Experimental and analytical study of the side cutting ability of drill bits

• Autorzy: Tellez C. , Singh K. , Miska S. , Ozbayoglu E. , Ziaja M.

Identyfikatory

DOI

10.7494/drill.2018.35.1.139

• Języki publikacji: EN

Abstrakty

EN

Side cutting ability of a drill bit is an important factor to ensure successful directional/horizontal drilling. In this study, a mathematical model of a drill bit has been developed to investigate the side cutting ability of a drill bit. In addition to the theoretical model, the study is also supported by experimental work. Experiments have been conducted for both PDC and tri-cone rotary roller drill bits. Equilibrium equations for BHA in a curved wellbore were established. The expression of internal forces and moments along the drill-string, which are the state variables, are derived. Because of the simplicity and fast computation capability, transfer matrix method (TMM) was adopted to determine these variables. Experiments were conducted on an indoor Tulsa University Drilling Research Projects (TUDRP) full-scale drilling rig. Tests have been conducted using 6 inch and 8.5 inch PDC drill bits. In addition, 8.5 inch tri-cone bit were tested as well. Bent sub was installed above the drill bit to enhance the side force at the bit. During the experiments, weight on bit (WOB) and flow rate were kept constant. The torque was recorded by torque gage. It was observed that RPM has little influence on torque. As expected, the bit side cutting abilities, also referred to as bit steer-ability, were different for different bits. For quantitative comparisons, a dimensionless quantity has been introduced that measures the relative difference in torque with bent sub and without with respect to torque without bent sub. In all tests, the torque with bent subs was found to be greater than those without. Hence, the relative difference is always positive. The higher the relative difference, the poorer the side cutting ability. For drill bits with side cutting ability equal to that of face cutting, the dimensionless quantity becomes zero. In conclusion, the main outcome of this paper is a new method of measuring face and side cutting ability for PDC and tri-cone bits. A similar approach has been applied to the analysis of data from offset wells using a computer program to predict side forces and the corresponding torques. This in turn permitted us to calculate the relative difference in torque and assess the side cutting ability of the drill bits. A comprehensive study of the side cutting ability of a drill bits missing in the current literature. Considering the important role side cutting ability plays in directional drilling, a very innovative mathematical model has been proposed to study the same. Experimental tests have been conducted to verify the model. The model can be used to analyze directional data and obtain useful information from offset wells to enhance future drilling projects.

Słowa kluczowe

EN

drill bits; directional drilling; BHA mechanics

• Wydawca: AGH University of Science and Technology Press
• Czasopismo: AGH Drilling, Oil, Gas
• Rocznik: 2018
• Tom: Vol. 35, no. 1
• Strony: 139--155
• Opis fizyczny: Bibliogr. 10 poz., rys., tab., wykr.

Twórcy

autor

Tellez C.

• The University of Tulsa, Drilling Research Projects

autor

Singh K.

• The University of Tulsa, Drilling Research Projects

autor

Miska S.

• The University of Tulsa, Drilling Research Projects

autor

Ozbayoglu E.

• The University of Tulsa, Drilling Research Projects

autor

Ziaja M.

• The University of Tulsa, Drilling Research Projects

Bibliografia

• [1] Chen H., Miska S., Mitchell R.F.: Prediction of transient wellbore trajectory under anisotropic drilling conditions. Wiertnictwo, Nafta, Gaz, vol. 20/2, 2003, pp. 317–329.
• [2] Chen S. et al.: Reexamination of PDC Bit Walk in Directional and Horizontal Wells. IADC/SPE-112641, IADC/SPE Drilling Conference held in Orlando, Florida, USA, 4–6 March 2006.
• [3] Gaynor T., Chen D.: Making Steerable Bits: Separating Side-Force from Side-Cutting. SPE-88446, SPE Asia Pacific Oil and Gas Conference and Exhibition held in Perth, Australia, 18–20 October 2004.
• [4] Ho H.: Prediction of Drilling Trajectory in directional Wells Via a New Rock-Bit Interaction Model. SPE-16658, SPE-62nd Annual Technical Conference and Exhibition of the Society of Petroleum Engineers held in Dallas, TX, Sept. 27–30, 1987.
• [5] Lubinski A., Miska S.: Developments in Petroleum Engineering. Gulf Publishing Company Textbook, vol. 1, 1987. Part 2, Chapter 5, pp. 219–242., Chapter 10, pp. 423–439.
• [6] Menand S. et al.: PDC Bit Steerability Modeling and Testing for Push-the-bit and Point-the-bit RSS. IADC/SPE-151283, IADC/SPE Drilling Conference, and Exhibition held in San Diego, California, USA, 6–8 March 2012.
• [7] Millhiem K., Warren T.: Side-cutting Characteristics of Rock Bits and Stabilizers while drilling. SPE-7518, SPE ATC, Houston, Texas, USA, 1–3 October 1978.
• [8] Miska S., Miska W.: Modeling of complex bottom hole assemblies in curved and straight holes. Archives of Mining Sciences, 51, iss. 1, 2006, pp. 35–54.
• [9] Miska S., Rajtar J., Luo F.: Type Curves for Predicting Directional Tendencies of Simple Bottom-Hole Assemblies. ASME Publication, September 1998.
• [10] Warren T.: Factors Affecting Torque for a Roller Cone Bit. SPE-11994, SPE Annual Technical Conference and Exhibition held in San Francisco, California, USA, 5–8 October 1984.

Uwagi

PL

Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2018).