The raptured believers are in heaven before the first seal is opened.
See Revelation 5:7-10:  "He came and took the scroll from the right hand
of Him who sat on the throne.  And when he had taken it from the four
living creatures and the twenty-four elders (the raptured believers)
fell down before the Lamb.  Each one had a harp and they were holding
golden bowls of incense, which are the prayers of the saints.  And they
sang a new song:  You are worthy to take the scroll and to open it's
seals because you were slain, and with your blood you purchased man for
God from every tribe and language and every people and nation.  You have
made them to be a kingdom and priests to serve our God, and they will
reign on the earth."

Wes K.