US 12,180,821 B1 · Method and system for predicting maximum build rate of push-the-bit rotary steering tool

Abstract

A method and system for predicting a maximum build rate of a push-the-bit rotary steering tool is provided. In the method, a mechanical mathematical model of a push-the-bit rotary steering device is combined with measured well inclination data of the rotary steering device during actual drilling, a theoretical maximum build rate of a steering tool is calculated by the mechanical mathematical model, and a correction factor is combined with the mechanical mathematical model to predict a maximum build rate of the steering tool during a drilling operation in a same layer of a same block. The method effectively solves the problem of predicting the maximum build rate of the push-the-bit rotary steering device with different parameter changes based on measured data. Therefore, the method and system provide a reliable means for operators to analyze the performance of the push-the-bit rotary steering device, thereby providing technical support for efficient drilling operations.

A method for predicting a maximum build rate of a push-the-bit rotary steering tool, comprising the following steps:

step 1:
selecting a push-the-bit rotary steering device that has been used in an actual directional well operation;
step 2:
calculating, by a mechanical mathematical model, a theoretical maximum build rate of the push-the-bit rotary steering device;
step 3:
calculating a measured maximum build rate in a working well depth interval based on measured well inclination data and a record of a steering force used by the push-the-bit rotary steering device in the working well depth interval;
step 4:
calculating a correction factor based on the theoretical maximum build rate and the measured maximum build rate;
and
step 5:
changing a parameter in the mechanical mathematical model based on the correction factor to predict a maximum build rate of the push-the-bit rotary steering device with a different configuration;
step 6:
adjusting a structure of the rotary steering tool based on the predicted maximum build rate during operation,
wherein, the mechanical mathematical model is established by:
setting a current wellbore curvature of the push-the-bit rotary steering device as kc, mechanically simplifying the push-the-bit rotary steering device by assuming the push-the-bit rotary steering device as being formed by two beam columns, and acquiring a beam column model of the push-the-bit rotary steering device, wherein the push-the-bit rotary steering device is simplified to comprise a drill bit, a stabilizer, and a steering device,
wherein in the calculation by the mechanical mathematical model, parameters are recorded, comprising:
an outer diameter Dbit of the drill bit, an outer diameter Dsta of the stabilizer, a weight on bit WOB, a pushing force Fp generated by a pushing pad, maximum pushing force Fpmax generated by a pushing pad a distance LAC from the drill bit to the pushing pad, a distance LCB from the pushing pad to the stabilizer, a length LAB of the steering device, an outer diameter Dot of the steering device, an inner diameter Dit of the steering device, a bending stiffness EI of the steering device, and a linear weight qt of the steering device, wherein LAB=LAC+LCB, wherein in the beam column model, a displacement yAC of the push-the-bit rotary steering device under a stress between the drill bit and the pushing pad and a displacement yCB between the pushing pad and the stabilizer are expressed as follows:
y
AC
=
c
2
⁢
cos
⁡
(
x
⁢
WOB
⁢
cos
⁡
(
L
AB
⁢
k
c
)
EI
)
+
c
1
⁢
sin
⁡
(
x
⁢
WOB
⁢
cos
⁡
(
L
AB
⁢
k
c
)
EI
)
+
x
2
⁢
q
t
⁢
sec
⁡
(
L
AB
⁢
k
c
)
2
⁢
WOB
+
c
3
⁢
x
+
c
4
;
(
1
)
y
CB
=
c
6
⁢
cos
⁡
(
x
⁢
WOB
⁢
cos
⁡
(
L
AB
⁢
k
c
)
EI
)
+
c
5
⁢
sin
⁡
(
x
⁢
WOB
⁢
cos
⁡
(
L
AB
⁢
k
c
)
EI
)
+
x
2
⁢
q
t
⁢
sec
⁡
(
L
AB
⁢
k
c
)
2
⁢
WOB
+
c
7
⁢
x
+
c
8
;
(
2
)
wherein, c1, c2, c3, c4, c5, c6, c7, and c8 denote 8 coefficients to be solved, and are calculated by the following boundary conditions:
y
A
⁢
C
|
x
=
-
L
AB
=
1
2
×
k
c
×
L
AB
2
+
D
bit
2
(
3
)
y
AC
|
x
=
-
L
CB
=
y
CB
|
x
=
-
L
CB
(
4
)
y
C
⁢
B
|
x
=
0
=
D
sta
2
+
(
D
bit
-
D
sta
)
(
5
)
dy
AC
d
⁢
x
❘
"\[RightBracketingBar]"
x
=
-
L
AB
=
0
(
6
)
d
⁢
y
AC
d
⁢
x
❘
"\[RightBracketingBar]"
x
=
-
L
CB
=
dy
CB
d
⁢
x
❘
"\[RightBracketingBar]"
x
=
-
L
CB
(
7
)
d
2
⁢
y
AC
dx
2
❘
"\[RightBracketingBar]"
x
=
-
L
CB
=
d
2
⁢
y
CB
dx
2
❘
"\[RightBracketingBar]"
x
=
-
L
CB
(
8
)
d
2
⁢
y
CB
dx
2
❘
"\[RightBracketingBar]"
x
=
0
=
0
(
9
)
-
EI
⁢
d
3
⁢
y
AC
dx
3
❘
"\[RightBracketingBar]"
x
=
-
L
CB
-
F
c
⁢
d
⁢
y
AC
dx
❘
"\[RightBracketingBar]"
x
=
-
L
CB
-
EI
⁢
d
3
⁢
y
CB
dx
3
❘
"\[RightBracketingBar]"
x
=
-
L
CB
-
F
c
⁢
dy
CB
dx
=
F
pmax
(
10
)
wherein
,
F
c
=
WOB
×
cos
⁡
(
k
c
×
L
AB
)
.

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Method and system for predicting maximum build rate of push-the-bit rotary steering tool

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Method and system for predicting maximum build rate of push-the-bit rotary steering tool

Life of this patent

Abstract

Claims14