Date of Award

Summer 8-2-2024

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Materials Science

Committee Chair

Lee Richards

First Advisor

Erick Johnson

Second Advisor

Peter Lucon

Third Advisor

Ryan Anderson

Fourth Advisor

Burt Todd

Abstract

As global demand for oil and gas continues to rise alongside pressures to curb climate change, Exploration and Production (E&P) companies look to reduce their surface footprint and increase drilling efficiency through longer horizontal well drilling. In addition, the depletion of conventional reservoirs is causing E&P companies to target more difficult reservoirs, often miles offshore (Gupta et al., 2014; Meader et al., 2000a). The increased horizontal reach of these wells often leads to increased challenges in adequate hole cleaning during drilling operations. Efficient hole cleaning becomes a greater challenge in high-angle wells, with gravitational forces causing pipe eccentricity, flow channeling, and cuttings bed development. Operators aim to maximize flow rates whenever possible to overcome cutting slip velocity, but are often restricted by equipment or formation limits. As a result, operators seek other means to increase hole cleaning such as drill pipe rotation. Pipe rotation has repeatedly been shown to increase hole cleaning in horizontal wells ((Luo et al., 1994; Nazari et al., 2010; Sanchez et al., 1997) – however, when annular size becomes large, pipe rotation has a lessened impact on cuttings transport below 120RPM. In many circumstances, operators are unable to rotate at these RPM due to equipment restrictions, and the result is poor hole cleaning and less efficient drilling operations. The following research utilizes computational fluid dynamics (CFD) modeling to identify the annular size threshold in which pipe rotation is less effective below 120 RPM. Further, it identifies the changes in flow patterns and fluid rheology at high RPM only seen in large-diameter annuli that cause a sudden increase in cuttings transport. A better understanding of the causes behind the delayed effectiveness of drill pipe rotation in large annuli could lead to better well design and operating practices, significantly reducing risk and increasing operational efficiencies.

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