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ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

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Modeling of Cuttings Transport in Horizontal Wellbores Using Computational<br />

Fluid Dynamics<br />

Mehmet Sorgun<br />

Atatürk University, Civil Engineering Department, Erzurum<br />

Accurate modeling of cuttings transport mechanism in horizontal wells becomes more critical<br />

while predicting frictional pressure loss and transport velocities. Since drillstring is usually rotating<br />

during drilling operations, it increases the complexity of the behavior of the drilling fluid and<br />

cuttings transport inside the wellbore. Experimental and numerical results demonstrated that<br />

pipe rotation significantly improves the cuttings transport ability of the fluids inside the wellbore,<br />

especially if the drillstring is in an eccentric position. Drilling fluid velocity is the most important<br />

drilling parameter affecting hole cleaning. The critical fluid velocity required for effective hole<br />

cleaning considerably decreases as pipe rotation is introduced. Moreover, a decrease in the<br />

pressure loss is observed due to the bed erosion while rotating the pipe. In this study, cuttings<br />

transport in fully eccentric horizontal annulus is modeled using Computational Fluids Dynamics<br />

(CFD) software for different flow rates, pipe rotation speeds and rate of penetrations. Extensive<br />

experimental studies have been conducted at Middle East Technical University, Petroleum &<br />

Natural Gas Engineering Flow Loop using water flow velocities from 0.64 m/s to 3.05 m/s, rate<br />

of penetrations from 0.00127 to 0.0038 m/s, and pipe rotations from 0 to 120 rpm. Pressure<br />

loss within the test section and stationary and/or moving bed thickness are recorded. Model<br />

predictions are compared with over 90 experimental frictional pressure loss values. Results show<br />

that, model can estimate frictional pressure loss within an error range of ± 20 %.<br />

Keywords : Hole cleaning, pressure loss, mechanistic model, pipe rotation, CFD, horizontal well<br />

355

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