Investigation of the effects of air injection fraction and velocity on cuttings transport in oil and gas drilling with aerated mud using kinetic theory of granular flow

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Vol. 35; no. 5; p. 104442
• Main Authors: Pang, Boxue, Ren, Xianghui, Wang, Shaoqin, Zhao, Yueqi, Liu, Xu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2024
• Subjects: Aerated mud; Cuttings transport; Kinetic theory of granular flow; Multiphase flow; Oil and gas drilling; Oil and gas drilling; Aerated mud; Multiphase flow; Cuttings transport; Kinetic theory of granular flow
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2024.104442

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•Gas-liquid–solid flow characteristics in aerated mud drilling is numerically studied.•Particles collisions and their bidirectional coupling with turbulence are modeled.•Proposed model is verified as a reliable method, with an average error of 6.88%.•Complex spiral stratified flow regime for the three-phase flow is predicted.•Effects of air injection fraction and velocity on cuttings transport are studied.
The underbalanced aerated mud drilling is used more widely in unconventional oil and gas exploitation to maintain bottom hole pressure below reservoir pressure. However, the three-phase flow of mud, air and cuttings brings more complex hole cleaning problems. Compared to previous investigations on two-phase liquid-solid cuttings transportation, in this work, cuttings transport in aerated mud was systematically investigated for the first time based on kinetic theory of granular flow. The proposed model is verified to be a reliable method to predict the wellbore cleaning in aerated mud drilling, with an average error of 6.88%. The flow patterns of the air, mud, and cuttings and the effects of air injection fraction and velocity on cuttings concentration, pressure loss, effective viscosity, mud turbulence and cuttings pulsation were revealed. The gas-liquid-solid system in aerated mud drilling exhibits not only a layered distribution, but also a swaying phenomenon with the direction of drill pipe rotation. As the air injection fraction of the aerated mud increases, the annular pressure drop decreases but the cuttings deposition increases. While a higher air injection velocity results in a lower concentration of cuttings retained in the annulus and a higher pressure drop.