This message has been cross posted to the following Discussions: Research and Development and Drilling .
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Hi all,
I would like to know your opinion regarding some questions I have about MPD and well control in MPD operations.
1. MPD technology uses flow meter. My question is anyone has experienced problem with the flow meter at low flow rate? If so, what is the minimum flow rate?
2. In HPHT wells with SBM the temperature effect on mud could be significant (Expansion-contraction change density-Volume). During tripping operation using MPD how this effect is seen. I am interesting to know the volume in/out in long trip
3. In tripping out operations for your experience is necessary to use the TIW even though a float valve is used? I have seen a couple of wells using it for redundancy but the tripping time is huge (install/uninstall...for each connection). Is it common practice?
4. During drilling operations, we can circulate gas trough the MPD choke. However we have the option to circulate through the rig choke as well (there are several reasons for that-RCD differential pressure limitation). Have anyone measure the risk on switching from MPD choke to rig choke in well control operations? Do you recommend it?. My first thought is that doing it is not good idea since we cannot measure the flow rate (in-out) in an accurate manner. Also when gas is at surface pressure fluctuates a lot because of the manual choke manipulation and if the MW window is very narrow is pretty easy to be underbalanced or fracture the formation.
5. Flow meter are good with low and big gas volume?
6. MPD is to drill safer and reduce NPT. Do you recommend long flow check before tripping out even though we have MPD?. My question is because in a long flow check in a deep well using SBM you will not see anything since gas may be in solution. So although you check for 30 minutes result may be the same. However, with MPD we may detect that faster . So if I do not know if flow check can be beneficial without sacrificing safety.
7. Let say I am drilling the well with a specific MW and back pressure in a deep well. I take FIT using MPD and get an EMW. Then I reduce the back pressure and increase the MW so that I get the EMW calculated during the FIT. How good it could be. Maybe I am missing something but if I do it even though I get the same EMW at one specific point. The pressure profile change along the wellbore and therefore the EMW, so FIT may not be representative, am I right? If not could you kindly explain why!!!
Thanks in advance for any comment
Regards
Carlos