bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of Jean-Paul Zahn discoveries on rotation and evolution
Authors: Maeder A. , Meynet G.
Published: June 2019

We first review the main effects of stellar rotation on evolution along the fundamental discoveries by Jean-Paul. Then, we examine some of the consequences of rotation in the evolution of single and binary stars. The proper account of meridional circulation in close binaries tends to increase the synchronization time because meridional currents always counteract the tidal interaction. We consider the case of the very low metallicity Z stars, in particular the CEMP-no stars, where rotational mixing may have played a dominant role in their strange chemical composition. Then, turning to “What are the mysteries?”, we emphasize that all over the evolution and for various masses the present models seem to still have a lack of rotational coupling between cores and envelopes. We suggest that magnetic fields may produce this missing internal coupling.
Vertical shear mixing in stellar radiative zones
Authors: Prat V. , Guilet J. , Vialler M. , Müller E.
Published: June 2019

Jean-Paul Zahn’s formalism for vertical shear mixing is used in several stellar evolution codes, but the physics of the shear instability in stellar radiative zones is still not completely understood. Over the last few years, numerical simulations have provided new constraints on the shear instability, including the effect of thermal diffusion and chemical stratification. We present here new simulations that show the effect of viscosity on the vertical turbulent transport due to the shear instability.
Spin evolution and saturation: new insights through 3D MHD simulations of young solar analogs
Authors: Réville V. , Brun A.S.
Published: June 2019

We examine how 3D MHD simulations can deliver clues on the mechanisms at the origin of angular momentum loss saturation of rapidly rotating solar-like stars. Based on a study of six targets, whose magnetic field has been observed by Zeeman Doppler Imaging (ZDI), we find that the saturation could be explained by a extremely strong coverage of the stellar surface of a large scale dipolar mode, in disagreement with recent works.
A brief history of our perception of the solar tachocline
Authors: Gough D.
Published: June 2019

I tell just part of the story of the quest to understand the dynamics of the solar tachocline, from the point of view of my relationship with my good friend Jean-Paul Zahn.
On the stability of a general magnetic field topology in stellar radiative zones
Authors: Augustson K. , Mathis S. , Strugarek A.
Published: June 2019

This paper provides a brief overview of the formation of stellar fossil magnetic fields and what potential instabilities may occur given certain configurations of the magnetic field. One such instability is the purely magnetic Tayler instability, which can occur for poloidal, toroidal, and mixed poloidal-toroidal axisymmetric magnetic field configurations. However, most of the magnetic field configurations observed at the surface of massive stars are non-axisymmetric. Thus, extending earlier studies in spherical geometry, we introduce a formulation for the global change in the potential energy contained in a convectively-stable region for both axisymmetric and non-axisymmetric magnetic fields.
Growth of eccentricity in planet-disc interactions
Authors: Teyssandier J. , Ogilvie G.
Published: June 2019

The origin and wide distribution of eccentricities in planetary systems remains to be explained, in particular in the context of planet-disc interactions. Here we present a set of linear equations that describe the behavior of small eccentricities in a protoplanetary system consisting of a gaseous disc and a planet. Eccentricity propagates through the disc by means of pressure, and is exchanged with the planet via secular interactions. Excitation and damping of eccentricity can occur through Lindblad and corotation resonances, as well as viscosity. Three-dimensional effects allow for an eccentric mode to be trapped in the inner parts of the disc. This eccentric mode can easily grow within the disc's lifetime. An eccentric mode dominated by the planet can also grow, although less rapidly. Application to a hot Jupiter surrounded by a gaseous disc suggests that the eccentricity of the planet can grow. Finally, the linear theory is compared to hydrodynamical simulations, and a very good agreement is found.
Impfung empfohlen – Hepatitis
Authors: Baumgärtner Martina
Published: June 2019

Es ist nicht auszuschließen, dass Physiotherapeuten bei der Behandlung mit einer offenen Wunde, Urin oder Speichel in Kontakt kommen. Viele Infektionskrankheiten wie Hepatitis übertragen sich auf diesem Weg. Weil das ernste Folgen haben kann, ist es wichtig, sich mit der Krankheit und den richtigen Schutzmaßnahmen auseinanderzusetzen.
Mondbein durch Bewegung regenerieren – Therapie bei Morbus Kienböck
Authors: Fischer Marion
Published: June 2019

Bei Morbus Kienböck handelt es sich um eine seltene Knochennekrose des Os lunatum – Ursache unklar. Bislang erfolgt die konservative Therapie in Form von Ruhigstellung. Dies führt jedoch zu negativen Folgen für alle Strukturen. Marion Fischer entwickelte ein neues Therapiemanagement, bei dem der Patient das Handgelenk begrenzt bewegt, um die Kompression des Mondbeins zu vermeiden und seine Ernährung zu verbessern.
Filamentation of capacitively coupled plasmas in large magnetic fields
Authors: Menati Mohamad , Thomas Edward , Kushner Mark J.
Published: June 2019

Over the last decade, dusty plasma research has sought to explore the physics of magnetized dusty plasmas. Due to the small charge-to-mass ratio of micron-sized dust grains, magnetic fields of B ≥ 1 T are needed to magnetize these particles. A peculiar phenomenon that occurs in capacitively coupled, glow discharge dusty plasmas at high magnetic fields that are perpendicular to the electrodes is the formation of stationary or mobile filamentary structures that are aligned along the magnetic field. In experiments, these filaments are found to form at a low neutral gas pressure, low applied radio frequency power, and a high magnetic field. This paper reports on new simulations of capacitively coupled plasmas at a high magnetic field for a configuration with a powered metal electrode and a grounded electrode with a dielectric barrier. It is shown that for this configuration, it is possible to form filamentary structures that appear in the electron density, potential, and light emission, which have properties that scale qualitatively with experiments. For these conditions, the dielectric strength of the boundary is most strongly correlated with the formation of the filaments. Implications of these observations and how they could be used to motivate future experiments are discussed.
Optimizing contact area geometry and taper composition in microknot resonators
Authors: Blank Alexandra , Linzon Yoav
Published: June 2019

We performed a comprehensive numerical study of the photonic transmission in manually prepared microknot resonators with different contact coupling area geometries and refractive index variations. A quantitative comparison between historical and state-of-the-art quality-factor values achieved in microring, microloop, and microknot resonators is included. In selective modifications of the microknot coupling area shape and the refractive index profile, we have studied the microknot transmission characteristics. A recipe for the experimental realization of a 4-fold increase of values in microknot resonators is prescribed, where resonance parameters are beneficial for sensing applications, both in physical (temperature and refractive index) and in chemical (humidity and other gas components) characterizations.
Non-volatility using materials with only volatile properties: Vertically integrated magnetoelectric heterostructures and their potential for multi-level-cell devices
Authors: Tang Xiao , Gao Min , Leung Chung Ming , Luo Haosu , Li Jiefang , Viehland Dwight
Published: June 2019

Different (1–3) heterostructures, such as BiFeO3-CoFe2O4 and BiFeO3-CuFe2O4 on Pb(Mg1/3Nb2/3)0.74Ti0.26O3 (PMN-26PT), were selected for study as possible materials for magnetoelectric (ME) random access memory. The (1–3) heterostructures were deposited, and multimagnetic states were found under different E-field (E) conditions. Upon removal of E, two possible remnant magnetization states remained stable. If an H-field (H) was also applied, two additional stable remnant magnetization states were found. Our investigations demonstrate (1–3) heterostructures with nonvolatility even though the individual phases/substrates had only volatile properties. This simplifies materials selection for multistate systems based on these heterostructures, averting difficulties with compositional nonuniformity and property repeatability, in particular, with regard to PMN-xPT crystal substrates. With such N≥4 magnetic state systems, a multilevel-cell memory device could readily be built with high ME coupling and numerous accessible magnetic states.
Analysis and simulation of the multiple resistive switching modes occurring in HfOx-based resistive random access memories using memdiodes
Authors: Petzold S. , Miranda E. , Sharath S. U. , Muñoz-Gorriz J. , Vogel T. , Piros E. , Kaiser N. , Eilhardt R. , Zintler A. , Molina-Luna L. , Suñé J. , Alff L.
Published: June 2019

In this work, analysis and simulation of all experimentally observed switching modes in hafnium oxide based resistive random access memories are carried out using a simplified electrical conduction model. To achieve switching mode variation, two metal-insulator-metal cells with identical stack combination, but varying oxygen stoichiometry of the hafnia layer, namely, stoichiometric vs highly deficient, are considered. To access the individual switching modes, the devices were subjected to a variety of cycling conditions comprising different voltage and current ranges. For modeling the device behavior, a single or two antiserially connected memdiodes (diode with memory) were utilized. In this way, successful compact simulation of unipolar, bipolar, threshold, and complementary resistive switching modes is accomplished confirming the coexistence of two switching mechanisms of opposite polarity as the basis for all observable switching phenomena in this material. We show that only calibration of the outer current–voltage loops with the memdiode model is necessary for predicting the device behavior in the defined region revealing additional information on the switching process. The correspondence of each memdiode device with the conduction characteristics of the individual top and bottom metal-oxide contacts allows one to assess the role played by each interface in the switching process separately. This identification paves the path for a future improvement of the device performance and functionality by means of appropriate interface engineering.
Charge and energy transfer in large molecular assemblies: Quantum state diffusion with an adaptive basis
Authors: Gao Xing , Eisfeld Alexander
Published: June 2019

We show that the stochastic, wave-function based quantum state diffusion approach in combination with an adaptive basis is well suited to numerically treat the motion of an excitation in large molecular aggregates in the complicated regime where the transfer-time between molecules is comparable to the decoherence caused by environmental degrees of freedom.
Effects of glassing matrix deuteration on the relaxation properties of hyperpolarized 13C spins and free radical electrons at cryogenic temperatures
Authors: Parish Christopher , Niedbalski Peter , Wang Qing , Khashami Fatemeh , Hayati Zahra , Liu Mengtian , Song Likai , Lumata Lloyd
Published: June 2019

Glassing matrix deuteration could be a beneficial sample preparation method for 13C dynamic nuclear polarization (DNP) when large electron paramagnetic resonance (EPR) width free radicals are used. However, it could yield the opposite DNP effect when samples are doped with small EPR width free radicals. Herein, we have investigated the influence of solvent deuteration on the 13C nuclear and electron relaxation that go along with the effects on 13C DNP intensities at 3.35 T and 1.2 K. For 13C DNP samples doped with trityl OX063, the 13C DNP signals decreased significantly when the protons are replaced by deuterons in glycerol:water or DMSO:water solvents. Meanwhile, the corresponding solid-state 13C T1 relaxation times of trityl OX063-doped samples generally increased upon solvent deuteration. On the other hand, 13C DNP signals improved by a factor of ∼1.5 to 2 upon solvent deuteration of samples doped with 4-oxo-TEMPO. Despite this 13C DNP increase, there were no significant differences recorded in 13C T1 values of TEMPO-doped samples with nondeuterated or fully deuterated glassing matrices. While solvent deuteration appears to have a negligible effect on the electron T1 relaxation of both free radicals, the electron T2 relaxation times of these two free radicals generally increased upon solvent deuteration. These overall results suggest that while the solid-phase 13C DNP signals are dependent upon the changes in total nuclear Zeeman heat capacity, the 13C relaxation effects are related to 2H/1H nuclear spin diffusion-assisted 13C polarization leakage in addition to the dominant paramagnetic relaxation contribution of free radical centers.
Water dynamics in the hydration shells of biological and non-biological polymers
Authors: Cerveny Silvina , Swenson Jan
Published: June 2019

The dynamics of water at supercooled temperatures in aqueous solutions of different types of solutes has been deeply analyzed in the literature. In these previous works and in most of the cases, a single relaxation of water molecules is observed. In this work, we analyze the dynamics of water in solutions for which a dual relaxation of water molecules is experimentally measured. We discuss the criteria for observing these two water relaxations in these specific solutions and their most likely origins. We also discuss how these two water relaxations relate to the relaxation behavior of bulk water and how the slower one is coupled to the solute dynamics and is essential for the dynamics and functional properties of proteins.
High-speed imaging system to visualize particle removal/collection via wipe sampling and aerodynamic sampling
Authors: Staymates Matthew , Gillen Greg , Staymates Jessica
Published: June 2019

This work describes a high-speed imaging system that enables the microscopic visualization of the removal and collection of micrometer-sized particles from surfaces during wipe sampling and aerodynamic sampling events. The system features a high-speed digital camera, microlens, custom sample mount and sampling sled, and an illumination source. This imaging system enables direct visualization of wipe-particle and particle-particle interactions during sampling and provides insights relevant to the dynamics of particle removal and collection. Examples of common and adhesive-modified wipe materials sampling polymer microspheres and an explosive-laden fingerprint are given, along with visualization of particle removal via air jet impingement.
Giant negative magnetoresistance and kinetic arrest of first-order ferrimagnetic-antiferromagnetic transition in Ge doped Mn2Sb
Authors: Singh Vikram , Karmakar Suman , Rawat R. , Kushwaha Pallavi
Published: June 2019

The effect of partial substitution of Ge for Sb on the first-order ferrimagnetic (FRI)–antiferromagnetic (AFM) transition in Mn2Sb has been studied. It shows that the transition temperature (Tt) can be tuned between 119 K and 271 K by substituting 2.5%–10% Ge at Sb sites in Mn2Sb. The variation of density of state at the Fermi level N(Ef) with Ge substitution shows that dN(E)/dE is positive at Ef in the AFM state. With the application of a magnetic field, Tt shifts to low temperature, which results in a giant negative magnetoresistance (MR) reaching a value of 70% for 2.5% substitution. Our results show that FRI to AFM transformation during cooling stops around 35 K, even though it remains incomplete. This, along with the nonmonotonic variation of lower critical field, open loop in isothermal MR, and increasing difference in zero field cooled warming and field cooled warming resistivity with increasing magnetic field, shows that the FRI to AFM transition is kinetically arrested in the case of 2.5% Ge substitution.
Superconducting flux pumps
Authors: Coombs T. A.
Published: June 2019

This paper presents a perspective on flux pumps. Flux pumps are a means of providing current to a coil or a magnet without direct electrical or physical contact. Typically, a coil would be charged directly using current leads, which would then be withdrawn if the magnets operated in the persistent mode (as with magnetic resonance imaging) or left in place if the field required maintenance or ramping. Flux pumps use the principle of magnetic induction. They present two distinct advantages. The first is that there is no direct connection to the external world and, therefore, no associated heat loss. The second is that, although high current can be developed in the magnet or the coil, these can be produced without the need for high-current power supplies, which are bulky and expensive. Flux pumps are especially appropriate for machines constructed from high temperature superconductors (HTSs). They facilitate the full use of the HTS’s current carrying capability, cheaply and simply, enabling smaller, lighter, and more powerful magnets, motors, and generators.
Nonlinear oscillatory fully-developed rarefied gas flow in plane geometry
Authors: Tsimpoukis A. , Vasileiadis N. , Tatsios G. , Valougeorgis D.
Published: June 2019

The nonlinear oscillatory fully developed rarefied gas flow between parallel plates due to an external harmonic force is investigated by the Direct Simulation Monte Carlo (DSMC) method in terms of the parameters characterizing the flow, namely, the gas rarefaction and oscillation parameters, and the force amplitude. The results are in dimensionless form and include the axial velocity, temperature, pressure, wall shear stress, and heat flow vector, as well as the flow rate, cycle-averaged wall shear stress, space-averaged axial heat flow, and pumping power. Even with large force amplitudes, all macroscopic distributions have a sinusoidal pattern with their fundamental frequency being the same with the driving frequency of the external force without the appearance of other harmonics, except of the axial heat flow where the nonlinearities are responsible for generating oscillatory motion containing several harmonics. Nonlinear effects are becoming more significant in highly rarefied flows and low oscillation frequencies. The temperature profile, including the bimodal shape encountered in steady-state flows in the continuum limit, strongly depends on the gas rarefaction and oscillation parameters. The DSMC results have been compared with the corresponding linear oscillatory results, available in the literature, to find out that at small and moderate external forces, the agreement between DSMC and linear flow rates is very good and always remain less than 10%, while at large external forces, the deviation in the flow rate amplitude reaches about 25%. The cycle-averaged oscillatory pumping power is not zero and smaller than the corresponding linear one, following the trend of the flow rates.
Design of singlet fission chromophores with cyclic (alkyl)(amino) carbene building blocks
Authors: Japahuge Achini , Lee Seunghoon , Choi Cheol Ho , Zeng Tao
Published: June 2019

We use MRSF-TDDFT and NEVPT2 methods to design singlet fission chromophores with the building blocks of cyclic (alkyl)(amino)carbenes (CAACs). CAAC dimers with C2, C4, and p-phenylene spacers are considered. The substitutions with trifluoromethyls and fluorine atoms at the α C position are investigated. The electronegative substituents enhance the π accepting capability of the α C while maintaining it as a quaternary C atom. The phenylene-connected dimers with the two substitutions are identified as promising candidates for singlet fission chromophores. The cylindrically symmetric C2 and C4 spacers allow for substantial structural reorganizations in the S0-to-S1 and S0-to-T1 excitations. Although the two substituted dimers with the C4 spacer satisfy (or very close to satisfy) the primary thermodynamics criterion for singlet fission, the significant structural reorganizations result in high barriers so that the fission is kinetically unfavorable.
A simplified semi-analytical model for the filling and cooling process in plastic molding
Authors: Mollaabbasi R. , Behzadfar E. , Taghavi S.M.
Published: June 2019

The effects of the operational conditions on the filling and cooling process in plastic molding are studied. First, a semianalytical model is developed to study the effects of thermal boundary conditions and imposed pressure on the velocity profile and blocking time in the filling stage of the molding process. To do so, a lubrication approximation type model is developed in which the shear viscous heating terms are neglected to simplify the governing equations. Using an equipped mold, molding experiments are conducted to validate the model predictions by using a well-controlled injection molding machine. Comparing the model and experimental results shows a reasonable agreement among them. Second, regarding the cooling process, a modified Avrami equation is used to capture the polymer crystallization in variable cooling rates. The model results show that the cooling time and the final solid fraction decrease by increasing the cooling rate.
Offshore data acquisition in shallow water: challenges and opportunities
Authors: Molyneux Simon J. , Jarvis Samantha , Dirstein James K.
Published: June 2019

The acquisition of geophysical data, in particular conventional marine seismic, in areas of shallow water (<20 m) has always been challenging in terms of cost, quality and permitting. A heightened sensitivity about the possible environmental impact of conventional marine seismic has made achieving environmental approval of marine seismic activity in water depths up to 60 m challenging in Australia. In this paper, a suggestion is made to re-frame permit work programs around in-permit mobilisations where impact to the exploration assessment is maximised, and environmental disturbance is minimised. This approach will be illustrated through a discussion of (1) recent approved Australian environmental plans and water depth issues and a good practice approach to permitting of shallow water seismic acquisition using the Zenaide 3D and Bethany 3D as examples, and (2) alternatives to conventional marine seismic acquisition, including an articulation of the technical strengths and weaknesses alongside a consideration of alternative approaches from an environmental, work program and regulatory point of view.
Technical safety: use of concept risk assessment for field development certainty
Authors: Crowley Colin , Ashton Dave
Published: June 2019

As technology advances and field development possibilities grow, the need for earlier guidance on the safety performance of concept designs is greater than ever. The SNC-Lavalin concept risk assessment (CRA) tool is a transparent and rapidly deployable model that is based on sound, industry-accepted quantitative risk assessment (QRA) principles. From the earliest stages of field development, when conceptualisation may be vague and data sparse, a wide range and variety of design options can still be assessed effectively and ranked on their safety performance. The CRA tool is proprietary software initially developed with BP and Shell. The model was first calibrated against 10 detailed QRAs, but is regularly benchmarked and updated with the most current failure rate data and has been used on nearly 50 projects globally. The database now incorporates established rule sets from hundreds of detailed QRAs performed, including floating liquefied natural gas and floating storage regasification units. This paper presents a CRA case study for a generic remote offshore field with a range of development options from conventional to minimal offshore facilities. The model calculates the associated risks for the options considered and is presented in terms of individual risk per annum, temporary refuge impairment frequency and potential loss of life. The results highlight the effects of each individual design feature on risk levels by comparison of similar options side by side, noting the main risk contributors and allowing investigation of the benefits of risk reduction measures. This enables identification of the best design features from each of the options and allows an optimised design to be carried forward.
How can we reduce the environmental impact of marine seismic surveys?
Authors: Long Andrew , Bastard Mickael , Asgedom Endrias , Wisløff Jens Fredrik , Christiansen Magnus
Published: June 2019

Marine seismic sources emit acoustic energy in the form of the seismic wavefield used for the remote sensing of subsurface impedance contrasts in the earth. The environmental impact of seismic sources is typically measured in terms of impulsive acoustic pressure (the sound pressure level, SPL) and the accumulated acoustic energy (the sound exposure level, SEL). We use global examples of the following marine source concepts to quantify the relative SPL and SEL in each scenario:
• Large arrays of air guns activated simultaneously with no significant overlap in emitted acoustic pressure,
• Small arrays of air guns activated simultaneously or in rapid succession with overlap in emitted acoustic pressure,
• Individual air guns activated continuously with overlap in emitted acoustic pressure, and
• Towed marine vibrators operated continuously.
Continuous sources clearly have the lowest SPL and SEL. Examples from various basin settings are shown where benefits in data quality and survey efficiency may also complement the lower environmental impact. Another surprising geophysical outcome is that continuous sources with low SPL do not have compromised signal penetration to deep target depths compared to traditional large arrays of air guns activated simultaneously. These outcomes are relevant to how future marine seismic surveys might be designed to meet stricter environmental controls as well as presenting various new opportunities for how the surveys could be acquired more efficiently and processed.
The hardy perennials of maintenance
Authors: Clegg Neil
Published: June 2019

This paper is about the maintenance of safety critical elements on oil and gas facilities. Different approaches can be applied to design the appropriate maintenance plans that will ensure the availability of safety critical barriers. The challenge and opportunity for maintenance engineers today is to apply their knowledge and experience to improve the issues that are already known to exist with the current approaches for maintaining safety critical elements. Additionally, collaboration is required between operators, regulators and the standard-setting authorities to ensure that the appropriate application of risk-based approaches to maintenance are being endorsed. The two examples considered in the paper are the maintenance and testing of firefighting water-deluge systems and lifeboats (TEMPSC). Overall, improvements using risk-based approaches to maintenance will lead to safer operations, more consistency in maintenance plans, greater alignment between standards and practice, and reduced costs.
Integration of biostratigraphy into a sequence stratigraphic framework for the Surat Basin, eastern Australia
Authors: de Andrade Vieira Filho Claudio L. , Reilly Mark , Hurter Suzanne , Hamerli Zsolt
Published: June 2019

A new sequence stratigraphic framework (SSF) for the Early–Late Jurassic Surat Basin, eastern Australia, is evolving. A second and third order framework based upon an integrated methodology of well-to-well correlations supported by well tied seismic data is being developed. The integration of an additional dataset (palynology) to test for regionally consistent sequence stratigraphic well correlations offers an improvement in defining sequence boundaries related to the geological timescale. The palynological data from 33 wells covering the north-east Surat Basin were extracted from the Queensland Digital Exploration (QDEX) open-file reports, some of which date back to the 1960s. These data were correlated and superposed on the SSF for age comparison. The dataset used in this study represents only a subset of all existing palynology information, as not all data are captured in QDEX. However, the palynology data in this exploratory study generally fits and supports the new SSF with only one exception, the reason for which is not understood at this stage. We recommend expanding this study to include more data because palynology can support stratigraphic interpretation, especially in wells that do not intercept, or have log data across, regional datums.
Prediction of groundwater impacts from coal seam gas extraction in the Surat Basin
Authors: Phillipson Keith
Published: June 2019

The Queensland regulatory framework recognises that the impacts of groundwater extraction activities can overlap in areas of concentrated development. Such areas of overlapping impacts can be declared ‘cumulative management areas’ (CMAs). When a CMA is established, the Office of Groundwater Impact Assessment (OGIA) becomes responsible for carrying out a cumulative impact assessment and preparing an Underground Water Impact Report (UWIR). The Surat CMA was declared in March 2011, and since this time, two iterations of the UWIR have been published in 2012 and 2016, underpinned by a gradually evolving regional groundwater flow model. This case study presentation will examine a number novel features of the regional groundwater flow model, resulting from OGIA’s ongoing research and development program, including the development of an adapted version of the MODFLOW-USG groundwater flow modelling code and approximation of coal desaturation and dual-phase flow effects using a modified van Genuchten function. The presentation will also look at the simulation of CSG extraction using a ‘descending drain’ methodology that recognises the gas-filled nature of CSG wells and generating up-scaled properties of highly heterogenous sedimentary material by first generating stochastic realisations of fragments of these layers, and then using ‘numerical permeameters’ to determine both the expected value and stochasticity of these properties, at the regional scale.
Managing well integrity in Queensland
Authors: Scott Michael P.
Published: June 2019

A significant increase in activity in the Queensland petroleum industry began around 2005 with the rapid growth of coal seam gas developments. The integrity of these drilled wells is paramount to the continued safe operation of the Queensland petroleum industry, ensuring no detrimental effect to safety, health and environment. The Queensland Petroleum and Gas Inspectorate (PGI) is responsible for monitoring industry compliance with well integrity management requirements under the regulatory framework. This is achieved through three proactive actions (engagement, inspections, audits) and three reactive actions (response to enquiries, complaints, incidents). This paper focuses on the well inspections and audits conducted by the PGI. The PGI conducts an annual program of well inspections as part of its risk-based compliance program. These inspections are in addition to the inspections performed by industry. Although recent inspections have found well integrity-related deficiencies requiring rectification, no major or systemic problems have been identified. In fact, industry generally appears to be proactively addressing any deficiencies they find through their own well integrity management processes. The PGI is in the process of ensuring a renewed focus on well integrity during its own well inspections through structured and standardised inspections that have clear aims. This is part of a continuous improvement process and is a risk-based decision informed by the data that have been gathered. This will help ensure the program is not simply focused on quantity of inspections, but also on outcomes and quality. To complement the well inspection program, several audits have been conducted over the past 4–5 years. As part of this, in the first quarter of 2019, the PGI began conducting audits of the well integrity management systems (WIMS) of the four major coal seam gas producers. The results of this audit show improvement in both WIMS documentation and the implementation of those systems. Future PGI work in this area includes continuing with the recent audit programs, reviewing inspection processes and a plan to increase focus on plug and abandoned wells over the next 18 months.
Finding a home for Australian LNG in developing power markets
Authors: Henderson Craig , Miller David
Published: June 2019

Recent energy market trends have opened the opportunity to exploit Australian liquefied natural gas (LNG) as a cost-competitive fuel source for power projects in developing markets. Regrettably, having favourable market conditions does not automatically lend itself to projects getting sanctioned and being successful. It is fair to say that the number of projects up and running in the current market is less than expected. This paper aims to explore some of the key reasons why LNG to power projects fail to become a reality and what Australian LNG producers could do to achieve their ambition of creating new markets to sell their LNG into. The paper concludes by outlining several development approaches that are being used in industry and how Australian LNG suppliers can partake in these approaches by standing out from the crowd, framing the opportunity, aligning agreements to the capability of the technology and understanding scale and industrial ecologies.
Some economic estimates of gas-fired power generation in a carbon constrained Australia
Authors: McConnell Chai H. , Dorgelo Christian
Published: June 2019

The future of Australia’s electricity industry has resulted in significant debate about the mix of electricity generating technologies. The Finkel Review and ensuing National Electricity Guarantee policy discussion have revealed divisions between key stakeholders over the future generating mix between renewable and fossil fuel power generation options. A portfolio of technologies will be required, including the need for gas-fired power generation with and without carbon capture and storage (CCS), to provide dispatchable synchronous electricity. Gas Vision 2050 has stated that CCS, along with biogas and hydrogen, will be one of the three transformational technologies affecting the gas industry going forward. Through the use of a techno-economic model, the costs for a hypothetical new-build gas-fired power plant in the Hunter Valley with and without CCS were estimated. The model is cross referenced with other authoritative publications including the CO2CRC Australian Power Generation Technology Report. The model considers the base-case scenario and sensitivity analysis of key cost drivers such as the domestic gas price and labour. The results of the model will enable key energy and gas industry stakeholders to make informed decisions about the vital role of gas as a power generation technology in Australia to deliver dispatchable synchronous electricity in a carbon constrained environment.
SEAR JIP: the value of sharing of lessons learned on subsea integrity and reliability
Authors: Botto Adriana
Published: June 2019

The award-winning Subsea Equipment Australian Reliability (SEAR) Joint Industry Project (JIP) is a partnership led by Wood and has participation of a group of OGAS Operators namely Chevron Australia, ConocoPhillips, Inpex, Quadrant, Shell Australia and Woodside. Now delivering Phase 6, the JIP is focused on collaboration and knowledge sharing, so as to improve the competitiveness of Australia’s oil and gas sector by addressing critical challenges associated with equipment that is failing prematurely subsea. The SEAR JIP was initiated in 2014 and has since developed a reliability database to collect failure information from SEAR members with Australian offshore operations. The SEAR database provides a low cost–high value method of capturing and sharing failures and lessons learnt for Australia. Over the years, the JIP has focused on different but common industry challenges, such as the impact of marine fouling affecting operability during interventions. To address this challenge, the JIP is deploying ‘living laboratories’ at different geographical locations and water depths across various Australian waters, in collaboration with suppliers and local universities to identify game-changing technology. The ability to better understand failures and intervention requirements has the potential to offer operators significant cost savings, by optimising equipment reliability and availability. This paper will provide an overview of SEAR JIP and outlines lessons learned and value created, and discusses how a similar collaborative approach can create value in other parts of the Australian LNG value chain.
Integrated activity planning: a proven approach to optimising operations outcomes
Authors: Farrell Bradley , Mulgund Vikrant
Published: June 2019

Integrated activity planning (IAP) is a proven approach for dealing with complexity and uncertainty when operating complex production systems. IAP is driven by the need to deliver on production forecasts, optimise the decision making for the planning, scheduling and execution of activities impacting production, mitigate the risk associated with major shutdowns or bringing capital projects online and optimise interfaces to allow engineering, supply, maintenance and operations to work together seamlessly. Planning is typically spread across several time horizons, including long-term strategic business plans, medium-term program plans and short-term maintenance plans and operational activity scheduling. This paper provides a definition of IAP, a description of its value, a detailed case study from one of the world’s leading IAP implementations and a series of lessons learned.
Darwin Harbour – a partnership approach to understanding and evaluating environmental challenges
Authors: Brinkman Richard , Butler Edward , O'Connor Terry , Streten Claire
Published: June 2019

Darwin Port plays a critical role in the Northern Territory’s export-oriented economy and in supporting the economy of northern Australia more generally. Darwin Port is the only true multi-modal port in northern Australia, with direct connectivity to southern Australia and beyond via the southern rail link. The port has developed rapidly over the past decades, with redevelopment of the Waterfront Precinct, development of numerous residential marinas, construction of the East Arm Wharf and marine supply base, and construction and operation of liquefied gas processing and export facilities. Future development plans include Middle Arm Industrial Precinct and Marine Industry Park. These developments have resulted in an order of magnitude increase in dredging requirements, an increase in vessel traffic and an increase in public focus on environmental quality within the harbour. A coordinated, multi-agency approach to understand the complex marine environment of Darwin Harbour has underpinned much of the development activity and provided a sound scientific basis to evaluate potential environmental impacts associate with past and future developments. Through a hierarchical process of environmental assessment and identification and mitigation potential risks, the Australian Institute of Marine Science has partnered with industry, government and other research providers to deliver projects to map and assess habitats, monitor environmental attributes and evaluate potential impacts, and provide environmental information in novel and accessible ways to support harbour operations and inform strategic planning. The partnership approach adopted for Darwin Harbour serves as a model for leveraging resources to understand and manage environmental and operational risks in northern ports.
Integrating multi-disciplinary data for building fit-for-purpose 3D mechanical earth model
Authors: Boothby Peter G. , Puspitasari Ratih , Thakur Sanjay , Pallikathekathil Zachariah John , Walton Chris
Published: June 2019

Understanding the influence of geomechanics early in the field development phase facilitates reservoir management planning. To capture complex geology and associated field development, a 3D mechanical earth model (3D MEM) with finite element method (FEM) approach was selected to analyse the geomechanical-related risks associated with two fields in the North West Shelf, Australia. The 3D MEMs were constructed using geological static models, and seismic-derived horizons and faults. The 3D properties were propagated based on core-calibrated 1D properties and controlled by stratigraphy, 3D facies and seismic inversion volumes. The FEM was used to calculate the equilibrium of stresses and strains within the 3D MEMs. The 3D properties and pre-production stresses were validated in blind test wells before forward modelling. The 3D MEMs were linked to the dynamic reservoir models to capture the pressure evolution throughout the field lifecycle. The results were used to analyse the risks associated with compaction, subsidence, fault instability, completion integrity and drilling stability of infill wells through depleted reservoirs. The results provided insight in managing the risk early in field development stage. The study’s largest challenge was integrating a large volume of data to ensure that the structural complexity and rock heterogeneity were captured and consistent with the geological understanding of the field. A multi-disciplinary team of earth scientists and reservoir and geomechanics engineers worked together, and the value of data integration, good communication and teamwork were key success factors. Lessons learned and best practices were captured throughout the study and provided valuable feedback for future works.
Forecasting growth of the Australian unconventional oil and gas services market
Authors: Carbrey Ryan
Published: June 2019

This paper examines the unconventional oil and gas oilfield services market in Australia. First, the paper gives an activity forecast through to 2025 on how many wells are expected to be completed. The paper looks at how the geology, supply chain, infrastructure, finance and other constraints compare to the Vaca Muerta in Argentina and the Permian in the United States. Finally, the paper looks at the completive landscape and supply demand balance of the frac services market within Australia.
Blue hydrogen production: a case study to quantify the reduction in CO2 emission in a steam methane reformer based hydrogen plant
Authors: Kritzinger Niel , Ravikumar Ravi , Singhal Sunil , Johnson Katie , Singh Kakul
Published: June 2019

In Australia, and globally, hydrogen is primarily produced from natural gas via steam methane reforming. This process also produces CO2, which is typically vented to the atmosphere. Under this configuration, the hydrogen produced is known as grey hydrogen (carbon producing). However, if the CO2 from this process is captured and stored after it is produced, the hydrogen product is CO2-neutral, or ‘blue hydrogen’. To enable production of blue hydrogen from existing natural gas steam methane reformers (SMRs) in Australia, gasification of biomass/bio waste can be utilised to produce fuel gas for use in a SMR-based hydrogen plant, and the CO2 in the shifted syngas can be removed as pure CO2 either for sequestration, enhanced oil recovery, or enhanced coal bed methane recovery. Australian liquefied natural gas that is exported and utilised as feedstock to existing SMRs in other countries can incorporate carbon emission reduction techniques for blue hydrogen production. The use of bio-derived syngas as fuel will generate hydrogen with only bio-derived CO2 emissions. Additional carbon credit can be obtained by replacing petrol or diesel consuming automobiles with fuel cell vehicles powered by hydrogen derived from gasification of biomass.
Geological and bioregional assessments – enabling future tight, shale and deep coal gas development – Cooper Basin case study
Authors: Robinson David , Gunning Merrie-Ellen , Evans Tim , Hall Lisa , Sundaram Baskaran , Swirepik Anthony , Stacey Andrew , Dann Rodney , Holland Kate
Published: June 2019

The Australian Government’s Geological and Bioregional Assessment (GBA) Program is a series of independent scientific studies conducted by Geoscience Australia and CSIRO, supported by the Bureau of Meteorology and managed by the Department of the Environment and Energy. These studies focus on the Cooper, Isa and Beetaloo GBA regions, all of which include basins which are prospective, but under-explored, for shale, tight and/or deep coal gas. The GBA Program seeks to expedite development in order to bring new gas resources to the east coast gas market within the next 5–10 years through increased understanding of the potential environmental impacts posed by gas development and increasing the efficiency of assessment, monitoring and ongoing regulation, including improved data capture and reporting. This multi-agency program addresses the potential environmental impacts of gas development through geological and environmental baseline assessments and identification of major information gaps (Stage 2), followed by an analysis of the potential impacts on assets, including groundwater, surface water, environmental and cultural assets as well as Commonwealth and State matters of environmental significance (Stage 3). This paper will discuss how integrated conceptual models of the geology and hydrogeology of selected unconventional petroleum resources can be utilised by industry, regulators and other stakeholders. By establishing a baseline assessment for the Cooper Basin, which includes an integrated shale, tight and deep coal prospectivity and groundwater study, future development scenarios can be envisaged and the potential impact on groundwater and other resources contemplated. Similar baseline assessments and conceptual models are being developed for the Isa and Beetaloo GBA regions.
Competency framework: environmental approval specialists
Authors: Raitt Petrina , Fidgeon Stacey
Published: June 2019

Environmental approvals take time, and scheduling and planning for their preparation and submission should be high on the list of priorities when planning a project. Understanding the regulatory process and knowing what level of information is required at each stage is critical. Providing quality environmental support to the oil and gas industry requires not only an understanding of the range of petroleum activities and their potential impacts and risks, but extensive knowledge of environmental receptors in each operational area, an understanding of complex technical methods for impact and risk quantification and a solid understanding of relevant regulations with an ability to navigate complex approval processes.
A common environmental competency framework could support the industry to:
• identify gaps in skills and knowledge for individuals, teams or across industry sectors
• develop people across the broad range of skills they require
• recruit the right people into the right positions for more effective teams
• engage environmental professionals to encourage longevity in their careers
• develop learning and development solutions including mentoring and coaching opportunities that will have increased relevance to the industry.
Green Light Environmental have developed an internal environmental competency framework as a means of assessing and documenting competency for staff and contractors working under the Green Light Environmental brand. The framework consists of a series of competency standards that reflect the core responsibilities for environmental consultant resources during planning, construction, operation and decommissioning of petroleum activities. Each standard clearly identifies the knowledge and experience required to achieve competence and is supported by assessment tools. The adoption of a shared competency framework would further support the shared desire across industry, regulator and stakeholders to increase collaboration and transparency in environmental approval processes and documentation.