Hi SL,You have to use some timeline - 15/20/30 yrs are popular ones. The tail after 15 years could still be 30 bopd - so 10-11Mboe (that's as much as KY produces now).Expect "Refrac" every 7 or so years to further improve EUR. Have a read of:http://www.halliburton.com/public/pe/contents/Papers_and_Articles/web/Q_through_Z/refracturing-extends-lifes.pdfandhttp://www.mydigitalpublication.com/article/Renewing+Mature+Shale+Wells+Through+Refracturing/1663466/0/article.html