USEFUL STUFF - UNITS OF MEASUREMENT amd COMVERSION FACTORS
 
INTERNATIONAL SYSTEM
OF UNITS (SI)
SI units are
widely used in scientific work. All the SI fundamental units and
derived units are listed on this page, as well as the universal
constants.
Unfortunately, much of the work done in the oilfields uses a mixed
set of units composed of British units (called English units in this
Handbook) , CGS Units (an early form of metric units), and SI Units
(called Metric units in this Handbook). Examples of English units
are the foot, mile, and pound. Examples of Metric units are the
meter, kilometer, and kilogram. Conversion back and forth between
sets of units is a constant task for a petrophysicist.
A
lengthy list of conversions is available at the bottom of this page.
A useful freeware units conversion calculator can be downloaded
HERE. This is an executable
(.EXE) file and may be blocked by your security settings.
|
LIST OF SI UNITS |
| UNIT |
SYMBOL |
DERIVATION |
BASE UNITS |
REPRESENTING |
| ampere |
A |
-- |
A |
electric current |
| becquerel |
Bq |
1/s |
s-1 |
activity |
| candela |
cd |
-- |
cd |
luminous intensity |
| coulomb |
C |
A s |
A s |
charge |
| farad |
F |
A s/V |
kg-1 m-2
s4 A2 |
capacitance |
| gray |
Gy |
J/kg |
m2 s-2 |
absorbed dose |
| henry |
H |
V s/A |
kg m2 s-2
A-2 |
inductance |
| hertz |
Hz |
1/s |
s-1 |
frequency |
| joule |
J |
N m |
kg m2 s-2 |
energy |
| kelvin
[footnote 1] |
K |
-- |
K |
temperature |
| kilogram |
kg |
-- |
kg |
mass |
| lumen |
lm |
cd sr |
cd sr |
luminous flux |
| lux |
lx |
lm/m2 |
cd sr m-2 |
illumination |
| metre |
m |
-- |
m |
length |
| mole |
mol |
-- |
mol |
amount of substance |
| newton |
N |
kg m/s2 |
kg m s-2 |
force |
| ohm |
O
[footnote 2] |
V/A |
kg m2 s-3
A-2 |
resistance |
| pascal |
Pa |
N/m2 |
kg m-1 s-2 |
pressure |
| radian |
rad |
-- |
rad |
plane angle |
| second |
s |
-- |
s |
time |
| siemens |
S |
1/O |
kg-1 m-2
s3 A2 |
electric conductance |
| sievert |
Sv |
J/kg |
m2 s-2 |
dose equivalent |
| steradian |
sr |
-- |
sr |
solid angle |
| tesla |
T |
Wb/m2 |
kg s-2 A-1 |
magnetic flux density |
| volt |
V |
W/A |
kg m2 s-3
A-1 |
voltage |
| watt |
W |
J/s |
kg m2 s-3 |
power |
| weber |
Wb |
V s |
kg m2 s-2
A-1 |
magnetic flux |
|
Non-SI unit
approved for use with SI. |
| UNIT |
SYMBOL |
Value in SI Units |
| minute |
min |
60 s |
| hour |
h |
60 min = 3600 s |
| day |
d |
24 h = 86 400 s |
| degree |
deg |
(pi/180)
rad |
| arcminute |
', arcmin |
(1/60) deg = (pi/10
800) rad |
| arcsecond |
", arcsec |
(1/60)' = (pi/648
000) rad |
| litre |
l, L
[footnote 4] |
1 dm3 =
10-3 m3 |
| tonne |
t |
103 kg |
| electronvolt |
eV |
(1.602 177 33 +-
0.000 000 49) x 10-19 J |
| unified atomic mass unit |
u |
(1.660 540 2 +-
0.000 001 0) x 10-27 kg |
| nautical mile |
-- |
1852 m |
| knot |
-- |
1 nautical mile
per hour = (1852/3600) m/s |
| angstrom |
A
[footnote 5] |
10-10 m |
| are |
a |
1 dam2
= 102 m2 |
| hectare |
ha |
104 m2 |
| barn |
b |
10-28 m2 |
| bar |
bar |
105 Pa |
| gal |
Gal |
10-2
m/s2 |
| curie |
Ci |
3.7 x 1010
Bq |
| roentgen |
R |
2.58 x 10-4
C/kg |
| rad |
rd, rad |
10-2 Gy |
| rem |
rem |
|
SI Prefixes |
| Factor |
Name |
Symbol |
| 1024 |
yotta |
Y |
| 1021 |
zetta |
Z |
| 1018 |
exa |
E |
| 1015 |
peta |
P |
| 1012 |
tera |
T |
| 109 |
giga |
G |
| 106 |
mega |
M |
| 103 |
kilo |
k |
| 102 |
hecto |
h |
| 101 |
deka |
da |
|
|
| Factor |
Name |
Symbol |
| 10-1 |
deci |
d |
| 10-2 |
centi |
c |
| 10-3 |
milli |
m |
| 10-6 |
micro |
µ |
| 10-9 |
nano |
n |
| 10-12 |
pico |
p |
| 10-15 |
femto |
f |
| 10-18 |
atto |
a |
| 10-21 |
zepto |
z |
| 10-24 |
yocto |
y |
|
UNIVERSAL CONSTANTS (SI Units)-
|
UNIVERSAL CONSTANTS |
|
CONSTANT |
SYMBOL |
VALUE
and UNITS |
| acceleration
due to gravity |
g
|
9.806 65 m/s2 |
| age of
Universe |
t0
|
15(5) Gy |
| atomic mass
unit, unified |
u |
931.494 32(28) MeV/c2
=
1.660 540 2(10) x 10-27 kg |
| astronomical
unit |
au |
1.495 978 706 6(2) x
1011 m |
| Avogadro
constant |
NA
|
6.022 136 7(36) x 1023
mol-1 |
| Bohr magneton
|
muB
|
5.788 382 63(52) x 10-11
MeV/T |
| Bohr radius
|
aoo
|
0.529 177 249(24) x
10-10 m |
| Boltzmann
constant |
k
|
1.380 658(12) x 10-23
J/K =
8.617 385(73) x 10-5 eV/K |
| cosmic
background energy density |
rhogamma
|
4.647 7 x 10-34
(T/2.726 K)4 g/cm3 =
0.260 71 (T/2.726 K)4 eV/cm3
|
| cosmic
background number density |
ngamma
|
410.89 (T/2.726
K)3 cm-3 |
| cosmic
background temperature |
T0
|
2.726 +- 0.005 K |
| critical
density of Universe |
rhoc
|
2.775 366 27 x 1011
h02 MS
Mpc-3 =
1.878 82(24) x 10-29 h02
g/cm3 =
1.053 94(13) x 10-5 h02
GeV/cm3 |
| day, mean
sidereal |
dsidereal
|
23h 56m
04s.090 53 |
| deuteron (2H)
mass |
md
|
1875.613 39(57) MeV/c2 |
| Earth mass
|
ME
|
5.973 70(76) x 1024
kg |
| Earth radius
(equatorial) |
RE
|
6.378 140 x 106
m |
| electron
charge magnitude |
e
|
1.602 177 33(49) x 10-19
C =
4.803 206 8(15) x 10-10 esu |
| electron mass
|
me
|
0.510 999 06(15) MeV/c2
=
9.109 389 7(54) x 10-31 kg |
| electron
radius, classical |
re
|
2.817 940 92(38) x 10-15
m |
| electron
Compton wavelength |
lambdabare
|
3.861 593 23(35) x 10-13
m |
| entropy
density/Boltzmann constant |
s/k
|
2.892 4 (T/2.726
K)3 cm-3 |
| fine structure
constant |
alpha
|
1/137.035 989 5(61) |
| gravitational
constant |
GN
|
6.672 59(85) x 10-11
m3/(kg s2) =
6.707 11(86) x 10-39 h c/(GeV/c2)2 |
| Hubble
constant |
H0
|
100 h0
km/(s Mpc) =
h0/9.778 13 Gy |
| Hubble
constant, normalized |
h0
|
0.5 < h0
< 0.85 |
| jansky
|
Jy |
10-26 W/(m2
Hz) |
| light year
(deprecated) |
ly |
0.306 6... pc =
0.946 1... x 1016 m |
| Naperian
(natural) logarithm base |
e
|
2.718 281 828 459 045
235 |
| nuclear
magneton |
muN
|
3.152 451 66(28) x 10-14
MeV/T |
| parsec (au/arcsec)
|
pc |
3.085 677 580 7(4) x
1016 m =
3.262... ly |
| permeability
of free space |
mu0
|
4 pi x 10-7
N/A2 =
12.566 370 614... x 10-7 N/A2 |
| permittivity
of free space |
epsilon0
|
8.854 187 817... x 10-12
F/m |
| pi
|
pi
|
3.141 592 653 589 793
238 |
| Planck
constant |
h
|
6.626 075 5(40) x 10-34
J s |
| Planck
constant, reduced |
hbar
|
1.054 572 66(63) x 10-34
J s =
6.582 122 0(20) x 10-22 MeV s |
| Planck mass
|
mP
|
1.221 047(79) x 1019
GeV/c2 =
2.176 71(14) x 10-8 kg |
| proton (1H)
mass |
mp
|
938.272 31(28) MeV/c2
=
1.672 623 1(10) x 10-27 kg =
1.007 276 470(12) u =
1836.152 701(37) me |
| Rydberg energy
|
h c Roo
|
13.605 698 1(40) eV |
| Schwarzschild
radius of Sun |
2 GN MS/c2
|
2.953 250 08 km |
| speed of light
in vacuum |
c
|
299 792 458 m/s |
| Stefan-Boltzmann
constant |
sigma
|
5.670 51(19) x 10-8
W/(m2 K4) |
| strong
coupling constant |
alphas
|
0.118(3) |
| Sun distance
from Core |
Ro
|
8.0(5) kpc |
| Sun luminosity
|
LS
|
3.846 x 1026
W |
| Sun mass
|
MS
|
1.988 92(25) x 1030
kg |
| Sun radius
(equatorial) |
RS
|
6.96 x 108
m |
| Sun speed
around Core |
Thetao
|
220(20) km/s |
| Sun speed to
cosmic background |
|
369.5 +- 3.0 km/s |
| Thompson cross
section |
sigmaT
|
0.665 246 16(18) barn |
| W+-
boson mass |
mW
|
80.33(15) GeV/c2 |
| Wien
displacement law constant |
b
|
2.897 756(24) x 19) x
10-3 m K |
| year, sidereal
(fixed star to fixed star, 1994) |
ysidereal
|
31 558 149.8 s |
| year, tropical
(equinox to equinox, 1994) |
y |
31 556 925.2 s |
| Z0
boson mass |
mZ
|
91.187(7) GeV/c2 |
|
OILFIELD UNITS CONVERSION TABLE |
|
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