I-OCTG sisishunqulelo se-Oil Country Tubular Goods, ikakhulu ibhekiselele kwiimveliso zemibhobho ezisetyenziselwa ukuveliswa kweoli kunye negesi (imisebenzi yokugaya). Iityhubhu ze-OCTG zidla ngokuveliswa ngokwe-API okanye ngokwemigangatho emiselweyo.

Kukho iintlobo ezintathu eziphambili, kubandakanywa umbhobho wokubhobhoza, i-casing kunye ne-tubing.

Umbhobho wokugrumba yityhubhu eyomeleleyo engenamthungo ekwazi ukujikelezisa intwana yokomba kwaye ijikelezise ulwelo lokomba. Ivumela i-drilling fluid ukuba ityhalwe kwi-drill bit yimpompo kwaye ibuyiselwe kwi-annulus. Umbhobho unoxinzelelo lwe-axial, i-torque ephezulu kakhulu kunye noxinzelelo oluphezulu lwangaphakathi.

I-Casing isetyenziselwa ukumisa umngxuma wokutsala amanzi owombiweyo ngaphantsi komhlaba ukufumana i-oyile. Kanye njengeentonga zokomba, iicasing zemibhobho yentsimbi nazo kufuneka zimelane noxinzelelo lwe-axial. Lo ngumbhobho onobubanzi obukhulu ofakwe kwiqula waze wafakwa isamente endaweni yawo. I-self-weight of the casing, i-axial pressure, uxinzelelo lwangaphandle kumatye ajikelezileyo, kunye noxinzelelo lwangaphakathi oluveliswa yi-flush flush yonke ivelisa i-axial tension.

Umbhobho we-tubing ungena ngaphakathi kumbhobho we-casing kuba ngumbhobho apho ioli iphuma khona. I-tubing yeyona ndawo ilula ye-OCTG, enemidibaniso enemisonto kuzo zombini iziphelo. Umbhobho ungasetyenziselwa ukuthutha irhasi yendalo okanye i-oyile ekrwada ukusuka kulwakhiwo lwemveliso ukuya kwiindawo, eziya kucutshungulwa emva kokugrunjwa.