bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility of Nonanatomical Liver Resection in Diligently Selected Patients with Hepatoblastoma and Comparison of Outcomes with Anatomic Resection
Authors: Qureshi Sajid S. , Kembhavi Seema A. , Kazi Mufaddal , Smriti Vasundhara , Baheti Akshay , Vora Tushar , Chinnaswamy Girish , Prasad Maya , Amin Nayana , Ramadwar Mukta , Khanna Nehal , Laskar Sidharth
Published: May 2020

Introduction Treatment guidelines for hepatoblastoma discourage nonanatomic liver resections. However, the evidence for this is inadequate and comes from a study performed almost two decades ago which additionally contained inherent limitations. This study aimed to assess the feasibility and oncologic outcomes of nonanatomic resections (NAR) performed in diligently selected patients and compare the results with anatomic resections (AR).

Materials and Methods A total of 120 patients who underwent liver resections for hepatoblastoma between January 2008 and July 2019 were reviewed. Feasibility of NAR was based on postchemotherapy relations to vessels, site of the lesion, and possibility of achieving negative resection margins.

Results AR was performed in 95 patients and 25 had NAR. The NAR cohort had similar International Childhood Liver Tumors Strategy Group (SIOPEL) risk group distribution. Blood loss and operative times were lower in patients undergoing NAR. No differences were noted between the two groups concerning postoperative morbidity and hospitalization. There were no pathologic positive margins or local recurrences in the NAR patients. Relapse free (RFS) and overall survival (OS) was similar in the two groups (p = 0.54 and 0.96, respectively). Subgroup analysis of only posttreatment extent of tumor (POSTTEXT) I and II patients also showed no difference in RFS or OS for the two groups with a persistent significant difference in operative times and blood loss.

Conclusion NAR is feasible with clear margins in carefully selected patients. It is not associated with more complications and outcomes are not inferior to AR. NAR is associated with lesser blood loss and operative time.
Fifteen-Year Single-Center Experience of Biliary Complications in Liver Trauma Patients: Changes in the Management of Posttraumatic Bile Leak
Authors: Stonelake Stephen , Ali Sana , Pinkey Benjamin , Ong Evelyn , Anbarasan Ravindar , McGuirk Simon , Perera Thamera , Mirza Darius , Muiesan Paolo , Sharif Khalid
Published: May 2020

Introduction Management of posttraumatic bile leak has evolved over time in our unit, from endoscopic retrograde cholangiopancreatography (ERCP) stenting to intraperitoneal drainage (IPD) alone as first-line treatment for intraperitoneal bile leak.

Materials and Methods Retrospective review of liver trauma patients from 2002 to 2017. Demographics, time and mode of diagnosis of bile leak, management, and outcome were analyzed of the box plot.

Results In 118 patients, there were 28 traumatic bile leaks. Eighteen were free intraperitoneal and 10 were localized bilomas. The median time of diagnosis was 6 days following injury. The modes of diagnosis were preemptive hepatobiliary scintigraphy (18), computed tomography (CT) or ultrasound (7), and laparotomy (3). Free intraperitoneal biliary leak management included 11 IPD alone, 3 IPD plus ERCP, 2 IPD plus transcystic biliary stent (TBS), 1 operative cholangiogram, and 1 no intervention. Median time of IPD duration was 7 days (4–95) in IPD alone versus 14 days (6–40) in IPD + ERCP/TBS (p = 0.3). Median inpatient length of stay was 13 days (8–44) in IPD alone versus 12 days (8–22) in IPD + ERCP/TBS (p = 0.4).

Conclusion Placement of IPD alone, as first-line treatment, is safe and effective in the management of intraperitoneal bile leaks, avoiding the costs and potential complications of ERCP.
Inflammatory Bowel Disease and Thrombosis: A National Inpatient Sample Study
Authors: Cohen Jessica B. , Comer Diane M. , Yabes Jonathan G. , Ragni Margaret V.
Published: May 2020

Introduction Thrombosis is more common in inflammatory bowel disease (IBD) patients than the general population, but disease-specific correlates of thrombosis remain unclear.

Methods We performed a retrospective analysis of discharge data from the National Inpatient Sample between 2009 and 2014, using International Disease Classification codes to identify IBD and non-IBD patients with or without thrombosis. We used NIS-provided discharge-level weights to reflect prevalence estimates. Categoric variables were analyzed by Rao-Scott Chi-square test, continuous variables by weighted simple linear regression, and covariates associated with thrombosis by weighted multivariable logistic regression.

Results Thrombosis prevalence in IBD was significantly greater than in non-IBD, 7.52 versus 4.54%, p < 0.0001. IBD patients with thrombosis were older and more likely to be Caucasian than IBD without thrombosis, each p < 0.001. Thrombosis occurred most commonly in the mesenteric vein. Thrombotic risk factors in IBD include surgery, ports, malignancy, dehydration, malnutrition, and steroids at 53.7, 13.2, 13.1, 12.4, 8.9, and 8.2%, respectively. Those with thrombosis had greater severity of illness, 1.42 versus 0.96; length of stay, 7.7 versus 5.5 days; and mortality, 3.8 versus 1.5%; all p < 0.0001. Adjusting for age and comorbidity, odds ratios for predictors of thrombosis included ports, steroids, malnutrition, and malignancy at 1.73, 1.61, 1.34, and 1.13, respectively, while Asian race, 0.61, was protective, each p < 0.001.

Conclusion Thrombosis prevalence is 1.7-fold greater in IBD than non-IBD patients. Adjusting for age and comorbidity, the odds ratio for thrombosis in IBD was 73% higher with ports, 61% higher with steroids, 34% with malnutrition, and 13% with malignancy. Whether long-term anticoagulation would benefit the latter is unknown.
Thr90Ser Mutation in Antithrombin is Associated with Recurrent Thrombosis in a Heterozygous Carrier
Authors: Lu Yeling , Villoutreix Bruno O. , Biswas Indranil , Ding Qiulan , Wang Xuefeng , Rezaie Alireza R.
Published: May 2020

Antithrombin (AT) is a serine protease inhibitor that regulates the activity of coagulation proteases of both intrinsic and extrinsic pathways. We identified an AT-deficient patient with a heterozygous Thr90Ser (T90S) mutation who experiences recurrent venous thrombosis. To understand the molecular basis of the clotting defect, we expressed AT-T90S in mammalian cells, purified it to homogeneity, and characterized its properties in established kinetics, binding, and coagulation assays. The possible effect of mutation on the AT structure was also evaluated by molecular modeling. Results demonstrate the inhibitory activity of AT-T90S toward thrombin and factor Xa has been impaired three- to fivefold in both the absence and presence of heparin. The affinity of heparin for AT-T90S has been decreased by four- to fivefold. Kinetic analysis revealed the stoichiometry of AT-T90S inhibition of both thrombin and factor Xa has been elevated by three- to fourfold in both the absence and presence of heparin, suggesting that the reactivity of coagulation proteases with AT-T90S has been elevated in the substrate pathway. The anticoagulant activity of AT-T90S has been significantly impaired as analyzed in the AT-deficient plasma supplemented with AT-T90S. The anti-inflammatory effect of AT-T90S was also decreased. Structural analysis predicts the shorter side-chain of Ser in AT-T90S has a destabilizing effect on the structure of AT and/or the AT-protease complex, possibly increasing the size of an internal cavity and altering a hydrogen-bonding network that modulates conformations of the allosterically linked heparin-binding site and reactive center loop of the serpin. This mutational effect increases the reactivity of AT-T90S with coagulation proteases in the substrate pathway.
Homoclinic organization in the Hindmarsh–Rose model: A three parameter study
Authors: Barrio Roberto , Ibáñez Santiago , Pérez Lucía
Published: May 2020

Bursting phenomena are found in a wide variety of fast–slow systems. In this article, we consider the Hindmarsh–Rose neuron model, where, as it is known in the literature, there are homoclinic bifurcations involved in the bursting dynamics. However, the global homoclinic structure is far from being fully understood. Working in a three-parameter space, the results of our numerical analysis show a complex atlas of bifurcations, which extends from the singular limit to regions where a fast–slow perspective no longer applies. Based on this information, we propose a global theoretical description. Surfaces of codimension-one homoclinic bifurcations are exponentially close to each other in the fast–slow regime. Remarkably, explained by the specific properties of these surfaces, we show how the Hindmarsh–Rose model exhibits isolas of homoclinic bifurcations when appropriate two-dimensional slices are considered in the three-parameter space. On the other hand, these homoclinic bifurcation surfaces contain curves corresponding to parameter values where additional degeneracies are exhibited. These codimension-two bifurcation curves organize the bifurcations associated with the spike-adding process and they behave like the “spines-of-a-book,” gathering “pages” of bifurcations of periodic orbits. Depending on how the parameter space is explored, homoclinic phenomena may be absent or far away, but their organizing role in the bursting dynamics is beyond doubt, since the involved bifurcations are generated in them. This is shown in the global analysis and in the proposed theoretical scheme.
Characteristics of plasma window with various channel diameters for accelerator applications
Authors: Ikoma N. , Miyake Y. , Takahashi M. , Okuno H. , Namba S. , Takahashi K. , Sasaki T. , Kikuchi T.
Published: May 2020

Plasma window is a feasible device as an atmosphere–vacuum interface, which can withstand energetic particle beams. It is, however, essential to enlarge the diameter to several tens of millimeters for actual beam passing in the accelerator applications. The pressure separation performance and discharge voltage V current I characteristics should be investigated in detail to design the plasma window for each purpose. Therefore, a cascade arc discharge device with a diameter of up to 20 mm was developed, and its characteristics as a function of diameter were examined. As a result, with an increase in the channel diameter, the discharge pressure that was achieved decreased, whose values were smaller compared with the values by the prediction formula, assuming the viscous gas flow with a constant plasma temperature. It showed that the bulk plasma temperature for the larger discharge channel was low because of the low-current density over the channel. Furthermore, the transition of the V−I slope was observed with an increase in the diameter.
Spinwave detection by nitrogen-vacancy centers in diamond as a function of probe–sample separation
Authors: Purser C. M. , Bhallamudi V. P. , Guo F. , Page M. R. , Guo Q. , Fuchs G. D. , Hammel P. C.
Published: May 2020

Magnetic field noise from magnons can reduce the lifetimes of proximate spins and degrade the performance of spin based technologies. However, spatial and temporal averaging over the area of typical field sensors makes measuring magnetic field noise challenging. Here, we use an ensemble of nitrogen-vacancy (NV) point-defects in diamond to measure the spectral profile of thermally excited spinwave noise at room temperature as a function of the distance away from a 20 nm thick Permalloy (Py) thin film. We systematically vary the separation between the NV and Py layers using a silicon-dioxide wedge and measure the longitudinal relaxation rate of the NV center ms = 0 state as a function of the separation. The measured spinwave-induced relaxation of an ensemble of NV centers is well described by a magnetostatic model of dipole fields from the spinwaves. We furthermore find that our all-optical, nonperturbative measurements of the spinwave noise can be used to extract information about the ferromagnetic source, such as magnetization, damping, and fluctuating amplitude. This technique is amenable to application with stand-off from ferromagnetic elements and from buried structures.
Femtosecond pump-probe studies of atomic hydrogen superfluorescence in flames
Authors: Wang Kai , Wang Yejun , Wang Jizhou , Yi Zhenhuan , Kulatilaka Waruna D. , Sokolov Alexei V. , Scully Marlan O.
Published: May 2020

We investigate the excited-state dynamics of hydrogen (H) atoms in flames by using a femtosecond (fs) pump-probe scheme and measuring directional emission signals. An approximately 100-fs pump pulse at 205.1 nm excites H atoms through a two-photon process (n = 3 ←← n = 1), which is followed by detection of the forward emission signals induced by a broadband fs probe pulse near 656 nm. Above a certain threshold, we observe a quadratic dependence of the emission signal on the pump laser energy. Moreover, the linewidth of the forward emission signal varies with the probe delay and the probe laser energy. This behavior can be explained in terms of superradiance. We perform a theoretical analysis and compare the experimental results with the theory, and conclude that, within the conditions of our experiment, the behavior of the atomic system involves atomic coherence, which is produced non-adiabatically and corresponds to a superradiant process. Variations in the duration of the gain time window and lifetime of the excited-state H atoms in flames are explored at different flame conditions (i.e., equivalence ratio and heights above the burner). The fs pump-probe technique demonstrated here can also be extended to characterize the time-resolved population dynamics and the corresponding collisional energy transfer rates for energy levels involved in laser-induced fluorescence detection of H atoms in flames relevant to practical combustion applications.
Nuclear magnetic shielding of molecule in solution based on reference interaction site model self-consistent field with spatial electron density distribution
Authors: Imamura Kosuke , Yamazaki Takeshi , Yokogawa Daisuke , Higashi Masahiro , Sato Hirofumi
Published: May 2020

A new method for calculating nuclear magnetic shielding in solutions is developed based on the reference interaction site model self-consistent field (RISM-SCF) with spatial electron density distribution (SEDD). In RISM-SCF-SEDD, the electrostatic interaction between the solute and the solvent is described by considering the spread of electron to obtain more realistic electronic structure in solutions. It is thus expected to allow us to predict more quantitative chemical shifts of a wide variety of chemical species in solutions. In this study, the method is applied to a water molecule in water and is validated by examining the dependence of the solvent temperature and density on chemical shifts. The dependence of solvent species is also investigated, and more accurate results are obtained for polar solvents compared to the previous RISM-SCF study. Another application example of this method is the 15N chemical shifts of two azines in water, which is difficult to predict with the polarizable continuum model (PCM). Our results are in good agreement with the previous quantum mechanical/molecular mechanics study and experimental results. It is also shown that our method gives more realistic results for methanol and acetone than the PCM.
Second-harmonic generation in zinc blende crystals under combined action of femtosecond optical and strong terahertz fields
Authors: Bodrov S.B. , Korytin A.I. , Sergeev Yu.A. , Stepanov A.N.
Published: May 2020

The influence of a short intense (with an electric field strength up to 250 kV cm−1) terahertz (THz) pulse on the generation of second harmonic (SH) of Ti : sapphire laser radiation in crystals of zinc blende type (InAs and GaAs), characterised by nonzero bulk quadratic susceptibility, is investigated. It is experimentally shown for InAs(100) that, in the case of s-polarised first and second harmonics, an application of s-polarised THz field changes significantly the SH signal. The THz field-induced azimuthal dependence of the SH signal is in good agreement with the results of theoretical calculation within a phenomenological approach. The dependence of the SH signal on the delay time between the optical and THz pulses is investigated. This dependence for the GaAs crystal repeats the envelope of the THz pulse intensity, whereas in the case of InAs crystal there is a significant discrepancy, caused by the nonlinear dynamics of strong THz field in InAs.
The role of carbon nanotubes (CNTs) and carbon particles in green enhanced oil recovery (GEOR) for Arabian crude oil in sandstone core
Authors: Haq Bashirul , Al Shehri Dhafer , Al Damegh Abdulaziz , Al Muhawesh Abdullatif , Albusaad Mustafa , Lardhi Mohammad , Barri Assad , Iddris Abdulsamed , Muhammed Nasiru , Hossain S. M. Zakir , Rahman Mohammad Mizanur , Aziz Abdul
Published: May 2020

Green enhanced oil recovery (GEOR) is a chemical enhanced oil recovery (EOR) involving the injection of specific green chemicals (surfactants/alcohols/polymers) that effectively displace oil because of their phase-behaviour properties, which decrease the IFT between the displacing liquid and the oil. Carbon nanoparticles application in EOR has sparked interest in the last few years due to its unique characteristics. Carbon nanotubes (CNTs) are one of the common carbon nanomaterials with EOR potential, but they are not used with green surfactant to improve oil recovery. In addition, the recently developed Date Leaf Carbon Particle (DLCP) method has not been applied to GEOR and requires further study. The role of carbon particles in GEOR is not well understood and requires further investigation. This study was conducted to examine the effectiveness of DLCP and CNT in green surfactant alkyl polyglucoside (APG) for recovering residual oil within rock pores. The study consisted of a set of laboratory experiments. Two formulations of DLCP, CNT and green surfactant mixtures were selected for core-flood experiments based on interfacial tension measurements to examine their potential for EOR. In the first formulation, 0.08% DLCP was mixed with 0.5% APG and produced 45% of tertiary oil and 89% of oil initially in place (OIIP). This formulation produced a significant quantity of incremental oil after water flooding. Lastly, 0.5% APG was blended with 0.08% CNT; this produced about 27% tertiary oil and 77% OIIP.
New insights into the stratigraphy of the Otway Basin
Authors: Bendall Betina , Forbes Anne , Revie Dan , Eid Rami , Herley Shannon , Hill Tony
Published: May 2020

The Otway Basin is one of the best known and most actively explored of a series of Mesozoic basins formed along the southern coastline of Australia by the rifting of the Antarctic and Australian plates during the Cretaceous. The basin offers a diversity of play types, with at least three major sedimentary sequences forming conventional targets for petroleum exploration in the onshore basin. The Penola Trough in South Australia has enjoyed over 20 years of commercial hydrocarbon production from the sandstones of the Early Cretaceous Otway Group comprising the Crayfish Subgroup (Pretty Hill Formation and Katnook sandstones) and Eumeralla Formation (Windermere Sandstone Member). Lithostratigraphic characterisation and nomenclature for these sequences are poorly constrained, challenging correlation across the border into the potentially petroleum prospective Victorian Penola Trough region. The Geological Survey of Victoria (GSV), as part of the Victorian Gas Program, commissioned Chemostrat Australia to undertake an 11-well chemostratigraphic study of the Victorian Otway Basin. The South Australia Department for Energy and Mining, GSV and Chemostrat Australia are working collaboratively to develop a consistent, basin-wide schema for the stratigraphic nomenclature of the Otway Basin within a chemostratigraphic framework. Variability in the mineralogy and hence inorganic geochemistry of sediments reflects changes in provenance, lithic composition, facies changes, weathering and diagenesis. This geochemical variation enables the differentiation of apparently uniform sedimentary successions into unique sequences and packages, aiding in the resolution of complex structural relationships and facies changes. In this paper, we present the preliminary results of detailed geochemical analyses and interpretation of 15 wells from across the Otway Basin and the potential impacts on hydrocarbon prospectivity.
Identifying pan-industry common contributors to major accident events
Authors: Mitchell Joelle , Turnbull Alice
Published: May 2020

Analysis of incident investigation findings as a means of identifying common precursors or causal factors is a common topic of safety research. Historically this type of research has been conducted through a single lens, depending on the researcher’s discipline, with incidents analysed in accordance with a favoured theory, or grouped according to industry or region. This has led to the development of numerous frameworks and taxonomies that attempt to predict or analyse events at various levels of granularity. Such theories and disciplines include safety culture and climate, human factors, human error, management systems, systems theory, engineering and design, chemistry and maintenance. The intent of such research is ostensibly to assist organisations in understanding the degree to which their operations are vulnerable to known precursors or causal factors to major accident events and to take proactive measures to improve the safety of their operations. However, the discipline-specific nature of much of this research may limit its application in practice. Specific frameworks and taxonomies may be of assistance when organisations have identified a relevant area of vulnerability within their operations, but are unlikely to assist organisations in identifying those vulnerabilities in the first place. This paper seeks to fill that gap. A multidisciplinary approach was taken to identify common causal factors. Investigation reports published by independent investigation agencies across various industries were analysed to determine common causal factors regardless of discipline or industry.
Implementation of seismic data quality characterisation using supervised deep learning
Authors: Thorp Joshua , Davies Krista , Bluteau Julien , Hoiles Peter
Published: May 2020

Success and failure in oil and gas exploration is heavily dependent upon the quantity and quality of the subsurface data used during the analysis. Traditionally, the quality of seismic data has been characterised through the domain expertise of geoscientists and through traditional analytical methods, such as frequency decomposition, autocorrelations and signal to noise ratios. Unfortunately, due to the non-linearity and spatial heterogeneity of the data, these analytical methods can be unreliable or difficult to interpret by geoscientists. Machine learning, in particular deep learning, has been shown to analyse subsurface data in a multitude of ways by integrating domain expertise with powerful non-linear mathematical analysis. Thus, it seems that deep learning could be a natural fit for evaluating seismic data quality. In this paper we outline the issues of what is considered good- and bad-quality seismic data and introduce the labelling scheme that was implemented for the supervised learning. Examples of the labelling are shown, as well as the challenges encountered during the extensive labelling process. Neural network architecture testing and validation of the architecture are shown. Finally, applications to three-dimensional datasets on the North West Shelf, how the results can be interpreted and potential further avenues of research are discussed.
Application of machine learning methods to assess progressive cavity pumps (PCPs) performance in coal seam gas (CSG) wells
Authors: Saghir Fahd , Gonzalez Perdomo M. E. , Behrenbruch Peter
Published: May 2020

In Queensland, progressive cavity pumps (PCPs) are the artificial lift method of choice in coal seam gas (CSG) wells, and this choice of artificial lift production stems from the ability of PCPs to better manage the production of liquids with suspended solids. As with any mechanical pumping system, PCPs are prone to natural wear and tear over their operational life, and with the production of coal fines and inter-burden, the run life of PCPs in CSG wells is significantly reduced. Another factor to consider with the use of PCPs is their reliability. As per the CSG production data available through the Queensland Government Data Portal, there are approximately 6400 wells operational in the state as of December 2018. This number is expected to grow significantly over the next decade to meet both international and domestic gas utilisation requirements. Operators supervising these wells rely on a reactive or exception-based approach to manage well performance. In order to efficiently operate thousands of PCP wells, it is pertinent that a benchmark methodology is devised to autonomously monitor PCP performance and allow operators to manage wells by exception. In this study, we will cover the application of machine learning methods to understand anomalous PCP behaviour and overall pump performance based on the analysis of multivariate time-series data. An innovative time-series data approximation and image conversion technique will be discussed in this paper, along with machine learning methods, which will focus on a scalable and autonomous approach to cluster PCP performance and detection of anomalous pump behaviour in near real-time. Results from this study show that clustering real-time data based on converted time-series images helps to pro-actively detect change in PCP performance. Discovery of anomalous multivariate events is also achieved through time-series image conversion. This study also demonstrates that clustering time-series data noticeably improves the real-time monitoring capabilities of PCP performance through improved visual analytics.
Verifying the extent of plumes from produced formation water: a Wheatstone case study
Authors: Robertson Tim , Young Peter , Driscoll Andrew , Antenucci Jason , Elsdon Travis , de Lestang Paul
Published: May 2020

Chevron Australia Pty Ltd operates the Wheatstone liquefied natural gas facility in Western Australia under a Joint Operating agreement. Hydrocarbons from Wheatstone, Iago and Julimar-Brunello fields are sent to the Wheatstone Platform (the Platform), located ~50 km north of the Montebello Islands, for dewatering and dehydration before being transported onshore for final processing. Produced formation water (PW) is processed (treated) and, once criteria are met, discharged overboard. PW at Wheatstone is predicted to rapidly dilute in the receiving ocean to concentrations below water quality criteria (Australian and New Zealand Environment Conservation Council guidelines and ecotoxicology), though empirical evidence is needed to verify the actual discharge risk. Seawater (i.e. cooling water, CW) is also abstracted for cooling duty on the Platform, chlorinated and discharged. This paper describes a field verification campaign aimed at understanding PW and CW behaviour in the water column post-discharge, dilution with distance and whether numerical modelling of dilutions is accurate. The campaign was designed to evaluate plume characteristics by monitoring both entrained PW constituents (i.e. hydrocarbons and metals) and using a Rhodamine WT tracer dye. Monitoring of these constituents was done using an array of sampling techniques, including fluorometry, remotely operated vehicles and discrete water samplers. Results indicate rapid dilutions post PW and CW discharge, with dye fluorometry proving a valuable tool for understanding plume characteristics. Water sampling data interpretation indicated dilutions were likely orders of magnitude greater than anticipated, likely due to variable flow effects and turbulence induced by the Platform structure for PW, and the influence of entrained air within the plume for CW.
Creative steps to bring new gas supply to the south-east Australian domestic gas market: the Sole Gas Project after 42 years
Authors: Glavas Eddy
Published: May 2020

The Sole Gas Project is a new offshore project delivering gas to south-east Australian domestic gas customers, and the first new offshore development introduced into a tight market since the three Gladstone liquefied natural gas projects have been in full production. During an overall industry downturn (~2015) an opportunity presented itself. The Sole Gas Project was always technically robust since the first development plan was assessed and selected but required a market signal for it to be commercialised and funded. As the foundation target in its burgeoning domestic gas strategy, Cooper Energy acquired the Sole gas field (VIC/L32) and the Orbost Gas Plant in two stages and pursued creative steps to combine focused subsurface and engineering techniques, a drilling campaign, partners, funding, gas marketing, regulators and community to deliver new gas supply without a single offshore lost-time injury or incident.
Performance evaluation of synthetic and natural polymers in nitrogen foam-based fracturing fluids in the Cooper Basin, South Australia
Authors: Tran Tuan , Gonzalez Perdomo M. E. , Wilk Klaudia , Kasza Piotr , Amrouch Khalid
Published: May 2020

Hydraulic fracturing is a well-known stimulation technique for creating fractures in a subsurface formation to achieve profitable production rates in low-permeability reservoirs. Slickwater has been widely used as a traditional fracturing fluid. However, it has multiple disadvantages, such as high consumption of water, clay swelling and low flowback recovery. Foam, as an alternative fracturing fluid, consumes less liquid and provides additional energy. However, foam bubbles are typically unstable due to the degradation of surfactants, particularly in high temperature reservoirs, which reduces their capabilities of carrying and placing proppants into fractures. The purpose of this study is to provide general guidelines for an optimised application of polymers to improve the foam stability in high temperature reservoirs while increasing the proppant placement and water usage efficiencies. In this paper, the effects of natural hydroxypropyl guar (HPG) and synthetic polyacrylamide (PAM) polymers on the rheological properties of nitrogen foam-based fluids were examined by laboratory experiments conducted using temperatures up to 110°C. Then, a 3D hydraulic fracture propagation model was developed to study the fracturing performance of HPG-foamed and PAM-foamed fluids in the Toolachee Formation, Cooper Basin. It was found that synthetic PAM polymers were more effective than natural HPG polymers in stabilising foam viscosity under high temperature conditions. The simulation results indicate that foam-based fluids totally outperform slickwater in the field case application. This paper emphasises the significance of crosslinkers, foam quality and thermal stability on the performance of foams in high temperature environments.
Standardisation of procurement equipment specifications: establishing a strong foundation for oil and gas capital project development and delivery
Authors: Postema Adri , Fletcher Ted
Published: May 2020

Industry-wide standardisation is needed for operators to manage the US$3 trillion in CAPEX expenditure forecast for 2018–2025 (Global Data 2018), while maintaining competitiveness and mitigating risks. With the backing of the World Economic Forum, Joint Industry Program 33 (JIP 33) was initiated to drive industry-level standardisation for procuring equipment, moving the industry across the value chain towards common engineering designs and solutions, established by means of cross-company collaboration. Fourteen standardised specifications have been delivered. Their adoption by 12 major oil and gas operators is being measured and is progressing well. This enables the program to capture and evaluate successes, challenges, key learnings and feedback. A further 35–40 specifications, based on recognised industry or international standards, will be developed by the end of 2020. The program is also establishing a process for future maintenance of JIP33 specifications so as to achieve sustained benefits. The present paper outlines the status of JIP33 and showcases some of its early successes, challenges and learnings.
From global upstream safety data to action
Authors: Skår Olav , Carvalho Mariana , Poore Wendy , Walker Kirsty
Published: May 2020

The International Association of Oil & Gas Producers (IOGP) is a global forum in which member companies identify and share best practices to achieve improvements in many areas, including upstream process safety. IOGP members encompass oil and gas companies, industry associations as well as major upstream service companies; collectively, members produce 40% of the world’s oil and gas. These member companies voluntarily report their annual safety data, which are used to compile an annual report on safety performance indicators. IOGP work groups use these data to identify industry-wide learning to enable an industry vision of no fatalities. This paper describes the trends and lessons learned from the most recent data received. The IOGP safety performance indicator dataset is the largest database of its kind in the upstream oil and gas industry, allowing the ability to analyse trends and learning from fatal incidents on an industry-wide basis. Having this large database of information and standardised reporting of fatality data by activity, category, Life-Saving Rule and causal factors allows trending and analysis on a scale that is not possible for any individual member company. The present paper provides an update on the upstream industry safety performance from the past 5 years of data collected, and discusses how this has led to Project Safira: eliminating fatalities in the upstream industry.
Development of a highly automated mobile rig for the Australian CSG market
Authors: de Mul Arthur
Published: May 2020

In Q2 2020, a fully automated rig will enter the coal seam gas fields of Queensland, to work for a major operator. It is expected to be 20–30% faster than current operations. This document describes the upfront iterative design process with local potential users. Following discussions with various contractors and operators it became evident that there was a gap to bridge between operator and contractor targets and in what current operations have to offer. Both strive for the highest safety levels and operational efficiency, reducing the overall time per well, completed by minimising environmental impact. The above fits in the overall industry trend of transformation from mechanised rigs towards fully automated hands-free operated rigs. It was with these ingredients that the basis of a new iterative design process was formed, in which input from the operator field lieutenants, contractor rig crews and the supporting office was translated into a technical design. The target was set to reduce 20–30% of time per well. Key elements were the choice for road legal trailerised loads with no loose items, which resulted in rig moves of 4–6 h. Fully automated sequenced pipe tripping and casing running contributed to big improvements in efficiency and safety level (no people on the floor during standard operations). Performance can be real-time evaluated and optimised by collecting all rig and downhole data on the OPC server. The server also controls the mud system, downhole data and other important systems. This enables through-life time optimisation.
Hydrate risk management at end of field life: opportunities to maximise recovery
Authors: Morrissy Shane A. , Mortimer Asher J. , Nielsen Preben
Published: May 2020

Hydrate management is a pervasive challenge for the offshore oil and gas industry. The consequences of a hydrate blockage in a flowline can be significant due to deferred production and additional expenditure to remediate a blockage. A common hydrate management strategy for gas-condensate systems is to avoid hydrate formation using a thermodynamic inhibition strategy. Towards end of field life, costs associated with inhibiting produced water can increase OPEX and CAPEX. The reduced production and increased costs associated with hydrate avoidance can create economic pressure to discontinue production. An alternative to this is to consider a commercial risk-based hydrate management strategy, which can result in considerable OPEX and CAPEX savings, making marginal developments economic. A case study on the adoption of a successful risk-based hydrate management strategy is presented. The goal was to maximise production from a declining asset to deliver incremental business value. Historically a hydrate avoidance strategy had been used; to continue with hydrate avoidance would have needed further capital outlay to manage the produced water from the declining reservoir. It was determined that during normal operation, hydrate risk could be managed without the need for continuous injection of a hydrate inhibitor. Further, in the event of an unplanned shutdown, where the hydrate risk is greater, it was also demonstrated that the production system could be restarted with minimal intervention.
New insights into the organic geochemistry of the Otway Basin
Authors: Hill Tony , Bendall Betina , Murray Andrew
Published: May 2020

The Penola Trough of the Otway Basin in South Australia has enjoyed over 20 years of commercial hydrocarbon production from the sandstones of the Early Cretaceous Otway Group with 71.46 PJ sales gas and 65840 kL of condensate produced from five fields until production ceased in 2011. Recent success in Haselgrove 3, where a newly discovered deeper reservoir underlying depleted reservoirs of the Pretty Hill Formation flowed 25 MMscfd on test heralds a new phase of exploration and appraisal with a 2C Contingent Resource of 87 PJ assigned to the discovery. These hydrocarbons are considered to have been principally derived from lacustrine, floodplain and back swamp facies of the Pretty Hill Formation and lacustrine facies of the underlying Casterton Formation. The South Australia Department for Energy and Mining is currently investigating an unnamed Late Jurassic syn-rift sequence of interbedded metasediments, tuffaceous sediments and organically-rich shale, first identified as fractured basement in Sawpit 1, located on the northern flanks of the Penola Trough and which unconformably underlies the Casterton Formation. A low-sulfur medium-gravity paraffinic oil was recovered from drill stem tests from this well and subsequent total organic carbon and Rock-Eval analyses for the same unit in nearby Sawpit 2 identified a source rock containing algal organic matter and thought to be deposited in a deep anoxic lake setting. In this paper, we will present the preliminary results of detailed geochemical analyses of rocks and rock extracts from this previously unrecognised syn-rift sequence and discuss implications for hydrocarbon prospectivity in the deeper portions of the Penola Trough.
Coal fracturing through liquid nitrogen treatment: a micro-computed tomography study
Authors: Akhondzadeh Hamed , Keshavarz Alireza , Awan Faisal Ur Rahman , Al-Yaseri Ahmed Z. , Iglauer Stefan , Lebedev Maxim
Published: May 2020

Low permeability of coal has been a constant obstacle to economic production from coalbed methane reservoirs, and liquid nitrogen (LN2) treatment has been investigated as one approach to address this issue. This study examined LN2 fracturing of a bituminous coal at pore-scale through 3D X-ray micro-computed tomography. For this purpose, a cylindrical sample was immersed into LN2 for 60 min. The micro-CT results clearly showed that the rapid freezing of the coal with LN2 generated fracture planes with large apertures originating from the pre-existing cleats in the rock. This treatment also connected original cleats with originally isolated pores and micro-cleats, thereby increasing pore network connectivity. Moreover, scanning electron microscopy highlighted the appearance of continuous wide conductive fractures with a maximum opening size of 9 µm. Furthermore, a nano-indentation technique was used to test the effect of LN2 on coal mechanical properties. The indentation moduli decreased by up to 14%, which was attributed to the increase in the cracked rock compressibility, showing considerable fracturing efficiency of the LN2 treatment. Through in-situ microscopic visualisation and surface investigation, this study quantified the pore structure and connectivity evolution of the rock based on the morphological alteration, and demonstrated the promising effect of LN2 freezing on fracturing of bituminous coals, thus aiding coalbed methane production. The significance of this study was investigating the mechanisms associated with and the efficiency of LN2 treatment of a coal rock in a 3D analysis inside the rock.
The effect of marine seismic surveys on the movement, abundance and community structure of demersal fish assemblages on the North West Shelf
Authors: Meekan Mark G. , Speed Conrad W. , McCauley Robert D. , Semmens Jayson M. , Newman Stephen J. , Fisher Rebecca , Parsons Miles J. G.
Published: May 2020

In 2018, the Australian Institute of Marine Science (AIMS) and its partners, conducted an experiment to investigate the effect of exposure to a 3D seismic survey on demersal fishes. The experiment involved the use of a commercial seismic vessel equipped with a 2600 cubic inch air-gun array, sailing a racetrack pattern with eight operational (high exposure zone) and eight inactive (vessel control zone) sail lines, with a 500 m sequential line separation and ≈18 m shot point spacing. The high exposure and vessel control lines were separated by 35 km. Demersal fishes were observed in five sampling surveys over a 6-month period (three surveys before and two after exposure), using acoustic telemetry and stereo baited remote underwater videos systems (BRUVS). The telemetry component included the capture, tagging with acoustic transmitters and release of 387 red emperor (Lutjanus sebae) within two telemetry receiver arrays. These arrays, one in each zone, comprised 37 and 39 acoustic receivers over ≈32 km2, to record movements of tagged fish. The receivers provided near-continuous data on tag locations, and, hence, movement of fish in the area, until removal in December 2018. During each sampling survey, BRUVS were deployed at various distances from the area of the seismic survey. Study results are currently being finalised for presentation.
A geochemical investigation into the resource potential of the Lawn Hill Platform, northern Australia
Authors: Jarrett Amber J. M. , Bailey Adam E. H. , Boreham Christopher J. , Palu Tehani , Hall Lisa , Shannon April , Collins Alan S. , Vinnichenko Galina , Brocks Jochen , Li Zhongsheng , Munson Tim J. , Edwards Sally , Carr Lidena , Henson Paul
Published: May 2020

The Lawn Hill Platform (LHP) is a sedimentary province in north-eastern Northern Territory and north-western Queensland that hosts a significant Paleoproterozoic–Mesoproterozoic sequence, often referred to as 'the ‘Isa Superbasin’, and includes the overlying South Nicholson Group. Shale gas resources and base-metals mineralisation are known in north-west Queensland, but the larger basin is underexplored. The Australian Government’s Exploring for the Future (EFTF) 2016−2020 program aims to boost resource exploration in northern Australia. New precompetitive geochemical data obtained in this program includes source rock geochemistry, kerogen kinetics, bitumen reflectance, biomarker and δ13C n-alkanes for understanding the petroleum potential, organic geochemistry of source rocks and fluids, stratigraphic correlations and mineralogy to determine the brittleness of shales. All data and derived reports are accessible on the EFTF portal (www.eftf.ga.gov.au), providing a central location for informed decision making. The results in this study demonstrate fair to excellent source rocks in multiple supersequences that are brittle and favourable to hydraulic stimulation. A comparison to the greater McArthur Basin demonstrates, that although there are many similarities in bulk geochemistry, LHP mudstones are largely heterogeneous, reflecting local variations that may be inherited from variations in contributing biomass, microbial reworking, depositional environment, sediment input and paleoredox conditions.
Adjusting to working away and as an expatriate: learnings on what organisations can do to promote the mental health and well-being of workers and their families
Authors: Freeman Melanie L.
Published: May 2020

Adjusting to frequent separations and reunions can put pressure on the relationships and families of those who work away. Although the work context is different, there are similar effects and challenges for workers, families and organisations across the military, expatriate and fly-in, fly-out (FIFO) research domains. Mental health, work performance, job satisfaction, relationships and parenting are all negatively affected by the extended periods of deployment or posting and the regular and ongoing shorter periods of FIFO work. At the individual level, personality dimensions (emotional stability, sociability, openness to new experiences), locus of control, intelligence, self-sufficiency and cultural intelligence have been shown to significantly affect these impacts and provide organisations with starting points for both the screening of candidates for roles and coaching them to better adjust and cope cross-culturally. The recruitment and onboarding processes should be underpinned by the principles of managing expectations and building capability, and this means that realistic and relevant information should focus on the realities of the work, the work environment and host country. The onboarding process that seeks to socialise the worker into the organisation and the culture should assume the worker will take at least 6 months to settle into the role. Predeparture training should engage with the worker and their families to ensure the development of coping skills and practical strategies for managing communication, parenting and relationships. Effectively managing the psychosocial risks faced by workers across these domains will improve the mental health and well-being of workers and their families.
Reducing cost of CCUS associated with natural gas production by improving monitoring technologies
Authors: Bagheri Mohammad , Ryan Scott , Byers David , Raab Matthias
Published: May 2020

This paper examines how we can reduce the cost of carbon capture, utilisation and storage (CCUS). The CO2CRC research and demonstration projects during the last 15 years and the upcoming Otway Stage 3 Project aim to reduce the cost of CCUS. The CO2CRC Otway Stage 3 Project will develop subsurface monitoring technologies which can significantly reduce the cost of the surveillance. The CCUS associated with natural gas processing carries the lowest cost compared to other industries because production of concentrated CO2 streams is already part of the gas production process. Transport and storage remain the highest cost components of CCUS for natural gas production. Ranges of storage and transportation costs based on different publicly available data are ~US$2–40/tCO2 and ~US$2–10/tCO2 respectively. Further, the US Department of Energy cost model identifies 40–60% of storage cost as relating to recurring monitoring. This is highly dependent on project specifications, regulatory requirements and geographical considerations. The application of Otway Stage 3 subsurface technologies show preliminary long-term monitoring cost savings estimates for a large Australian project of up to 75% compared to conventional surface seismic-based methodologies. Depending on total injection mass, this would equate to an estimated cost saving of up to AU$12/tonne of CO2 injected for such a project. Reduced monitoring costs could be applied to all CCUS projects but would be of most interest to gas projects because storage is likely to be the biggest contributor to overall CCUS cost.