bluuebunny/crossref_metadata_2025 huggingface dataset:
Vitamin D Regulation of a SOD1-to-SOD2 Antioxidative Switch to Prevent Osteosarcoma Transformation
Authors: Lisse Thomas S.
Published: March 2020

Superoxide, a form of reactive oxygen species (ROS), is catabolized by superoxide dismutase (SOD) and contributes to carcinogenesis via the oxidative damage it inflicts on cells. The aim of this research was to analyze the potential vitamin D-mediated regulation of the antioxidative “SOD1-to-SOD2 switch” within the human MG-63 osteosarcoma model. For this study; real-time PCR analysis was performed using MG-63 cells exposed to metabolically active 1,25(OH)2D3. Frist; a sustained statistically significant >2-fold suppression of proliferating cell nuclear antigen (PCNA) transcripts was observed after 10nM but not at 100nM of 1,25(OH)2D3 treatment; suggesting a cytostatic effect. In order to assess regulators of mitochondrial oxidative phosphorylation; gene expression of COX2 and COX4l1 of the mitochondrial complex IV and antioxidative enzymes (SOD1; SOD2 and Catalase (CAT)) were monitored. For COX2 and COX4l1; no changes in gene expression were observed. However; a concomitant decrease in CAT and SOD1 mRNA; and increase in SOD2 mRNA after 24 hours of 10nM 1,25(OH)2D3 treatment were observed. A ~8-fold increase in SOD2 mRNA was apparent after 48 hours. The significant increase in SOD2 activity in the presence of vitamin D indicates an antioxidant potential and sensitization of vitamin D during osteosarcoma transformation and mitochondrial detoxification over time.
Surgical Treatment of Wrist Arthritis in Young Patients
Authors: Campbell Collier C. , Neustein Thomas M. , Daly Charles A. , Wagner Eric R.
Published: March 2020

» Surgical treatment of wrist arthritis in the younger patient population remains a challenging issue, and various surgical options need to be carefully considered for each patient.

» Proximal row carpectomy and 4-corner arthrodesis have proven to be reliable options for reducing pain and restoring adequate function in most young high-demand patients if the lunate facet is spared.

» Selective neurectomy has proven to be a promising stand-alone or complementary procedure for the treatment of pain that is associated with wrist arthritis in patients of all ages, with spared motion and the opportunity to perform additional procedures if pain continues.

» Alternative procedures, including capitolunate arthrodesis, total wrist arthrodesis, radial styloidectomy, total wrist arthroplasty, and wrist hemiarthroplasty, have considerable strengths and weaknesses and need to be studied further in younger patients.
Integrating Distributed Acoustic Sensing, Treatment-Pressure Analysis, and Video-Based Perforation Imaging To Evaluate Limited-Entry-Treatment Effectiveness
Authors: Cramer David , Friehauf Kyle , Roberts Glyn , Whittaker Jeff
Published: March 2020

The primary objectives of perforating a lengthy cased-and-cemented wellbore section for fracture stimulation are to enable extensive communication with the reservoir and control the allocation of fluid and proppant into multiple intervals as efficiently as possible during fracturing treatments. Simultaneously treating multiple intervals reduces the number of fracture stages required, thus reducing treatment cost. One way to control the allocation is to use limited-entry perforating. Execution and optimization of limited-entry perforating requires awareness of the factors that can affect performance. This paper presents a case study of plug-and-perforate horizontal-well treatments in an unconventional shale play in which various diagnostic methods were used to better understand these factors.

Within the case study, three types of perforation-evaluation diagnostics were implemented: injection step-down tests and pressure analysis of the fracturing treatments, video-based perforation imaging, and distributed acoustic sensing (DAS).

Injection step-down tests indicated that all perforations were initially accepting fluid. Surface-pressure analysis of the main fracturing treatments indicated that in certain cases, several perforations were not accepting fluid and proppant (slurry) by the end of the job.

Video-based imaging indicated that a large majority of perforations showed unambiguous evidence of significant proppant entry. Evaluation of the erosion patterns on the perforations showed a positional bias where for a given fracture stage, perforations in clusters nearest the heel of the well were more eroded than perforations in clusters nearest the toe of the well.

DAS analysis showed a positional bias, allocating more slurry volume to clusters nearest the heel of the well. However, DAS analysis also showed that changing the number of perforations in a cluster had a larger effect than the positional bias.

The results of the case study indicated that a staggered perforation design using more gradual changes among clusters would lead to a more balanced treatment. This scenario was evaluated along with a job design featuring high excess perforation friction and an equal number of perforations in each cluster. Fracture-simulation runs indicated that both tactics are likely to improve slurry allocation.
Productivity Index for SAGD Producers During Steam-Flashing: Coning Model I and II
Authors: Irani Mazda
Published: March 2020

Over the last decade, steam assisted gravity drainage (SAGD) process has been successfully commercialized in Alberta and Saskatchewan thermal projects. Remediation of slotted liner wells in cases of erosion, or high gas/steam production later in life requires a different basis of design based on specific well challenges and will be challenged by the additional pressure drops due to poor or variable sand control productivity. Flow Control Devices (FCDs) have demonstrated significant potential for improving recovery in SAGD production wells. FCD experience in SAGD has been primarily positive and most producers performed better with FCDs. While for some operators the results are mixed or negative. The first generation of FCDs deployed in SAGD projects were not designed for such process and in some cases ill-suited. Furthermore, current modeling methods deployed have significant limitations that prevent appropriate FCD design or understanding, and although they can be history matched, typically do not provide useful insight into the pressure drops encountered or held understand the benefit of different devices. In order to design and optimize FCDs for SAGD, it is necessary to characterize different FCDs under the steam-breakthrough condition, and accurately model the flashing in the near wellbore area associated with low-subcool operation. The extensive chocking in FCDs, far greater than initial design, in many cases is due to near-wellbore flashing.

This work is a continuation of three previous parts discussing the liquid pool modeling for SAGD producers (Irani, 2018, 2019 and Irani and Gates, 2018). The purpose of this work is to create a PI that fit for purpose of SAGD liquid pool pre- and post-flashing that mainly can be used for analysis and optimization of FCDs. With FCDs, the draw-down pressure is typically higher, resulting in flashing near the well bore. If there is flashing in the near wellbore area, the temperature gradient within liquid pool yields the saturation curve. The flashing causes the reduction in the relative permeability of the liquid phase, that creates new equilibrium that stabilizes at lower rates. Such new equilibrium analysis is conducted by forcing a new temperature gradient to the model. The main output of such analysis is the produced steam quality at the producer sand-face. The steam quality is an important input for the flow control devices (FCDs) especially at subcool close to the zero, as it controls its behavior. This type of analysis can help the operators evaluate the effectiveness of different type of FCDs, whether they are primarily momentum- or friction-style devices.
Performance and Comprehensive Mechanisms of Non-Condensable Gas Assisted Steam Process in Enhanced Heavy Oil Recovery: An Experimental Study
Authors: Gao Hao , Pu Wanfen , Li Yibo , Luo Qiang , Luo Haoyu , Sun Ziqi , Ding Liangliang
Published: March 2020

Non-condensable gas assisted steam, being recognized as a promising technique in enhanced heavy oil recovery, has been successfully employed in oilfield for many years. Nevertheless, the displacing mechanism of this technology is complicated and has not been thoroughly understood. The emphasis of this study lies in the performance of non-condensable gas assisted steam flooding in improving heavy oil recovery and its comprehensive mechanism has been discussed.

In the research, carbon dioxide (CO2) addition to steam injection process is proposed. The influence of CO2 dissolution on oil properties and interfacial tension (IFT) between oil and gas was investigated via PVT and IFT tests. Experiments on high temperature relative permeability were made to study the effect of CO2 on flow characteristic of oil and water in porous media. Based on above studies, the displacing performance of CO2 assisted steam process was investigated through one-dimensional sand-packed physical experiment. CO2 alternating steam flooding followed the constant CO2/steam volume ratio of 1:10.

The experimental results showed that CO2 dissolving in heavy oil was able to swell oil volume, reduce oil viscosity and IFT, and enhance oil phase relative permeability. Addition of CO2 effectively could maintain soaking pressure in steam huff and puff process and offered more oil production energy. CO2 alternating steam flooding could delay injection pressure drop and push the thermal front forward heating more heavy oil to be produced out. The performance of CO2 assisted steam process markedly outperformed single steam injection in oil recovery, which attributed to the increment of both microscopic oil displacement efficiency and macroscopic volume sweep efficiency. Oil swelling and low IFT were beneficial to reduce residual oil which was trapped in capillary resistance. The reduction of oil viscosity and the increment of oil phase relative permeability indicated that mobility of viscous oil was improved, which could enhance displacing efficiency in porous media. Meanwhile, maintenance of reservoir pressure through introducing CO2 to steam injection process could lead more oil to be heated, which contributed to improve sweep efficiency. Moreover, the dramatic decrease of oil viscosity lowered the mobility contrast between oil and water in porous media, probably mitigating viscous fingering and channeling to some extent.

This study has provided more powerful evidences to fully understand comprehensive mechanisms of non-condensable gas assisted steam process. Results may prove that this method is an efficient technology for improving oil recovery in heavy oil reservoir.
Innovative Fluid-Loss Control Pill Improved Workover Operations in a Shallow Low-Pressure Heavy Oil Unconsolidated Sandstone Reservoir in Kuwait
Authors: Reda Mahmoud , Albahri Abrar , Pandey Dharmesh , AlFaudari Mohammad , Kommaraju Srinivas , Malik Satinder , Pallath George , Ali Mohamed
Published: March 2020

Workover operations in shallow low pressure heavy oil unconsolidated sandstone reservoir in Kuwait presents a major challenge due to significant killing fluid loss which causes wellbore plugging, incremental operational costs due to more rig days, excess brine volumes, and more importantly the impact of deferred production due to formation damage. This paper presents an innovative fluid-loss control pill added to killing fluids, which has resulted in significant cost savings and well productivity improvements.

The subject heavy oil reservoir have formation pressure equivalent to 6.3 PPG versus 9.3 PPG Potassium Chloride brine used as killing fluid. This overbalance condition is a requirement as safety barrier but conversely it leads to hundreds of barrels of killing fluid losses with the consequently invasion and formation damage. Kuwait Oil Company recently added a new customized fluid loss control pill of high purity vacuumed dried evaporated salt to the well killing procedure. Using this fluid loss control pill both drilling and reservoir engineers achieved their aim in terms of safety operation and no formation damage.

To test this new pill, two shallow wells with 220 psi reservoir pressure and perforation set at 630 ft were selected to record the losses. The first well had undergone workover including recordings from caliper, cement, and ultrasonic logs, which measured the positive impact of the new control pill on logs quality by excluding fluid pumping while logging and having constant fluid level at surface, which saved cable head from unnecessary tensions. In a second well, there was hanged standalone screen on a packer against the perforation and there is no direct access to the perforation. The control pill was customized to be pumped into the screen, which sealed the screen itself perfectly. The control pill flowed back easily in both wells and same loss rate was observed after removing the pill, which confirmed no negative impact on reservoir permeability.

KOC confirmed that the two jobs were successful and the pill to be approved for full field implement in other operations. The achieved success criteria summarized as follows: Hydrostatic column is a safety barrier that assuring fluid level at surface during workover is safety requirement especially in high Gas oil ratio wells.Full circulation enhances sand cleanup operation.Fluid level at surface results in accurate logging by eliminating invasion into reservoir and support improved operations.
Enhanced Oil Recovery in Post-CHOPS Cold Heavy Oil Production with Sand Heavy Oil Reservoirs of Alberta and Saskatchewan Part 1: Field Piloting of Mild Heating Technologies
Authors: Coskuner Gokhan , Huang Haibo
Published: March 2020

Lloydminster area that straddles Alberta and Saskatchewan border contains vast amounts of heavy oil deposits in thin unconsolidated formations. It is believed that the heavy oil resource volume is in the 50 to 70 billion bbl range which makes it a world class resource. This work briefly summarizes the reservoir properties of these formations and provides an overview of the primary CHOPS recovery mechanism which only recovers on average 8% of the original oil in place. Therefore, the target for Enhanced Oil Recovery (EOR) processes are substantial. For instance, if an additional 2% (25% of the primary) oil can be recovered, this means an additional 1 to 1.5 billion bbls of oil production which can sustain the oil industry for many years in this area providing jobs and contributing significantly to government royalties.

A number of EOR processes are reviewed in this study from the conventional water flooding technologies to more state of the art processes such as Horizontal well Hot Oil Circulation. It is shown that part of the resource with viscosities less than 5,000 to 10,000 cp can be a target for water/polymer flooding.

While steam injection in heavy oil reservoirs can be very successful, more than 95% of the resource in Lloydminster is less than 10 m thick and, thus, is not amenable to steam injection due to excessive heat losses to the surrounding formations. However, EOR processes involving mild heating or no heating can be feasible in these thinner formations. A number of mild heating technologies are discussed. Two of these technologies have been piloted in the field: Hot Water Vapour Process and Horizontal Well Hot Oil Circulation. Field results from these pilots are presented and discussed in this paper. It appears that these technologies can offer significant commercial potential in post-CHOPS reservoirs as well as in areas where CHOPS or horizontal primary production wells have not been successful.
Artificial Intelligence for Real-Time Monitoring of Fracture Driven Interactions and Simultaneous Completion Optimization
Authors: Stephenson Hayley , Nguyen Thomas , Murrell Glen , Shahkarami Alireza , Klenner Rob
Published: March 2020

This paper builds on Klenner et al. 2018, which utilized machine learning to understand well-to-well communication ("Frac hits") or fracture-driven interaction (FDI) during hydraulic fracturing operations. This paper introduces an infrastructure that enahances the process for real-time enablement including data acquisition, visualization, and alerting for completion adjustments during operations. A use case is also presented which monitored, characterized, and provided understanding to the root causes of FDI during operations in the field. Machine learning in real-time provided insights and informed decisions regarding treating pressure, slurry rates, or proppant concentrations.

The analysis included real-time streaming of time series completion data of the hydraulically completed infill wells and the time series pressure data of the offset wells. The processing of the data in real-time uses s a 3-step process: 1) Apply analytics to detect and characterize interference events during the active stimulation and offset monitoring 2) Utilize alert mechanisms to notify operators when a significant communication event is occurring and 3) Apply machine learning techniques to determine what completion parameters inform the occurrence of FDI events, and quantify those parameters in order to provide operators with suggestive actions to help control the event in real-time.

The novelty of this approach is the application of analytics and machine learning to multiple streaming data sets in order to alert the operator of events, identify causality and consequently optimize completion design in real-time. The quantification of the completion parameters provides rules or recommendations that enable operators to make informed decisions to mitigate or manage communication. Furthermore, the methodology lends a fundamental analytics framework for visualization, continuous learning to create and optimize other real-time completion and stimulation operations at the asset level.
Quantitative Analysis of Inter-Well Communication in Tight Reservoirs: Examples from Montney Formation
Authors: Haghshenas Behjat , Qanbari Farhad
Published: March 2020

Well spacing and completion optimization in tight and shale reservoirs is a multi-dimensional task which comprise reservoir rock and fluid characterization, well performance study, inter-well communication analysis, and economic evaluation. Two sources of pressure data for characterization of inter-well communication include offset well pressure monitoring during hydraulic fracturing and controlled communication (interference) tests through staggered production. Both types of inter-well communication tests have become common among the operators in tight and shale reservoirs. However, quantitative analysis tools for interpretation of the test results are in their infancy. The focus of this study is quantitative analysis of pressure interference tests.

In this study, an analytical model is developed for quantitative analysis of communication between multi-fractured horizontal wells (MFHWs) using pressure data from production and monitoring well pairs. The governing partial differential equation for the more general case of coupled flow in hydraulic fracture and matrix systems is solved using the Laplace transform. In order to validate the analytical model, the results from the analytical solution are compared against numerical simulation models.

The analytical model of this study is applied to two field case from Montney formation. In these cases, a well from a multi-well pad is put on production and bottom-hole pressure of a monitoring well from the same pad is recorded using down-hole recorders. Communications between the wells is quantified using the analytical models of this study.

The model of this study serves as a novel and practical tool for quantitative analysis and interpretation of inter-well communication in MFHWs. Integration of the model with other direct diagnostic and measurement tools can provide insight into optimized completion intensity for MFHWs.
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

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

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

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

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

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

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

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

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

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

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

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

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.
Mental health and psychosocial support for families of missing persons in Sri Lanka a retrospective cohort study
Authors: Andersen Ida , Poudyal Bhava , Abeypala Arundathi , Uriarte Carla , Rossi Rodolfo
Published: March 2020

Background: The International Committee of the Red Cross (ICRC) has developed its ‘Accompaniment model’ to address the multi-faceted needs of relatives of people who go missing during armed conflict. In Sri Lanka an Accompaniment Programme was launched in 2015 for the relatives of the more than 16,000 missing persons who remain unaccounted for. Method: 1,783 relatives who took part in the mental health and psychosocial support (MHPSS) component of the ICRC’s Accompaniment Programme in Sri Lanka between April 2016 and August 2017 were offered eight peer-support group sessions, individual home visits, referrals to local services, and commemoration events to pay tribute to their missing relatives. Symptoms of anxiety and depression (using the HADS scale), somatic difficulties (using the BSI scale) and daily functioning (ICRC scale) were assessed before and after the MHPSS intervention. Results: Prior to receiving support, Tamil and Muslim ethnicity, ≥60 years of age and civilian status were predictors of severe symptoms of anxiety; Tamil ethnicity, ≥50 years of age and being the mother of a missing person were predictors of severe symptoms of depression; and ≥50 years of age and severe symptoms of anxiety and depression were predictors of severe somatic difficulties. After receiving support, the vast majority of the relatives of missing persons showed reduced levels of anxiety (81%), depression (79%) and somatic pain (77%), as well as increased functioning (75%). Predictors of improvement following support were severe levels of distress at baseline and Tamil and Muslim ethnicity. In addition, attending at least three group sessions was a predictor of decreased anxiety, age group 51-60 was a predictor of decreased depression, female gender was a predictor of decreased somatic difficulties, and referrals were a predictor of increased functioning. Conclusion: The MHPSS component of the ICRC’s Accompaniment Programme is a relevant approach to helping families to cope with not knowing the fate and whereabouts of their missing relatives, to reduce distress, to break their social isolation and to resume more functional lives. However, further research is needed, possibly through a controlled trial, to better establish the effectiveness of this approach.
Prevalence of Risk factors for non-communicable chronic disease in Shaanxi province of China
Authors: Author) Weihua Wang(Former Corresponding , Qiu Lin , Sa Rina , Li Xia , Author) Feng Liu(New Corresponding , Zhou Zhongliang
Published: March 2020

Background

Risk factors including both behavioral risk factors (BRFs) and biological risk factors contribute majorly to the development of non-communicable chronic diseases. We aimed to explore the covariation, cluster and distribution of risk behaviors in Shaanxi province of China.

Methods

Multistage clustering sampling was adopted to select participants for the survey. We obtained the data and investigate the prevalence and clustering pattern (mean number of risk factors) of eight risk factors for non-communicable chronic diseases, including four behavioral risk factors (smoking, drinking, consumption of fruit and vegetables, physical activity) and four biological risk factors (overweight and obesity, raised blood pressure, raised fasting blood glucose and raised total serum cholesterol). Ordinal logistic regression was conducted to investigate the independent demographic and socioeconomic covariates of clustering of the eight risk factors.

Results

The prevalence of eight risk factors in Shaanxi province were found: insufficient fruit and vegetable intake,59.82%; overweight and obesity, 46.82%; raised blood pressure, 30.88%; current smoking, 28.21%; physical inactivity, 24.63%; raised total serum cholesterol, 20.96%; raised blood glucose, 4.27% and harmful use of alcohol, 2.16%. 64.73% of the Chinese in Shaanxi province had two or more risk factors. Being a male, old, living in rural areas, having a lower education level and being separated, divorced or widowed all tends to have more risk factors.

Conclusion

There is a high prevalence of risk factors for non-communicable chronic diseases among residents in Shaanxi province of China. Public health interventions are needed to reduce these risk factors and ought to target those who are male, old, poorly educated and live in rural areas.