By BILL HANNA and ALEX BRANCH Calling their company’s decision to shut down two disposal wells "strictly precautionary," Chesapeake Energy officials said Friday that they remain skeptical about any link between small earthquakes near D/FW Airport and a saltwater disposal site on the airport’s southern end.Julie Wilson, a spokeswoman for Chesapeake, said it is too early to say how long the disposal wells — one at D/FW and another in Cleburne in Johnson County — will remain closed while their own scientists study the issue.