Mapombi emafuta akakosha anonyanya kushandiswa kuchera matsime emafuta negasi uye kutakura oiri negasi. Inosanganisira pombi yekuchera oiri, ganda remafuta, uye pombi yekupomba mafuta. Oiri yekubooresa pombi inonyanya kushandiswa kubatanidza makora ekudhirowa uye mabhiti ekuchera uye kutumira simba rekuchera. Oiri casing inonyanya kushandiswa kutsigira madziro emutsime panguva yekuchera uye mushure mekupedzwa kwetsime kuti ive nechokwadi chekuchera uye kujaira kushanda kwemafuta ese mutsime mushure mekupedza. Pombi yekupomba inonyanya kutakura mafuta negasi kubva pasi petsime remafuta kuenda pamusoro.

Oiri casing ndiyo nzira yehupenyu kuchengetedza kushanda kwematsime eoiri. Nekuda kweakasiyana mamiriro e geological uye akaomarara kushushikana mamiriro pasi, kushushikana, kudzvanya, kukotama, uye torsion kushushikana kuita zvakazara pane pombi muviri, iyo inoisa yakakwirira zvinodiwa pamhando yecasing pachayo. Kana iyo casing pachayo yakuvadzwa nekuda kwechimwe chikonzero, tsime rose rinogona kudzikiswa mukugadzirwa kana kutoputswa.

Zvinoenderana nesimba resimbi pachayo, iyo casing inogona kukamurwa kuita akasiyana simbi mamakisi, anoti J55, K55, N80, L80, C90, T95, P110, Q125, V150, etc. Mamiriro akasiyana etsime uye kudzika kwakadzika kunoda magiredhi akasiyana esimbi. . Munzvimbo dzine corrosion, iyo casing pachayo inodiwawo kuve necorrosion resistance. Munzvimbo dzine yakaoma geological mamiriro, iyo casing inodiwa zvakare kuve ne-anti-kudonha zvivakwa.