The method as in claim 1, wherein forming a ratio R comprises determining a logarithmic mean for at least one of the transverse relaxation time, T2, and the longitudinal relaxation time, T1.
10. The method as in claim 1, further comprising replacing peak values with a logarithmic mean combined relaxation time, T1,2, when a combined relaxation time distribution exhibits one of a sharp appearance and a Gaussian shape.
11. The method as in claim 1, wherein the viscosity, \u03b7, is related to at least one of the transverse relaxation time, T2, the longitudinal relaxation time, T1, and the ratio, R, by one of a power function, an exponential function and a Taylor series.
12. A computer program product comprising stored on machine readable media and comprising machine readable instructions for determining viscosity, \u03b7, of a fluid downhole, the instructions comprising instructions for:
performing a nuclear magnetic resonance (NMR) survey of the fluid;
determining a longitudinal relaxation time, T1, and an apparent transverse relaxation time, T2app, for the fluid;
forming a ratio R of T1T2app for the fluid; and
determining the viscosity, \u03b7, according to the ratio, R.
13. The computer program product as in claim 12, wherein obtaining a magnetization decay of multiple NMR echo trains provides for determining T1 and T2app.
14. The computer program product as in claim 13, wherein determining T1 and T2app comprises solving the relationship:
M(t,Tw)=\u222b\u222bf(T2app,T1)1\u2212eTwT1)e\u2212tT2appdT1dT2pp
where
Tw represents a wait time;
t represents a duration of an echo train; and
f represents a two dimensional porosity distribution function.
15. The computer program product as in claim 14, wherein the following relationship is substituted for the longitudinal relaxation time, T1:
T1=R*T2app.
16. The computer program product as in claim 15, wherein the substitution provides the relationship:
E(t,Tw)=\u222b\u222bg(T2pp,R)(1\u2212eTwR*T2app)e\u2212tT2appdR dT2app
where
g represents an acquisition parameter.
17. The computer program product as in claim 12, wherein the survey is performed using a magnetic field frequency of about 0.5 MHz to about 100 MHz.
18. The computer program product as in claim 12, wherein the wait time, TW, is between about 5 milliseconds (ms) and about 10,000 ms.
19. The computer program product as in claim 12, wherein forming a ratio R comprises determining a logarithmic mean for at least one of the transverse relaxation time, T2, and the longitudinal relaxation time, T1.
20. The computer program product as in claim 12, wherein the viscosity, \u03b7, is related to at least one of the transverse relaxation time, T2, the longitudinal relaxation time, T1, and the ratio, R, by one of a power function, an exponential function and a Taylor series.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A warming device, comprising:
a clinical garment having an inside surface and an upper portion with opposing sleeves;
an upper body convective apparatus attached to the inside surface in the upper portion;
the upper body convective apparatus disposed transversely across the upper portion, along the sleeves;
at least one inlet port in the upper body convective apparatus; and
a lower edge on the upper body convective apparatus and an attachment mechanism along the lower edge;
wherein:
the upper body convective apparatus includes two laterally-extending sides, each side disposed in a folded configuration in a respective sleeve;
each sleeve includes an inside cuff retaining a side in the folded configuration, and one or more lines of perforation near the cuff for being opened to provide access through the end of the sleeve to the side in the folded configuration; and,
each side includes an end of the upper body convective apparatus, and each side being extendable from the folded configuration to an unfolded configuration in which the respective end extends outwardly from the clinical garment.
2. The warming device of claim 1, further including means in each sleeve for releasably retaining a side in the folded configuration in the sleeve.
3. The warming device of claim 2, each side including an end of the upper body convective apparatus, and each side being extendable from the folded configuration to an unfolded configuration in which the end extends outwardly from the clinical garment.
4. The warming device of claim 1, wherein the upper body convective apparatus includes perforation lines extending transversely across each side to enable the separation of the ends from the convective apparatus.
5. A warming device, comprising:
a clinical garment having an inside surface and an upper portion with opposing sleeves:
an upper body convective apparatus attached to the inside surface in the upper portion;
the upper body convective apparatus disposed transversely across the upper portion, along the sleeves;
at least one inlet port in the upper body convective apparatus; and
a head drape adjacent the upper surface, in the upper portion;
wherein:
the convective apparatus includes two laterally-extending sides, each side disposed in a folded configuration in a respective sleeve;
each sleeve includes an inside cuff retaining a side in the folded configuration, and one or more lines of perforation near the cuff for being opened to provide access through the end of the sleeve to the side in the folded configuration; and,
each side includes an end of the convective apparatus, and each side being extendable from the folded configuration to an unfolded configuration in which the respective end extends outwardly from the clinical garment.
6. A warming device, comprising:
a clinical garment having an inside surface and an upper portion with opposing sleeves:
an upper body convective apparatus attached to the inside surface in the upper portion;
the upper body convective apparatus disposed transversely across the upper portion, along the sleeves;
the upper body convective apparatus including two laterally-extending sides, each side disposed in a folded configuration in a respective sleeve, each side including an end of the convective apparatus, and each side being extendable from the folded configuration to an unfolded configuration in which the end extends outwardly from the clinical garment;
means in each sleeve for releasably retaining a side in the folded configuration in the sleeve;
at least one inlet port in the upper body convective apparatus; and
a head drape adjacent the upper surface, in the upper portion.
7. The warming device of claim 6, wherein the convective apparatus includes perforation lines extending transversely across each side to enable the separation of the ends from the convective apparatus.