Not a natural color. What you see at the base of the stem is where the blue dye was injected. The flowers take up the dye as they develop, they should stay blue. Next flowering spike... well, I'd say not blue. Maybe just a touch if some of the dye has migrated backward.
Most of the "blue phals" that are natural are a blue violet (think blue violet tanzanite).
Phal violacea has been bred to enhance "blue" and H.P.Norton is responsible for some landmark crosses regarding this. You can read about and purchase his orchids on his website: Orchidview - About Us
I am a simple admirer of his work
They are much more beautiful than the unnatural injected blue things.