Method for mitigating barite sag in water-based mud with thermochemical fluid
Described is a method for mitigating particulate settling in a drilling fluid. A set of rheological data for a first drilling fluid is obtained, where the set of rheological data includes a measured viscosity value. A thermal effect of the measured viscosity value is determined, and a predicted viscosity value for a second drilling fluid having a similar composition as the first drilling fluid is determined based on the thermal effect. Based on the predicted viscosity value, an amount of a thermochemical fluid to add to the second drilling fluid is determined to increase a temperature and a viscosity of the second drilling fluid such that settling of a particulate is mitigated.
1 . A method for mitigating particulate settling in a drilling fluid, comprising:
obtaining, by measuring a viscosity of a first drilling fluid, a set of rheological data for the first drilling fluid having a composition, wherein the set of rheological data comprises a measured viscosity value;
determining a thermal effect of the measured viscosity value;
determining, based on the thermal effect, a predicted viscosity value for a second drilling fluid having a composition that is similar to the composition of the first drilling fluid;
determining an amount of a thermochemical fluid to add to the second drilling fluid;
adding the determined amount of the thermochemical fluid to the second drilling fluid, thereby increasing a temperature and a viscosity of the second drilling fluid such that settling of a particulate is mitigated; and
determining a flow consistency index K and a flow behavior index n for the first drilling fluid according to the following:
μ
a
=
K
γ
.
n
-
1
and
ln
μ
a
=
ln
K
+
(
n
-
1
)
ln
γ
.
,
where μ a is the measured viscosity value and {dot over (γ)} is a shear rate,
wherein the predicted viscosity value μ p is determined according to the following:
μ
p
=
K
0
exp
(
E
a
R
T
)
γ
.
n
-
1
,
where K o is the thermal effect, E a is a flow activation energy, R is a universal gas constant, and T denotes temperature.
2 . The method of claim 1 , wherein the thermal effect is a temperature dependency of the measured viscosity value.
3 . The method of claim 1 , wherein the thermochemical fluid comprises one or more of NH 4 Cl and NaNO 2 .
4 . The method of claim 1 , wherein the thermochemical fluid is added to the second drilling fluid in amount ranging from 3 mol/dm 3 to 5 mol/dm 3 .
5 . The method of claim 1 , wherein the first drilling fluid and the second drilling fluid are water-based drilling fluids.
6 . The method of claim 1 , wherein the particulate is barite.
7 . The method of claim 1 , wherein the amount of the thermochemical fluid is determined based on a quantity of the second drilling fluid, a heat capacity of the second drilling fluid, and a heat capacity of the thermochemical fluid.
8 . A system for mitigating particulate settling in a drilling fluid, comprising:
a processor configured to perform operations of:
obtaining, by measuring a viscosity of a first drilling fluid, a set of rheological data for the first drilling fluid having a composition, wherein the set of rheological data comprises a measured viscosity value;
determining a thermal effect of the measured viscosity value;
determining, based on the thermal effect, a predicted viscosity value for a second drilling fluid having a composition that is similar to the composition of the first drilling fluid;
determining, based on the predicted viscosity value, an amount of a thermochemical fluid to add to the second drilling fluid to increase a temperature and a viscosity of the second drilling fluid such that settling of a particulate is mitigated,
wherein the system is configured to add the determined amount of the thermochemical fluid to the second drilling fluid,
wherein the processor is configured to perform an operation of determining a flow consistency index K and a flow behavior index n for the first drilling fluid according to the following:
μ
a
=
K
γ
.
n
-
1
and
ln
μ
a
=
ln
K
+
(
n
-
1
)
ln
γ
.
,
where μ a is the measured viscosity value and {dot over (γ)} is a shear rate, and
wherein the predicted viscosity value μ p is determined according to the following:
μ
p
=
K
0
exp
(
E
a
R
T
)
γ
.
n
-
1
,
where K o is the thermal effect, E a is a flow activation energy, R is a universal gas constant, and T denotes temperature.
9 . The system of claim 8 , wherein the thermal effect is a temperature dependency of the measured viscosity value.
10 . The system of claim 8 , wherein the thermochemical fluid comprises one or more of NH 4 Cl and NaNO 2 .
11 . The system of claim 8 , wherein the thermochemical fluid is added to the second drilling fluid in amount ranging from 3 mol/dm 3 to 5 mol/dm 3 .
12 . The system of claim 8 , wherein the first drilling fluid and the second drilling fluid are water-based drilling fluids.
13 . The system of claim 8 , wherein the particulate is barite.
14 . The system of claim 8 , wherein the amount of the thermochemical fluid is determined based on a quantity of the second drilling fluid, a heat capacity of the second drilling fluid, and a heat capacity of the thermochemical fluid.