oc ene ▁succession ▁consists ▁of ; ▁( 1 ) ▁lower ▁zone ▁of ▁fine ▁to ▁co arse ▁s ands ▁with ▁some ▁cl ay ▁part ings ▁and ▁dol om ite ▁b eds ; ▁( 2 ) ▁middle ▁zone ▁of ▁gray - green , ▁red - b rown ▁sh ales ▁and ▁cl ays ; ▁and ▁( 3 ) ▁an ▁upper ▁zone ▁of ▁largely ▁un con sol id ated , ▁slightly ▁f eld sp ath ic ▁s ands . ▁This ▁is ▁typical ▁of ▁the ▁area ▁where ▁total ▁thick ness ▁is ▁ 9 1 4 ▁m , ▁almost ▁equally ▁divided ▁into ▁the ▁three ▁main ▁components . ▁ ▁T rap ▁Sar ir ▁C ▁is ▁contained ▁in ▁a ▁struct ural - str at ig raph ic ▁trap , ▁represented ▁by ▁di ps ▁to ▁the ▁east , ▁south , ▁and ▁west ▁and ▁the ▁major ▁n ortheast - s outh west - tr ending ▁fault ▁on ▁its ▁north west ▁fl ank . ▁In ▁much ▁of ▁the ▁central ▁and ▁north west , ▁the ▁res er voir ▁sub cro ps ▁and ▁is ▁se aled ▁by ▁sh ales ▁that ▁un con form ably ▁over lie ▁it . ▁Minor ▁sand ▁accum ulations ▁in ▁the ▁trans gress ive ▁series ▁above ▁the ▁bas al ▁s ands ▁occur ▁in ▁upd ip , ▁pin ch out ▁tra ps . ▁ ▁Sar ir ▁C ' s ▁main ▁trap ▁is ▁not ▁full ▁to ▁the ▁sp ill ▁point , ▁which ▁is ▁down pl unge ▁on ▁the ▁r idge ▁west ▁of ▁the ▁structure . ▁The ▁oil ▁column ▁has ▁a ▁maximum ▁height ▁of ▁ 9