get_volumetric_rates() should use get_smry_meta()

[berland]

get_smry_meta() provides upstream information from libecl on whether vectors are cumulative/rates or not, which is better than the current test on characters in the name.

libecl code determining rates is not much more complex, but it is upstream:

https://github.com/equinor/libecl/blob/6f89be14d0c8c62c606d2da17c580115cfce3b75/lib/ecl/smspec_node.cpp#L444-L458

[asnyv]

Think in that case you should use get_smry_data() is_total and not is_rate. Both because is_total is what you need to calculate your volumetric rates, and because the is_rate is not stable as seen in this discussion equinor/webviz-subsurface#284 (comment), while is_total seems a lot more mature. Vectors that are not volumetric rates like [FWG]WCT and [FWG]GOR are considered rates, while several actual rates like reservoir condition rates are not included. Just noticed this yesterday afternoon, so will take some initiative to get this improved over easter. For our webviz visualization purpose it is probably better to expand the is_rate to cover as many as possible of the vectors that are sensitive to rate shifts, including ratios, bhp and etc, instead of removing the current is_rate=True for e.g. water-cut and GOR. Feel free to add some comments in the webviz issue if you disagree 😄

assume that you already know, but the is_total source is just below your is_rate link: https://github.com/equinor/libecl/blob/6f89be14d0c8c62c606d2da17c580115cfce3b75/lib/ecl/smspec_node.cpp#L461-L509