1 6 7 6 ▁m ▁below . ▁Thus , ▁while ▁the ▁second ▁and ▁third ▁well s ▁were ▁d ril led , ▁a ▁se ism ic ▁ref raction ▁survey ▁was ▁shot . ▁It ▁gave ▁control ▁over ▁the ▁bas ement ▁structure , ▁but ▁since ▁the ▁first ▁four ▁well s ▁proved ▁res er voir ▁s ands ▁varied ▁from ▁ 1 4 1 - 4 1 0 m ▁in ▁thick ness ▁over ▁a ▁relatively ▁short ▁distance , ▁the ▁survey ▁gave ▁little ▁control ▁over ▁the ▁tra pping ▁structure . ▁Se ism ic ▁maps ▁on ▁both ▁hor iz ons ▁and ▁sub sur face ▁information ▁showed ▁the ▁res er voir ▁structure ▁and ▁helped ▁limit ▁dr illing ▁in ▁dry ▁holes . ▁ ▁After ▁discovery ▁continuous ▁dr illing ▁occurred ▁with ▁up ▁to ▁five ▁rig s ▁at ▁a ▁time . ▁Initial ly , ▁short ▁out steps ▁up ▁to ▁ 4   km ▁were ▁made , ▁followed ▁by ▁b older ▁dr illing ▁to ▁confirm ▁res erves ▁and ▁justify ▁costs ▁for ▁a ▁ 5 1 6   km ▁oil ▁pipeline ▁to ▁Tob ru k . ▁Once ▁confirmed , ▁C - 1 - 6 5 ▁was ▁stead ily ▁d ril led ▁on ▁a ▁ 2   km ▁grid ▁spacing . ▁At ▁this ▁time , ▁two ▁smaller ▁fields ▁were ▁discovered : ▁Sar ir ▁North ▁and ▁L - 6 5 . ▁ ▁In ▁May ▁ 1 9 6 5 ▁five ▁inf ill ▁well s ▁were ▁sab ot aged . ▁The ▁incident ▁occurred ▁during ▁the ▁reign ▁of ▁King ▁Id ris ▁before ▁the ▁ 1 9 6 9 ▁coup ▁led