120ksi primary grade sulfur-resistant drill pipe and manufacturing method thereof

Abstract

The invention discloses a 120ksi primary grade sulfur-resistant drill pipe, which comprises the following chemical elements in percentage by weight: 0.24 to 0.30 percent of C, 0.1 to 0.5 percent of Si, 0.8 to 1.4 percent of Mn, 0.8 to 1.4 percent of Cr, 0.5 to 0.8 percent of Mo, 0.05 to 0.10 percent of V, 0.01 to 0.05 percent of Nb, 0.002 to 0.007 percent of Ca, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, and the balance of Fe and other inevitable impurities. Correspondingly, the invention also provides a manufacturing process of the 120ksi primary grade sulfur-resistant drill pipe, wherein the 120ksi primary grade sulfur-resistant drill pipe has a certain capability of sulfur resistance while maintaining the strength of 120ksi grade by controlling a quenching step and a tempering step. Furthermore, the primary sulfur-resistant drill pipe has the advantage of low cost.

Description

technical field [0001] The invention relates to a drill pipe and a manufacturing method thereof, in particular to a sulfur-resistant drill pipe and a manufacturing method thereof. Background technique [0002] Drill pipes for oil and gas drilling are manufactured according to API standards. According to the API SPEC 5DP standard, there are only four steel grades for drill pipes: E, X, G, and S, corresponding to four strengths of 75ksi, 95ksi, 105ksi, and 135ksi respectively. However, the four steel grades of API standard E, X, G, and S are not suitable for drill pipes containing H 2 S oil and gas well drilling. [0003] For H 2 S oil and gas wells and oil fields generally use sulfur-resistant drill pipes for drilling operations. The so-called sulfur-resistant drill pipe refers to the drill pipe product that is resistant to sulfide stress corrosion cracking and should pass the NACE 0177 standard test under the specified tensile load. Sulfur-resistant drill pipe is genera...

AI Technical Summary

Problems solved by technology

In fact, a considerable part contains H 2 H in oil and gas wells of S 2 The S content is very low, and the output of oil and gas is also very low. If the sulfur-resistant drill pipe is used, the production cost will be quite high, but if the API steel grade drill pipe is used, the sulfur-resistant performance cannot be satisfied.

Especially for some ultra-deep wells with low sulfur content, if the strength of 105SS anti-sulfur drill pipe is too low, overload fracture will easily occur; if ordinary 120ksi drill pipe is used, because it cannot resist sulfur, it is prone to sulfide stress corrosion cracking

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