Operators are increasing capital budgets in the wake of tariffs and quotas initiated by the US government on steel imports, and the product exclusion process has revealed a host of other issues. If the tariffs are here to stay, what does industry hope to see moving forward? How will a US steel tariff affect the oil and gas supply chain? Industry criticism points to a noticeable effect on construction expenditure and jobs, but where will the pain be most felt?
Operators are increasing capital budgets in the wake of tariffs and quotas initiated by the US government on steel imports, and the product exclusion process has revealed a host of other issues. If the tariffs are here to stay, what does industry hope to see moving forward? Supply and Demand in Unconventionals: Where Do Service Companies Fit? Service company executives examine how the oil price downturn affected supply and demand for their services in the unconventional sector, and strategies they have undertaken to stay afloat as operators adjust to uncertainty.
The Charles F. Rand Memorial Gold Medal is awarded for distinguished achievement in mining administration, including metallurgy and petroleum. If they are a recipient of SPE Honorary Membership. If they are on the current SPE Board of Directors, Charles F. Rand Memorial Gold Medal award committee, or have served in these positions during the past 2 years. If they have received the Anthony F. Lucas Medal or the Robert Earll McConnell Award. If they are a recipient of SPE Honorary Membership.
A rupture of buckled steel pipes on the tensile side of a cross-section is studied in this paper as the most plausible case of ultimate failure for the pressurized buried pipelines under monotonically increasing curvature. Finite element simulation of full-scale bending tests on two pressurized X80 pipes with different yield-to-tensile strength (Y/T) ratios were conducted. The Y/T ratio and internal pressure were identified as the crucial factors that have a coupled effect on the ultimate failure mode of buckled pipes. That is, the high values of Y/T ratio and internal pressure mutually trigger the rupture of buckled pipes on the opposite side of the wrinkling.
Steel pipelines are so ductile and can accommodate a large amount of post-buckling deformations while preserving their operational safety and structural integrity. To benefit from this outstanding quality and prevent the buckled (wrinkled) pipelines from premature rupture, the postbuckling behavior of the steel pipes should be well understood.
Rupture is one of the major failure limits to the integrity of pipelines that endangers the environment as well as the public safety and property. Comprehensive experimental and numerical studies on the fracture of buckled steel pipes (Das, 2003; Sen, 2006; Mohajer Rahbari, 2017) show that under increased monotonic curvature, successive buckles (wrinkling) are formed on the compressive side of the wall, and the occurrence of rupture at the wrinkling location is unlikely because of the ductile nature of steel material. Rupture of wrinkling can occur once buried pipelines are subject to a very rare and changing boundary conditions accompanied by extremely large plastic deformations toward tearing the wrinkled wall (Ahmed, 2011). However, experiments have shown that the increasing curvature can easily trigger the postbuckling rupture of the tensile wall on the opposite side of the wrinkling (Sen, 2006; Mitsuya et al., 2008; Tajika and Suzuki, 2009; Igi et al., 2011; Tajika et al., 2011; Mitsuya and Motohashi, 2013; Mitsuya and Sakanoue, 2015). This mode of failure seems very likely to be the rupture limit of the wrinkled pipes, as it occurs following the same regime of monotonic bending deformations that have previously made the pipe buckle.
Royal Dutch Shell is changing its tune on carbon, saying it will tie executive pay to shorter-term reductions in emissions. Shareholders will vote on the revisions in 2020. Shell's announcement marks a change in stance by Chief Executive Officer Ben van Beurden, who for years rejected investor demands that Shell detail its plans to curtail emissions, saying it would make the company more vulnerable to lawsuits. "Meeting the challenge of tackling climate change requires unprecedented collaboration, and this is demonstrated by our engagements with investors," the Shell chief said in a statement. "This joint statement is the first of its kind, sets a benchmark for the rest of the oil and gas sector, and shows the benefit of engagement—aligning institutional investors' long-term interests with Shell's desire to be at the forefront of the energy transition," Matthews said.
Relating to what organizations may prioritize, safety climate also entails the kind of behaviors that are expected, supported and rewarded (Schneider, 1990). Characteristics of safety climate can impact workers' own safety values, which, in turn, influence their behaviors (Naveh, et al., 2011). Further, a positive safety climate has been linked to less burnout and fewer errors, near-hits and incidents that result in lost time from work (Christian, Bradley, Wallace, et al., 2009; Nahrgang, Morgesun & Hofmann, 2011). In this sense, not only has safety climate been identified as a potential leading indicator of incident occurrence, but also evidence exists that a positive safety climate might strengthen the impact of job factors (e.g., job autonomy, supervisor support, coworker support) on workers' proactive behavior (Bronkhorst, 2015), although these factors are not well understood (Parker, Axtell & Turner, 2001). To that end, this article examines what role job autonomy, in particular, may have in forming workers' perceptions and subsequent OSH performance on the job. The authors begin by defining autonomy in the workplace to provide a consistent platform for studying the term.
In joining technology, welding is one of the vital techniques used to make continuous pipelines in industry. The thermal and mechanical loading in the process has a profound impact on the integrity of the pipeline over its service life. An accurate and thorough assessment is needed on the associated residual stress and its effect on the structural properties of the pipeline. One of the novelties of this research is the understanding of the welded joints' temperature responses, as demonstrated by positioning high-temperature thermocouples at strategic points on the welded joints to capture the transient temperature response at different points. It is not enough to assume that the distribution of heat through the weld metal will depend on the distance from the thermocouples to the heat source only; the temperature profile must actually be studied to uncover any peculiar trends.
As the oil and gas industry and international shipping companies push their assets into high latitude marine environments, it is important to thoroughly understand the performance of construction materials exposed to extremely low temperature and / or subjected to high ice loads. In the past, the design considerations have addressed the uncertainty in these areas by adopting conservative approaches. While proven effective, there exists a need for additional testing to gain insight into the safety margin levels that have been implicitly included. The work presented has the potential to lead to a better understanding of how steel materials behave in long-term Arctic conditions.
This paper presents the results of mechanical property tests of aged steel samples from the Kulluk, an ice-class rated drilling barge. This barge was exposed to the Arctic environment for almost 30 years. The Kulluk was built in Japan in 1983, specifically for exploration drilling operations in the Arctic environment. When the barge was scrapped in 2014, hull steel was selectively harvested. The intent was to conduct tests to better understand the behavior of shipbuilding steels that have endured long-term exposure to Arctic environments.
As an initial project phase, four sample groups of hull plate, from four different locations of the barge (one below the waterline, one in the ice belt region and two above the ice belt), were chosen for testing. The laboratory tests included tensile tests, Charpy impact tests and hardness tests. The test results indicate that the yield strengths, ultimate strengths, toughness and hardness of the aged steels continue to satisfy the ABS Rules requirements. A degradation assessment of these samples was also performed using these testing results and the limited data available as tracked from the barge's construction stage.
It is observed that the yield strengths and ultimate strengths remain consistent within the scatter of original or time period data. With respect to Charpy toughness values no conclusions concerning degradation can be made conclusively as the scatter in the data is substantial, especially at low temperatures. The steel in this study that has aged in the Arctic environment appears to maintain its original mechanical properties.
Based on the study presented in this paper, further studies could be performed such as additional sample tests to increase the reliability of results, material properties test for steel samples with butt/fillet welds to understand the variation of the heat affected zone (HAZ) and Crack Tip Opening Displacement (CTOD) tests to get a better understanding of the material toughness.
Zheng, Jianwei (Tiandi Science & Technology Co., Ltd. / China Coal Research Institute) | Ju, Wenjun (Tiandi Science & Technology Co., Ltd. / China Coal Research Institute) | Fu, Yukai (Tiandi Science & Technology Co., Ltd. / China Coal Research Institute) | Wang, Zhihe (The University of Adelaide) | Pan, Haibing (Tiandi Science & Technology Co., Ltd. / Holsinghe Mine, Shanxi Coal Import & Export Group) | Jiang, Wei (Tiandi Science & Technology Co., Ltd. / China University of Mining and Technology Beijing)
The distribution and evolution characteristic of abutment pressure is a key factor to controlling surrounding rock-mass in underground coal mining. Aiming to analyze the formation mechanism and dynamic evolution characteristic of abutment pressure, different surrounding rock-mass models of stope at corresponding multi-time-space conditions were established based on mechanics of materials. It is demonstrated in this study that the whole life cycle of a fully-mechanized mining face in flat seams, including open-off cut, regular advancing zone and finish line, could be divided into four stages which include: Initial stage (I), Steadily growing stage (II), Dynamic stage (III) and Final stage (IV), where the Final stage (IV) could be further divided into the higher pressure situation and lower pressure situation based on different surrounding rock-mass structures. The open-off cut zone and first collapse of immediate roof are within the Initial stage (I) and Steadily growing stage (II) respectively. The abutment pressure of Initial stage (I) is a static load and the abutment pressure of Steadily growing stage (II) is steadily growing with the advancing of mining face; the value of abutment pressure before periodic weighting is larger than that after periodic weighting when it enters the Dynamic stage (III); the roadways are easily controlled in lower pressure situation of Final stage (IV) and it may avoid the support crushing in higher pressure situation of Final stage (IV). According to the dynamic evolution of abutment pressure featured in life cycle of a mining face, it could make the prediction of high stressed zone, and reinforcement support or pressure-relief methods could be done in advance, thus the occurrence of dynamic hazards of surrounding rock-mass could be effectively prevented.
The stability of roadway surrounding rock-mass in underground mining plays a significant role in safety and high production, and can be easily influenced by the distribution and dynamic evolution of abutment pressure (Tan, 2012; Zhang, 2014). Qian et al. (1995, 1996) adopted key stratum theory and “voussior beam” hypothesis to study the interaction between overlying stratums movement and mining induced pressure. Xia et al. (2017) conducted numerical simulation of the whole process of longwall mining on stope pressure in underground mining using FLAC3D. Lai et al. (2014, 2016) studied the transformation mechanics of advanced abutment pressure through physical simulation. Hosseini et al. (2012, 2013) used passive seismic velocity tomography to analyze the variations of abutment pressure around the panel during coal mining. Ren et al. (2014) studied the dynamic feature of advanced abutment pressure in shallow mining through physical simulation，numerical simulation (FLAC3D) and in-situ observations. Xia et al. (2011) analyzed the wave form and inversion of the in-situ micro-seismic data obtained from a fixed mining face to determine the interaction between micro-seismic activities and advanced abutment pressure. Zhu et al. (2016) adopted micro-seismic monitoring technical for abutment pressure monitoring in coal mining. Jiang et al. (2002, 2006) analyzed the peak value of abutment pressure in coal mining through mechanical model on stope. Zhao et al. (2006) adopted ADINA finite element to discuss the range and peak value point of abutment pressure. Li et al. (2005) hold the view that the abutment pressure was consisted of static pressure and dynamic pressure. Zhou et al. (2016) used hollow inclusion strain cells measurement technique to get the evolution law of abutment pressure with mining face advancing. Zhang et al. (1994) studied the distribution law of abutment pressure with advanced support resistance. Pan et al. (2014, 2015) took the coal seam and immediate roof in front the mining face as elastic basement firstly, then used mechanical model to analyze the mechanical behavior of roof before periodic weighting.
While mechanized mining operations are integral part of mining activities in soft rocks, drill and blast fragmentation method still dominates the hard rock mining operations. Mechanized fragmentation technology for hard rock mining should be robust, relatively small, and flexible; however, development of such system has been a challenge due to energy requirement of cutting hard rocks and the short life span of the cutters. These limitations strongly suggest the need for alternative solutions to reduce the energy requirement of hard rock failure. Actuated Disc Cutting (ADC) is a new dynamic cutting method, which uses disk-shape cutters attacking the rock in an undercutting mechanism. This new system dynamically actuates the cutter, while it is moved across the rock. Breaking the rock under direct tension, ADC consumes less energy for fragmenting rock than conventional methods, hence, reducing the overall power requirement of mechanical hard rock excavation. Introducing the characteristics of an ADC system, this paper summarizes the findings of an experimental study, which investigates the rock failure mechanism and the forces associated with the cutting process using a laboratory ADC test unit.
Application of mechanized cutting/fragmentation technologies in hard rock mining environment is impeded with the limitations of the existing technologies: being power, size, mobility, and cutter life. Overall there are two main classes of cutting tools: drag cutters, such as picks, which are used on road header type machines; and indenters, such as roller disc cutters, used on tunnel boring machines. Drag cutters are more efficient tools than indenters by directly encouraging tensile cracks when moved across the rock surface at a certain penetration depth. Indenter, however, are more wear resistant, due to the rolling mechanism of the cutter, while requiring higher forces for breaking the rock under compression induced tensile failure. Susceptibility to wear and failure has therefore limited the use of drag cutters to excavating low-to-medium strength and non-abrasive rocks (Ramezanzadeh and Hood, 2010); indenters, on the other hand, despite their need for very high thrust forces, have found widespread use in full-faced hard rock cutting of civil applications, where large and heavy machines can be used.