Title: Cutting breakage and transportation mechanism of air drilling

Authors: Jun Li; Shunji Yang; Gonghui Liu

Addresses: China University of Petroleum (Beijing), 18 Fuxue Road, Changping, Beijing, 102249, China ' China University of Petroleum (Beijing), 18 Fuxue Road, Changping, Beijing, 102249, China ' China University of Petroleum (Beijing), 18 Fuxue Road, Changping, Beijing, 102249, China

Abstract: In the air drilling, the mechanism of cutting removal in the annulus is very complicated. The research on this field is limited to theoretical discussion, the explanation using mathematical model have been lacking. This paper proposes a mathematical model of cutting breakage and transportation in air drilling based on the mechanism of rock fragmentation and the theory of gas-solid flow. Also, simulations have been conducted to determine and classify the cuttings concentration and particle size distribution at the surface. The results showed that the concentration of larger cuttings decrease rapidly while the concentration of the small cuttings increase constantly. The results also explain the reason that the cuttings are small at surface in air drilling. [Received: October 18, 2011; Accepted: January 9, 2012]

Keywords: air drilling; return cutting; transportation; cutting breakage; cutting concentration; mathematical modelling; rock fragmentation; gas-solid flow; simulation; particle size distribution.

DOI: 10.1504/IJOGCT.2013.052237

International Journal of Oil, Gas and Coal Technology, 2013 Vol.6 No.3, pp.259 - 270

Published online: 29 Jan 2014 *

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