Actually, those ROP’s are quite normal, we are finding. The density of the sand and limestone is much higher than the Sydney area. (40 miles west on 201) It also is hard to get much background isolation using invert. Everything comes across the MWD gama as one hydrocarbon, if you know what I mean. Our normal background is steadily 4 to 6 thousand units and we have to flare continuously. Trips are also a nightmare. We have to spot 13# mud above the curve to hold it. When we get back on bottom, it’s a full blown kick/emergency and the flares are SPECTACULAR! (50 to 100 feet.)
We have to use a double membrane rotating head to hold it and we must go through the annular preventer and choke to handle the initial flow when we break circulation. It truly is wild........
We achieved those ROP’s ( 40 to 70 fph in the Sydney area) using 9.6# Salt water. Here is much different. Because of the high gas content, we have to use Invert with a YP of at least 14 to stabilize the sands. Our ROP suffers as a result. But what we are finding is that this method is worth the wait.
Of course now we use 29# on the intermediate, but back then,(’80’s) they had lots and lots of cheap casing available because of the Oil field depression going on
At that time, I was in Prudhoe Bay for BP. then.
The payoff is in getting p-rates of 20-30 ft/hr in zone--but remember, we could get a six inch bit through, and that means a bigger mud motor, too. We were also running hole lube and sweeps to clear out the bedload. Still, it is a bunch slower over there.
I've seen sprints of 1800 ft/day over here in the lateral, 3500 in 2 days (and then we ran out of lease).
The bottom line, though, is whatever works and makes a good well. As for hard and fast rules, the more I learn, the less I know.
Places over there do not have a well defined clean streak on the Gamma Ray log, and the MWD logs don't quite look the same as the old open hole logs, with thinner (as a rule) or inconsistent low GR stringers. You have to get creative on occasion to keep in the good stuff. Use all the available data, especially what the samples tell you, and you can do pretty well.
It sure is a bear to try to get invert off the samples in the lateral though, especially when you get out a ways and everything is milled to powder. That is where the brine really makes the job easier for us rockhounds.