Experimental Study on Gasketed Bell and Spigot Joint Behaviour of Lined-Corrugated HDPE Pipe Subjected to Normal Fault

Although structural response of pipelines has been studied in relation to different geohazards, few studies have focused on the behaviour of flexible pipeline joints. In this paper, the response of a bell and spigot joint in a 600 mm diameter lined-corrugated High Density Polyethylene (HDPE) pipe was investigated under the differential ground movements imposed using a facility that simulates a normal fault. Two experiments were undertaken in this facility. In the first experiment, the kinematic responses of the pipe joint (i.e. axial, shear displacements and rotational angles) were measured using Particle Image Velocimetry (PIV) and string potentiometers. Strains were also monitored using optical fibres. In the second experiment, the pipe was sealed and leakage of the joint was captured through monitoring of internal vacuum pressure of the pipe. The results show that axial shortening, rotational angle and shear displacement of the pipe joint increased with increasing fault offsets. The joint began to leak when axial shortening, rotational angle and shear displacement of the pipe joint were 0.65 mm, 0.44° and 3.40 mm, respectively, and the joint clearly lost its functionality when those values were 0.85 mm, 0.58° and 4.32 mm.

Corrosion and Wear Behavior of WC–10Co4Cr Coating under Saturated Salt Drilling Fluid

Coating on the surface is one of the main ways to improve the corrosion resistance and wear resistance of materials. In this work, the corrosion, erosion, and wear resistance of WC–10Co4Cr coating and 27CrMoV substrate were compared by simulating the actual working conditions of the drill pipe. The simulation results show that the most serious corrosion occurred at the pipe body and the dominating erosion arose at the pipe joint closing to the inlet of the flow field. WC–10Co4Cr coating has excellent protection to 27CrMoV substrate, resulting in a 400 mV increase in corrosion potential, a two-orders-of-magnitude decrease in the corrosion current, and four times the improvement of the impedance value. The erosion resistance of the WC–10Co4Cr coating increased to more than 30% higher than that of the 27CrMoV substrate. The friction coefficient of the WC–10Co4Cr coating was much lower than that of the 27CrMoV substrate, and the wear resistance of the coating was higher than that of the substrate.

Study on the Physical Properties of Split-type Iron Base Shape Memory Alloy Pipe Joint

Aiming at the leakage phenomenon of pipeline system due to corrosion and other reasons, a split type iron-based shape memory alloy pipe joint based on the button bond connection was designed for repair. This split-type pipe joint can be used for quick in-situ maintenance of pipelines without cutting off pipelines or stopping transmission without pressure relief. It is especially suitable for intensive pipeline maintenance and online emergency maintenance. In order to study the connection performance of the split iron-based shape memory alloy pipe joint, this paper took the Fe17Mn4Si10Cr4Ni alloy pipe joint as the research object, and carried out pressure sealing and pull-out experiments respectively on the integral pipe joint and the split pipe joint which had not been carried out and had been subjected to one heat and mechanical training. The results showed that, compared with the integral pipe joint, the pressure seal value of the split pipe joint decreased by 40% to 20MPa and the pulling force decreased by 48.9% without heat-mechanical training. However, after 1 time of thermal-mechanical training, the pressure sealing value of the split-type pipe joint decreased by 12.5% to 32MPa and the pulling force decreased by 21.2% compared with the integral pipe joint. It can be seen that thermal-mechanical training can significantly improve the joint performance of split pipe joints, and the split pipe joint can meet the requirements of medium and low pressure pipeline connection and maintenance.

Experimental research on improving the wear resistance and anti-friction properties of drill pipe joints

Purpose The purpose of this study is to solve the oil drill pipe joints and casing excessive wear problems and to improve the drill pipe joint-casing wear resistance and anti-friction properties. Design/methodology/approach On the surface of the drill pipe joints using oxyacetylene flame bead weld (BW) wear-resistant welding wire ARNCO-100XTTM prepares welding layer, high-velocity oxygen fuel (HVOF) Cr3C275-NiCr25 prepares coating and subsonic flame spray and remelt (SFSR) Ni60 prepares coating, then comparing and analyzing the friction and wear of the three types of wear-resistant layers and the casing under the condition of 1.8 g/cm3 mud drilling fluid lubrication. The wear resistance and anti-friction performance of the drill pipe joints were evaluated based on the wear situation, finally revealing its friction and wear mechanisms. Findings Three types of wear-resistant layers can improve the surface wear resistance of drill pipe joints, the wear-resistant layer and the substrate are well combined and the welding layers and coating are both dense and uniform. The wear resistance of the HVOF-Cr3C275-NiCr25 coating is 10.9 times that of the BW-ARNCO-100XTTM weld layer, and the wear resistance of the SFSR-Ni60 weld layer is 2.45 times that of the BW-ARNCO-100XTTM weld layer. The anti-friction properties of SFSR-Ni60 welding layer is the best, followed by HVOF-Cr3C275-NiCr25 coating, and the anti-friction properties of BW-ARNCO-100XTTM welding layer is the worst among the three. Originality/value The research results of this paper have great practical value in the process and material of improving the wear resistance and anti-friction performance of the drill pipe joint casing.

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Welding costs associated with the laying of pipes for deepwater oil and gas extraction can be reduced using high interpass temperatures (ITs). However, a high IT can decrease the mechanical properties of the heat-affected zone (HAZ) of welded joints. With the use of high strength-toughness stees, this decrease may be an acceptable trade-off. Therefore, it is necessary to evaluate the influence of high ITs on the HAZ. The influence of the IT on the coarse grain HAZ (CGHAZ) and intercritically reheated coarse-grain HAZ (ICCGHAZ) of an API 5L X70 pipe joint welded by gas metal arc welding was investigated. The welding was numerically simulated using finite element method software. The microstructure of the HAZ was predicted using thermodynamic simulation software. The CGHAZ and ICCGHAZ were also physically simulated and evaluated via optical microscopy and scanning electron microscopy, dilatometry, and Vickers microhardness and Charpy V-notch (CVN) impact tests. The increase in IT led to a decrease in CGHAZ microhardness, but did not affect the ICCGHAZ. The CVN energies obtained for all ITs (CGHAZ and ICCGHAZ) were higher than that set by the DNVGL-ST-F101 standard (50 J). These results show that increasing the IT is an interesting and effective method to reduce welding costs. In addition, thermodynamic simulation proved to be a valid method for predicting the phases in the HAZ of API 5L X70 pipe welded joints.

How Impact the Design of Aluminum Swaging Circle Fitting on the Sealing for Piping Systems: Analytical and Numerical Model

Installation and repair of hydraulic installations are carried out by joining the pipes in the field. Pipe connections in aviation are made in a very narrow space and field. For this reason, fitting swaging method is used to connect the fittings to the pipes with a hydraulic hand tool. The basis for developing a swaging tool is knowledge of the design parameters for the plastic deformation of the swaging circle fitting. In addition to the design parameter, pipes have to be joined in cryogenic vacuum conditions, which require sealing in such sensitive and harsh conditions. In this study, the effect of swaged circle fitting designs on tightness and strength was determined and different swaging methods were examined for its improvement. Different geometric swaged circle fittings are designed and analytical and numerical models are solved. The solution results obtained show the characteristic effect of the fitting swaging analysis methodology and the swaged circle fitting design on the sealing of the pipe joint. The innovation is mainly the effect of the swaging circle connection design on the sealing of the pipe joint. With the finding in this work, it is now possible to develop or develop new tools for engineered swaging circle fitting.

Research on the mechanism of the influence of flooding on the killing of empty wells

In empty well killing, in order to save the time and cost of killing the well, the dynamic replacement method is often used to kill the well. The main problem of the dynamic replacement method for killing wells is how to avoid terrible working conditions caused by flooding, such as gas carrying fluid, killing fluid being brought to the wellhead. Based on the principle of flooding formation and the basic tenets of flooding correlation experiment and dynamic replacement method, this paper incorporates the kill fluid viscosity, surface tension, droplet diameter, inclination angle, drill pipe joint outer diameter, and drill pipe eccentricity into the calculation range and establishes a new mathematical model suitable for dynamic replacement kill. Based on the calculation results, the influencing factors of flooding are analyzed, and the following conclusions are drawn: the increase of dynamic viscosity, gas density in the well, casing pressure, well angle, the outside diameter of drill pipe, the outer diameter of drill pipe joint, and eccentricity of drill pipe can promote the occurrence of flooding; The increase of surface tension, well-killing fluid density, and casing inner diameter have an obstacle to flooding.