Abstract: Analyzed in the paper are the service conditions of the extra-deep complex oil well,and the special requirements as for the exploitation/exploration of a certain oil field in western China.Based on the analysis,the Φ293.45 mm×23.55 mm TP140V extra-high strength oil casing is designed and developed.Details concerning the R&D of the said casing are as follows.The properties and high-temperature strength of the pipe is in full compliance with relevant design requirements owing to such technological measures as carbon steel-based chemical composition and optimized micro-alloying with addition of Cr,Mo and V,adoption of clean-steel melting technique,and proper heat treatment process;and the pipe has high dimension tolerances as ovality ≤ 0.25% and WT unevenness ≤ 8%,and collapse resistance satisfactory to applicable requirement thanks to employing continuous rolling process and optimizing the distributed deformation amounts for different rolling steps.