... N80,P110 etc. 4.Thread:LTC,STC,BTC · API 5CT N80 oil casing pipe 1. Size:OD: ... J55,K55,L80,P110,C75,C95 etc.3. Standard:API 5CT & 5B4. thread type:STC,BTC,LTC5. ... and the wellbore from collapsing and to allow drilling fluid to circulate and extraction to take place.· ... Steel,Baotou Steel , Anshan Steel etc. standard: API SPEC 5CTTubing and CasingApplicationTubing is used to extracting petroleum ...