bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrated Workflow for Analysis of the Adsorbed Phase Contribution in Liquid Rich Wells in the Unconventional Duvernay Formation
Authors: Sharma Gaurav , Galvis-Portilla Henry 
Published: March 2020

Abstract
To achieve economic production from shale gas reservoirs hydraulic fracturing is required. This stimulation technology facilitates the interconnection of the multiple pore systems with the wellbore. Particularly, shale gas reservoirs exhibit a dual porosity system linked to the free and adsorbed fluid phases, being the adsorbed phase a significant control on the long-term production. The adsorbed volume is strongly related to the total organic carbon (TOC) and thus, it is often assumed that higher hydrocarbons in place occur within the high TOC intervals. This study evaluates this relationship and the impact of the adsorbed phase to OGIP (original gas in place) and production behaviors. Analysis of petrophysical data and log-derived TOC of the Duvernay Formation reveals that variations in mineralogy impacts the quantity of TOC. It is observed that increase in carbonate contents correlate with lower organic contents, whereas increase in quartz and clays correlate with higher organic contents. Results of Langmuir isotherms indicate that methane adsorption capacity is directly proportional to the TOC content. Further, this study analyzes production data of two multi-fractured horizontal wells by analyzing the relative contribution of the adsorbed phase to the free gas. It is found that contribution of the adsorbed phase is maximum during the initial phase of the production cycle which declines as the reservoir pressure drops. The estimated relative contribution of the adsorbed phase to OGIP is nearly 50% which is significant to be considered negligible. Further, the contribution from the adsorbed phase is found to be 45% in the early phase of the production which drops down to 25% after 10 years of the production. Finally, this study illustrates that the relation of TOC with fluid characterization and recoverable reserves is complex and should be analyzed with the variation in adsorption and desorption capacity of lighter and heavier components.
Insights on Trigger Mechanisms of Two Large Hydraulic Fracturing-Induced Earthquakes and Sensitivity Analysis
Authors: Hui Gang , Chen Shengnan , Gu Fei 
Published: March 2020

Abstract
Two earthquakes with the moment magnitude of 3.9 and 4.1 occurred in January 2015 and January 2016 near the Crooked Lake region, Alberta. Both earthquakes were attributed to the hydraulic fracturing operations of three horizontal wells located at the same well-pad. The underlying mechanisms of both earthquakes are still unclear and required to be investigated to mitigate risks of future seismicity in this region. In this study, the coupled simulations of the fluid flow and geomechanics were conducted to characterize the temporal and spatial evolution of pore pressure diffusion and stress perturbation during and after hydraulic fracturing operations. The Coulomb Failure Stress along the pre-existing fault near the horizontal wells were then calculated to study the reactivation of the fault. Sensitivity analysis was finally conducted to understand the effects of the fault's orientation, injection layer permeability, and distance between the fault and hydraulic fractures on the induced seismicity. The results showed that one North-South-oriented fault was activated twice after the sequential fracturing operations of three horizontal wells in 2015 and 2016. The Mw 3.9 earthquake was triggered by the stress and pore pressure changes that activated the fault in the basement. The relatively long-time interval between the stimulation and the induced earthquake was attributed to the low permeability and geomechanics property from the injection layer to the fault. The subsequent Mw 4.1 event was triggered by the direct connection between the hydraulic fractures, natural fractures, and the fault. Sensitivity analysis has suggested that the activation of faults were susceptible to the proximity between stimulated well and seismogenic faults, low permeability of the injection layer, and the low angle between the fault strike and the maximum horizontal stress.
Understanding the Mechanisms of Huff-n-Puff, CO2-EOR in Liquid-Rich Shale Plays: Bakken Case Study
Authors: Ellafi Abdulaziz , Jabbari Hadi 
Published: March 2020

Abstract
A revolution of unconventional reservoirs is a turning point in the global oil and gas industry since these resources have massive reserves with large potential in contributing to hydrocarbon production. Previous EOR laboratory experiments and simulation studies in the literature illustrated promising results in terms of recovery factor for different EOR applications, such as CO2, surfactant, and natural gas. However, pilot tests performance reported contrast behavior due to misleading predicting for the EOR physics processes. This paper presents the experimental work to evaluate the feasibility of CO2-EOR using the huff-n-puff (HNP) protocol in the Middle Bakken (MB) Formation, the Mountrail County, Williston Basin, ND. We evaluate the oil recovery from CO2-EOR under several scenarios of operational and well/reservoir conditions. The parameters considered in the sensitivity study include temperatures, pressure, soak time, and number of injection cycles to obtain optimum conditions under which the incremental oil recovery from the MB Formation is increased. The wettability alteration (i.e. contact angle) was also studied using rock-chip samples before and after the HNP experiment at the Bakken reservoir conditions (present for example P & T in psi/F). The outcomes indicated on the effect of the reservoir temperature and pressure on the performance of the CO2, where the recoverable oil increases as the temperature and pressure increase until reach the optimum. As a previous research outcome, the number of cycling and soaking time are crucial design parameters for the HNP experiment and on the field as well to let the CO2 time to diffuse into the deep formation and swell more oil. In addition, the wettability alteration was changed by CO2-EOR as injection pressures increase and the wetting phase move from the oil-wet toward the water-wet system. As overall outcomes from this research, the CO2 HNP process has a good potential in the lab, and could be succeeded economically in field applications that might reduce the need for refracturing stimulation or infill drilling.
A Laboratory Protocol for Evaluating Microemulsions for Enhanced Oil Recovery while Fracturing
Authors: Eghbalvala Maryam , Habibi Ali , Dehghanpour Hassan 
Published: March 2020

Abstract
In this paper, we developed a laboratory protocol to evaluate the performance of three microemulsion (ME) additives in fracturing water for enhanced oil recovery. We applied the protocol on oil, brine, and core samples from two wells completed in the Montney (MT) Formation in the following steps: 1) Performing bulk-phase tests to evaluate fluid properties, particle size and stability of nanodispersions (ND) generated by mixing the ME additives with water, 2) Characterizing natural wettability of the core plugs by spontaneous imbibition and contact angle tests, and 3) Evaluating surfactant-assisted imbibition oil recovery during the shut-in time by conducting systematic contact-angle and counter-current imbibition tests under different conditions of brine salinity.
Results of fluid-fluid tests, showed that one of the MEs, gives the smallest particle size (36.54 nm), the lowest IFT (0.1753 mN/m), the closest oil-solubility to Winsor III, and the best stability compared with other MEs. In rock-fluid experiments, performed by the candidate ME from fluid-fluid tests, we observed higher and faster imbibition oil recovery by mixture of ME with tap water (52% oil-recovery) compared with mixture of ME with brine (16.6% oil-recovery). In addition, adding the ME additives in brine does not improve imbibition oil recovery compared with the brine without ME additive (7.5%).
Development of a Ball Seat Event Recognition Algorithm with Convolutional Neural Network for the Real-Time Hydraulic Fracturing Analytics System
Authors: Shen Yuchang , Cao Dingzhou 
Published: March 2020

Abstract
This paper provides the technical details of our latest progress of the hydraulic fracturing ball seat event recognition model. In our previous work (Shen et al., 2020), the U-Net architecture was used to build models to recognize the ball seat event. In this paper, we train the Convolutional Neural Network (CNN) to solve the same problem. Comparing with U-Net approach, the CNN model requires less computation resource during training phase while it has slight better performance.
Are Displacement-Type EOR Processes Feasible in the Liquids-Rich Portion of the Montney?
Authors: M. Faskhoodi Majid , Rivero Jose A. , Zhmodik Alexey , Mukisa Herman , Bayestehparvin Bita 
Published: March 2020

Abstract
Cyclic gas injection in hydraulically-fractured wells has been successfully applied as an enhanced oil recovery (EOR) method in tight unconventional basins such as the Permian and Eagle Ford. However, displacement processes (continuous gas, solvent or water injection) such as those piloted in the relatively more permeable Bakken formation have not been considered in tighter basins. In this work, we present a novel displacement process that uses alternating injecting and producing hydraulic fractures to flood the inter-fracture region around a horizontal well. We demonstrate that the method is feasible as long as suitable fracture geometries can be generated.
A reservoir geomodel of a typical Montney gas condensate reservoir was constructed using publicly available data. Rock mechanics parameters were integrated into the model alongside completion and pumping schedule information to predict hydraulic fracture propagation and geometries representative of the typical stimulated volumes in Montney. A compositional numerical reservoir simulator was then used to test the proposed EOR process in a gas condensate reservoir where we forecast liquid recovery under different frac-to-frac continuous gas injection flooding scenarios. Sensitivities to study the effect of fracture spacing and complexity, solvent composition, starting time of gas injection, and matrix permeability were performed.
With simultaneous injection and production from alternating hydraulic fractures, it is possible to flood the volumes between them and consequently avoid the drawbacks of huff ’n’ puff processes. By using a more rigorous fracture description, we can reproduce the interactions between fractures and determine how they affect the conformance of the displacement front.
Modeling results showed that frac-to-frac displacement process can significantly improve the condensate recovery compared to primary or even huff n puff EOR process. They also showed that the frac-to-frac EOR process is feasible only if the formation mechanical properties and in-situ stresses are such that the resulting hydraulic fractures exhibit aligned planar geometries. If high-intensity natural fracture networks are present, the hydraulic fractures tend to form complex geometries that negatively affect the conformance of the flooding front. The study also showed that there is an optimal spacing between the injecting and producing fractures that would allow for the efficient utilization of the EOR agent; this spacing was shown to have a strong dependence on matrix permeability. Composition of injected solvent and starting time of gas injection doesn’t seem to have considerable impact on incremental recovery due to frac-to-frac displacement.
Retrospective Validation of the Robustness of Reservoir Simulation Predictions
Authors: Habib Mohamad , Joslin Kevin 
Published: March 2020

Abstract
Reservoir simulation projects are ubiquitous across the oil and gas industry. A less common practice is retrospective validation of the accuracy and robustness of the original model's predictions. This paper highlights the importance of validating previous simulation work with field data in order to test predictability and acquire more confidence in future simulation work.
A fully implicit coupled wellbore-reservoir simulator was used to history match the performance of four steam-assisted gravity drainage (SAGD) well pairs after one year of operation. The purpose of this effort was to build a representative model that mimicked the observed field behavior and captured the key performance drivers such as reservoir quality, completion type, and operating strategy. A representative history matched model was achieved with an overall accuracy within 9.5% of actuals after one year of operation. This model was used to forecast well pair performance after three years.
After three years of field operation, the predicted simulation forecast was compared against the actual field data. The accuracy and robustness of model's predictions remained valid and improved to within 7.5% of actuals after three years of operation. For two out of the four well pairs, the observed trends between the actuals and the simulation appeared to deviate due to completion type and operating strategy changes that occurred after the original history match was completed. Once these changes were reflected in the simulation model, predictability was restored and improved reaching an accuracy within 4.7%.
This paper aims to deliver two key learnings and best practices. First, a coupled wellbore-reservoir simulation approach was successfully applied to build a representative model that captures the key performance drivers and observed field behavior. Second, a retrospective validation of the model's predictions was completed and resulted in more accurate, robust, and confident performance predictions. These robust models can be used to better understand, forecast and optimize the productive potential of oil and gas operations over their life cycle.
Patient Centred Medical Home (PCMH) transitions in western Sydney, Australia: A qualitative study
Authors: Metusela Christine , Usherwood Tim , Lawson Kenny , Angus Lisa , Kmet Walter , Ferdousi Shahana , Reath Jennifer 
Published: March 2020

Abstract
Objectives
Patient Centred Medical Homes (PCMHs), increasingly evidenced to provide high quality primary care, are new to Australia. To learn how this promising new healthcare model works in an Australian setting we explored experiences of healthcare providers in outer urban Sydney, where a number of practices are transitioning from traditional Australian general practice models to incorporate elements of PCMH approaches.
Design
We collected qualitative data from semi-structured interviews with healthcare providers working in a range of transitioning practices and thematically analysed the data.
Setting and participants
We interviewed 35 participants including general practitioners, practice managers and practice nurses from 25 purposively sampled general practices in western Sydney, Australia, seeking maximal variation in practice size, patient demographics and type of engagement in practice transformation.
Results
Interviewees described PCMH transformation highlighting the importance of whole of practice engagement with a shared vision; key strategies for transformation to PCMH models of care including leadership, training and supportive information technology; structures and processes required to provide team-based, data-driven care; and constraints such as lack of space and the current Australian fee-for-service general practice funding model. They also reported their perceptions of early outcomes of the PCMH model of care, describing enhanced patient and staff satisfaction and also noting fewer hospital admissions, as likely to reduce costs of care.
Conclusions
Our study exploring the experience of early adopters of PCMH models of care in Australia, informs the international movement towards PCMH models of care. Our findings provide guidance for practices considering similar transitions and describe the challenges of such transitions within a fee-for-service payment system.
The Visitor and Migrant Cost Recovery Programme – A threat to health?
Authors: Potter Jessica Louise , Burman Matthew , Tweed Conor D , Vaghela D , Kunst H , Swinglehurst D , Griffiths CJ 
Published: March 2020

Abstract

Background
In April 2014 the UK government launched the ‘NHS Visitor and Migrant Cost Recovery Programme Implementation Plan’ which set out a series of policy changes to recoup costs from ‘chargeable’ (largely non-UK born) patients. In England, approximately 75% of tuberculosis (TB) cases occur in people born abroad. Delays in TB treatment increase risk of morbidity, mortality and transmission in the community. We investigated whether diagnostic delay has increased since the Cost Recovery Programme (CRP) was introduced.

Methods
There were 3,342 adult TB cases notified on the London TB Register across Barts Health NHS Trust between 1st January 2011 and 31st December 2016. Cases with missing relevant information were excluded. The median time between symptom onset and treatment initiation before and after the CRP was calculated according to birthplace and compared using the Mann Whitney test. Delayed diagnosis was considered greater or equal to median time to treatment for all patients (79 days). Univariable logistic regression was used to manually select exposure variables for inclusion in a multivariable model to test the association between diagnostic delay and the implementation of the CRP.

Results
We included 2,237 TB cases. Among non-UK born patients, median time-to-treatment increased from 69 days to 89 days following introduction of CRP (p<0.001). Median time-to-treatment also increased for the UK-born population from 75.5 days to 89.5 days (p=0.307). The multivariable logistic regression model showed non-UK born patients were more likely to have a delay in diagnosis after the CRP (adjOR 1.37, 95% CI 1.13-1.66, p value 0.001)

Conclusion
Since the introduction of the CRP there has been a significant delay for TB treatment among non-UK born patients. Further research exploring the effect of policies restricting access to healthcare for migrants is urgently needed if we wish to eliminate TB nationally.
Change in Angle of Eyes with Primary Angle Closure Suspects One Year after Laser Peripheral Iridotomy : a randomised study
Authors: mou dapeng , Liang Yuan Bo , Fan Su Jie , Peng Yi , Wang Ning Li , Thomas Ravi 
Published: March 2020

Abstract
Background: To report the changes in anterior chamber angle and progression rate to PAC(primary angle closure) following laser peripheral iridotomy (LPI) in primary angle closure suspects(PACS).Methods: Prospective, randomized controlled interventional clinical trial conducted at the Handan Eye Hospital, China. 134 bilateral PACS, defined as non-visibility of the posterior trabecular meshwork for ≥ 180 degrees on gonioscopy were randomly assigned to undergo LPI in one eye. Gonioscopy and Goldmann applanation tonometry were performed prior to, on day 7 and 12 months’ post LPI.Results: 80 of 134 patients (59.7%) could be followed up at one year. The mean IOPin treated eyes was 15.9±2.7 mmHg at baseline, 15.4±3.0 mmHg on day 7; 16.5±2.9 mmHg at one month and 15.5±2.9 mmHg at 12 months; the IOP in untreated eyes was similar (p=0.834). One or more quadrants of the angle opened in 93.7% of the LPI treated eyes, but 67.0% (53/79) remained closed in two or more quadrants. The progression rate to PAC in untreated eyes was 3.75% and one developed acute angle closure glaucoma(AACG), the progression rate to PAC(primary angle closure) in treated eyes 2.5% in treated eyes, none had developed PAS or AACG. Conclusion: LPI can open some of the occludable angle in the majority of eyes with PACS, but 67% continue to have non-visibility of the trabecular meshwork for over 180 degrees. IOP remained similar in treated and untreated eyes. Further research is needed to determine the full implications of residual closure as well as the need for follow up and treatment in PACS. The cumulative incidence for PAC/AACG in treated eyes were not significantly different from untreated eyes.Trial registration: Chinese Clinical Trial Registry ChiCTR-TCH-10000820. Registered on 08 April 2010(retrospectively registered).
Stable intronic sequence RNAs (sisRNAs) are selected regions in introns with distinct properties
Authors: Jin Jing , He Ximiao , Silva Elena M 
Published: March 2020

Abstract
Background: Stable introns and intronic fragments make up the largest population of RNA in the oocyte nucleus of the frog Xenopus tropicalis. These stable intronic sequence RNAs (sisRNAs) persist through the onset of zygotic transcription when synchronous cell division has ended and the developing embryo consists of approximately 8000 cells. Despite their abundance, the sequence properties and biological function of sisRNAs are just beginning to be understood. Results: To characterize this population of noncoding RNA, we identified all of the sisRNAs in the X. tropicalis oocyte nucleus using published high-throughput RNA sequencing data. Our analysis revealed that sisRNAs, have an average length of ~360 bps, are widely expressed from genes with multiple introns, and are derived from specific regions of introns that are GC and TG rich, while CpG poor. They are enriched in introns at both ends of transcripts but preferentially at the 3’ end. The consensus binding sites of specific transcription factors such as Stat3 are enriched in sisRNAs, suggesting an association between sisRNAs and transcription factors involved in early development. Evolutionary conservation analysis of sisRNA sequences in seven vertebrate genomes indicates that sisRNAs are as conserved as other parts of introns, but much less conserved than exons. Conclusion: In total, our results indicate sisRNAs are selected intron regions with distinct properties, and may play a role in gene expression regulation.
Circulating betatrophin/ANGPTL8 levels correlate with body fat distribution in individuals with normal glucose tolerance but not those with glucose disorders
Authors: Author) jing zheng(Former Corresponding , Liu Juan , Hong Beverly S , Author) Yanbing Li(New Corresponding 
Published: March 2020

Abstract
Background: The relationship between betatrophin/ANGPTL8 and obesity has been investigated using body mass index (BMI); however, since BMI reflects overall adiposity rather than body fat distribution, it remains unclear whether fat deposition in different areas of the body affects betatrophin expression. Here, we investigated the correlation between circulating betatrophin levels and body fat distribution in patients with different glucose tolerance. Methods: ﻿We performed a cross-sectional study in 128 participants with impaired glucose tolerance (IGT; n = 64) or normal glucose tolerance (NGT; n = 64). Circulating betatrophin levels were detected by enzyme-linked immunosorbent assay. Body fat distribution (subcutaneous, visceral, and limb fat) was measured by magnetic resonance imaging (MRI) and a body fat meter.Results: After controlling for age, sex, and BMI, betatrophin was correlated positively with visceral adipose tissue-to-subcutaneous adipose tissue ratio ( VAT/SAT ratio; r = 0.339, p = 0.009) and negatively with body fat ratio (BFR; r = -0.275, p = 0.035), left lower limb fat ratio (LLR; r = -0.330, p = 0.011), and right lower limb fat ratio (RLR; r = -0.288, p = 0.027) in the NGT group, with these correlations remaining after controlling for triglycerides. VAT/SAT ratio (standardized β = 0.419, p = 0.001) was independently associated with serum betatrophin levels; however, betatrophin was not associated with body fat distribution variables in the IGT group.Conclusions: Circulating betatrophin levels correlated positively with VAT/SAT ratio and negatively with lower limb fat, but not subcutaneous or upper limb fat, in individuals with normal glucose tolerance. Thus, betatrophin may be a poten­tial biomarker for body fat distribution in individuals without glucose disorders.