Analysis of stress in circular hollow section by fea and analytical technique
T&D relation to cutting bed thickness
1. To study the effects of downhole problem on
torque and drag calculation in directional wells
Presented by:
Nikhil Barshettiwar
ME (Petroleum)
Maharashtra Institute of Technology,
Pune
2. Contents
•
•Basics of Torque and Drag calculation
•Soft string models and Stiff string models
•Areal Clearance Factor Calculation
•Analysis of results by analytical methods
•Introduction to finite element analysis
•Contact force calculation
•Results
•Conclusion
3. F1
F2 = F1 + We*L + μ*Fn
Soft String Model Vs Stiff String
Model
13. Input data for MATLAB Program
1. Drill string specifications
- Length of drillpipe
- Diameters
- Density of Pipe
- Young’s Modulus
-Poisson’s ratio
2. Survey data
- Measured depth
- Inclination
- Azimuth
3. Controlling parameters for Wilson-theta method
- Time step
- alpha and beta
-Total steps
-Clearance
- Stiffness
4. Boundary Conditions
14. nnd=4;
nel=3;
nne=2;
nodof=6;
eldof=nne*nodof;
%%nodes coordinates X and Y %%%
geom=zeros(nnd,1);
geom=[0.;a.;b.;c.];
%%element connectivity%%%
connec=zeros(nel,2);
connec=[1 2;2 3;3 4];
%%geometrical properties%%%
%%prop(1,1)=E; prop(1,2)=I
prop=zeros(nel,2);
prop=[200000 200e6;200000 200e6;200000 200e6];
%%%Boundry conditions%%%
nf=ones(nnd,nodof);
nf(1,1)=0; nf(1,2)=0;
nf(2,1)=0;
nf(3,1)=0;
nf(4,1)=0; nf(4,2)=0;
%%counting the no. of degrees of freedom%%%
n=0;
for i=1:nnd
for j=1:nodof
if nf(i,j)~=0
n=n+1;
nf(i,j)=n;
end
end
end
%%%%Internal Hinges%%%
Hinge=ones(nel,2);
%%loading%%%
Joint_loads=zeros(nnd,2);
%%%Enter here the forces in X and Y directions at node i
Element_loads=zeros(nel,4);
Element_loads(1,:)=[-1.e4 -1.e7 -1.e4 1.e7];
Element_loads(2,:)=[-1.e4 -8.333e6 -1.e4 8.3333e4];
%%%%%End of Input %%%%%%
15. Solution for FEA using Newmark-Beta Method
Steps involved in FEM
1. Setting up matrices [M], [K] and [C]
2. Initialize {X}, {X’} and {X”}
3. Selection of time steps Δt , calculating α and β
4. Forming effective stiffness matrix
5. Calculating effective force vector
6. Solving for Displacement matrix at t+Δt
7. Calculating Velocity and Acceleration matrix
19. Results
5700
5800
5900
6000
6100
6200
6300
6400
50000 150000 250000 350000
Depth(ft)
Force (lb)
Force (10mm-Hoisting)
Force (10mm-lowering)
Force (100mm-Hoisting)
Force (100mm-lowering)
Force (150mm-Hoisting)
Force (150mm-lowering)
• Increase in drag linearly with increase in bed thickness
• Base case value is 2000 lb assume for calculations. Increase in drag for 10mm,
100mm and 150mm are obtained as 2017.321 lb, 2934.031 lb and 6037.383 lb
respectively.
20. Conclusion
•Analytical model gives exaggerated results since it assumes the complete drillstring is
in contact with the cutting bed.
•Finite Element Analysis with help of contact analysis can improve the results because
it takes stiffness of drillstring into account, hence the increase amount of drag wherever
contact force is occurring.
•There is always fold increase in torque and drag due to accumulation of cuttings bed.
The amount of increase in drag due to this can reduce the efficiency of equipments.
21. References
1.Aadnoy,S.B., Fazaehizadeh, M.,Hareland,G. “A 3D Analytical model for wellbore friction”, JCPT, vol.49,No.10,
October 2010
2.Aadnoy,B.S.,Andersen,K. “Friction analysis for long reach wells” ,SPE/IADC 39391,IADC/SPE Drilling
Conference held in Dallas, Texas, 3-6 March 1998
3.Fazaelizadeh, M.,Hareland,G.,Aadnoy,B.S. “Application of New 3-D Analytical Model for Directional Wellbore
Friction” Modern applied science , Vol.4 No.2 February 2012
4.Fazaelizadeh,M. “Real time Torque and Drag Analysis during Directional Drilling, Ph.d Thesis, Department of
chemical and Petroleum engineering, Calgary, Alberta, March 2013)
5. Francis Effiong., ‘Experimental cuttings transport in horizontal wellbore-The determination of cuttings bed
height’, NTNU.
6. Haduch,G.A.,Procter,R.L., Samuels,D.A. “Solution of common stuck pipe problems through the adaption of
Torque/Drag Calculations” IADC/SPE 27490,IADC/SPE Drilling Conference held in Dallas, Texas, 15-18
February 1994)
7. Hareland,G.,Wu,A.,Fazaelizadeh,M. “Finite element analysis of drillstring and Its application on torque and
drag calculation, The International Journal of Engineering and Science, Vol.2,Issue 2, Pages 9-16, 2013.
8. Johancsik,C.A.,Friesen,D.B.,Dawson,R. “Torque and Drag in Directional Wells- Prediction and Measurement”
,1983 IADC/SPE Drilling Conference held in New Oriens 20-23 Feb
22. 10. Maidla,E.,Haci,M. “Understanding Torque: The Key to slide-drilling Directional wells”, IADC/SPE 87162,
IADC/SPE drilling conference held in Dallas, Texas, USA,2-4 March 2004
11. Mirhaj, S.A., Kaarstad, E.,Aadnoy, B.S. “Improvement of Torque and Drag modeling in Long reach wells”
Modern applied science, Vol.5 No.5 october 2011
12.Orkhan Ismayilov ,”Application of 3-D Analytical Model for wellbore friction calculation in actual
wells”Norwegian Institute of Science and Technology, Department of Petroleum Engineering and Applied
Geophysics
13.Wu, A., Hareland ,G. “Calculation of friction coefficient and downhole weight on bit with finite element
analysis of drillstring”,ARMA 12-195, 46th rock mechanics/geomechanics symposium held in Chicago, IL,USA,
24-27 June 2012
