The largest breakthrough in the Barnett came in 1997, when Mitchell Energy petroleum engineer Nick Steinsberger suggested that a slickwater frac, which was being successfully used by other companies in wells to the Cotton Valley Sandstone of east Texas, might work better in the Barnett Shale than the gel fracs. By going against conventional wisdom and switching to the slickwater frac, Mitchell Energy not only lowered the cost of completing wells by $75,000 to $100,000, but also dramatically increased the recovery of gas. Mitchell tried to buy more leases in the area before word spread, but soon many other operators started buying leases and drilling Barnett wells, in what had been until then essentially a Mitchell Energy play.