RE: Interesting7 Nov 2020 19:21
"Pressure test takes hours not days or weeks."
They take as long as the Petroleum Engineer wants Gibbon - it was explained to me a while back by someone in the business
You flow the well until you get a steady flow. Then you shut in and record times and pressures.
these are plotted on various graphs and from them you can estimate things like the connected volume, the presence and distance (tho not the direction) of any barriers, limits or baffles.
The problem is that the vertical axis is pressure on a linear scale 100, 200, 300 etc but for the theory to work the TIME is plotted on a log scale - so 1 second, 10 seconds, 100 seconds, 1000 seconds ...... increasing every step. You don't know when the graph is going to stabilise to start with so you just keep recording - the longer you do it the more accurate your interpretation. So the 7th point on your graph is at 1 million seconds = 277 hours or 11.6 days and the point after that............
If all you want to know is "is it going to flow oil or gas" you can flow it for an hour - - a "seagull scorcher" offshore or a "bankers burn" at full throttle.
http://folk.ntnu.no/perarnsl/Literatur/lecture_notes.pdf
But that's were you get the massive flows that CEO's love to RNS - and they have little to do with how it will flow long term. AIM is littered with examples Brockham for a start
UKOG have been pretty good I think at conducting long shut-ins - they don't report the details but they do collect a lot of data