Abstract

During the process of drilling, the drillstring inadvertently comes in contact with the wellbore generating frictional losses in rotating moment (torque) and axial force (drag). These losses reduce the rotational power available at the drill bit, thus making adequate torque and drag modeling a critical piece in the drilling puzzle. The simplifying assumptions of the widely used soft-string model for torque and drag modeling make it less accurate for new complex well designs, therefore creating the need for the use of the more robust stiff-string model. This work focuses on a new approach for developing a stiff-string model that can be easily implemented for well planning. The stiff-string model addresses the pitfalls of the soft-string model by using cubic splines for its well-path trajectory and solving three coupled, non-linear ordinary differential equations that describe the motion of the drillstring at each survey point to account for the shear forces and bending stiffness. The stiff-string model is then applied to design 4 horizontal wells. In comparison with the soft-string model, results show that the stiff-string model is able to capture the extra contact loads as the drillstring goes through bends, consequently predicting higher hookload and torque values than the soft-string model. This paper also highlights how both models can be applied to well planning for improved results.

References

1.
Brett
,
J. F.
,
Beckett
,
A. D.
,
Holt
,
C. A.
, and
Smith
,
D. L.
,
1989
, “
Uses and Limitations of Drillstring Tension and Torque Models for Monitoring Hole Conditions
,”
Society of Petroleum Engineers
.
2.
Aadnoy
,
B. S.
, and
Andersen
,
K.
,
1998
, “
Friction Analysis for Long-Reach Wells
,”
Society of Petroleum Engineers
.
3.
Banks
,
S. M.
,
Hogg
,
T. W.
, and
Thorogood
,
J. L.
,
1992
, “
Increasing Extended-Reach Capabilities Through Wellbore Profile Optimization
,”
Society of Petroleum Engineers
.
4.
Diaz
,
N.
,
Paila
,
P.
,
Kirby
,
C.
,
Akl
,
B.
,
Mahmoud
,
D.
,
Al Kindi
,
R. K.
, and
Leon
,
V.
,
2018
, “
Successful Implementation of Torque and Drag Management Techniques in High Departure Wells is the Key to Safely Reach Wells Planned Total Depth in Offshore Artificial Islands
,”
Society of Petroleum Engineers
.
5.
Morrison
,
A.
,
Serov
,
N.
, and
Fahmy
,
A.
,
2019
, “
Completing Ultra Extended-Reach Wells: Overcoming the Torque and Drag Constraints of Brine
,”
Society of Petroleum Engineers
.
6.
Haddad
,
M.
,
AL-Aleeli
,
A. R.
,
Zaheer
,
B.
,
Ruzhnikov
,
A.
,
Husien
,
M.
, and
Marinescu
,
P.
,
2017
, “
Drilling of Challenging ERD Wells with Water-Based Mud: How to Significantly Reduce Torque and Drag by New Generation Lubricant
,”
Society of Petroleum Engineers
.
7.
Reiber
,
F.
,
Vos
,
B. E.
, and
Eide
,
S. E.
,
1999
, “
On-Line Torque & Drag: A Real-Time Drilling Performance Optimization Tool
,”
Society of Petroleum Engineers
.
8.
Borjas
,
R.
,
Creegan
,
A.
,
Perdomo
,
A.
, and
Caraway
,
J.
,
2017
, “
A Synchronized Rigsite-to-Office Approach to the Management of Automated Torque and Drag Data
,”
Society of Petroleum Engineers
.
9.
Shahri
,
M.
,
Wilson
,
T.
,
Thetford
,
T.
,
Nelson
,
B.
,
Behounek
,
M.
,
Ambrus
,
A.
, and
Ashok
,
P.
,
2018
, “
Implementation of a Fully Automated Real-Time Torque and Drag Model for Improving Drilling Performance: Case Study
,”
Society of Petroleum Engineers
.
10.
Carpenter
,
C.
,
2019
, “
Automated Real-Time Torque-and-Drag Analysis Improves Drilling Performance
,”
Society of Petroleum Engineers
.
11.
Cao
,
D.
,
Hender
,
D.
,
Ariabod
,
S.
,
Ruddy
,
K.
, and
James
,
C.
,
2020
, “
Digital Transformation Strategy Enables Automated Real-Time Torque-and-Drag Modeling
,”
Society of Petroleum Engineers
.
12.
Hegde
,
C. M.
,
Wallace
,
S. P.
, and
Gray
,
K. E.
,
2015
, “
Real Time Prediction and Classification of Torque and Drag During Drilling Using Statistical Learning Methods
,”
Presented at SPE Eastern Regional Conference
,
Morgantown, WV
,
Oct. 13–15
, SPE-177313.
13.
Oyedere
,
M.
, and
Gray
,
K. E.
,
2020
, “
ROP and TOB Optimization Using Machine Learning Classification Algorithms
,”
J. Nat. Gas Sci. Eng.
,
77
. 10.1016/j.jngse.2020.103230
14.
Rae
,
G.
,
Lesso
,
W. G.
, and
Sapijanskas
,
M.
,
2005
, “
Understanding Torque and Drag: Best Practices and Lessons Learnt From the Captain Field's Extended Reach Wells
,”
Society of Petroleum Engineers
.
15.
Rizkiani
,
D.
,
Yustendi
,
K.
,
Rusli
,
B.
,
Mbouw
,
A. N.
,
Mcken
,
D. R.
,
Effendi
,
H.
, and
Mahry
,
A.
,
2017
, “
Drilling Optimization to Overcome High Torque Problem: Lesson Learned on Kujung First Offshore-Near HPHT-Horizontal-Critical Sour-Slim Hole Development
,”
Society of Petroleum Engineers
.
16.
Johancsik
,
C. A.
,
Friesen
,
D. B.
, and
Dawson
,
R.
,
1984
, “
Torque and Drag in Directional Wells-Prediction and Measurement
,”
Society of Petroleum Engineers
.
17.
Sheppard
,
M. C.
,
Wick
,
C.
, and
Burgess
,
T.
,
1987
, “
Designing Well Paths to Reduce Drag and Torque
,”
Society of Petroleum Engineers
.
18.
Wu
,
A.
,
Harelang
,
G.
, and
Fazaelizadeh
,
M.
,
2011
, “
Torque and Drag Analysis Using Finite Element Method
,”
Modern Appl. Sci.
,
5
(
6
), pp.
13
.
19.
Aadnoy
,
B. S.
,
Fazaelizadeh
,
M.
, and
Hareland
,
G.
,
2010
, “
A 3D Analytical Model for Wellbore Friction
,”
Society of Petroleum Engineers
.
20.
Ho
,
H. S.
,
1988
, “
An Improved Modeling Program for Computing the Torque and Drag in Directional and Deep Wells
,”
Society of Petroleum Engineers
.
21.
McSpadden
,
A.
, and
Newman
,
K.
,
2002
, “
Development of a Stiff-String Forces Model for Coiled Tubing
,”
Society of Petroleum Engineers
.
22.
Mitchell
,
R. F.
, and
Samuel
,
R.
,
2007
, “
How Good Is the Torque/Drag Model?
,”
Society of Petroleum Engineers
.
23.
Mirhaj
,
S. A.
,
Kaarstad
,
E.
, and
Aadnoy
,
B. S.
,
2016
, “
Torque and Drag Modeling; Soft-String Versus Stiff-String Models
,”
Society of Petroleum Engineers
.
24.
Cayeux
,
E.
,
2018
, “
On the Importance of Boundary Conditions for Real-Time Transient Drill-String Mechanical Estimations
,”
Society of Petroleum Engineers
.
25.
Zhang
,
Y.
, and
Samuel
,
R.
,
2019
, “
Engineers’ Dilemma: When to Use Soft String and Stiff String Torque and Drag Models
,”
Society of Petroleum Engineers
.
26.
Abughaban
,
M. F.
,
Eustes
,
A. W.
,
de Wardt
,
J. P.
, and
Willerth
,
M.
,
2017
, “
Improving Torque and Drag Prediction Using the Advanced Spline Curves Borehole Trajectory
,”
Society of Petroleum Engineers
.
27.
Mitchell
,
R. F.
,
Miska
,
S. Z.
,
2011
, “Directional drilling,”
Fundamental of Drilling Engineering
, Vol.
12
, Textbook Series,
Society of Petroleum Engineering
,
Richardson, TX
.
28.
Shampine
,
L.
, and
Gear
,
C.
,
1979
, “
A User’s View of Solving Stiff Ordinary Differential Equations
,”
SIAM Rev.
,
21
(
1
), pp.
1
17
. 10.1137/1021001
29.
Shampine
,
L.
,
Gladwell
,
I.
, and
Thompson
,
S.
,
2003
,
Solving ODEs With MATLAB
,
Cambridge University Press
,
New York
.
30.
Hindmarsh
,
A. C.
,
1983
, “
ODEPACK, A Systematized Collection of ODE Solvers
,”
IMACS Trans. Sci. Comput.
,
1
, pp.
55
64
.
31.
Brown
,
P. N.
, and
Hindmarsh
,
A. C.
,
1989
, “
Reduced Storage Matrix Methods in Stiff ODE Systems
,”
J. Appl. Math. Comput.
,
31
, pp.
40
91
. 10.1016/0096-3003(89)90110-0
32.
Atkinson
,
K. E.
,
1978
, “Interpolation theory,”
An Introduction to Numerical Analysis
, 2nd ed.,
Malloy Lithographing, Inc, John Wiley& Sons, Inc.
,
New York City
, Chap 3, pp.
131
194
.
33.
Abughaban
,
M. F.
,
Bialecki
,
B.
,
Eustes
,
A. W.
,
de Wardt
,
J. P.
, and
Mullin
,
S.
,
2016
, “
Advanced Trajectory Computational Model Improves Calculated Borehole Positioning, Tortuosity and Rugosity
,”
Society of Petroleum Engineers
.
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