Petroleum Units

Sources: API Manual of Petroleum Measurement Standards (MPMS) Chapter 11, SPE nomenclature conventions.

Tagged Units

The following units are semantically tagged — they share SI dimensions with their base unit but will not cancel when divided by a differently tagged unit. Use them to build GOR and FVF ratios that preserve petroleum meaning through calculations.

Symbol	Base	Tag	Typical use
m3_res (1)	m3	reservoir	Reservoir pore/fluid volumes
m3_sep (1)	m3	separator	Separator fluid volumes
m3_sc (1)	m3	standar condition	Stock-tank fluid volumes
cf_res (2)	ft3	reservoir	Reservoir gas volumes
cf_sep (2)	ft3	separator	Separator gas volumes
RB	bbl	reservoir	Reservoir liquid barrels
STB	bbl	stock_tank	Stock-tank liquid barrels
bbl_sep	bbl	separator	separator liquid barrels
Mcf_res	ft3	reservoir	Reservoir gas volumes
Mcf_sep	ft3	separator	Separator gas volumes

(1) It is also available in fluid-specific versions. Example: m3_o_res, m3_g_res or m3_w_res.

(2) cf_sc does not exist because it is covered by scf (standard cubic foot).

Api Gravity

Symbol	Name	SI unit	Factor to SI
°API	API gravity	1	1

Flow Rate

Symbol	Name	SI unit	Factor to SI
bbl/day	barrels per day	m^3/s	1.84013e-06
bbl/h	barrels per hour	m^3/s	4.41631e-05
BLPD	barrels of liquid per day	m^3/s	1.84013e-06
Bscf/day	billion scf per day	m^3/s	327.741
gal/min	US gallons per minute	m^3/s	6.30902e-05
L/s	litres per second	m^3/s	0.001
m3/day	cubic metres per day	m^3/s	1.15741e-05
m3/h	cubic metres per hour	m^3/s	0.000277778
Mbbl/day	thousand barrels per day	m^3/s	0.00184013
MMbbl/day	million barrels per day	m^3/s	1.84013
MMscf/day	million scf per day	m^3/s	0.327741
Mscf/day	thousand scf per day	m^3/s	0.000327741

Gas Volume

Symbol	Name	SI unit	Factor to SI
scf	standard cubic foot	m^3	0.0283168
Mscf	thousand standard cu ft	m^3	28.3168
MMscf	million standard cu ft	m^3	28316.8
Bscf	billion standard cu ft	m^3	2.83168e+07
Tscf	trillion standard cu ft	m^3	2.83168e+10

Gas Volume Reservoir

Symbol	Name	SI unit	Factor to SI
Mcf_res	thousand standard cu ft [reservoir]	m^3	28.3168

Gas Volume Separator

Symbol	Name	SI unit	Factor to SI
Mcf_sep	thousand standard cu ft [separator]	m^3	28.3168

Volume

Symbol	Name	SI unit	Factor to SI
acre_ft	acre-foot	m^3	1233.48
bbl	barrel	m^3	0.158987
Mbbl	thousand barrels	m^3	158.987
MMbbl	million barrels	m^3	158987
ft3	cubic foot	m^3	0.0283168
gal	US gallon	m^3	0.00378541
m3	cubic metre	m^3	1
k(m3)	thousand cubic metres	m^3	1000
MMm3	million cubic metres	m^3	1e+06

Volume Reservoir

Symbol	Name	SI unit	Factor to SI
cf_res	cubic foot [reservoir]	m^3	0.0283168
m3_g_res	cubic metre [reservoir]	m^3	1
m3_o_res	cubic metre [reservoir]	m^3	1
m3_res	cubic metre [reservoir]	m^3	1
m3_w_res	cubic metre [reservoir]	m^3	1
RB	barrel [reservoir]	m^3	0.158987

Volume Separator

Symbol	Name	SI unit	Factor to SI
bbl_sep	barrel [separator]	m^3	0.158987
cf_sep	cubic foot [separator]	m^3	0.0283168
m3_g_sep	cubic metre [separator]	m^3	1
m3_o_sep	cubic metre [separator]	m^3	1
m3_sep	cubic metre [separator]	m^3	1
m3_w_sep	cubic metre [separator]	m^3	1

Volume Standar Conditions

Symbol	Name	SI unit	Factor to SI
m3_g_sc	cubic metre [standar_conditions]	m^3	1
m3_o_sc	cubic metre [standar_conditions]	m^3	1
m3_sc	cubic metre [standar_conditions]	m^3	1
m3_w_sc	cubic metre [standar_conditions]	m^3	1

Volume Stock Tank

Symbol	Name	SI unit	Factor to SI
STB	barrel [stock_tank]	m^3	0.158987