Drilleksp Small Research and Production Enterprise, Moscow, Russia:

S. V. Sinev, Leading Researcher, Candidate of Engineering Sciences, stanislav-vs@mail.ru

The article discusses simplified generalizing characteristics of drilling such as drillability and drilling mode in the form of relationship between drilling penetration rate, drilling bit pressure and rotations per minute, which allow selecting drill bit and drilling parameters in case of significant headway per drill bit. When high-durability drill bits appeared, the drillability parameter has lost its significance in dividing a hole cross section into pads but remains important in drilling rate setting. Three ways of modeling, i.e. analytical, experimental and statistical are described. The experimental modeling is selected as handy and comprehensible method for drilling people, having advantages borrowed from the statistical modeling on a real-time basis, and implementable directly on a drilling rig. Separation of a drilling model in the form of the drilling penetration rate as function of drilling bit pressure into intervals by rock–bit interaction types and mechanisms of rock failure into volumetric, fatigue–volumetric and abrasion destruction is erroneous. Dependences of the drilling penetration rate on the drill bit pressure and rotations per minute are linear, and departure from linearity is conditioned by both bottomhole cleaning and, in a greater degree, by integration of drilling tool and hole wall interaction in the drilling process. Surveys of drilling models at the minimal headway of 200 mm are illustrated. These surveys are carried out at the beginning of drilling, in the time of drill changing and during connection with and without loss of time of drilling process. The model can be used to determine rock drillability to separate a hole cross section into pads. The primary purpose is to reveal technical-and-economic indexes of new equipment and tools, including drill bits. The drill bits efficiency of which has been estimated using the drilling models are presented. These drill bits have produced a 300 % increase in the drilling penetration rate as compared with the massproduced tools and enabled improving bit bearings by introduction of the second retaining drill bit bearing in the unloaded side of the tool with leaving a gap for sealing.

1. Capik M., Yilmaz A. O., Yasar S. Relationships between the drilling rate index and physicomechanical rock properties. Bulletin of Engineering Geology and the Environment. 2017. Vol. 76, Iss. 1. pp. 253–261.
2. Hoseinie S. H., Ataei M., Aghababaie A. A laboratory study of rock properties affecting the penetration rate of pneumatic top hammer drills. Journal of Mining and Environment. 2014. Vol. 5, No. 1. pp. 25–34.
3. Blasthole Drilling in Open Pit Mining. 3rd edition. Texas : Atlas Copco, 2012. 304 р.
4. Gilev A. V., Bovin K. A., Shigin A. O., Belozerov I. R. Analysis of penetration of drill bits in terms Olimpiadinskiy GOK ZAO “Polyus”. Sovremennye problemy nauki i obrazovaniya. 2015. No. 2.
5. Bai P. Experimental Research on Rock Drillability in the Center of Junggar Basin. The Electronic Journal of Geotechnical Engineering. 2013. Vol. 18. pp. 5065–5074.
6. Beshenkov P. S., Polushin N. I., Gkhorbani S., Sorokin E. N. Stress distribution analysis of PDC drill bits by computer modeling. Eurasian Mining. 2017. No. 2. pp. 25–28. DOI: 10.17580/em.2017.02.06
7. Shchelchkova I. N., Sinev S. V. Some features of physical modeling of drilling by means of microbits. Stroitelstvo neftyanykh i gazovykh skvazhin na sushe i na more. 2011. No. 6. pp. 12–18.
8. Kaledin O. S. Innovative construction technology of ultra deep shafts. Gornyi Zhurnal. 2014. No. 4. pp. 77–81.
9. Sinev S. V. Mechanisms, methods and ways of destruction of rocks in rollerbit drilling. GIAB. 2016. No. 1. pp. 149–159.
10. Yunin E. K. The introduction to deep-hole drilling dynamics. Second edition. Moscow : Librokom, 2013. 168 p.
11. Miyora T., Jónsson M. Þ., Þórhallsson S. Modelling of Geothermal Drilling Parameters – A Case Study of Well MW-17 in Menengai Kenya. Geothermal: Always on: Geothermal Resources Council Annual Meeting (GRC 2015). New York : Curran Associates, 2015. Vol. 39. pp. 197–208.
12. Nascimento A., Kutas D. T., Elmgerbi A., Thonhauser G., Mathias M. H. Mathematical Modeling Applied to Drilling Engineering: An Application of Bourgoyne and Young ROP Model to a Presalt Case Study. Mathematical Problems in Engineering. 2015. Vol. 2015. 9 p.
13. Eremenko V. A., Neguritsa D. L. Efficient and active monitoring of stresses and strains in rock masses. Eurasian Mining. 2016. No. 1. pp. 21–24. DOI: 10.17580/em.2016.01.02
14. Sinev S. V. Drilling In Situ Models. Oil and Gas Territory. 2016. No. 11. pp. 41–49.
15. Shigin A. O., Shigina A. A., Bovin K. A. Improving roller bit drilling rig performance by timely regulation of operating parameters. Vestnik Irkutskogo gosudarstvennogo tekhnicheskogo universiteta. 2015. No. 8. pp. 65–72.