bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Implementation of Subterranean Barriers to Reduce Shallow Gas Migration and Coal Mine Methane Emissions from Open-Cut Metallurgical-Coal Mines
Authors: Johnson Raymond L. , Sedaghat M. 
Published: November 2023

Abstract
The implementation of low-permeability barriers was originally proposed to reduce gas influx into areas of pre-drainage prior to or after mining operations (Johnson Jr, 2014). Currently, barriers are being proposed to provide a real opportunity to dramatically reduce methane emissions from open-cut, metallurgical coal (MC) mines, essential to meet steel production targets for international urbanisation and energy transformation. Finally, barrier implementations can accelerate peak gas production and recovery in areas of undersaturated coals or coal wells subject to aquifer influx.
The basis of barriers is similar to naturally occurring barriers (i.e., igneous intrusions or dikes) that have shown effectively separate areas of drained and undrained mine works (as observed in adjoining drained and undrained mines in Central Queensland). In the environmental and in civil engineering sectors, artificial impermeable barriers have been implemented in shallow reservoirs to manage flow or contain contaminant plumes in groundwater or to prevent water influx into groundworks, respectively. In the oil and gas sector, barriers have been proposed to control gas or water leakage or breakthrough in areas of storage, initial production, or secondary recovery processes, mostly involving gas or water egress into outlying reservoirs or unwanted influx into productive intervals. This paper builds on previous research and provides a working framework for the use of impermeable materials to create permeability barriers. It also builds on complementary research into more effective low permeability coal extraction technologies and technology implementation currently being deployed to improve underground mine gas drainage systems.
Our paper describes the design, execution and evaluation workflows and the relative importance of variables required for a barrier implementation in two key applications. Firstly, we will report the results of ongoing planning and modelling to implement and assess a barrier application for the primary application of eliminating gas migration from unmined, in-seam sections in conjunction with open-cut MC mining operations. Similarly, barriers can be used to improve underground mine pre-drainage, improving safety, and lowering methane influx and overall emissions from down-dip coals. Next, we will demonstrate using a representative model the application of barriers to reduce aquifer influx into and gas migration from a coal seam gas (CSG) well near a subcrop with an aquifer connection. Similarly, barrier applications can improve gas production and recovery for undersaturated coal seams where conventional shielding methods to reduce water influx and improve desorption have been ineffective.
Impact of Surface Roughness and Liquid Salinity on Shale Wettability
Authors: Qian Sijin , Zhu Yiran , Shi Zhang , Lu Mingyuan , Shen Luming , Li Jimmy Xuekai , Chen Zhongwei 
Published: November 2023

Abstract
This study explores the effect of surface roughness and liquid salinity on the wettability of shale. Varying levels of surface roughness are imparted onto the shale samples using sandpapers with differing grits and polishing disks. An optical profiler is also applied to determine the surface roughness and create 3D tomography models for each shale sample. Furthermore, contact angle tests were conducted using liquids with different salinity levels to determine the effect of salinity to surface wettability. The results indicate a marked increase in contact angle with decreasing surface roughness. This suggests that a smoother surface can considerably mitigate water-lock effects and reduce water flow resistance within the shale. Additionally, the results obtained from utilizing liquids with varying salinity demonstrate that higher salinity levels lead to lower shale contact angles. Moreover, the salinity effect is more pronounced on smoother surface than on a rougher one. A power function was found to aptly describe the mathematical relationship between the arithmetic average of surface roughness (Ra) and contact angle, validated by a high R² value of 0.863. The implications of these findings are significant for hydraulic fracturing and gas production strategies, as they can provide more reliable guidance for selecting operational parameters.
Microbiology in Unconventional Operations: A Journey from Surveillance Integrity to Operational Excellence
Authors: Shepherd A. G. , Lomans B. P. , Tsesmetzis N. 
Published: November 2023

Abstract
This work describes how microbiology surveillance can be used to drive improvements in unconventional assets. Various microbiology enumeration tools are compared in different case histories for well workovers, surface facilities and production sites. When correctly deployed, new tools and strategies for microbiology management can be powerful resources to further risk assess operations and improve understanding of operating envelopes for safe and reliable production.
Accounting Green and Blue Hydrogen in a Net Cash Flow Model for Techno-Economic Assessment on Underground Hydrogen Storage in Australia
Authors: Bo Z. , Hurter S. , Hoerning S. , Underschultz J. , Garnett A. 
Published: November 2023

Abstract
Hydrogen is expected to play a significant role in the process of decarbonizing the global energy sector where Underground Hydrogen Storage (UHS) may be the only option for large-scale seasonal energy storage. Studies conducted so far to investigate the economic feasibility of UHS in porous reservoirs focus on the levelized cost of energy (LCOE) while the other economic indicators are left unattended. To better assess the techno-economic feasibility of UHS, we built a knowledge-based net cash flow model to estimate the net present value (NPV) and internal rate of return (IRR) of UHS projects under different hydrogen price assumptions. Specifically, we incorporate expected green and blue hydrogen prices by 2030 in Australia into our model to evaluate the resulting project economic performance. Our model calculated net cash flows illustrate the inherent technical and economic disadvantages of UHS in Australia compared to alternative technologies such as underground gas storage (UGS). Under current expectations, both the storage of hydrogen-methane mixtures and pure hydrogen cannot make considerable economic profits without policy support in the near future. The commercialization of UHS is in need of support measures such as an Australian carbon credit unit (ACCS) of at least $18.17 AUD.
Disposable Fibre Optic Surveys Optimise Wells and Reduce CO2 Emissions in Unconventional Assets
Authors: Crawford R. , Green A. , Lynch P. , Feherty C. 
Published: November 2023

Abstract
The large quantity of batch wells typical in unconventional fields results in per well incremental optimisation gains compounding and significantly improving asset economics. A disposable, cost effective, fibre optic intervention system safely and efficiently provides high quality data to optimise completion design and hydraulic fracturing, calibrate reservoir models and inform future well design. CO₂ efficiency estimates and technology applications in unconventional fields including Vertical Seismic Profiling (VSP), cement cure analysis and hydraulic fracture optimisation are outlined.
The upper end of one or two bare fibre optic cables are fixed inside a light-weight pressure control cap, while the downhole ends are deployed along the wellbore as they unspool from a disposable probe which is pumped along horizontal sections. Distributed Acoustic Sensing (DAS) is used for seismic and micro-seismic fracture analysis, whereas Distributed Temperature Sensing (DTS) is used to monitor well and near wellbore fluids. The high-quality data is used both in real time and subsequent enhanced analysis with disposable fibre having been successfully deployed in over 200 unconventional wells. The high level of acoustic and strain coupling as well as the elevated sensitivity of disposable bare optic fibre produce high quality data, with recent studies favourably comparing disposable fibre data with that obtained by retrievable fibre optic intervention. When compared with well monitoring methods utilising Wireline or Coiled Tubing, the disposable fibre system is extremely light weight with a micro footprint, requires only one person to deploy, has static seals, and does not require a BOP. The result is a low risk, efficient, method of highly sensitive, complete wellbore, fibre optic sensing. The transportation weight saving, reduced survey time, power consumption and reduced personnel requirements result in significant operational CO₂ reductions.
Examples of unconventional well VSP, cement cure analysis, well integrity and fracture optimisation applications demonstrate efficiency gains and impact on asset economics. Unconventional field lifecycle applications of a new disposable fibre optic system are presented along with field optimisation and economic benefits. In addition, an example operation illustrating comparative CO₂ emissions for a hydraulic fracture monitoring application demonstrates disposable fibre CO₂ emissions at 8% of comparable wireline operations.
Limited Entry Liner Completion and Acidizing Design with Consideration of Reservoir Heterogeneity for MRC Wells
Authors: Liu Huifeng , Jia Wanting , Cui Longlian , Xu Ning , Yang Guobin , Liqiu Ping , Chen Zhangxin 
Published: November 2023

Abstract
MRC (Maximum Reservoir Contact) wells with extra-long laterals (formation contact length＞5000m) are drilled in many oilfields in the world to develop tight and thin reservoirs. LEL (Limited Entry Liner) completion and acidizing are an effective technology to stimulate these wells because they distribute the acid uniformly along the long laterals. The design of a distribution of holes in LEL is the key to this technology, especially for reservoirs with high heterogeneity.
This study focuses on the optimization of the current LEL completion design strategy by considering the porosity heterogeneity along the lateral and the permeability anisotropy within each segment. Firstly, a model for designing a distribution of holes in LEL is established by incorporating a newly developed model for calculating a post-stimulation equivalent skin factor. Secondly, three LEL completion design strategies are proposed: uniform acid coverage, uniform wormhole length and uniform equivalent skin factor. Thirdly, a real well case is introduced to show the difference between the three strategies in terms of the distribution of holes, generated wormhole length and post-stimulation skin factor.
In our new design model, the variances of formation porosity, the differences in acid outlet flow velocity among different segments and the difference in permeability in different directions are considered. This model is used in a horizontal well to achieve uniform post-stimulation equivalent skin factor and the result is compared with those by the other two design strategies. The result from the uniform acid coverage strategy shows that the total number of holes is 198, the length of the generated wormhole is 4.46ft and the equivalent skin factor is -2.88. The result from the uniform wormhole length strategy indicates that fewer holes (totally 135) and a more irregular holes distribution are obtained; the wormhole length is 0.43ft. The result from the uniform equivalent skin factor design strategy shows that the total number of holes is 161; the wormhole length and acid coverage are bigger at the heel but smaller at toe. It also shows that the equivalent skin factor is much bigger (even positive at the heel) than in the other two strategies, which indicates that more acid and consequently more holes should be added at the heel. It is also recommended for an appropriate selection of the three design strategies.
Our work is an optimization for LEL completion design based on the current design strategy in the industry, which only aims for uniform acid distribution. A guideline chart of the three design strategies we have proposed is also useful for engineers to select the appropriate LEL design methods based on the specific well conditions.
Unlock the Conventional and Unconventional Potential of North Kuwait Jurassic Reservoirs
Authors: Ameer A. , Al-Saffaar A. , Narhari S. , Emera M. , Jin M. 
Published: November 2023

Abstract
The success of production from unconventionals in North America, encourage Kuwait to focus on Najmah Kerogen and unconventional resources that have value of significant hydrocarbon resource potential in North Kuwait Jurassic Area. Kuwait Oil Company has embarked on a journey to unlock these unconventional resources by screening the subsurface targets in the reservoirs which have potential to contribute to the gas production ambitions of the country. Unconventional field development team has evaluated these difficult reservoirs through an End To End (E2E) hydrocarbon maturation (HCM) framework, with a clear roadmap to appraise and develop these resources to sustain the required plateau of the unique Gas Asset in Kuwait.
The reservoirs of focus are a mix of naturally fractured carbonates with conventional "Middle Marat (MM)" reservoirs and tight unconventional reservoirs ("Najmah/Sargelu"&"Kerogen") at a depth of 15000+ ft in a HPHT setting. The E2E-HCM Modules have been used as key building blocks for the economic evaluations. The modules can be flexibly combined as needed to model the economic potential of each of the Common Value Areas (CVAs), where a CVA is defined as an area that has been demonstrated to have common economic metrics based on Play-Based Exploration (PBE), infrastructure, and field development characteristics.
Aggregating modelling tools (eg Proviso), using decline curves of 23 conventional volatile oil and gas condensate reservoirs (3D simulation) and five unconventional reservoirs have been used. Long term production forecast is generated by combining these simulation results and flowing through 8 production facilities. An optimized drilling sequence of 500+ wells is worked-out to achieve this production forecast. This exercise also facilitated in screening potential targets for further drilling for meeting and sustaining the promised gas production plateau. In this paper, the methodology and workflow used for unlocking the potential of conventional and unconventional resources of north Kuwait Jurassic reservoirs is highlighted.
Computational Analysis of Proppant Transport and Screen-Out in Natural and Induced Fractures
Authors: Leonardi Christopher R. , Di Vaira Nathan J. , Laniewski-Wollk Lukasz , Ganpule Sameer , Flottmann Thomas 
Published: November 2023

Abstract
Predicting the pressure drop (or, equivalently, the effective permeability) across a fracture due to proppant injection is integral to the design of hydraulic fracturing treatments. This theoretical study investigates the relationship between permeability and proppant solid volume fraction, φ, for synthetic rough fractures via direct numerical simulation. For high aperture widths, it is found that permeability decreases in accordance with the cubic law with viscosity adjusted to that of a suspension. This is commensurate with what is currently employed in commercial hydraulic fracturing simulators. Moreover, permeability decreases with increasing fracture roughness. In narrow fractures, however, the permeability deviates further due to arching and localised clogging. However, screen-out, or complete fracture clogging, does not occur instantaneously. Instead, fracture permeability decreases as a continuous function of increasing φ, with gradually-increasing arching and localised clogging. The current binary criteria used by hydraulic fracturing simulators, which model a discontinuous jump in permeability at some φ, are therefore not reflective of the reality of particle transport in rough fractures because they grossly under-predict the permeability. Instead of the existing apparent viscosity and binary screen-out models, the permeability decline curves which are presented in this work should be incorporated into simulators as corrections to the cubic-law fracture permeability.
Study on Parameters Optimisation of Fracturing Stages & Perforation Clusters in Luzhou Deep Shale Gas Horizontal Wells Based on Integrated Drilling and Logging Data
Authors: Yuan L. , Hu S. L. , Mu L. Y. , Wang D. L. , Yang X. T. , Song Y. , Wang J. C. 
Published: November 2023

Abstract
Considering the high temperature environment and high operation cost, only a small number of deep shale gas horizontal wells in Luzhou would conduct logging in horizontal sections. If the neighboring wells were rather far away, it would be difficult to accurately obtain the reservoir heterogeneity along the lateral; therefore, most completions were designed geometrically, with little or no guidance for the location optimizations of fracturing intervals & perforation clusters. In such a case, it was most likely to occur a low opening rate of perforation clusters in the same stage, resulting in a poor stimulation effect.
For the first time, this paper proposed a novel optimization method for the fracturing parameters of horizontal sections based on integrated drilling & logging data. Firstly, the available data type was evaluated. If the logging data was missing, geometrically designed stages and clusters would be relocated based on drilling data; otherwise, it could be easily accessible by logging data. Then, when relocating, the drilling data (torque, drilling pressure, mechanical drilling speed, etc.) were used to calculate the rock mechanical specific energy (RMSE) along the lateral. Next, the RMSE values were calibrated with the indoor rock mechanics experiments to establish a standard classification of Luzhou deep shale rock hardness. Finally, based on the principle of similar rock hardness, the perforation clusters in the same fracturing stage were re-positioned to ensure their locations at the same or adjacent rock hardness level.
The above design method was applied and verified in Luzhou deep shale gas wells, the results demonstrated that, after the geometrically distributed segments & clusters were adjusted and relocated, their positions had a high matching rate of 85.47% with the optimized design of fracturing segments & perforation clusters using logging data. What's more, the VideoLog technology was utilized to observe the erosion of the perforation holes after fracturing, 9 out of 11 perforation clusters effectively opened, with an opening rate of up to 81.8%. Compared to the previous geometrically fracturing design with only 2 out of 10 perforation clusters effectively opened, it was a 124.7% improvement. In addition, the shape and size of the opening perforation holes were the same after erosion, which indicated that the hardness of the rock at the locations where the perforation holes were arranged was nearly the same, resulting in almost all clusters simultaneously opening & initiating.
Therefore, this method can effectively compensate for the blindness of the segment & cluster parameters design caused by the lack of logging data, ensure the effective opening efficiency of perforation clusters in the same stage, and maximize the uniformity and effectiveness of reservoir stimulation.
Do Caregivers Hava an Effect Extended Hospitalization in Patient Fallowed Palliative Care Center? A Study From Turkey
Authors: Çakmak Nuray Yılmaz 
Published: November 2023

Abstract
Background
Since palliative care clinics are clinics that strive to solve the pain caused by the disease as well as other physical and psychological symptoms and social problems as a caregiver burden, the length of stay becomes important in our clinics with high demand from patients.
One of the purposes of palliative care centers is to evaluate the patient for discharge, to provide devices that the patient needs at home or in a nursing home, and to provide caregivers with care and device usage training. We aimed to investigate whether the length of stay is caused by the caregivers as well as clinical conditions.
Methods
In this study, we retrospectively investigated the days of hospitalization of 915 patients followed in a palliative care center and the factors that prolong hospitalization in patients with extende hospitalization.
Results
The average length of stay of the patients was found to be 15.65±11.43 days. Hospitalization longer than 28 days was found to be 97(10.6%) patients. The most common reason for extende hospitalization was the reluctance of care givers to discuss discharge in 47 (48.5%) patients. The second most frequent discharge was delayed in 25 (25.8%) patients due to clinical instability. 23(23.7%). A significant relationship was detected between length of stay and TPN and nutrition. A significant relationship was detected between patients with comorbid cancer (p>0.042) and coronary artery disease (p<0.01) and extended stay.
Conclusion
With the aging of the world population and the improvement of health care services, the need for palliative care is increasing day by day. In order to use resources efficiently, there is a need to optimize the length of stay in palliative care with a multidisciplinary approach.
Trial registration
This study registerded retrospectively.
Phase Dependent Hanbury-Brown and Twiss effect
Authors: Ou Zhe-Yu , Tang Xuan , Zhang Yunxiao , Guo Xueshi , Cui Liang , Li Xiaoying 
Published: November 2023

Abstract
Hanbury-Brown and Twiss (HBT) effect is the foundation for stellar intensity interferometry. However, it is a phase insensitive two-photon interference effect. Here we extend the HBT interferometer by mixing a reference field with the input fields before intensity correlation measurement. With the freely available coherent state serving as the reference field, we experimentally demonstrate the phase sensitive two-photon interference effect when the input fields are thermal fields in either continuous wave or non-stationary pulsed wave and measure the complete complex second-order coherence function of the input fields without bringing them together from separate locations. Moreover, we discuss how to improve the signal level by using the more realistic continuous wave broadband anti-bunched light fields as the reference field. Our investigations pave the way for developing new technology of remote sensing and coherent imaging.
Nickel-plated SiCp/Al composites brazed in the air: Microstructure and mechanical properties of brazed joints under different processes
Authors: Qiu Dechao , Cheng Dongfeng , Niu Jitai , Ba Xianli , Brnic Josip 
Published: November 2023

Abstract

55% SiCp/ZL102 composites were surface metalized by electroless nickel plating. The Al-17Cu-8Mg-2Ni as-cast brazing alloy was treated by an ultra-cold thin strip system using a melt-spinning machine to realize the redistribution of solutes. The obtained foil-like brazing alloy has better flexibility, more uniform element distribution, and higher free energy than the as-cast brazing alloy. The 55% SiCp/ZL102 composites after nickel plating were brazed by different brazing processes in the air. The Ni-P coating effectively inhibited the formation of alumina film on the composite surface. However, the presence of an oxide layer on the foil filler caused a negative effect on the Ni-P coating and hindered the diffusion between elements. SiC, Ni2Al3, and other phases were detected in the joint port. The characteristic morphologies such as furrows and massive particles indicated that the fracture behavior is brittle fracture. The maximum shear strength of the joint was 88.31 MPa at 590°C.