<p class="MsoNormal" style="text-align: justify">The prediction of frictional pressure loss in many oil wells drillings is of the utmost importance. Most earlier studies in this area were concerned with the frictional losses due to fluid flow in pipes and annulus. &nbsp;&nbsp;However, studies on the tool-joint effect on the frictional pressure loss were limited to only a few experimental and theoretical studies using the water-based power-law drilling muds.&nbsp;&nbsp; (Tool-joint is the part where two drill strings connect where the annulus has a gradual decrease and increase area). &nbsp;Since the tool-joint has an important role in extending the drill pipe, its effect on pressure losses cannot be ignored. The drilling muds generally must have certain qualities such as keeping the formation integrity, transporting the cuttings from bit to surface, lubricating the drill pipe, and transporting heat.&nbsp;&nbsp; Therefore, it is important to predict the pressure loss for qualified and effective drilling fluid. &nbsp;The drilling muds have become more complex and expensive, and selecting an appropriate drilling fluid is of great importance. For this reason, oil-based viscoplastic drilling muds are being used in more drilling operations. However, for these drilling muds, little if any studies were conducted to predict the effect of the tool-joints on flow behavior and pressure loss.</p><p>In this paper, the behavior of fluid flows and frictional pressure losses in tool-joints of different grades according to the IADC standard manual was studied using CFD simulations. The simulations were conducted using a viscoplastic drilling fluid that is governed by the Herschel–Buckley model. &nbsp;The corresponding fluid flow patterns in these tool-joints under different thermal boundary conditions were studied. The results show that tool-joints have a significant effect on the frictional pressure loss in the drilling muds.&nbsp;&nbsp; The simulation results were used to propose an empirical correlation for accurate pressure loss prediction for the flow of oil-based viscoplastic muds passing through the tool-joint geometry.&nbsp; Furthermore, assuming thixotropic behavior using the More-Cheng model, the effects of the restart process of drilling on the flow behavior of the drilling mud were investigated</p>

Investigation of Tool-Joint Effect on Non-Newtonian Drilling Fluids Following the Herschel–Bulkley Model Flow Behavior in Oil Well Drilling

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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