LOST CIRCULATION MATERIAL (LCM)
Mud Level Drop with Time
With natural fractures: Marginal pit level reduction with time for fractures with small apertures, while an exponential decline in pit level with time for the fluid losses into a larger fracture aperture.
With induced fractures: Large increase in pit level with a smaller increment in time at the early stages, and then, pit level reaches its maximum value - QUICKY - before start receding with time, and finally reaching the asymptoticity of the pit level with time.
1. Is there any other way, by which, we can distinguish the fluid leak-off pattern into an induced formation - that will have significant variation from the fluid leak-off pattern associated with a naturally fractured formation?
2. Can we blindly replace UBD or MPD to get rid off the problems associated with the lost circulation? In other words, do we have any specific advantage of conventional over-pressured drilling with reference to Under-balanced drilling?
3. Whether "kick" and "dry drilling" could happen simultaneously?
4. Any recent technique on LCM for HP/HT conditions?
Thanks.
Suresh
I try to help with No. 1 as it is the one I am more familiar with
1. The patterns are clearly reconisable particularly in the early and middle parts of both the naturally fractured formations and formations where fractures are induced. Both cases are dependent on what the Pb and FPP are, as that will dictate if they open and its eventual geometry for a given pressure hence time to fill it up. I have done some laboratory experiments a few years ago if you are interested. I hope it helps, let me know.
3. Whether "kick" and "dry drilling" could happen simultaneously?
yes, it's called Underground Blowout. You may lose kick fluid into low pore pressure formation https://www.netwasgroup.us/engineering-4/underground-blowout.html
2. Can we blindly replace UBD or MPD to get rid off the problems associated with the lost circulation? In other words, do we have any specific advantage of conventional over-pressured drilling with reference to Under-balanced drilling?
The advantage of drilling under balance is that minimixa the risk of damage to the training by invasion of drilling fluid, allowing greater control of the work.
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