Due to a recent comment I made concerning my notion of the superior manual vessel handling ability of the old AHTS and the tug guys of the past a discussion has ensued.
I was asked if the DP operator on an unmoored DP semi or a drillship would be able to stay in position and not emergency disconnect regardless of previous experience.
I have an opinion that the guys I have seen in action may been able to for a short period of time if the sea state is calm but I defer to those that have been in this situation as it is not my area of expertise.
How many of you DP folks have had the DP system fail and you had to take over station keeping? What was the water depth, amount of drill string down, sea state etc? How did things work out? The more details the better.
[QUOTE=tengineer1;159734]Due to a recent comment I made concerning my notion of the superior manual vessel handling ability of the old AHTS and the tug guys of the past a discussion has ensued.
I was asked if the DP operator on an unmoored DP semi or a drillship would be able to stay in position and not emergency disconnect regardless of previous experience.
I have an opinion that the guys I have seen in action may been able to for a short period of time if the sea state is calm but I defer to those that have been in this situation as it is not my area of expertise.
How many of you DP folks have had the DP system fail and you had to take over station keeping? What was the water depth, amount of drill string down, sea state etc? How did things work out? The more details the better.[/QUOTE]
It’s possible provided the arrangement was there for an extended period. On the AHTS vessels, you are sitting down, with controls arranged in such a way that you are comfortable. I live boated with ROVs for several years, with no DP, in 5000’+WD when suction piles first came on the scene. We did have auto-head during that time (thrusters only), just turn the rudders inboard and did what you had to do to keep the vessel in a 20 foot circle with the mains for a 12 hours shift - changing out every so often to keep your mind fresh. From my experience doing that in the late 90s, your mind starts to wonder after a few hours. DP certainly had a place and was nice to see. You still cannot DP running anchors. Most of the newer anchor handlers have interface DP control screens, manual controls, and joystick right on the arms of the aft pilot chairs, the adjacent chair has the winch controls the same way. You can auto-head, leaving the mains in manual (for pulling), and most of the time you have more power on one main compared to the other (most large anchor handlers have double drums, meaning you are pulling off centerline more than likely). You do what your experience tells you is the right way to go it. Too many variables.
Regarding a DP drill ship. Yeah, you can repeat above in joystick, it would be difficult as far as posture and how most consoles are set-up, and getting to that point is not realistic either; an emergency situation as far as a drive off is actually more probable. You could do it long enough to set a packer and get the BHA above the BOP, of course depending on where you are in a drilling program will dictate the plan forward. With my background, I had tried this scenario, and we train the same between wells, getting the guys time on IJS, learn the gain settings, bias, linear - progressive reaction settings. It’s not a difficult task, but over a period it would be very difficult for reasons above. You can do it long enough to get out of a bad situation, you would not have much of a choice, or much sleep until it was over.
[QUOTE=anchorman;159739]It’s possible provided the arrangement was there for an extended period. On the AHTS vessels, you are sitting down, with controls arranged in such a way that you are comfortable. I live boated with ROVs for several years, with no DP, in 5000’+WD when suction piles first came on the scene. We did have auto-head during that time (thrusters only), just turn the rudders inboard and did what you had to do to keep the vessel in a 20 foot circle with the mains for a 12 hours shift - changing out every so often to keep your mind fresh. From my experience doing that in the late 90s, your mind starts to wonder after a few hours. DP certainly had a place and was nice to see. You still cannot DP running anchors. Most of the newer anchor handlers have interface DP control screens, manual controls, and joystick right on the arms of the aft pilot chairs, the adjacent chair has the winch controls the same way. You can auto-head, leaving the mains in manual (for pulling), and most of the time you have more power on one main compared to the other (most large anchor handlers have double drums, meaning you are pulling off centerline more than likely). You do what your experience tells you is the right way to go it. Too many variables.
Regarding a DP drill ship. Yeah, you can repeat above in joystick, it would be difficult as far as posture and how most consoles are set-up, and getting to that point is not realistic either; an emergency situation as far as a drive off is actually more probable. You could do it long enough to set a packer and get the BHA above the BOP, of course depending on where you are in a drilling program will dictate the plan forward. With my background, I had tried this scenario, and we train the same between wells, getting the guys time on IJS, learn the gain settings, bias, linear - progressive reaction settings. It’s not a difficult task, but over a period it would be very difficult for reasons above. You can do it long enough to get out of a bad situation, you would not have much of a choice, or much sleep until it was over.[/QUOTE]
Thanks for your considered response. I understand the drilling scenario well. But have you ever seen an occasion where the DP system went kaput and you had to actually grab the other console? How did it work out? I was on a vessel once several years ago that had that occur and thank God there was a person on the desk that had the experience of being on vessels such as an AHTS and also had great situational awareness.
Drive off is another scenario which would test the meddle of the DP operator and is as you said much more likely.I have been on a vessel or two when a drive off occurred. Have you seen a drive off and if so how was it handled by the guy on the desk and what was his/her experience level? Does you company allow you to train hands on between wells for such scenarios?