Date of Award
Master of Science (MS)
Exploration and Production companies are continually focusing more time, energy and resources into Extended Reach Drilling in order to maximize reservoir production while minimizing both environmental impact and development costs. These long laterals (2:1 Measured Depth: True Vertical Depth) are often more difficult to drill and can be severely impacted by inadequate drilling practices. Cuttings transport efficiency is a critical parameter of Extended Reach Drilling operations, and poor wellbore cleaning can lead to excessive torque, drag, and several other serious downhole problems.
Although many studies have been performed that identify the importance of drill string rotation on cuttings movement, there is still much to be learned about the correlation between rotation and hole cleaning. This increase in transport cuttings efficiency is more pronounced in larger diameter holes, where often sudden increases in transport efficiency occur when drill string rotation nears both 120 and 180 RPM.
This document presents a design of a flow loop capable of emulating downhole flow conditions and high RPM drill string rotation in a large diameter wellbore, which would allow for the study and better understanding of this phenomenon. This design will also be the first that allows drill string interchangeability and adjustment of drill string centerline within the casing, further increasing research capabilities. A comprehensive computational fluid dynamics (CFD) model has also been designed. This model will be used alongside the flow loop and will be refined and validated by future flow loop experiments. This flow loop and CFD model can be used to develop working correlations and provide real world predictive models.
A strong comprehension of these step changes in cuttings removal rates could allow for the development of new technology or drilling practices that could replicate this effect, increasing transport efficiency dramatically. With the ever-increasing importance of successful Extended Reach Campaigns, companies are relying heavily on technological and operational breakthroughs to push the envelope of Extended Reach.
Rathgeber, David C., "HORIZONTAL FLOW LOOP DESIGN FOR THE STUDY OF DRILL STRING ROTATION EFFECTS ON CUTTINGS TRANSPORT" (2019). Graduate Theses & Non-Theses. 203.