We're excited to begin the year with the commemoration of JPT's 75th anniversary. This issue launches our special features dedicated to JPT's reporting of technology and practices over the past 7½ decades. Emerging Technology Senior Editor Stephen Rassenfoss and Senior Technology Editor Trent Jacobs penned this month's articles highlighting innovations in drilling, completions, and reservoir engineering. Each month, our editors will dive into the archives to round up milestones of industry advancements and achievements as reported in JPT. Since its inaugural issue in January 1949, JPT has remained true to its mission of reporting the technological and scientific learnings and advancements in the global oil and gas industry.

Peter Hatherly is a geophysicist with 35 years experience in research and consulting for coal mining. Over that time, he has had involvement with many geophysical techniques but mostly with geophysical logging, seismic reflection methods, and microseismic monitoring. The applications cover diverse areas such as mapping coal seam structures, geotechnical characterisation of rock masses, monitoring of the stability of rock masses, and estimation of greenhouse gas emissions. In seeking to solve practical mining problems, he has worked closely with geologists, geotechnical engineers, and other geophysicists. Peter currently offers geophysical services through his own company, Coalbed Geoscience. He is also employed part-time at the University of Sydney where he is contributing to a large mine automation project funded by Rio Tinto.

Oil sands are a naturally occuring combination of clay, sand, water and bitumen. Bitumen is a fossil fuel that is separated from the rest of the oil sand to eventually become synthetic crude. It is very thick at room temperature and can not be extracted from the ground unless it is diluted or heated to reduce it's viscosity. Oil sand deposits are found in about 70 countries throughout the world, with the largest reserves and majority of the industry located in Canada. Some bitumen is found about 200 feet under Earth's surface, but the majority of it is found much deeper underground.

Kim Hein (Ncube-Hein) received a B.S. in economic geology from the University of Adelaide and a Ph.D. (1995) from the University of Tasmania. She undertook research at the Universiteit Utrecht from 2000 to 2004. In 2004, she accepted the Chamber of Mines chair and professorship of mining geology at the University of the Witwatersrand Johannesburg and is actively involved in geoscience research and education in South Africa and francophone West Africa. She has many years of experience in the fields of metals exploration and mining, research and development, management, and geoscience education. She was the 1989 recipient of the Ralph Tate Medal for Geology and the 1989 Homestake Prize for Economic Geology.

A black smoker is a type of hydrothermal vent typically found on the sea floor. These vents are often referred to as underwater geysers. Black smokers can get up to 180 feet tall, and they are also considered to have the highest temperature of the hydrothermal vents. The plumes of burning hot water contain multiple kinds of minerals. The average temperature of the heated water hovers around 750 F. [2] When the sulfide from the molten hot lava hits the colder sea water, it turns the water leaving the vents black.

Having had the privilege of living on three continents, working across multiple industries, and conducting business in several countries, I have seen the impact digital technology has on business, people, and communities. Throughout my career, I have witnessed lifesaving and life-changing digital innovation that changes the trajectory of organizations and industries. As someone who entered the workforce during the dot-com era with a background in computer science, I continue to be amazed by how yesterday's differentiation becomes today's necessity … and tomorrow's obsolescence challenge. The pace of innovation in digital is unprecedented in the annals of human innovation. Personally, I only need to look at my kids to get a sense of that.

ABSTRACT: Wallonia and Hauts-de-France regions encounter complex developments of multi-level mining cavities that may affect the stability of shallower ones. This work focusses on an abandoned room-and-pillar quarry that extracted phosphatic chalk. On the same site, coal was mined out at depths from 200 to 750 m. To evaluate the influence of deep coal mines on the stability of shallow cavities, the geometry of created voids was modelled, integrating the mining sequence. In addition, detailed topographic and structural surveys of the chalk quarry were completed by rock mass quality assessment. Then a finite element geomechanical model combining the room-and-pillar quarry and the longwall mining was created. Specific vertical cross sections were investigated. The model revealed the progressive influence of coal mining on the room-and-pillar quarry as the surface mined out increased. These large models finally provide boundary conditions for local models in which the influence of specific parameters can be investigated. INTRODUCTION Numerous underground cavities, either man-made or natural, occur in Wallonia (Belgium) and Hauts-de-France regions. Both territories exhibit a comparable geological context and, hence, similarities in the typology of underground cavities. In particular, chalk, limestone, sand and clay were extracted by underground quarries. About 900 abandoned underground quarries are identified in each region. Their size varies from a couple of galleries around an access shaft to a well-structured network of rooms and pillars on areas covering several dozens of hectares. Beside the quarries, other cavities are also known. Some of them are particular to a region: karsts are mainly a concern in Wallonia, whereas military works are specific to Hauts-de-France. This variety of shallow depth cavities represent an issue for the authorities and the communities in terms of land management and planning and economic development of the territories. Also in relation with a common geology, both regions have a similar industrial history, closely related to coal mining. The coal fields extend from the Nord-Pas-de-Calais basin towards Liège area, and even further northwards. They are characterized by numerous thin coal seams with a limited thickness (0.5 to 1 m in Wallonia, 0.8 to 2.9 m in Nord-Pas-de-Calais), separated by quite thick sandstone-claystone interburden. Most seams cover large areas, up to several dozen km, and are influenced by complex geological processes (folding, faulting, underthrust). Mining generally started at shallow depth but reached 1000 m or more in some areas. During the 19th-20th centuries, coal was mined out quite intensively by the longwall technique. Cumulated production reached about 2 billion tons in each region.

ABSTRACT: As mines are getting deeper, mining induced seismicity becomes a major hazard threatening the health, safety, and security of operations. In today's mines, seismicity is well measured and documented. However, the ability to foresee events lags behind. This paper will discuss the correlation between numerically simulated Rate of Energy Release (RER) and measured seismic potency in the real rock mass. RER is defined as the rate of elastic strain energy emitted into the surrounding rock as a result of abrupt fracture or deformation. RER has proven to be a good candidate for probabilistic forecasting of seismic potential (the capacity to develop seismogenic activity) in the rock mass. In the following sections, we will describe a computational framework for simulating RER and subsequent analyses for evaluating the likelihood of mining induced seismic events. We will present example results from mines where model predictions matched measured seismicity. INTRODUCTION As underground hard rock mines are getting deeper, they are experiencing more seismicity and ground control challenges. Seismicity poses the highest risk to the frontline crew at the mining or excavation face. Whilst improvements in seismic monitoring systems have enabled operations to monitor mining induced seismicity and identify areas with high seismogenic activity, these systems do not have the predictive power to forecast if and when the risk of a high magnitude event is elevated. Therefore, seismicity remains one of the major hazards in mining. The source of seismicity in mines is very similar to acoustic emissions captured at various stages of the stress-driven failure process during a simple compression test. A seismic event is the sudden release of potential or stored energy in the rock as a result of abrupt deformation or failure. The released energy is then radiated through the rock mass as seismic waves that are captured by seismic monitoring sensors (seismic event). The nature of seismic events depends on physical and mechanical properties of the rock mass and discrete structures.

ABSTRACT Solution mining is the most critical process for salt cavern gas storage. So far Salt cavern gas storages in China are mainly single-well-cavity, and the time of dissolution between two and four years. Solution mining utilize intermediate hanging string and long hanging string for direct circulation and reverse circulation. In the process of solution mining, fluid velocity and different mode of circulation have a great influence on the longitudinal and transverse expansion of the cavity. Therefore, in order to research the changes of the flow field in different working conditions, this study uses Particle Image Velocimetry for flow field analysis. In the laboratory, using large-scale transparent models for laboratory simulation experiments. According to the experimental results, under direct circulation mode, water flows through the right space to upper part. Angle of reflux was in the range of 28° − 56°. The maximum influence radius of direct circulation flow field is 48.1m. In reverse circulation mode, if the distance from the intermediate hanging string to the insoluble matter is less than 2.44m, insoluble matter may affect circulation. INTRODUCTION Underground gas storage is important composition part of transporting pipeline system of natural gas (LI Tie et al., 2000). In 2021, China's natural gas consumption will reach 372.6 billion m, and the reserves required for peak adjustment of natural gas will be 55 billion m, but the actual reserves only reach about ⅓ of the demand (YANG Chunhe and WANG Tongtao, 2022). Overcoming the unstable supply of clean energy requires accelerating the construction of underground space for large-scale storage (WANYAN Qiqi et al., 2020). Salt cavern gas storage is the main technology for natural gas storage due to its stronger integrity, higher gas injection efficiency and less gas consumption of cushion (ZHU Xingshan et al., 2022). It can not only satisfy the peak regulation demand of the city, but also optimize the production system and gas pipeline network (ZHENG Yali and ZHAO Yanjie, 2010). A mass of cavity completion data shows that the final cavity volume of salt cavern gas storage deviates from the initial design volume to some extent (WANG Yuangang et al., 2020), so it is particularly important to research the influence of different factors on solution mining.

ABSTRACT Shale gas wells in longwall chain pillars are subject to longwall-induced overburden movements. Longwall mining on either side of the chain pillars can induce deformations in gas well casings. The casing deformations induced by longwall mining has raised the safety concern that casing integrity might be diminished so that intrusive shale gas could leak into the longwall mine with serious consequences. This study deals with longwall-induced casing deformations of eight shale gas wells in the chain pillars between two adjacent longwall panels in the Pittsburgh coal seam under a cover depth of 314 m and a mining height of 2.1 m. The longwall panels were 457-m wide, and the chain pillars were 66-m wide. The longwall faces passed by the shale gas wells as each adjacent longwall panel was retreated. Gas well casing deformations were measured by a multi-finger caliper after each panel was mined. The first panel mining induced casing deformations less than 1.7 cm above the coal seam horizon. The second panel mining caused an increase of casing deformation up to 20%–30% on average. The casing deformations were also predicted by the FLAC3D modeling technique based on site-specific mining and geological conditions. The study demonstrates that the predicted casing deformations are generally in good agreement with the measurements. The study shows that the casing deformations first occur at the weak/strong rock interfaces after first panel mining and then increase by a small amount at the same locations after second panel mining. The study reveals that longwall-induced casing deformations under deep cover are smaller than those under shallow cover. The study also provides a quantitative method for using numerical modeling to assess the stability of shale gas wells in longwall chain pillars. INTRODUCTION Gas wells drilled in longwall pillars are influenced by longwall mining. Due to longwall-induced subsurface ground movements, the gas wells in the vicinity of longwall panels are subject to longwall-induced stresses and deformations. Excessive stresses and deformations induced in gas well casings could lead to a casing breach. More safety concerns have been focused on unconventional shale gas wells in the presumption that the casing breach could allow high-pressure gas to leak into the mine, potentially causing a fire and explosion. Over the past decade, more than 1,500 shale gas wells have been drilled in the current and future reserves of the Pittsburgh coal seam. The impact of longwall mining on these shale gas wells will have to be evaluated as future longwall panels are mined. Therefore, it is important to quantify longwall-induced subsurface movements and casing deformations and to develop reliable models to assess the stability of shale gas wells in longwall pillars.