▁This ▁turned ▁out ▁to ▁be ▁a ▁good ▁decision , ▁since ▁C - 1 - 6 5 ▁was ▁subsequently ▁shown ▁to ▁be ▁a ▁pro l ific ▁res er voir ▁with ▁initial ▁production ▁rates ▁of ▁. ▁ ▁Disc overy ▁For ▁years ▁B P ▁avoided ▁using ▁gas ▁detect ors ▁on ▁its ▁oil ▁platforms , ▁cit ing ▁numerous ▁false ▁al ar ms . ▁However , ▁in ▁ 1 9 6 1 , ▁Bar oid ▁was ▁h ired ▁to ▁set ▁up ▁gas ▁detect ors ▁on ▁B P ' s ▁Lib yan ▁well s . ▁C - 1 - 6 5 ▁gave ▁high ▁read ings . ▁This ▁was ▁assumed ▁to ▁be ▁a ▁false ▁alarm , ▁but ▁high ▁read ings ▁pers isted . ▁Ex amin ations ▁of ▁sh ale ▁c aving ▁samples ▁revealed ▁oil - st ained ▁sand ▁gra ins ▁at ▁the ▁bottom ▁of ▁the ▁pl ates . ▁ 6 1 ▁m ▁of ▁pet role um ▁play ▁was ▁d ril led . ▁The ▁top ▁play ▁in ▁Lower ▁C ret ace ous ▁sand st ones ▁occurred ▁at ▁ 2 6 3 1 ▁m . ▁On ▁dr ill - st em ▁tests ▁C - 1 - 6 5 ▁produced ▁at ▁a ▁rate ▁of ▁. ▁ ▁Post - Dis cover y ▁C - 1 - 6 5 ▁had ▁an ▁oil ▁column ▁exceed ing ▁ 7 6 ▁m , ▁above ▁predicted ▁closure ▁for ▁its ▁shall ow ▁reflection ▁structure . ▁Although ▁se ism ic ▁maps ▁gave ▁struct ural ▁indic ations , ▁details ▁were ▁un re li able ▁at ▁the ▁res er voir s ▁top ▁