Umbhobho wepetroleum okhethekileyo usetyenziselwa ikakhulu ukomba oyile nerhasi kunye nokuhanjiswa kweoyile negesi. Iquka umbhobho wokwemba i-oyile, isingxobo se-oyile kunye nombhobho wokumpompa i-oyile. Umbhobho wokugaya ioli usetyenziselwa ukudibanisa i-collar drill kwi-drill bit kunye nokudlulisa amandla okugaya. I-oyile ye-oyile isetyenziselwa ukuxhasa udonga lomthombo ngexesha lokugaya kwaye emva kokugqitywa, ukwenzela ukuba kuqinisekiswe inkqubo yokugaya kunye nokusebenza okuqhelekileyo kwequla lonke emva kokugqitywa. Umbhobho wokupompa ikakhulu udlulisela ioli kunye negesi ukusuka ngaphantsi komthombo ukuya phezulu.

Isingxobo se-oyileyindlela yokuphila yokusebenza kwequla leoli. Ngenxa yeemeko ezahlukeneyo zejoloji, imeko yoxinzelelo lwangaphantsi komhlaba iyantsonkotha, iyanyibilika, icinezelekile, iyagoba kunye nesenzo soxinzelelo lwe-torsional kumzimba wombhobho, obeka phambili iimfuno eziphezulu kumgangatho we-casing ngokwayo. Ukuba i-casing ngokwayo yonakaliswe ngenxa yesizathu esithile, iqula lonke linokunciphisa imveliso okanye lishiywe.

Ngokwamandla ensimbi ngokwayo, i-casing inokwahlulwa ibe ngamabakala ahlukeneyo ensimbi, oko kukuthiJ55, K55, N80, L80, C90, T95, P110, Q125, V150, njl. Iimeko ezahlukeneyo zomthombo, ubunzulu obunzulu, ukusetyenziswa kwebakala lensimbi kukwahluke. Isingxobo ngokwaso sikwafuneka ukuba sibe nokumelana nomhlwa kwindawo enomhlwa. Endaweni yeemeko ze-geological eziyinkimbinkimbi, i-casing nayo iyafuneka ukuba ibe namandla okumelana nokuwa.