Olsen shot a 7-under 65 and posted a two-day total of 9-under 135. The event is played over six rounds with the top 30 earning their way onto the PGA Tour next year.
There are 169 players attempting to earn their way onto the tour.
Olsen, 37, highlighted his round with an eagle at the par-5 seventh on the Nicklaus Tournament Course.
PGA Tour veteran Esteban Toledo and Brian Davis, who has won twice in Europe, were tied for eighth at 137 with David Hearn and Mario Tiziani.
Scott Gump, who led after the opening round, shot a 2-over 74 and was tied for 16th at 140.