US2011303463A1PendingUtilityA1
Method for Determining the Content of A Plurality of Compounds Contained In A Drilling Fluid
Est. expiryJan 16, 2029(~2.5 yrs left)· nominal 20-yr term from priority
Inventors:Jacques Lessi
E21B 21/067E21B 49/005G01N 2030/065
39
PatentIndex Score
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Claims
Abstract
A method for the extraction of a gas fraction of each compound, the measurement of information representative of the gas fraction of each compound and the calculation, for each first compound of a first group of compounds, of the content of said first compound in the drilling fluid on the basis of information measured for the gas fraction of the first compound and on the basis of a first correction factor (ρ i ).
Claims
exact text as granted — not AI-modified1 . A method for determining the content (t 0 (i)) of a plurality of compounds contained in a drilling fluid, of the type comprising:
extracting a gas fraction of each compound out of the drilling fluid; measuring representative information (y 1 (i)) of the gas fraction of each compound; obtaining for each first compound of a first group of compounds, a first correction factor (ρ 1 (i)) linking the measured information (y 1 (i)) for the gas fraction of the first compound under first given extraction conditions to the content of said first compound in the drilling fluid; wherein the method comprises the following steps: calculating for at least each second compound of a second group of compounds, the content of said second compound in the drilling fluid on the basis of the representative information measured for the second compound under second given extraction conditions, advantageously identical with the first given extraction conditions, and a second correction factor (ρ 2 (i)) calculated from a calculation equation relating the second correction factor (ρ 2 (i)) to a plurality of parameters (a, b, c, d) independent of the second compound and of the given extraction conditions and to a thermodynamic factor characteristic of the second compound (Fi) which depends at least on one thermodynamic parameter representative of the second compound, the independent parameters (a, b, c, d) being determined from each first correction factor (ρ 1 (i)) and from the calculation equation.
2 . The method according to claim 1 , characterized in that the characteristic thermodynamic factor (Fi) is calculated from at least one thermodynamic parameter selected from the boiling temperature of the second compound at atmospheric pressure, the critical temperature of the second compound and the critical pressure of the second compound.
3 . The method according to claim 1 , characterized in that the characteristic thermodynamic factor (Fi) is calculated from the temperature of the drilling fluid under given extraction conditions.
4 . The method according to claim 2 , characterized in that the characteristic thermodynamic factor (Fi) is calculated by the equation:
F
i
=
[
1
θ
b
(
i
)
-
1
θ
]
[
1
θ
b
(
i
)
-
1
θ
c
(
i
)
]
·
log
(
P
c
(
i
)
P
atm
)
wherein θ is the temperature of the drilling fluid under given extraction conditions, θ b (i) is the boiling temperature of the second compound at atmospheric pressure, θ c (i) is the critical temperature of the second compound, P c (i) is the critical pressure of the second compound and P atm is the atmospheric pressure.
5 . The method according to claim 1 , characterized in that the equation for calculating the second correction factor (ρ 2 (i)) comprises at least one term of the type a×exp(b·F i ), wherein a and b are parameters independent of the second compound determined on the basis of each first correction factor, and Fi is the thermodynamic factor characteristic of the second compound.
6 . The method according to claim 1 , characterized in that the extraction step is applied in an enclosure ( 71 ) comprising means ( 73 ) for stirring the drilling fluid, the second correction factor (ρ 2 (i)) being calculated as a function of at least one parameter selected from the flow rate of drilling fluid injected into the enclosure, the average volume of drilling fluid present in the enclosure ( 71 ), the volume of the gas head space present in the enclosure ( 71 ), and the total flow rate of gas fraction extracted out of the enclosure ( 71 ).
7 . The method according to claim 6 , characterized in that the second correction factor (ρ 2 (i)) is calculated by the following calculation equation:
ρ
2
(
i
)
=
1
+
Q
m
V
g
·
1
a
·
c
×
exp
[
(
b
+
d
)
·
F
i
]
+
Q
m
V
m
·
1
c
×
exp
(
d
·
F
i
)
+
Q
m
Q
g
·
1
a
×
exp
(
b
·
F
i
)
wherein Q m is the volume flow rate of drilling fluid injected into the enclosure, V m is the average volume of drilling fluid present in the enclosure, V g is the volume of the gas head space present in the enclosure, Q g is the volume flow rate of gas fraction extracted out of the enclosure, a, b, c, d are the parameters independent of the second compound determined on the basis of each first correction factor (ρ 1 (i)) and Fi is the thermodynamic factor characteristic of the second compound.
8 . The method according to claim 1 , characterized in that it comprises a step for determining each first correction factor (ρ 1 (i)),
the determination step comprises the following phases:
providing a drilling fluid calibration sample containing at least each first compound;
at least two successive stages for extracting the same calibration sample under the first given extraction conditions, each extraction stage comprising the extraction out of the drilling fluid of a gas fraction of each first compound and the measurement of a representative piece of information (y n (i)) of the gas fraction of each first compound;
calculating, for each first compound, the first correction factor on the basis of representative pieces of information (y n (i)) measured at each extraction stage.
9 . The method according to claim 8 , characterized in that the number of successive extraction stages is equal to 2.
10 . The method according to claim 8 , characterized in that providing the calibration sample comprises mixing of a given amount of drilling fluid and of a measured amount of each first liquid compound.
11 . The method according to claim 1 , characterized in that each compound of the first group of compounds has a boiling temperature at atmospheric pressure below the boiling temperature at atmospheric pressure of each compound of the second group of compounds.
12 . The method according to claim 1 , characterized in that each compound of the first group of compounds has a boiling temperature at atmospheric pressure above the boiling temperature at atmospheric pressure of each compound of the second group of compounds.
13 . The method according to claim 1 , characterized in that it comprises a step for correcting the value of the first correction factor (ρ 1 (i)) of at least one first compound, the correction step comprising the calculation for said first compound of a first correction factor corrected on the basis of the calculation equation linking the plurality of parameters (a, b, c, d) independent of the second compound and on the basis of the thermodynamic factor (Fi) characteristic of the first compound, and the calculation of the content of said first compound in the drilling fluid on the basis of measured information (y 1 (i)) for the gas fraction of the first compound and on the basis of the corrected correction factor.
14 . The method according to claim 1 , characterized in that it comprises, for at least one first compound of the first group of compounds, the calculation of the content of said first compound in the drilling fluid on the basis of measured information (y 1 (i)) for the gas fraction of the first compound and on the basis of the first correction factor (ρ 1 (i)).
15 . The method according to claim 1 , characterized in that the first given extraction conditions are distinct from the second given extraction conditions, the calculation equation comprising at least one parameter representative of the given extraction conditions having a first value under the first extraction conditions and a second value significantly different from the first value under the second extraction conditions, the independent parameters (a, b, c, d) being determined on the basis of the calculation equation in which the representative parameter is equal to its first value, the second correction factor being calculated on the basis of the calculation equation in which the representative parameter is equal to its second value.Join the waitlist — get patent alerts
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