Yes, these are the good words here.
Souvenir is for something you remember, a remembrance... It also design an object who recall a moment of your life to you (like an object you got on a trip).
"J'ai souvenir d'un long voyage..." -> I remember a long trip...
"Je me souviens de ce jour..." -> I remember this day...
"J'ai acheté ce souvenir..." -> I bought this token...
Mémoire has approximately the same definition than memory and can be sometime used in place of Souvenir :
"J'ai mémoire d'un long voyage..." -> I remember a long trip...