I think the color scheme is working well, since it is based on the primary colors (which you really can't go wrong with). Personally, I feel that this would work better as a vertical piece (portrait) rather than a horizontal/landscape. I have done some abstract paintings before and sometimes I would start out painting them as landscapes but later they became vertical pieces because the movement and composition were stronger vertically.
The feeling you expressed here seems almost blocked by the orange (but not in a bad way!) .The tints of green go great with blue as they mix but the orange seems like it wants to make a statement, as if saying, "look at me"! The feeling has now changed from the quiet blues and greens with a bold standing orange, it seems like he/she wants to be the one, the one to be the center of attention while the blue and green, feel "disused". But they are not! They support the orange so much in everyone's view. Maybe them [blue and green] feel like background colors than the "main attraction". I think this piece is wonderful and hearing everybody's view on it is awesome! I love it!