Well depth factor
The depth of the oil well is one of the primary factors in material selection, which directly affects the strength and durability of the pipe. Generally speaking, the deeper the well, the more high-temperature resistant, corrosion-resistant and high-strength OCTG pipe is needed, such as high-strength steel pipes with API X80, X100, X120 grades.

Well pressure factor
The well pressure in the oil well is also an important factor affecting the selection of OCTG pipes. When selecting OCTG pipes, the wall thickness and pressure resistance of the pipe need to be considered. Generally speaking, the higher the well pressure, the more high-pressure resistant OCTG pipes need to be selected, such as WT98, WT108, WT118 and other high-pressure and pressure-resistant OCTG pipes.

Well temperature factor
The temperature of the oil well is also an important consideration in material selection. In a high-temperature environment, ordinary OCTG pipes are susceptible to thermal expansion, reduced plasticity, etc., so it is necessary to select special materials that are resistant to high-temperature expansion, high-temperature resistance and corrosion resistance. Commonly used high-temperature and pressure-resistant OCTG pipes include 316L, Inconel625, Hastelloy C-276, etc.

Medium types
Different types of oil well media will also have a great impact on the selection of OCTG pipes. For example, oil wells containing CO2, H2S and high-sulfur media need to select sulfur-resistant and corrosion-resistant materials, such as 13Cr, 22Cr, Super13Cr, etc.; oil wells containing sand, asphalt and other media need to select wear-resistant and corrosion-resistant OCTG pipes.

In summary, the selection of OCTG pipes generally considers multiple factors such as well depth, well pressure, well temperature, and medium type, and selects different materials and specifications to ensure the safety and reliability of OCTG pipes.