Engineering Commons^™

Influence Of Frictional Or Rotational Kinetic Energy On Wellbore-Fluid/Temperature Profiles During Drilling Operations, Ahmed Q. Al Saedi, Ralph E. Flori, C. Shah Kabir

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Temperature-profile distributions in a wellbore during drilling operations might take different forms when applying the energy balance in the overall system. For steady-state conditions, wherein the wellbore is considered a closed system, adding any source of additional energy to this system can influence the predicted temperature profiles. This study presents a new analytical model to investigate the influence of rotational energy arising from the drillstring operation on the wellbore-temperature behavior.

A significant part of the drilling operation is rotation of the drillstring. Depending on the drilling rig, various equipment provides this kind of energy, such as the rotary table or …

Percussive Penetration Of Unconsolidated Granular Media In A Laboratory Setting, Leslie S. Gertsch

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This controlled study examined the feasibility of a simple percussive approach to drilling through unconsolidated regolith deposits on Mars. The experiments showed that the approach is feasible at the low power levels and low confining pressures used, and that the rate of impact is more important to the penetration rate than is the mass of the impactor (hammer). More massive impactors tend to lower energy efficiency, as they do in terrestrial pile-driving. Unexpectedly, penetration plotted against applied energy tends to cluster into parallel linear trends. Within a given cluster, penetration is very sensitive to applied energy, while between clusters, the …