Try this:
with open(file_dmp_path, 'rb') as file:
fsize = bsize = os.path.getsize(file_dmp_path)
word_len = len(SEARCH_WORD)
while True:
p = file.read(bsize).find(SEARCH_WORD)
if p > -1:
pos_dec = file.tell() - (bsize - p)
file.seek(pos_dec + word_len)
bsize = fsize - file.tell()
if file.tell() < fsize:
seek = file.tell() - word_len + 1
file.seek(seek)
else:
break