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

No.

While the meaning and spelling of "desculpar" are identical in both variants, there are significant differences in grammar (syntax), usage, and pronunciation:

• Grammar (Clitic Placement): This is the most notable difference. In Brazilian Portuguese (BP), it is extremely common and natural to use proclisis (placing the pronoun before the verb), such as "Me desculpa." In Continental Portuguese (CP), this is considered grammatically incorrect in most contexts; speakers prefer enclisis (placing the pronoun after the verb), such as "Desculpa-me."
• Usage (Fillers): Brazilians frequently use the word "aí" as a conversational filler when apologizing (e.g., "Desculpa aí"), whereas Portuguese people often use "lá" in similar social contexts (e.g., "Desculpa lá").
• Pronunciation: Brazilian Portuguese tends to have more open, melodic vowels. Continental Portuguese features significant "vowel reduction," where unstressed vowels are shortened or almost swallowed, making the speech sound more "closed" or consonant-heavy.

Brazilian Portuguese Examples

1. Me desculpa por ter esquecido o seu nome. (Sorry for having forgotten your name.)
2. Você me desculpa se eu chegar um pouco atrasado? (Will you excuse me if I arrive a little late?)
3. Desculpa aí, eu não vi que você estava aqui. (Sorry there, I didn't see you were here.)
4. Eu te desculpo, não precisa se preocupar. (I forgive you, you don't need to worry.)
5. Me desculpa o incômodo, mas você pode me ajudar? (Excuse the inconvenience, but can you help me?)

Continental Portuguese Examples

1. Desculpa-me por ter esquecido o teu nome. (Excuse me for having forgotten your name.)
2. Podes desculpar-me se eu chegar um pouco atrasado? (Can you excuse me if I arrive a little late?)
3. Desculpa lá, eu não te vi. (Excuse me/Sorry there, I didn't see you.)
4. Eu desculpo-te, não precisas de te preocupar. (I forgive you, you don't need to worry.)
5. Desculpe-me o incómodo, mas pode ajudar-me? (Excuse the inconvenience, but can you help me?)