In cutting operation. There is linear decreasing in specific energy by increasing in penetration rate. Where as in drilling penetration rate increases with increasing in specific energy. What is main reason behind this.
Dear Vijay Kumar,
There is a rigid distinction between the term specific energy used in rock cutting and rock drilling. I have to state a few things here to make this isuue more clear.
1. Rock cutting specific energy is a machine "independent" parameter, actually it is a rock property which changes with cutter configurations. However, it is not an intrinsic rock porperty like hardness or porosity. It changes with the effect of many parameters. However, several researchers (See papers of Prof. Emmanuel Detournay and his collogues) are using a term so-called the intrinsic specific energy which is real rock property, according to their statements) and is determined generally from shallow cutting tests which represent a ductile cutting condition and it is a well-known fact that in ductile region with a negative rake-angled pick compressive and shear stresses are dominant. You may consult many papers on this issue.
2. Another point to be illuminated is that the linear plot between specific energy (SE)-penetration (cutting depth). You said that there is a linear decrease in SE with increasing cutting depth (d) (drag bit cutting) or penetration (disc cutting). This statement is not true. There is an exponential decrase in SE with increasing d to a certain point. After this point SE starts to increase and this region is regarded as groove-deepening point which is an inefficient way of cutting rocks. This SE-d curve has a shape of trough.
3. SE in rock drilling is, as far as I know, is a machine related parameter. If you consult to Teale's paper entitled as "The concept of specific energy in rock drilling", you will see that SE (e was used as a notation instead of SE) has two components, namely thrust and rotary. Thrust component is a function of applied pressure and area. And rotary component, which is crucial for this answer, is a function of torque, rotational speed, penetration rate etc. So this plot contains machine related parameters, e.g. if you increase the torque SE increases and you consume more energy.
So as a concluding remark, there is a phenomenological distinction between SE of rock cutting and drilling in terms of machine parameters.
I hope this answer will contribute you.
Regards,
Serdar.
Please elaborate your question. Are RPM, Torque, and WOB constant? If so, increase ROP with decrease of MSE means you have less bit dysfunctions.
See also
Dupriest, F. E., Witt, J. W., & Remmert, S. M. (2005, January 1). Maximizing ROP With Real-Time Analysis of Digital Data and MSE. International Petroleum Technology Conference. doi:10.2523/IPTC-10607-MS
Drill bit diameter is constant, RPM and Penetration rate increase. how the specific energy will behave, sir. in our case specific energy is increasing with constant drill bit diameter, by varying RPM and penetration rate.
In field units for downhole values MSE can be calculated as follows:
- Badges
- Science topic
- Similar topics
- Geoscience
- Cartography
- Mapping
- Maps