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Unstable crack propagation velocity following the failure of pipeline steel has always been a problem. In this study, differences between the existing unstable crack propagation calculation models were analysed, and the deficiencies within the crack propagation velocity models were overcome. The hardening coefficient and hardening index of the ductile material were considered, and a velocity model of unstable crack propagation of pipelines based on the Hutchinson‐Rice‐Rosengren (HRR) theory elastic‐plastic stress‐strain field and the displacement field was established. Consequently, the limit propagation velocity was obtained. In full‐scale burst test, the pipe with diameter of 1422 mm was chosen to simulate the natural gas pipeline transportation environment. Compared with the theoretical result, the error was limited in 13%. The research result solved the problem of quantifying the propagation velocity of the crack in X80 pipeline, which was significant for describing the forecast of velocity and length of unstable propagation and failure characteristics of pipelines.

Oil well tubing is used in oil extraction in offshore oil well. Under the force of tubular columns, erosion and pressure of drilling fluids, the oil well tubing usually fails in long-term service, which always leads to accidents and stagnation of production. So it’s especially necessary to detect faults in tubing. Intense-magnetic memory testing equipment for reusable offshore oil well tubing is developed for this consideration. The equipment is composed of feeding machines, baiting machines, transport machines and a detection machine. Measurement and control system decides the running sequence logic of these components and obtains fault signals of tubing. The avoidance of transport machines for oil well tubing coupling makes the transport of tubing stable. The synchronization control of transport and detection of tubing decides the accurate location of faults. The automatic switch of both detection units and measurement of fault signals makes it convenient to detect oil well tubing of multiple sizes.

Well site safety plan, which included well design, emergencyresponse plan (ERP) etc, is the key prerequisite for drilling the critical sour gas well. A right emergency response zone (EPZ) is quite difficult to make sure on the site, because that it affected by release rate of H2S, gas composition, the well site surrounding topography, and other specific circumstances. To solve this problem, A blowout simulation software based on FLUENT be developed, which could predict affected areas when the critical sour blowout, the gas flow direction, and the H2S concentration distribution. On this basis, the safety layout surrounding the well site can be planned. The article provides the design structure and main functions of the software. The software can provide the theoretical basis of industrial safety.