Numerical Analysis and Experimental Validation of a Downhole Stress/Strain Measurement Tool

Real-time measurement of applied forces, like tension, compression, torsion, and bending moment, identifies the transferred energies being applied to the bottomhole assembly (BHA). These forces are highly detrimental to measurement/logging-while-drilling tools and downhole equipment. Real-time measurement of the dynamic downhole behavior, including weight, torque, bending on bit, and vibration, establishes a real-time feedback loop between the downhole drilling system and drilling team at the surface. This paper describes the numerical analysis of the strain data acquired by the measurement tool at different locations on the strain pockets. The strain values obtained by FEA for various loading conditions (tension, compression, torque, and bending moment) are compared against experimental results obtained from an identical experimental setup. Numerical analyses results agree with experimental data within 8% and, therefore, substantiate and validate the FEA model. This FEA model can be used to analyze the combined loading conditions that reflect the actual drilling environment.

• Abhay Bodake
• Ping Sui
• Hafeez Syed
• Ratish Kadam

• FEA
• M/LWD
• Oil & Gas
• Strain Measurement.

[1] Millheim, K. 1978. Bottom-Hole Assembly Analysis Using the Finite-
Element Method. Paper SPE 6057 presented at the SPE-AIIME 51st
Annual Fall Technical Conference and Exhibition, New Orleans,
Louisiana, USA, 3-6 May.
[2] Young, K., Alexander, C., Biel, R., and E. Shanks. 2005. Updated
design methods for HPHT equipment. Paper SPE 97595 presented at the
Applied Technology Workshop on High Pressure/High Temperature
Sour Well Design, The Woodlands, Texas, USA, 17-19 May.
[3] Aslaksen, H., Annad, M., Duncan, R., Fjaere, A., Paez, L., and Tran, U.
2006. Integrated FEA modeling offers system approach to drilling
optimization. Paper IADC/SPE 99018 presented at the IADC/SPE
Drilling Conference, Miami, Florida, USA, 21-23 February.
[4] Chen, D.C-K and Wu, M. 2007. Maximizing drilling performance with
state-of-the-art BHA program. Paper SPE/IADC 104502 presented at the
SPE/IADC Drilling Conference, Amsterdam, The Netherlands, 20-22
February.