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

Yes

The word "naquelas" is identical in meaning, grammar, and spelling in both Brazilian and Continental Portuguese. It is a contraction of the preposition em (in/at/on) and the feminine plural demonstrative pronoun aquelas (those). The only difference between the two dialects is pronunciation. In Brazilian Portuguese, vowels are generally more open and the rhythm is more syllable-timed, whereas in Continental Portuguese, unstressed vowels are often "reduced" or almost swallowed, making the word sound more closed or clipped.

Brazilian Portuguese Examples:

1. Eu adoro dançar naquelas festas. (I love dancing at those parties.)
2. A gente se perdeu naquelas ruas estreitas. (We got lost in those narrow streets.)
3. Você fica muito bonita naquelas roupas. (You look very beautiful in those clothes.)
4. Eu não gosto de comprar nada naquelas lojas. (I don't like buying anything in those stores.)
5. Ela estava pensando naquelas memórias de infância. (She was thinking about those childhood memories.)

Continental Portuguese Examples:

1. Adoro dançar naquelas festas. (I love dancing at those parties.)
2. Perdemo-nos naquelas ruas estreitas. (We got lost in those narrow streets.)
3. Ficas muito bem naquelas roupas. (You look very good in those clothes.)
4. Não gosto de comprar nada naquelas lojas. (I don't like buying anything in those stores.)
5. Ela estava a pensar naquelas memórias de infância. (She was thinking about those childhood memories.)