Natural Gas Wells Research Articles

A Visual Color Response Test Paper for the Detection of Hydrogen Sulfide Gas in the Air.

Hydrogen sulfide (H2S) is widely found in oil and natural gas wells and industrial wastewater tanks. Owing to its high toxicity, the monitoring and detection of H2S in the air is essential. However, recent techniques for the quantitative detection of H2S gas suffer from limitations such as high cost, complicated operation, and insufficient sensitivity, preventing their practical application in industry. Thus, we have developed a portable test paper for real-time and inexpensive monitoring of H2S gas by color changes. The test paper had a significantly low H2S detection limit of 200 ppb, which is considered safe for humans. Moreover, the color of the test paper did not change noticeably when exposed to CO2, N2, O2, and air environments, indicating that the test paper is selective for H2S gas and can be stored for a long time. In addition, we fitted a color difference linear model between the color difference values (ΔE) and the concentrations of H2S gas. The establishment of the linear model substantiates that the test paper can provide accurate intensity information when detecting H2S gas leakage.

Employment and Income Effects of Investments Made Using the Act 13 Unconventional Natural Gas Impact Fee in Pennsylvania

Unconventional natural gas extraction presents numerous opportunities and risks for communities across the United States. To capture a portion of the revenue generated by the resource states tax unconventional natural gas development. While most states collect revenue via severance taxes, Pennsylvania took a novel approach and established an impact fee on the industry instead. Unlike severance taxes in other states, the fee is collected annually and distributed directly to municipalities. While reports show that municipalities use the funds to pay for critical infrastructure, no best practices on how to allocate the funds exist. Citing the literature on mineral resource extraction and infrastructure-led development in American communities, this study examined impact fee payments made to counties with unconventional natural gas wells. The study evaluated whether counties that used the funds to invest in infrastructure were better off in terms of employment and income than other shale-producing counties that did not. Panel fixed- and random-effects regressions suggested that no statistically significant employment or income effects existed. The results suggest that local infrastructural investments are not a successful way to overcome the resource curse issues identified in the literature.

Experimental and computational investigations on foaming properties of anionic-nonionic-zwitterionic surfactants and amino acid compounds to address the liquid loading of natural gas wells

Liquid buildup in gas wells would undoubtedly obstruct the gas production. The use of foaming surfactants to generate foams and remove the loaded liquid is very common. Due to the undesirable conditions (e.g., high condensate cut (ratio of condensate oil volume to total liquid volume) and high salinity, etc.) that often encountered in the wells, different foaming surfactants were often compounded together to unload liquid in gas wells. In this paper, lauramide propyl dimethylamine (C12 Amine), palmitamide propyl dimethylamine (C16 Amine) and cocamidopropyl betaine (CAPB) were synthesized and compounded with L-aspartic acid (Asp) and N-lauroylsarcosine sodium (LSS) to form foaming supramolecular complexes through optimization (with Waring blender method and liquid unloading tests) to quantify their application potentials in foam-based deliquification treatment for gas wells. The C12 Amine-Asp-LSS-CAPB complex (in an optimized mole ratio of 10:4:14:7) exhibited superior condensate tolerance than the C16 Amine-Asp-LSS-CAPB complex (in an optimized mole ratio of 10:4:14:42). The salinity posed a significant influence on the liquid unloading performance (k) and foaming efficiency (ƞ, defined as the ratio of the foam mass to the initial liquid mass) of the C12 Amine-Asp-LSS-CAPB complex, however, the nitrilotriacetic acid trisodium (NTA) can greatly enhance the properties of the C12 Amine-Asp-LSS-CAPB complex against the salinity (up to 6 × 104 mg/L). The temperature (25 °C −90 °C) favored the performances (as indicated by k and ƞ) of the C12 Amine-Asp-LSS-CAPB complex, which achieved k and ƞ values of 85.0% and 100% at 90 °C, respectively. Meanwhile, the synergy observed in the foaming ability, foam stability and liquid unloading performance tests using the C12 Amine-Asp-LSS-CAPB mixture was also proved by the surface tension analysis and the calculations of the supramolecular interactions (interaction energies and electrostatic interactions).

Advances in Gas Well Fluid Accumulation Modeling

Liquid accumulation at the bottom of a well is an important cause of production reduction or even shutdown of natural gas wells, and it is inevitable that water-bearing formations generate liquid accumulation when producing natural gas. Therefore, it is important to study gas well liquid accumulation models and identify liquid accumulation at the bottom of a well in order to take timely and reasonable process measures to deal with liquid accumulation at the well. Based on this, this paper analyzes the current status of domestic and international research on gas well critical fluid-carrying droplet models and critical fluid-carrying film models through literature research, analyzes the problems and development trends of research on gas well fluid accumulation prediction, and provides a comprehensive and systematic summary of the progress of gas well fluid accumulation model research.

Study on double differential pressure measurement method of gas-liquid two-phase flow in high gas content wells

The production of natural-gas wells contains natural gas and a small amount of liquid, which is a wet gas composed of oil, gas and water. For dynamically monitor the liquid and gas production from a single well, there is an urgent need for a low-cost, small-volume online metering device for wet gas flows through a single well. Aiming at the problem, this paper designs a wet gas flow measurement device for a long-throated Venturi tube based on the double differential pressure method. By combining experiments and numerical simulations, a matching flow calculation model was developed. Based on the experimental data of NEL's 6-inch standard Venturi tube wet gas over-reading, the numerical simulation method is used to carry out the research of high-pressure wet gas measurement under the pressure condition of 2, 4 and 6 MPa. The simulation results of two multiphase flow models, DPM and Euler, are compared with the experimental values of NEL. The results show that the maximum relative error is less than 10%, and the Euler model is more suitable for the numerical simulation of high-pressure wet gas. According to the actual production from the gas well, a long-throated Venturi tube with a throttling ratio of 0.5 and a diameter of DN50 was designed, and a numerical simulation study of wet gas under a pressure of 2, 3 and 4 MPa was carried out. Numerical simulation results show that the change laws of over-reading and liquid-gas mass ratios of high-pressure wet gas are consistent with those of low-pressure wet gas. The numerical simulation results are used to correct the flow calculation model of low-pressure wet gas, and a flow calculation model suitable for high-pressure wet gas in gas wells is obtained. The gas flow prediction accuracy of the flow calculation model was lower than ±3%, and the liquid flow prediction value was lower than ±10%. Compared with other measurement methods without separation of wet gas, the long-throated Venturi tube based on the double differential pressure method has a simple structure and low measurement cost. By further optimizing and expanding the measurement model, after improving the accuracy, it can be installed in the wellhead pipeline to monitor the oil and gas production from a single well in real time. This can provide support for gas reservoir exploitation decisions.

Oil and natural gas wells across the NASA ABoVE domain: fugitive methane emissions and broader environmental impacts

Arctic-boreal regions are experiencing major anthropogenic disturbances in addition to intensifying natural disturbance regimes as a consequence of climate change. Oil and natural gas (OG) activities are extensive in the Arctic-boreal region of western North America, a large portion of which is underlain by permafrost. The total number and distribution of OG wells and their potential fate remain unclear. Consequently, the collective impacts of OG wells on natural and cultural resources, human health and emissions of methane (CH4), are poorly understood. Using public OG well databases, we analysed the distribution of OG wells drilled between 1984 and 2018 across the Core Domain of the NASA Arctic-Boreal Vulnerability Experiment (‘ABoVE domain’). We identified 242 007 OG wells drilled as of 2018 in the ABoVE domain, of which almost two thirds are now inactive or abandoned OG wells. We found that annual drilling has increased from 269 to 8599 OG wells from 1984 to 2014 with around 1000, 700 and 1800 OG wells drilled annually in evergreen forest, deciduous forest and herbaceous land cover types, respectively. 65 588 OG well sites were underlain by permafrost in 2012. Fugitive CH4 emissions from active and abandoned OG wells drilled in the Canadian portion of the ABoVE domain accounted for approximately 13% of the total anthropogenic CH4 emissions in Canada in 2018. Our analysis identified OG wells as an anthropogenic disturbance in the ABoVE domain with potentially non-negligible consequences to local populations, ecosystems, and the climate system.

Dynamic Operability Analysis for Process Design and Control of Modular Natural Gas Utilization Systems.

Process modularization is an alternative process design and construction framework, in which modular units are independent and replaceable blocks of a process system. While modular plants have higher efficiency and are safer to construct than conventional stick-built plants (Roy, S. Chem. Eng. Prog. 2017, 113, 28-31), they are significantly more challenging to operate because of the loss in the control degrees of freedom that comes with process integration and intensification (Bishop, B. A.; Lima, F. V. Processes 2021, 9, 2165). To address this challenge, in this work, operability analyses are performed to consider the design and operation of modular units. Initially, a steady-state operability analysis is employed to find a set of feasible modular designs that are able to operate considering different modular plant conditions. A dynamic operability analysis is then applied to the feasible designs to identify the operable designs that are capable of rejecting the operational disturbances. Lastly, a closed-loop control measure is introduced to compare the performances of the different operable designs. The proposed approach is implemented in a modular membrane reactor to find a set of operable designs considering different natural gas wells, and the respective closed-loop nonlinear model predictive control performance of these units is evaluated.

Experimental investigation of film reversal evolution characteristics in gas–liquid annular flow

In natural gas wells, liquid loading is a severe problem threatening production safety. Published studies have verified that liquid loading is closely related to film reversal in gas–liquid annular flow, but the evolution of the film reversal is still unclear. This article reports on experiments conducted to reveal the film reversal evolution characteristics. Experiments were conducted in a 50-mm-diameter vertical pipe with superficial gas velocities ranging from 5.66 to 22.64 m/s and superficial liquid velocities ranging from 0.014 to 0.170 m/s. A camera and electrical resistance tomography were used to obtain qualitative and quantitative results, and an error analysis verified the experiments’ repeatability and reliability. The evolution process is divided objectively into three stages to clarify the film reversal: no film reversal (No-FR), the onset of film reversal (Onset-FR), and complete film reversal (Complete-FR). The three stages occur successively with decreasing gas velocity. The characteristics of the individual stages are elaborated, including the interfacial structures, morphological features, and motion trajectories. The void fractions are analyzed in both the time and frequency domains, where the statistical parameters of the probability density function, average value, and standard deviation are presented. The results show that the Onset-FR stage exhibits characteristics similar to both the No-FR and Complete-FR stages, indicating that it plays an intermediate role in the gradual evolutionary process. The current experimental results also achieve excellent agreement with published datasets and correlations.

Corrosive Influence of Carbon Dioxide on Crack Initiation in Quartz: Comparison With Liquid Water and Vacuum Environments

AbstractThe stimulation of crack growth in quartz and siliceous materials by injecting carbon dioxide (CO2) represents a key technology in long‐term carbon storage and in the development of natural gas wells. While this technology is widely used, the molecular impact of CO2 interactions on the solid matrix is only incompletely understood. In this work, we employ reactive molecular dynamics simulations to study how the CO2 fluid environment affects the mechanical properties of pre‐cracked single‐crystal quartz. The thermodynamic conditions of interest are those relevant to subsurface reservoirs. We report how structural properties of quartz—bond length distribution and crack tip shape—evolve upon introduction of a fluid. These properties are directly related to macroscopic quantities of the global stress–strain curves, thus reaffirming the inherent coupling across multiple scales for fluid–solid interactions in the subsurface. We find that CO2 reduces the fracture toughness of quartz by 12.1% compared to that of quartz in vacuum, thereby promoting crack growth and enhancing fluid transport in the subsurface.

Experimental Study on the Attenuation Law of Vibration Wave Propagation in Natural Gas Wells in Coal-Gas Cross-Mining Area

Experimental Study on the Attenuation Law of Vibration Wave Propagation in Natural Gas Wells in Coal-Gas Cross-Mining Area

A Comprehensive Method for the Optimization of Cement Slurry and to Avoid Air Channeling in High Temperature and High-Pressure Conditions

Air channeling in the annulus between the casing and the cement sheath and/or between the cement sheath and formation is the main factor affecting the safe operation of natural gas wells at high temperatures and pressures. Prevention of this problem requires, in general, excellent anti-channeling performances of the cement sheath. Three methods to predict such anti-channeling performances are proposed here, which use the weightless pressure of cement slurry, the permeability of cement stone and the volume expansion rate of cement sheath as input parameters. Guided by this approach, the anti-channeling performances of the cement slurry are evaluated by means of indoor experiments, and the cement slurry is optimized accordingly. The results show that the dangerous transition time of the cement slurry with optimized dosage of admixture is only 76 min, the permeability of cement stone is 0.005 md, the volume shrinkage at final setting is only 0.72%, and the anti-channeling performances are therefore maximized. The effective utilization of the optimized cement slurry in some representative wells (LD10–1-A1 and LD10–1-A2 in LD10–1 gas field) is also discussed.

A land use regression model to predict emissions from oil and gas production using machine learning

Emissions from oil and natural gas (O&G) wells such as nitrogen dioxide (NO2), volatile organic compounds (VOCs), and ozone (O3) can severely impact the health of communities located near wells. With the O&G industry growing and 17.6 million people living within a mile from an O&G well, the effect of O&G activity on residents is especially pertinent. In this study, we used O&G activity and wind-carried emissions to quantify the extent to which O&G wells affect the air quality of nearby communities, revealing that NO2, NOx, and NO are correlated to O&G activity. We then developed a novel land use regression (LUR) model using machine learning based on O&G prevalence to predict emissions. Many LUR models fail to account for O&G sources, therefore we hypothesized that the inclusion of O&G sources in land use regression models provides an increase in accuracy when predicting emissions. The model performed effectively for NO2, outperforming past LUR models which did not involve O&G activities. The model makes it possible for not only communities, but also families and individuals, to determine the effect that O&G has on their homes. With current modeling techniques failing to observe the effects of O&G in the face of the growing O&G industry in the U.S., it is crucial that the public is educated on the effect of the O&G industry on their daily lives and has the tools to monitor these effects.

Adsorption kinetics investigation of surfactant molecules at the short-chain alkane-water interface

Foam drainage technology based on surfactants is considered the most promising measure to solve liquid accumulation in natural gas wells and gathering pipelines. However, the presence of multiple alkane components in condensate and natural gas will affect the properties of aqueous foam containing surfactants, which greatly limits the application of this technology. To clarify the mechanisms of different condensate oil and natural gas components on foam properties, the interface characteristics of different alkane-surfactant-water systems were systematically analyzed from thermodynamics and kinetics by molecular dynamics simulation and experimental methods. The results show that the interfacial adsorption of alkanes and the interaction between alkanes and surfactants are the main factors affecting the surface tension and stability of interfacial films of different systems. This study has guiding significance and reference value for foam drainage in oil and gas fields.

The temporalities of extractive frontiers: The promises of booms and going bust in the Tanzanian gas sector

Research on extraction in the global margins has often emphasised the transformative effects that occur during the process of becoming a ‘resource frontier’. However, much of this research often focuses on the spatial transformations, with the temporalities of the resource frontier often being relegated to the background. This article places the temporalities of resource frontiers at the forefront. It does so by exploring the onshore and offshore gas sector in Mtwara, Tanzania, specifically how the international commodity cycle and the lifecycle of natural gas wells changed Mtwara from an ‘economic backwater’ to a ‘resource frontier’, and how this reshaping of territory has altered perceptions of time. High global gas prices, combined with the most labour-intensive period of the gas well lifecycle, led to an anticipated resource boom for the region, with national and local elites changing their economic activity in preparation for this boom. Such anticipation was met with promises of increased employment and economic development, and initial changes aided the impression that such anticipation for the boom was justified. When the construction of wells and facilities was finished and global gas prices were falling, Mtwara as a ‘resource frontier’ was once again reshaped to one of a ‘quasi frontier’ – where the potential for extraction remains but lacks the correct market factors to fully create an economic ‘boom’ and become a ‘resource frontier’. The result was that while a traditional ‘resource boom’, did not occur, the speculative effects of extractive investment ensured that both a boom, and a ‘bust’ occurred in the region, severely affecting short-, medium-, and long-term economic plans of local inhabitants and domestic investors alike, with many negative effects of the boom remaining.

Research and Application of Surface Throttling Technology for Ultra-High-Pressure Sour Natural Gas Wells in Northwestern Sichuan Basin

The gas reservoirs in the Northwestern Sichuan Basin have great development potential. However, their production efficiency is seriously reduced by the complex surface multistage throttling process and frequent hydrate plugging caused by the ultra-high-pressure sour gas. Considering the prevention and control of hydrates, properly designing the throttling temperature and pressure to optimize the surface production process is the key to solving this problem. First, this work presents a method for predicting the hydrate formation conditions of ultra-high-pressure sour natural gas based on the vdW-P (van der Waals–Platteeuw) model and the CPA (cubic-plus-association) equation of state (EoS) and considering the association between acid gases (H2S, CO2) and H2O. Secondly, the throttling temperature prediction method was developed by coupling the isenthalpic throttling model and the modified Lee–Kesler EoS mixing rule; the maximum throttling pressure difference calculation method was constructed based on the critical flow principle. Finally, field cases are given to illustrate the distribution process of assigning the maximum throttling pressure differences. The results show that the proposed model can accurately predict the hydrate formation conditions and throttling temperature of ultra-high-pressure sour natural gas, and reveal their changing laws. The surface throttling technology of the ultra-high-pressure sour gas wells Long 004-X1 and Long 016-H1 was optimized from five-stage to three-stage, and the application of the fixed throttle valve in the field is successfully demonstrated.

A novel multi-path sand-control screen and its application in gravel packing of deepwater horizontal gas wells

Gravel packing is a promising sand control method for natural gas wells in deepwater environments. However, premature screenout, wellbore shrinkage, and packer installationlimit gravel packing efficiency in long-reach horizontal wells. In this paper, we introduce a novel multi-path screen that provides alternative pathways once the circulating annulus is blocked. The basic geometric parameters of the screen are given first. Then, the frictional pressure loss in each circulating unit during packing is evaluated. Finally, the application of this screen in a long-reach horizontal well in the northern South China Sea is discussed. The application results demonstrate the applicability of multi-path screens in complex downhole completion conditions. The multi-path screen described here may widen the application ranges of gravel packing techniques to meet the exploitation demand for unconventional natural gas resources, such as marine natural gas hydrate.

Environmental Geology of Barite Deposits in Nevada

Abstract Barite is an important industrial mineral used as a weighing agent in fluids during the drilling of oil and natural gas wells, with the majority of United States production originating from Nevada. This paper considers three barite properties at varying stages of development—Rossi, Heavy Spar, and Ann—all located within the northern Nevada barite belt. At all three sites, barite is hosted in the Roberts Mountains allochthon consisting of siliceous sedimentary rocks. Geochemical characterization of waste rock, ore, and process products has been undertaken as part of project development at each site, including 212 acid-base accounting (ABA) analysis and 19 humidity-cell tests operated for up to 114 weeks. This study demonstrates that the presence of barite greatly limits the application of using traditional Sobek-style ABA methods. Barite will undergo incomplete dissolution and extraction in the ABA tests that will result in an overprediction of acid generation for materials that contain barite (i.e., ore and jig by-products). Results indicate use of the net acid generation test to inform waste rock management represents a more reliable indicator of acid generation for these three deposits and potentially also other barite deposits. Potential barite mine sites should continue to be evaluated using the same geochemical testing tools as base metal mines but using those tools in a selective way to achieve balance between regulatory requirements and costs.

Global Progress in Oil and Gas Well Research Using Bibliometric Analysis Based on VOSviewer and CiteSpace

Studies related to oil and gas wells have attracted worldwide interest due to the increasing energy shortfall and the requirement of sustainable development and environmental protection. However, the state of oil and gas wells in terms of research characteristics, technological megatrends, article-produced patterns, leading study items, hot topics, and frontiers is unclear. This work is aimed at filling the research gaps by performing a comprehensive bibliometric analysis of 6197 articles related to oil and gas wells published between 1900 and 2021. VOSviewer and CiteSpace software were used as the main data analysis and visualization tools. The analysis shows that the annual variation of article numbers, interdisciplinary numbers, and cumulative citations followed exponential growth. Oil and gas well research has promoted the expansion of research fields such as engineering, energy and fuels, geology, environmental sciences and ecology, materials science, and chemistry. The top 10 influential studies mainly focused on shale gas extraction and its impact on the environment. More studies were produced by larger author teams and inter-institution collaborations. Elkatatny and Guo have greatly contributed to the application of artificial intelligence in oil and gas wells. The two most contributing institutions were the Southwest Petr Univ and China Univ Petr from China. The People’s Republic of China, the US, and Canada were the countries with the most contributions to the development of oil and gas wells. The authoritative journal in engineering technology was J Petrol Sci Eng, in environment technology was Environ Sci Technol, in geology was Aapg Bull, and in materials was Cement Concrete Res. The keyword co-occurrence network cluster analysis indicated that oil well cement, new energy development, machine learning, hydraulic fracturing, and natural gas and oil wells are the predominant research topics. The research frontiers were oil extraction and its harmful components (1992–2016), oil and gas wells (1997–2016), porous media (2007–2016), and hydrogen and shale gas (2012–2021). This paper comprehensively and quantitatively analyzes all aspects of oil and gas well research for the first time and presents valuable information about active and authoritative research entities, cooperation patterns, technology trends, hotspots, and frontiers. Therefore, it can help governments, policymakers, related companies, and the scientific community understand the global progress in oil and gas well research and provide a reference for technology development and application.

An extensive scope of flow loops with a focus on particle transport

All the oil and natural gas wells from underground reservoirs to the surface resemble flow loops. Over the past couple of decades, a variety of flow loops have been established in order to create real field environments in the laboratories. The flow loops help to further advance the efficiency of drilling, production, and hydraulic fracturing operations. This can be achieved by better understanding the mechanisms behind particle transport within the flow loops such as fluid velocity and rheology, particle size and concentration, acting forces on particles, and pressure drop. The objective of the current review is to critically investigate several flow loops with different applications addressing transportation of particles such as cuttings, sands, condensate droplets, hydrates, and proppants.

Proximity and density of unconventional natural gas wells and mental illness and substance use among pregnant individuals: An exploratory study in Canada.

Hydraulic fracturing (fracking) is a method used to extract unconventional natural gas (UNG). Living near UNG operations has been associated with various health outcomes, but few have explored the association between UNG and mental health and substance use. Our objective was to evaluate the association between metrics of residential UNG well density/proximity and mental illness and substance use among pregnant individuals in Northeastern British Columbia, Canada. Individuals who gave birth at the Fort St John hospital between December 30, 2006 and December 29, 2016 (n=6278) were included in the study. Exposure was determined using inverse distance weighting (IDW) to calculate the density and proximity of UNG wells to the postal code centroid ofindividual's residential address at delivery. Four exposure metrics, categorized by quartiles, were calculated based on 50, 10, 5 and 2.5km buffer zones around each postal code centroid. Logistic regression was used to separately evaluate associations between IDW quartiles of each metric and diagnosis of depression and anxiety prior to or during pregnancy, and self-reported substance use during pregnancy, controlling for relevant and available confounders. The second and third quartile (Q) of the 10km IDW were associated with greater odds of depression (Q2: adjusted (aOR) 1.30, 95% (confidence interval) CI 1.03-1.64; Q3: aOR 1.35, 95% CI 1.07-1.70) compared to the first quartile, but not the fourth. Using the 5km IDW, we observed a suggestive positive association with depression in the second and third quartile (aOR Q2: 1.21, 95% CI 0.96-1.53; aOR Q3: 1.24, 95% CI 0.98-1.57) compared to the first quartile. No statistically significant association was observed using the 2.5km IDW exposure metric. We observed some evidence of greater odds of mental illness prior to or during pregnancy, and substance use during pregnancy in pregnant individuals living in postal codes with increased UNG well density/proximity, although associations were not observed in smaller buffer zones. This study adds to the growing literature on the adverse health outcomes surrounding living in proximity to UNG operations.