Engineering solutions for sludging prevention at bottomhole

Failure-free drilling in many ways depends on efficiency of borehole cleanout. Sludging at bottomhole leads to regrinding of rock cuttings, and this, in its turn, results in reduction of rate of penetration, increases energy consumed by a rock-cutting tool for regrinding, and elevates risks of wall packing. For another thing, sludging at bottomhole intensifies abrasive wear of a drilling assembly. The article gives a theoretical description of movement of drilled rock particle, proving the need to apply an external force to direct the particle to the surface. The described improved design of a tricone drill bit enables a vortex flow of sludge at bottomhole, which full-blast directs rock particles from under the rock cutting tool toward the borehole walls. The developed vortex generator speeds up the upward motion of washing solution to the top of the drilling assembly, which prevents sludging and wall packing in the drilling string. The tests of the proposed engineering solutions are described. The tests allowed determining efficient bent angles for the drilling bit leg, as well as the number and bent angles of screws for the vortex generator. The analysis of the test data shows that the designed drilling assembly improves the quality of cleanout at bottomhole and enhances efficiency of drilling owing to prevention of sludging at the bottomhole, increased rate of penetration and reduced power consumed by the motor of the swivel head and pump.

Djuraev R. U., Merkulov M. V., Khatamova D. N., Asanov A. T. Engineering solutions for sludging prevention at bottomhole. MIAB. Mining Inf. Anal. Bull. 2025;(7):102-114. [In Russ]. DOI: 10.25018/0236_1493_2025_7_0_102.

R.U. Djuraev¹, Dr. Sci. (Eng.), Professor, e-mail: r.u.djuraev@yandex.ru, ORCID ID: 0000-0003-2712-3003,
M.V. Merkulov, Dr. Sci. (Eng.), Professor, Sergo Ordzhonikidze Russian State University for Geological Prospecting (MGRI), 117997, Moscow, Russia, e-mail: mvm.07@mail.ru,
D.N. Khatamova¹, Dr. Sci. (Eng.), Assistant Professor, e-mail: dilyon_hat@bk.ru, ORCID ID: 0009-0002-8336-9884,
A.T. Asanov¹, Assistant,
¹ Navoi State University of Mining and Technology, Navoi, 210100, Uzbekistan.

D.N. Khatamova, e-mail: dilyon_hat@bk.ru.

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