HI Friedrich & All, On 29 March 2010 23:44, Friedrich Romstedt wrote: > 2010/3/29 Andrea Gavana <andrea.gav...@gmail.com>: >> If anyone is interested in a follow up, I have tried a time-based >> interpolation of my oil profile (and gas and gas injection profiles) >> using those 40 interpolators (and even more, up to 400, one every >> month of fluid flow simulation time step). >> >> I wasn't expecting too much out of it, but when the interpolated >> profiles came out (for different combinations of input parameters) I >> felt like being on the wrong side of the Lala River in the valley of >> Areyoukidding. The results are striking. I get an impressive agreement >> between this interpolated proxy model and the real simulations, >> whether I use existing combinations of parameters or new ones (i.e., I >> create the interpolation and then run the real fluid flow simulation, >> comparing the outcomes). > > I'm reasoning about the implications of this observation to our > understanding of your interpolation. As Christopher pointed out, it's > very important to know how many gas injections wells are to be > weighted the same as one year. > > When you have nice results using 40 Rbfs for each time instant, this > procedure means that the values for one time instant will not be > influenced by adjacent-year data. I.e., you would probably get the > same result using a norm extraordinary blowing up the time coordinate. > To make it clear in code, when the time is your first coordinate, and > you have three other coordinates, the *norm* would be: > > def norm(x1, x2): > return numpy.sqrt((((x1 - x2) * [1e3, 1, 1]) ** 2).sum()) > > In this case, the epsilon should be fixed, to avoid the influence of > the changing distances on the epsilon determination inside of Rbf, > which would spoil the whole thing. > > I have an idea how to tune your model: Take, say, the half or three > thirds of your simulation data as interpolation database, and try to > reproduce the remaining part. I have some ideas how to tune using > this in practice.
This is a very good idea indeed: I am actually running out of test cases (it takes a while to run a simulation, and I need to do it every time I try a new combination of parameters to check if the interpolation is good enough or rubbish). I'll give it a go tomorrow at work and I'll report back (even if I get very bad results :-D ). >> As an aside, I got my colleagues reservoir engineers playfully >> complaining that it's time for them to pack their stuff and go home as >> this interpolator is doing all the job for us; obviously, this misses >> the point that it took 4 years to build such a comprehensive bunch of >> simulations which now allows us to somewhat "predict" a possible >> production profile in advance. > > :-) :-) > >> I wrapped everything up in a wxPython GUI with some Matplotlib graphs, >> and everyone seems happy. > Not only your collegues! >> The only small complain I have is that I >> wasn't able to come up with a vector implementation of RBFs, so it can >> be pretty slow to build and interpolate 400 RBFs for each property (3 >> of them). > > Haven't you spoken about 40 Rbfs for the time alone?? Yes, sorry about the confusion: depending on which "time-step" I choose to compare the interpolation with the real simulation, I can have 40 RBFs (1 every year of simulation) or more than 400 (one every month of simulation, not all the monthly data are available for all the simulations I have). > Something completely different: Are you going to do more simulations? 110% surely undeniably yes. The little interpolation tool I have is just a proof-of-concept and a little helper for us to have an initial grasp of how the production profiles might look like before actually running the real simulation. Something like a toy to play with (if you can call "play" actually working on a reservoir simulation...). There is no possible substitute for the reservoir simulator itself. Andrea. "Imagination Is The Only Weapon In The War Against Reality." http://xoomer.alice.it/infinity77/ ==> Never *EVER* use RemovalGroup for your house removal. You'll regret it forever. http://thedoomedcity.blogspot.com/2010/03/removal-group-nightmare.html <== _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
