Determination of continuous oil density log for reservoir characterization
A determination of a continuous oil density log for a hydrocarbon reservoir accessible via a well drilling into the formation having the reservoir. The logging operations may be conducted in the well to generate a carbon-oxygen ratio (C/O) log, a water saturation log, and a porosity log. A continuous oil density log may be determined using the C/O log, the water saturation log, the porosity log, and carbon and oxygen density values. The continuous oil density log may be used in further characterization and development of the hydrocarbon reservoir.
1. A method of determining continuous oil density log of a hydrocarbon reservoir accessed by a well extending into the hydrocarbon reservoir, the method comprising:
conducting a pulsed neutron (PN) logging operation in the well to generate a carbon/oxygen (C/O) log for the well;
conducting a water saturation logging operation to generate a water saturation log for the well, wherein the water saturation logging operation comprises the PN logging operation, a resistivity logging operation, or a dielectric logging operation;
conducting a porosity logging operation to generate a porosity log for the well;
obtaining a carbon density value and an oxygen density value, the carbon density and oxygen density each associated with reservoir rock or pore fluids of the hydrocarbon reservoir; and
determining, based on the C/O log, the water saturation log, the porosity log, and the carbon density value and the oxygen density value, a continuous oil density log for the well;
developing the hydrocarbon reservoir based on the continuous oil density log for the well, the developing comprising:
determining, based on the continuous oil density log for the well, well operating parameters comprising an injection rate; and
operating the well in accordance with the well operating parameters, the operating comprising injecting a fluid into the reservoir at the injection rate.
2. The method of claim 1 , wherein the plurality of carbon density value comprises a carbon density of carbonates and the oxygen density value comprises an oxygen density of rocks and an oxygen density of water.
3. The method of claim 1 , wherein determining, based on the C/O log, the water saturation log, and the plurality of carbon density values and a plurality of oxygen density values, a continuous oil density log for the well comprises determining the continuous oil density log using the following:
ρ
o
=
2.16
×
(
Y
c
Y
0
(
ϕ
S
w
n
o
,
w
+
V
ls
n
0
,
ls
)
-
V
ls
n
c
,
ls
)
10
23
ϕ
S
o
where ϕ is porosity, n o,w is the oxygen density of water, n o,ls is the oxygen density of limestone, n c,ls is the carbon density of limestone, V ls is the volume fraction of limestone, Y c /Y o is a measure of C/O ratio, S w is water saturation, S o is oil saturation where S o +S w =1, and ρ o is the density of oil.
4. The method of claim 1 , wherein determining, based on the C/O log, the water saturation log, and the plurality of carbon density values and a plurality of oxygen density values, a continuous oil density log for the well comprises determining the continuous oil density log using the following:
ρ
o
=
1
2
+
R
6
.
0
2
3
*
1
0
2
3
Y
c
Y
0
(
∅
S
w
n
o
,
w
+
V
l
s
n
o
,
l
s
)
-
V
l
s
n
c
,
l
s
∅
S
o
where R, is the ratio of hydrogen (H) to carbon (C), ϕ is porosity, n o,w is the oxygen density of water, n o,ls is the oxygen density of limestone, n c,ls is the carbon density of limestone, V ls is the volume fraction of limestone, Y c /Y o is a measure of C/O ratio, S w is water saturation, S o is oil saturation where S o +S w =1, and ρ o is the density of oil.
5. The method of claim 1 , comprising comparing the continuous oil density log to a viscosity log associated with the well.
6. A non-transitory computer-readable storage medium having executable code stored thereon of determining continuous oil density of a hydrocarbon reservoir accessed by a well extending into the hydrocarbon reservoir, the executable code comprising a set of instructions that causes a processor to perform operations comprising:
conducting a pulsed neutron (PN) logging operation in the well to generate a carbon/oxygen (C/O) log for the well;
conducting a water saturation logging operation to generate a water saturation log for the well, wherein the water saturation logging operation comprises the PN logging operation, a resistivity logging operation, a dielectric logging operation;
conducting a porosity logging operation to generate a porosity log for the well;
obtaining a carbon density value and an oxygen density value, the carbon density and oxygen density each associated with reservoir rock or pore fluids of the hydrocarbon reservoir; and
determining, based on the C/O log, the water saturation log, the porosity log, and the carbon density value and the oxygen density value, a continuous oil density log for the well;
developing the hydrocarbon reservoir based on the continuous oil density log for the well, the developing comprising:
determining, based on the continuous oil density log for the well, well operating parameters comprising an injection rate; and
operating the well in accordance with the well operating parameters, the operating comprising injecting a fluid into the reservoir at the injection rate.
7. The non-transitory computer-readable storage medium of claim 6 , wherein the carbon density value comprises a carbon density of limestone and the oxygen density value comprises an oxygen density of limestone and an oxygen density of water.
8. The non-transitory computer-readable storage medium of claim 6 , wherein determining, based on the C/O log, the water saturation log, and the plurality of carbon density values and a plurality of oxygen density values, a continuous oil density log for the well comprises determining the continuous oil density log using the following:
ρ
o
=
2
.
1
6
×
(
Y
c
Y
0
(
∅
S
w
n
o
,
w
+
V
ls
n
o
,
l
s
)
-
V
ls
n
c
,
l
s
)
1
0
2
3
∅
S
o
where ϕ is porosity, n o,w is the oxygen density of water, n o,ls is the oxygen density of limestone, n c,ls is the carbon density of limestone, V ls is the volume fraction of limestone, C/O is a measures C/O ratio, S w is water saturation, S o is oil saturation where S o +S w =1, and ρ o is the density of oil.
9. The non-transitory computer-readable storage medium of claim 6 , wherein determining, based on the C/O log, the water saturation log, and the plurality of carbon density values and a plurality of oxygen density values, a continuous oil density log for the well comprises determining the continuous oil density log using the following:
ρ
o
=
1
2
+
R
6
.
0
2
3
*
1
0
2
3
Y
c
Y
0
(
∅
S
w
n
o
,
w
+
V
l
s
n
o
,
l
s
)
-
V
l
s
n
c
,
l
s
∅
S
o
where R is the ratio of hydrogen (H) to carbon (C), ϕ is porosity, n o,w is the oxygen density of water, n o,ls is the oxygen density of limestone, n c,ls is the carbon density of limestone, V ls is the volume fraction of limestone, Y c /Y o is a measure of C/O ratio, S w is water saturation, S o is oil saturation where S o +S w =1, and ρ o is the density of oil.
10. The non-transitory computer-readable storage medium of claim 6 , comprising comparing the continuous oil density log to a viscosity log associated with the well.
11. A system of determining continuous oil density of a hydrocarbon reservoir accessed by a well extending into the hydrocarbon reservoir, comprising:
a processor;
a non-transitory computer-readable memory accessible by the processor and having executable code stored thereon, the executable code comprising a set of instructions that causes a processor to perform operations comprising:
conducting a pulsed neutron (PN) logging operation in the well to generate a carbon/oxygen (C/O) log for the well;
conducting a water saturation logging operation to generate a water saturation log for the well, wherein the water saturation logging operation comprises the PN logging operation or a resistivity logging operation;
conducting a porosity logging operation to generate a porosity log for the well;
obtaining a carbon density value and an oxygen density value, the carbon density and oxygen density each associated with reservoir rock or pore fluids of the hydrocarbon reservoir; and
determining, based on the C/O log, the water saturation log, the porosity log, and the carbon density value and the oxygen density value, a continuous oil density log for the well;
developing the hydrocarbon reservoir based on the continuous oil density log for the well, the developing comprising:
determining, based on the continuous oil density log for the well, well operating parameters comprising an injection rate; and
operating the well in accordance with the well operating parameters, the operating comprising injecting a fluid into the reservoir at the injection rate.
12. The system of claim 11 , wherein the carbon density value comprises a carbon density of limestone and the oxygen density value comprises an oxygen density of limestone and an oxygen density of water.
13. The system of claim 11 , wherein determining, based on the C/O log, the water saturation log, and the plurality of carbon density values and a plurality of oxygen density values, a continuous oil density log for the well comprises determining the continuous oil density log using the following:
ρ
o
=
2
.
1
6
×
(
Y
c
Y
0
(
∅
S
w
n
o
,
w
+
V
ls
n
o
,
l
s
)
-
V
ls
n
c
,
l
s
)
1
0
2
3
∅
S
o
where ϕ is porosity, n o,w is the oxygen density of water, n o,ls is the oxygen density of limestone, n c,ls is the carbon density of limestone, V ls is the volume fraction of limestone, Y c /Y o is a measure of C/O ratio, S w is water saturation, S o is oil saturation where S o +S w =1, and ρ o is the density of oil.
14. The system of claim 11 , wherein determining, based on the C/O log, the water saturation log, and the plurality of carbon density values and a plurality of oxygen density values, a continuous oil density log for the well comprises determining the continuous oil density log using the following:
ρ
o
=
1
2
+
R
6
.
0
2
3
*
1
0
2
3
Y
c
Y
0
(
∅
S
w
n
o
,
w
+
V
l
s
n
o
,
l
s
)
-
V
l
s
n
c
,
l
s
∅
S
o
where R, is the ratio of hydrogen (H) to carbon (C), ϕ is porosity, n o,w is the oxygen density of water, n o,ls is the oxygen density of limestone, n c,ls is the carbon density of limestone, V ls is the volume fraction of limestone, Y c /Y o is a measure of C/O ratio, S w is water saturation, S o is oil saturation where S o +S w =1, and ρ o is the density of oil.