Is the word ópera the same in Brazilian and European Portuguese?

Yes

The spelling, meaning, and grammatical function of the word "ópera" are identical in both Brazilian and Continental Portuguese. The only difference is in pronunciation. In Brazilian Portuguese, the unstressed "e" in the middle of the word is usually more clearly articulated (sounding like a light "eh" or even a "ee"). In Continental Portuguese, unstressed vowels undergo much more significant reduction, meaning the "e" is often almost silent, making the word sound shorter and more clipped.

Brazilian Portuguese Examples

1. Eu amo assistir a óperas clássicas. (I love to watch classical operas.)
2. A ópera de hoje à noite está esgotada. (Tonight's opera is sold out.)
3. Ela é uma ótima cantora de ópera. (She is a great opera singer.)
4. O figurino da ópera estava incrível. (The opera costume was incredible.)
5. Você já foi a uma ópera no Teatro Municipal? (Have you ever been to an opera at the Municipal Theater?)

Continental Portuguese Examples

1. Eu adoro ver óperas clássicas. (I love to see classical operas.)
2. Os bilhetes para a ópera de hoje estão esgotados. (The tickets for today's opera are sold out.)
3. Ela é uma excelente cantora de ópera. (She is an excellent opera singer.)
4. O figurino da ópera era fantástico. (The opera costume was fantastic.)
5. Já foste a uma ópera no Teatro Nacional? (Have you been to an opera at the National Theater?)