US2014318865A1PendingUtilityA1
Method and system for controlling vibrations in a drilling system
Est. expiryNov 25, 2031(~5.3 yrs left)· nominal 20-yr term from priority
Inventors:Apostolos Doris
E21B 44/00
27
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
A control system and method for limiting vibrations in a drilling system, including a drill string and a drive system for providing drive torque for rotating the drill string at a reference frequency. The control system includes a sensor module for determining an uphole parameter of the drilling system, a model module provided with a model of the drilling system and adapted to provide modeled parameters of the drilling system using the drive torque as an input, a model gain module for providing a model gain vector to the model module in response to one or more of the modeled parameters and the drive torque. The model gain vector enables the model module to update the model thereby obtaining an updated model, and a control module provides a torque correction factor to the drive system depending on the modeled parameters, the uphole parameter, the reference frequency, and the drive torque.
Claims
exact text as granted — not AI-modified1 . A control system for controlling vibrations in a drilling system, the drilling system including an elongate body extending from surface into a borehole formed in an earth formation and a drive system for providing a drive torque (Tm) to the elongate body for rotating said elongate body at a reference frequency (Ωref), the control system comprising:
a sensor module for determining at least one uphole parameter of the drilling system;
a model module provided with a model of the drilling system, the model module being adapted to provide modeled parameters of the drilling system using the drive torque (Tm) as an input;
a model gain module for providing a model gain vector (L) to the model module in response to one or more of the modeled parameters and the drive torque (Tm), the model gain vector enabling the module to update the model thereby obtaining an updated model; and
a control module for providing a torque correction factor (u) to the drive system depending on the modeled parameters, the uphole parameter, the reference frequency (Ωref), and the drive torque (Tm).
2 . The system of claim 1 , wherein the modeled parameters include:
modeled uphole angular position ({circumflex over (θ)} u ); modeled downhole angular position ({circumflex over (θ)} l ); and modeled downhole rotary velocity (ω l,m ).
3 . The system of claim 1 , wherein the uphole parameter of the drilling system as determined by the sensor module comprises the uphole rotary velocity (ω u ).
4 . The system of claim 1 , wherein the control module is adapted to determine a difference in uphole angular position and downhole angular position (θ u −θ l ) using the drive torque (Tm).
5 . The system of claim 4 , wherein the difference in uphole angular position and downhole angular position (θ u −θ l ) is determined by formula:
(
θ
u
-
θ
l
)
=
T
m
k
θ
wherein k θ is a constant.
6 . The system of claim 1 , wherein the control module ( 20 ) is provided with the following formula to calculate the torque correction factor (u):
u
=
-
k
1
·
[
θ
^
u
-
θ
^
l
-
(
T
m
k
θ
)
]
-
k
2
·
[
ω
u
-
Ω
ref
)
]
-
k
3
·
[
ω
l
,
m
-
Ω
ref
]
wherein k 1 , k 2 , k 3 and k θ are constants.
7 . A method of controlling vibrations in a drilling system, the drilling system including an elongate body extending from surface into a borehole formed in an earth formation and a drive system for providing a drive torque (Tm) to the elongate body for rotating said elongate body at a reference frequency (Ωref), the method comprising the steps of:
providing the reference frequency (Ωref) to the drive system;
the drive system providing the drive torque (Tm) to the elongate body of the drilling system;
determining at least one uphole parameter of the drilling system;
providing the drive torque (Tm) to a model module which is provided with a model of the drilling system, the model module providing modeled parameters of the drilling system;
providing one or more of the modeled parameters and the drive torque (Tm) to a model gain module for providing a model gain vector (L) to the model module in response thereto;
obtaining an updated model by the module using the model gain vector; and
providing the modeled parameters, the uphole parameter, the reference frequency (Ωref), and the drive torque (Tm) to a control module;
the control module providing a torque correction factor (u) to the drive system to correct the drive torque (Tm).
8 . The method of claim 7 , wherein the modeled parameters include:
modeled uphole angular position ({circumflex over (θ)} u ); modeled downhole angular position ({circumflex over (θ)} l ); and modeled downhole rotary velocity (ω l,m ).
9 . The method of claim 7 , wherein the uphole parameter of the drilling system comprises the uphole rotary velocity (ω u ).
10 . The method of claim 7 , wherein the control module determines a difference in uphole angular position and downhole angular position (θ u −θ l ) using the drive torque (Tm).
11 . The method of claim 10 , wherein the difference in uphole angular position and downhole angular position (θ u −θ l ) is determined by formula:
(
θ
u
-
θ
l
)
=
T
m
k
θ
wherein k θ is a constant.
12 . The method of claim 7 , wherein the control module calculates the torque correction factor (u) using formula:
u
=
-
k
1
·
[
θ
^
u
-
θ
^
l
-
(
T
m
k
θ
)
]
-
k
2
·
[
ω
u
-
Ω
ref
)
]
-
k
3
·
[
ω
l
,
m
-
Ω
ref
]
wherein k 1 , k 2 , k 3 and k θ are constants.
13 . The method of claim 7 , including the step of:
Replacing the drive torque (Tm) with a corrected drive torque (Tc), using formula:
T c =T m −u.
14 . The method of claim 7 , including the step of using only parameters which can be measured or modeled uphole.
15 . A method of controlling vibrations in a drilling system, the drilling system including an elongate body extending from surface into a borehole formed in an earth formation and a drive system for rotating the elongate body by providing a drive torque to the elongate body, the method comprising:
a) operating the drive system to provide the drive torque to the elongate body, and determining a system parameter that relates to an uphole parameter of the drilling system; b) obtaining a model of the drilling system; c) applying the model to determine a modeled system parameter that corresponds to said system parameter; d) determining a difference between the system parameter and the modeled system parameter; e) updating the model in dependence of said difference, thereby obtaining an updated model; f) determining from the updated model at least one modeled parameter of rotational motion, and adjusting the drive torque in dependence of each modeled parameter of rotational motion to control vibrations of the elongate body.
16 . The method of claim 15 , wherein said uphole parameter of the drilling system relates to an uphole torque in the drilling system.
17 . The method of claim 15 , wherein said uphole parameter of the drilling system relates to torque (T) in the elongate body at or near the earth's surface.
18 . The method of claim 16 , wherein said model of the drilling system includes a modeled torsional stiffness (k θm ) of the elongate body, and wherein said drilling parameter comprises a ratio of said torque (T) over said modeled torsional stiffness (k θm ).
19 . The method of claim 15 , wherein said modeled system parameter relates to a modeled difference between an uphole rotational position of the elongate body and a downhole rotational position of the elongate body.
20 . The method of claim 15 , wherein said uphole parameter of the drilling system is a first uphole parameter, and wherein step (c) comprises applying the model using an input parameter relating to a second uphole parameter of the drilling system.
21 . The method of claim 20 , wherein the drive system comprises a rotary drive coupled to an uphole end of the elongate body, and wherein said second uphole parameter is or comprises torque provided by the rotary drive to said uphole end of the elongate body.
22 . The method of claim 15 , wherein the model includes at least one modeled state parameter and wherein step (e) comprises adding to each modeled state parameter the product of said difference and a respective gain factor pertaining to the modeled state parameter.
23 . The method of claim 22 , wherein each modeled state parameter relates to a modeled parameter of rotational motion of the elongate body.
24 . The method of claim 22 , wherein said at least one modeled state parameter is selected from a modeled difference between an uphole angular velocity and a downhole angular velocity of the elongate body, a modeled uphole angular acceleration of the elongate body, and a modeled downhole angular acceleration of the elongate body.
25 . The method of claim 22 , wherein step (b) comprises obtaining a state observer in which the model is included, the state observer further including a gain module for calculating each said gain factor.
26 . The method of claim 15 , wherein said at least one modeled parameter of rotational motion includes at least one of a modeled difference between an uphole rotational position and a downhole rotational position of the elongate body, a modeled uphole angular velocity of the elongate body, and a modeled downhole angular velocity of the elongate body.Join the waitlist — get patent alerts
Track US2014318865A1 — get alerts on status changes and closely related new filings.
We store only your email — no account needed. See our privacy policy.