An oven door that opens sideways (or from the top down) seems to be preferable in that scenario. A door that opens from the bottom up might be easy for a person to initially open, but they would then have to reach a long way up from their wheelchair to close it. They would also have to be completely off to one side of the oven to open it so that they/their wheelchair would not block the door. (Not fun trying to dodge the door as it opens up!) Here's some reading:
http://www.cmhc-schl.gc.ca/en/co/maho/gemare/gemare_013.cfm
http://appliances.bobvila.com/Article/334.html
http://www.cs.wright.edu/bie/rehabengr/kitchens/fintro.htm
http://www.cmhc-schl.gc.ca/en/co/maho/gemare/gemare_013.cfm
http://appliances.bobvila.com/Article/334.html
http://www.cs.wright.edu/bie/rehabengr/kitchens/fintro.htm