bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Resources Audit: Dimensions Increased Productivity and Job Performance (Ethnographic Study of the Bureau of Human Resources at the University of Widyatama)
Authors: Manurung Daniel T. H. , Paryati Retno
Published: March 2020

Human Resources Audit is a systematic and objective assessment of the examination, as well as documenting the organizational functions that are affected by the management of human resources with a view to ensuring compliance with the principle of appropriateness, effectiveness, and efficiency in the management of human resources for the achievement of organizational goals, objectives, and functions of the work program to improve the productivity performance of the staff of the University of Widyatama. This study tries to reveal the importance of the audit of human resources in achieving the productivity and performance of employees at the University Widyatama. This research was conducted on the assessment of the Bureau of Human Resources for the performance of its employees, whether working well run each program of work and behave according to the cultural character and discipline in accordance with the behavior of the corporate culture to improve productivity and performance by applying the principle of reward and punishment for put positions. This study uses a qualitative and ethnographic approach interpretive paradigm through observation and in-depth interviews of the informants in the bureau of human resources to find out the gains in accordance with the characteristics, culture, discipline, and motivation of employees working at the University of Widyatama.
A Systematic Review of Unsystematic Total Ankle Replacement Wear Evaluations
Authors: Mujukian Angela , Ho Nathan C. , Day Matthew J. , Ebramzadeh Edward , Sangiorgio Sophia N.
Published: March 2020

Background:

Numerous studies have reported the use of laboratory multistation joint simulators to successfully predict wear performance and functionality of hip and knee replacements. In contrast, few studies in the peer-reviewed literature have used joint simulation to quantify the wear performance and functionality of ankle replacements. We performed a systematic review of the literature on joint simulator studies that quantified polyethylene wear in total ankle arthroplasty. In addition to the quantified wear results, the load and motion parameters were identified and compared among the studies.

Methods:

A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify articles reporting total ankle replacement polyethylene wear using joint simulators.

Results:

Nine studies that used joint simulators and 1 study that used a computer simulation were found. Although all studies used physiological multidirectional motions (i.e., internal/external rotation, plantar flexion/dorsiflexion, anterior/posterior translation), there was large variability among the studies in the magnitudes of these motions. Among these studies, mean non-cross-linked polyethylene wear ranged from 3.3 ± 0.4 to 25.8 ± 3.1 mm3 per million cycles. In contrast, mean highly cross-linked polyethylene wear ranged from 2.1 ± 0.3 to 3.3 ± 0.4 mm3 per million cycles. The wide distribution in wear rates was attributable to the highly inconsistent kinematic parameters and loads applied as well as differences in implant design and materials.

Conclusions:

There is a severe lack of clinically applicable data on wear performance of total ankle replacements in the peer-reviewed literature. No universal set of kinematic load parameters has been established. Furthermore, only 2 of the published studies have validated their findings using independently derived data, such as retrieval analysis. These shortcomings make it difficult to compare findings as a function of design parameters and materials, or to draw clinically relevant conclusions from these simulations. More work is required to enhance the predictive capability of in vitro simulations of total ankle replacements.

Clinical Relevance:

The results of joint wear simulator studies may not accurately represent in vivo wear of total ankle replacements. Joint simulator studies should establish that they are accurately replicating in vivo wear, thus enabling use of their predictive capabilities for new materials and designs.
Steam Allocation Optimization in Full Field Multi-Pad SAGD Reservoir
Authors: Kumar Anjani , Warren Gregory , Joslin Kevin , Abraham Anson , Close Jason
Published: March 2020

Computing hardware and reservoir simulation technologies continue to evolve in order to meet the ever-increasing requirement for improving computational performance and efficiency in the oil and gas industry. These improvements have enabled the simulation of larger and more complex reservoir models. When working with steam assisted gravity drainage (SAGD) operations, determining the optimal steam injection rates and allocation of steam among various multi-well pads is very important, especially given the high cost of steam generation and the current low oil price environment. As SAGD operations mature, steam chambers start to coalesce and interact with each other, forcing producers to face declining oil rates and increasing steam oil ratios (SOR). Operators must work to reduce injection rates on declining wells to maintain a low SOR and free up capacity for newer, more productive wells. Steam injection and allocation between wells and multiple pads then becomes an exercise of optimizing cost, and improving productivity and net present value (NPV).

A case study is performed on a full field SAGD model by optimizing steam delivery aided by Artificial Intelligence (AI) and machine learning enabled algorithms for automated numerical tuning, and dynamic gridding technologies. The model contains 15 pads, 96 well pairs (192 wells), 12.6 million active simulation grid blocks, and represents a typical Athabasca formation geology and fluid properties. The proposed steam delivery optimization considers two main scenarios. The first scenario considers the case in which steam generation capacity is limited, and the optimization process intelligently determines the optimal well and pad level steam injection rates dynamically during the life of the project. The second scenario assumes that steam generation availability is not constrained and the field development plan is optimized based on steam required for maximum recovery from the field as fast as possible. A full field optimized development plan is created for the 15 SAGD pads and 96 well pairs.

Following the optimization, an increase in NPV and reduction in SOR is achieved for the entire field due to the efficient utilization of total available steam. The optimization study required several full field SAGD simulations to be completed in a practical time period, demonstrating that workflows such as this can be carried out for full field thermal models. These models can also be used to evaluate production responses due to varying operating strategies in the field.

This paper presents the optimization of steam allocation for a full field, multi pad SAGD simulation model. It demonstrates that advances in computing and reservoir simulation technology have enabled the simulation of full field models within a reasonable timeframe, allowing engineers to tackle a new class of problems that were previously impractical.
Scale Up of Multi-Phase Flow Properties from Micro to Core Scale
Authors: Bashtani Farzad , Kantzas Apostolos
Published: March 2020

Multiphase relative permeability is a key parameter in reservoir simulation. Typically, end-point based correlations are employed in order to obtain such curves for reservoir simulation purposes. However, those correlations are not capable of capturing micro-scale physical phenomenon which can significantly affect flow pattern at larger scales. Consequently, it is necessary to obtain a scale-up methodology in order to transfer the micro-scale physics to reservoir-scale. The objective of this research is developing a scale up procedure which can be applied to multi-phase flow properties obtained by micro-scale flow simulation to compute the equivalent macro-scale and core-scale flow properties having the micro-scale flow properties. Two different sets of media are employed: media representing unconsolidated oil sands and media based on experimental data obtained from the Mesaverde formation located in the Poweder River Basin. The former is used for validating the scale up methodology since not all the required information is available in the experimental data set. Pore scale network modelling is used for calculating micro-scale multi-phase flow properties such as porosity, and absolute and relative permeability. Then the generated subsegments are populated in space to reconstruct the macro scale medium. Flow properties of such medium are then obtained by network modelling and the proposed scale-up methodology and the results are compared. Furthermore, macro-scale media are distributed in space in layers and stacks of increasing and decreasing permeability to form a core-level medium. Single and multi-phase flow properties are then calculated by applying a pressure drop across the core. Permeability and relative permeability curves are calculated using the combination of mass balance, equation of state, and Darcy equation assuming steady-state flow while capillary pressure curve is obtained using the modified Leverett-J function procedure used in micro-to-macro scale up section. Results show good agreement between the expected and calculated properties for both unconsolidated and consolidated media. Finally, physical behavior observed at micro and macro scale is transferred to the core scale.
Experimental Evaluation of a Hydraulically Actuated Double-Acting Positive Displacement Quad-Pump System for SAGD Oil Production Applications
Authors: Ding Yuchang Bob , Li Ming , Ding Xuefeng Kevin , Su Ze Kevin
Published: March 2020

A novel positive displacement hydraulically actuated quad-pump system (Quad-Pump) has been developed to improve production in deviated and horizontal oil wells. This downhole pump technology can be used in high temperature environment with large volume production such as SAGD wells.

This paper describes the working principle of Quad-Pump downhole assembly and its hydraulic power system. Its operation advantages in SAGD environment are also presented.

Design details of a test apparatus (flow loop) used to test the newly developed Quad-Pump is provided in this paper. A series of experiment is designed to verify the pump working principle and evaluate pump performance. A 4.75" Quad-Pump was manufactured and tested with producing fluid temperature of 100 °C and 200 °C. Testing results show the pump can produce up to 3600 bbl/day of fluid when a 60 hp electric motor is used to power the hydraulic drive system.
Progress of the Artificial Lift Technology Suitable for Offshore Thermal Recovery in Bohai Bay, China
Authors: Liu Yigang , Shang Baobing , Bai Jianhua , Yu Fahao , Han Xiaodong , Gao Hao , Wu Xuanren
Published: March 2020

There is abundant heavy oil resource in Bohai Oilfield and thermal recovery is an effective method to realize the high-efficient development. Till now, several field pilots have been conducted. However, for the offshore thermal recovery well, the onshore common used rod pump artificial lift technology is not applicable. The ordinary electric submersible pump (ESP) system cannot be directly used either, because it cannot stand the high-temperature steam. Therefore, artificial lift technologies suitable for offshore thermal recovery well is developed in recent years.

For the ESP system, a high-temperature safety control system was developed, consisting of downhole safety valve, cable packer, and vent valve. The overall temperature and pressure resistance value could reach as high as 350°C and 21MPa, respectively. And the high temperature electric submersible pump could stand 250°C cyclic steam. This ESP system has been used in about 30 thermal recovery wells in Bohai Oilfild, satisfying the artificial lift requirements for the moment. With this ESP system, the overall process of each huff-and-puff cycle includes: lowering steam injection tubing, steam injecting, soaking, replacing production tubing, producing. That means two workover operations for tubing changes are required in each huff-and-puff cycle, which adds more cost to the oil production and has bad effect on the thermal recovery.

Considering the drawbacks of the current ESP system, a new concentric-tubing jet pump system suitable for offshore oilfield with function of both steam injection and oil production is developed. Besides, the matched surface equipment, such as oil-water-sand separator and power fluid pump, are designed. The temperature resistance of the designed jet pump system reaches 400°C. With this system, no workover for tubing replacement is needed any more during one huff-and-puff cycle. Till now, this new jet pump system has been put into field pilot in one thermal recovery well. Both the steam injection and oil production process completed successfully, indicating its applicability for the offshore thermal recovery wells. In this paper, the tubing string structure details of the jet pump system and the specific field operation process is introduced. This new artificial lift technology will be gradually applied in other wells to improve the thermal recovery effect because of its advantages comparing with ESP system.

Great progress and breakthrough of the artificial lift technologies suitable for offshore thermal recovery have been achieved in recent years in Bohai Oilfield, which will provide powerful technical support for the high efficiency development of the heavy oil resource in Bohai Bay.
Simulation of Non-Condensable Gases Co-Injection in Steam Assisted Gravity Drainage: The Role of Gas-Liquid Relative Permeability Curves
Authors: Mendoza Ana Maria , Kantzas Apostolos
Published: March 2020

The simulation of thermal recovery processes and their variations like non-condensable gases (NCG) co-injection with steam in SAGD require reliable gas-liquid relative permeability curves. In this work, three experiments were conducted to extract equivalent thermal relative permeability curves, and the experimental curves were used as an input in a numerical simulation model to evaluate the NCG co-injection with steam in SAGD. Heavy oil was diluted with toluene to mimic the viscosity of the oil at 165, 195, and 225°C. It was assumed that the viscosity variation was the main factor affecting the temperature-dependent gas-liquid relative permeability curves. Athabasca sand was packed, and after water and oil were flooded, gas was injected. Three sets of gas-liquid relative permeability curves were extracted through history match. The experimental curves were used as an input in a simulation model to evaluate the effect of the amount of NCG and time of NCG co-injection in SAGD using CMG STARS.

In contrast to previous simulation studies, the current simulation results showed that most of the injected gas leaked from the steam chamber and accumulated at the top of the reservoir. Part of the gas stayed at the top of the steam chamber insulating the steam chamber from the overburden rock. The gas that leaked from the steam chamber aided in additional recovery of oil. According to the simulation results, for a homogeneous reservoir, small amounts of NCG (about 1 mole %) can be co-injected with steam at any time of a SAGD project to reduce its energy requirements without a negative impact in the oil recovery. This amount can be progressively increased to further reduce the energy requirements and increase the ultimate oil recovery. With the introduction of the new experimental gas-liquid relative permeability curves, it would be possible to optimize NCG co-injection processes in SAGD with the use of numerical simulation, taking into account the flow behaviour of gases in the reservoir that usually is not considered.
Advances in Understanding the Scaling Potential for Thermal Wells: A Mechanistic Study
Authors: Habibi Ali , Fensky Charles , Roostaei Morteza , Mahmoudi Mahdi , Fattahpour Vahidoddin , Zeng Hongbo , Sadrzadeh Mohtada
Published: March 2020

Scale deposition and its treatment are crucial part of any thermal recovery method. High temperature variation, phase change associated with steam condensation and flashing, and complex flow dynamics of the wells make the thermal wells more susceptible to scale deposition. Several studies evaluated the type of scales collected from plugged sand screens; however, more investigation is required to address the reservoir conditions and wellbore hydraulics affecting the scaling potential of minerals at downhole conditions.

A laboratory workflow combined with a predictive modeling toolbox to evaluate scaling tendency of minerals for different downhole conditions has been developed. First, saturation indices (SI) for different minerals were calculated at reservoir temperature and pressure using water chemistry analysis and the Pitzer theory. Then, the mineral composition of deposited materials collected from thermal wells in Athabasca and Cold Lake area were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS), Total Organic Carbon (TOC) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses. Finally, a comparison analysis was performed between predictive and characterization results.

The results of SI calculations showed that Mg-based silicates and Fe-based minerals are positive (SI>5) even at high temperatures (T>430 K). This indicates that the possibility of deposition for these minerals is high. Carbonates (calcite and aragonite) minerals are the most common depositing minerals. However, the extent of scaling index of carbonates is controlled by the concentration of Ca, HCO3, and CO3 in the water sample. The characterization results confirm the results of modeling part. The results of SEM/EDS, ICP-MS analyses showed that carbonates, Mg-based silicates, and Fe-based corrosion products are the most common depositing materials among all minerals.

The workflow presented in this study will help the industry to evaluate the scaling potential for thermal wells at different downhole conditions to make a proper decision to prevent plugging of the completion tools.
Fiber Optics Application for Downhole Monitoring and Wellbore Surveillance; SAGD Monitoring, Flow Regime Determination and Flow Loop Design
Authors: Soroush Mohammad , Mohammadtabar Mohammad , Roostaei Morteza , Hosseini Seyed Abolhassan , Fattahpour Vahidoddin , Mahmoudi Mahdi , Keough Daniel , Tywoniuk Matthew , Cheng Li , Moez Kambiz
Published: March 2020

Effective Steam Assisted Gravity Drainage (SAGD) operation relies on subcool management to reduce the risk of steam breakthrough. Monitoring of several parameters is performed to assure uniform development of steam chamber and heating of reservoir. This paper discusses the application of Distributed Acoustic Sensing (DAS), a monitoring platform to achieve reliable reservoir and wellbore surveillance in SAGD projects.

In this study, a comprehensive review of DAS deployment in oil and gas industry was performed including vertical seismic profiling, hydraulic fracturing, well/pipe integrity and flow profiling applications. Then, SAGD flow monitoring was investigated in detail. To utilize DAS in SAGD projects, knowing completion designs are necessary. Therefore, various SAGD completion designs and corresponding flow regimes were discussed as well. Finally, four flow loop designs were proposed to accurately simulate the complex wellbore hydraulics of the SAGD producer using DAS recordings.

This work started with an overview of DAS systems in downhole monitoring including real time high resolution vertical seismic profiling, hydraulic fracturing characterization and optimization, well and pipe integrity, leak detection and assessing completion effectiveness. Then, flow profiling including flow rate, flow fractions and flow regimes determinations using DAS were discussed with focus on SAGD monitoring. Completion designs directly impact on SAGD monitoring and DAS recordings, more specifically on flow regimes inside the tubing and annulus. Therefore, various completion designs with their tubing and screen sizes were presented and corresponding flow regimes were determined in both tubing and annulus. It was observed that flow regimes vary with type of completion design, liquid flow rate, steam breakthrough locations and tubing/screen sizes. Eventually, four flow loop designs were proposed based on the discussions for future DAS application.

This paper discusses existing completion designs and possible flow regimes in SAGD projects. Consequently, novel designed flow loops are introduced for DAS deployment to better understand the complex wellbore hydraulic of the well and measure the key parameters in optimizing the production operation. This study is a design stage for future quantitative measuring of flow profiling using DAS systems.
A Novel Experimental Method CCEC and Modelling of Methane Dissolution and Exsolution in Heavy Oil
Authors: Dong Xiaomeng , Xi Zhiyu , Badamchi Zadeh Amin , Jia Na , Gates Ian D.
Published: March 2020

The phase behavior and physical properties of heavy oil have been considered of great importance during cold production process. In this study, constant composition expansion and compression (CCEC) tests were performed to measure and evaluate the live oil expansion and compression under various temperatures and pressures conditions through a PVT apparatus. The live oil viscosity and density were also obtained from the the experiments. CCEC tests were conducted using the recombined live oil (with specified gas-oil ratio) in the PVT cell without mixing by utilizing three different constant volume change rates (i.e. "Fast Rate", 1.5 cc/min; "Moderate Rate", 0.015 cc/min; and "Slow Rate", 0.0003 cc/min) at 75°C and 15°C. During the expansion period, the total volume was monitored continuously until it reaches the cell maximum. Following the expansion process, the oil and gas were compressed back to the initial pressure following the same rates as the expansion stage. The P-V diagram has been plotted according to the PVT data, therefore pseudo-bubblepoint pressure was able to be determined based on the slope change of the P-V curve. It is found that pseudo-bubblepoint pressure determined at 75°C is higher than that of 15°C. For different volume expansion rates, a faster rate results in a lower determined pseudo-bubblepoint pressure, indicating a strong foamy oil behavior. On the other hand, however, the volume compression rate did not significantly affect the tendency of total volume reduction curve regarding the PVT experiments. The results obtained from the current study will facilitate industry to make better design for heavy oil reservoir development.
Enhanced Oil Recovery in Post-CHOPS Cold Heavy Oil Production with Sand Heavy Oil Reservoirs of Alberta and Saskatchewan Part 2 : Field Piloting of Cycling Solvent Injection
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 critical literature review of Cyclic Solvent Injection (CSI) as a post-CHOPS EOR technology is conducted. The key aspects of laboratory and theoretical studies of methane and propane mixtures, CO2 and propane mixtures and pure CO2 injection are summarized. A number of field pilots have been conducted using these solvents in post-CHOPS reservoirs in Lloydminster.

Implementation of field pilots is presented and results are discussed using publicly available data. It is shown that while CSI technology is technically successful, economic feasibility is more elusive. However, it appears that CO2 injection is more likely to be economically successful. Furthermore, the economic attractiveness of Cyclic CO2 Injection increases in an environment where greenhouse gas emissions are taxed and credits for disposal are available.
Development of a Rigorous Erosion Prediction Physical Model for Thermal Standalone Sand Control Screens
Authors: Hosseini Seyed Abolhassan , Roostaei Morteza , Velayati Arian , Soroush Mohammad , Mohammadtabar Mohammad , Mahmoudi Mahdi , Fattahpour Vahidoddin
Published: March 2020

Erosion of standalone screens in thermal wells can lead to significant damage and reduction in production. The dominant failure mechanism is the development of localized high-velocity hot spots in the screen due to steam breakthrough or flashing of the steam across the screen. This study provides methods to assess the erosion potential of screen material devices to determine the allowable production conditions which avoid erosion.

In this study the effects of impact angle, flow rate, sand concentration, particle size, and fluid viscosity on erosion are systematically investigated through a multivariable study. Experimental impingement testing is performed on screens in different orientations. Erosion is accessed by collecting weight loss data of the screen. Empirical erosion models are calibrated to provide predictions of functional relationships between erosion rate and varied parameters. Computational Fluid Dynamic (CFD) simulations are performed prior to the experimental work to visualize particle flow paths through the screen and determine local flow and impact velocities and wear patterns.

The performance of five existing erosion models is assessed through experimental testing of sand control screens. In order to translate short-term, high-velocity laboratory test results into field erosion predictions, an empirical erosion model is then developed and employed to provide well flow guidelines and minimize erosion potential. This suggests that the use of erosion prediction models in situations in which due to lack of time/data tuning is not possible, may still provide a reasonable estimate for the rate of material loss of the screen. The model is used to obtain threshold superficial velocity curves for several conditions.

The main concern associated with existing erosion models is that they do not consider sand production, nor do they account for many other factors that affect erosion process. An erosion model, coupled with CFD simulation, has been developed, that account for factors such as geometry, size, material, fluid properties and rate, sand size, shape, and density in downhole flow conditions.
A Comprehensive Review of Enhanced Oil Recovery Projects in Canada and Recommendations for Planning Successful Future EOR projects
Authors: Vishnumolakala Narendra , Zhang Jingjing , Ismail Norasyikin Bte
Published: March 2020

A database is developed from multiple sources to comprehensively present and evaluate enhanced oil recovery (EOR) projects in Canada. The datasets comprising of in-situ reserves, corresponding production and EOR information of Canada and worldwide EOR projects are made publicly available on a custom-built interactive data analysis platform TIBCO Spotfire. EOR projects for light, medium and heavy oils in Canada are classified into 65 solvent flooding, 6 polymer flooding and 13 Alkali-Surfactant-Polymer (ASP) flooding. Thermal methods, particularly SAGD & CSS are conducted for extra heavy oil and bitumen in oil sands. Another 31 of immiscible flooding projects are also identified. Factors contributing to success of these projects in respective fields are evaluated based on reservoir properties and EOR parameters such as miscibility, wettability, mobility ratio, capillary number, minimum miscibility pressure. With detailed technical analysis, EOR screening criterion for each method is updated and validated with world EOR data as well as Alberta oil pools data of 2019. Primary and secondary flooding projects that have potential for tertiary recovery are matched with historic EOR data to estimate future enhanced production. It has been observed that 257 pools currently employing water flooding have some similarities to fields that have seen success with EOR. Upgrading these primary or secondary projects to enhanced recovery has the potential of increasing daily production by as much as 14%.
Impact of Carbonates on Reaction Kinetics of a Bitumen Combustion
Authors: Pope Connor , Ismail Norasyikin Bte , Hascakir Berna
Published: March 2020

Reaction kinetics experiments are conducted to estimate important combustion parameters for crude oils. However, at elevated temperatures not only crude oil, but also reservoir rock is reactive, and the interaction of reservoir rocks with fluids may change the fate of the In-Situ Combustion (ISC) process. This study investigates the role of carbonates on the reaction kinetics of a bitumen sample from Canada.

To reach this goal, Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC) experiments were conducted at a constant heating rate on a bitumen sample and the blends of bitumen with calcite (CaCO3) and dolomite (CaMg(CO3)2) minerals. The bitumen sample has been divided into its saturates, aromatics, resins, and asphaltenes (SARA) fractions. TGA/DSC experiments were conducted on the individual fractions and their pseudo blends in the presence and absence of carbonates to understand the contribution of each fraction in ISC success and their mutual interactions. Model fitting approach was used to analyze TGA/DSC graphs analytically to obtain activation energy and heat of reaction for each pseudo fraction, their blends, and initial bitumen samples at low (LTO) and high (HTO) temperature oxidation regions.

It has been observed that among all SARA fractions, the aromatics fraction alone generated the greatest amount of energy. Saturates are known as the ignitor for the combustion and its ignition characteristics are enhanced with the presence of carbonates. Similarly, the energy generation at low temperature oxidation (LTO) region for saturates becomes more significant for the saturates-aromatics pseudo blend. While the aromatics heat generation increased more for the pseudo blend with asphaltenes in the presence of carbonates, the energy generation of aromatics is negatively affected for the pseudo blend prepared with resins and carbonates. Thus, it was concluded that for the specific bitumen sample worked in this study, resins are the critical fraction determining the ISC fate in a carbonate reservoir. Moreover, we found that thermal decomposition of carbonate minerals negatively affects asphaltenes cracking and combustion reactions since both asphaltenes cracking and thermal decomposition of carbonate rock start at around the same temperature.

Our findings indicate that reaction kinetics studies should be conducted in the presence of all reservoir components (rock and fluids). However, because it is difficult to understand the contribution of each component to overall ISC performance, we recommend conducting reaction kinetics experiments on pseudo blends of reservoir fluid components. This procedure has been introduced for the first time with this study and enhanced our understanding towards ISC kinetics but should be extended to different crude oil and reservoir rock pairs.
Completion Optimization of Child Wells in a Depleted Environment, a Duvernay Example
Authors: Garcia Ferrer Giselle , Faskhoodi Majid , Zhmodik Alexey , Li Qiuguo , Mukisa Herman
Published: March 2020

With increased drilling activity associated with development of unconventional reservoirs, many operators are reporting both stimulation and production interference between wells. Interference between existing production wells (parent wells) and newly completed infill wells (child wells) is often associated with production impairment (Marongiu-Porcu et al. 2015; Ajisafe et al. 2017; Defeu et al. 2018 and Manchanda et al. 2018a). The objective of this work is to develop guidelines concerning infill wells completion scheme to minimize parent-child wells interference in a typical pad, with infill drilling in the Duvernay formation.

The area of interest selected within the Duvernay formation consists of three parent wells and two child wells. An integrated mechanical earth model (MEM) was constructed for the area using public databases. The created 3D-geological model included petrophysical and geomechanical properties along with a 2D discrete natural-fracture network representing the distribution of natural fractures in the reservoir. Hydraulic fractures in parent wells were modeled using original stress settings from the 3D-MEM. Then, a dynamic model was constructed for the three parent wells and production simulation was run for five years. Pressure distribution at the time when child wells came into production was extracted and 3D depleted stress distribution was computed using a finite element method that included the effect of pore pressure decrease and principal stress magnitude and orientation changes. Then, hydraulic fracture modeling was performed for the two child wells using the new depleted stress distribution, and finally a five-well dynamic model was created. Sensitivity analyses were performed on the hydraulic fracture parameters of the child wells with the objective of maximizing recovery by accessing more virgin reservoir area between the parent wells. Hydraulic fracture modeling followed by dynamic simulation was done in the pad for multiple cases. Fracture geometry, hydraulic/propped surface area, and fracture conductivity in child wells were extracted and analyzed against production performance of the wells.

This study shows a holistic approach in modeling the impact of completion modifications on the child wells performance in an infill drilling scenario. A 3D-geomechanical model coupled with reservoir simulation allowed simulating the propagation of hydraulic fractures in the presence of pressure depleted regions. Results confirmed that the main reason for under-performance of child wells in Duvernay is the stress change induced by the reservoir pressure depletion associated with the parent wells production hence, influencing the child wells hydraulic fractures propagation patterns.
Analysis of Alberta Natural Gas Well Productivity, and its Effects on Price: Could Implementing Allowables, Better Stabilize the Market?
Authors: Chodzicki John D.
Published: March 2020

The natural gas industry in Western Canada, has seen tremendous changes in the last decade, resulting in significantly increased horizontal well initial production rates. It is of interest to review some of the history of "allowables" and "prorationing", originally placed on Texas oil production in the 1930's, and also used in Alberta, in the past. It is hypothesized that allowable rate restrictions on high productivity gas wells, could restrict gas output enough, to provide a more stable market.

This paper examines output from a large "Control Area" in western Alberta. A review of the new wells drilled during the last 5 years, that produce a total of 6.2 Bcf/D, shows a wide distribution of productivity from high rate horizontal wells, contrasted with lower rate gas wells, and significant solution gas production from horizontal oil wells. Production from 10,170 oil and gas wells is reviewed, to see how applying different maximum allowable rates to individual wells, could change the area's total production rate.

Individual well decline rates might be high, but the aggregate production is significant, and 6.2 Bcf/D, of Alberta's total current raw gas production of 13.1 Bcf/D, comes from wells finished drilling, after 2013. The intent with many of the newer wells drilled in Alberta, has been to target liquids rich shale plays, to produce condensate or oil. Unfortunately, while liquid production might start out at decent rates, wells quickly produce a higher percentage of gas, over time. The end result is still more natural gas production, further squeezing into a maxed-out transportation system, causing additional localized downward price stress. Allowables are a regulatory tool that can be used to more fairly give market access for all producers, to the gas transportation system, and provide more of a price floor, by reducing excess production. The anticipation is that a slightly reduced total gas rate, could bring about a higher average price, as the local market is brought into a better supply/demand balance.

LNG plants, currently under construction on the west coast of British Columbia, will eventually provide some access to world LNG markets. Currently, the gas from British Columbia flows into Alberta, where it places additional strain on the gas transportation system, already full with gas from recently drilled, high rate horizontal wells. This has resulted in Alberta average market natural gas prices reaching decade lows, to the point where prices can barely cover operating costs, let alone pay capital costs, resulting in the shut-in of many uneconomic wells. Restricting production from higher rate gas wells, may cause other potential "unintended consequences", but needs to be considered as a way to help restore higher prices, in addition to working on other solutions, that industry has proposed.
Learning from Behavioral Frac Maps: A Montney Case Study in Integration of Modern Microseismic and Production Data Analyses
Authors: Moradi Peyman , Angus Doug , Jeziorski Katie , Greig Amanda , de Groot Michael
Published: March 2020

Aimed at sharing the unconventional wisdom gained from a hydraulic fracturing monitoring case study in the Montney tight gas play, the work showcases the ability of 4D modeling of collective behaviors of microseismic events to chase the frac fluid and navigate the spatiotemporal fracture evolution. Moreover, microseismicity-derived deformation fields are integrated with volumetric estimates made by rate transient analysis to calibrate spatially-constrained SRV models. Through the case study, we give evidence of fracture containment, evaluate the role of natural fractures and the use of diverting agents, estimate cluster efficiencies, conduct analytical well spacing optimization, model productivity decline induced by communication frac-hits from offsets, and provide contributing fracture dimensions and numerical production forecasts. To support the interpretations, we supplement the work by the results of 3D physics-based analytical modeling and multi-phase numerical simulations, and the findings are then validated using two extensive datasets: production profiles acquired by fiber optic DAS, and reservoir fluid fingerprints extracted from mud logs. Besides describing the evolution of seismicity during the treatment, the applied integrated fracture mapping process gives a more reliable and unique SRV structure that streamlines forward modeling and simulations in unconventional reservoirs as well as contributes to solving inverse problems more mechanistically.
Reducing Barriers to Post-9/11 Veterans’ Use of Programs and Servicesas They Transition to Civilian Life
Authors: Morgan Nicole R. , Aronson Keith R. , Perkins Daniel F. , Bleser Julia A. , Davenport Katie , Vogt Dawne , Copeland Laurel A. , Finley Erin P. , Gilman Cynthia L.
Published: March 2020

Background - Numerous programs exist to support veterans in their transitions to civilian life. Programs are offered by a host of governmental and non-governmental stakeholders. Veterans report encountering many barriers to program participation. This study identified barrier reduction strategies offered by programs that new post-9/11 veterans reported using, determined which strategies veterans use and value, and examined veteran characteristics that impact their odds of using programs that offer barrier reduction strategies. Method - This study reflects findings from the first wave of data collection of The Veterans Metrics Initiative (TVMI) , a longitudinal study examining the military-to-civilian reintegration of new post-9/11 veterans. The websites of programs used by respondents were coded for barrier reduction components. Veterans also indicated which barrier reduction components they found most helpful in meeting their reintegration goals. Results - Of 9,566 veterans who participated in Wave 1 data collection, 84% reported using a program that offered at least one barrier reduction component. Barrier reduction components included tangible supports (e.g., scholarships, cash), increased access to programs, decreased stigma, and encouraged motivation to change. Although only 4% of programs that were used by veterans focused on helping them obtain Veterans Administration benefits, nearly 60% of veterans reported that this component was helpful in reaching their goals. Access assistance to other resources and supports was also reported as a helpful barrier reduction component. For instance, approximately 20% of veterans nominated programs that offered transportation. The study also found evidence of a misalignment between the kinds of barrier reduction components veterans valued and those which programs offered. Veterans from the most junior enlisted ranks, who are at most risk, were less likely than those from other ranks to use barrier reduction components. Study limitations and ideas for future research are discussed.Conclusions – Despite the evidence that barrier reduction components enhance access to programs and contribute to program sustainability, many programs used by post-9/11 veterans do not offer them. There was also a misalignment between the barrier reduction strategies that veterans value and the strategies offered by programs. Veteran serving organizations should increasingly implement barrier reduction strategies valued by veterans.
Reduced serum levels of pro-inflammatory chemokines in Fragile X Syndrome
Authors: Dijck Anke Van , Barbosa Susana , Bermudez-Martin Patricia , Khalfallah Olfa , Gilet Cyprien , Martinuzzi Emanuela , Elinck Ellen , Kooy R Frank , Glaichenhaus Nicolas , Davidovic Laetitia
Published: March 2020

Background: Fragile X syndrome (FXS) is the most frequent cause of inherited intellectual disability and the most commonly identified monogenic cause of autism. Recent studies have shown that long-term pathological consequences of FXS are not solely confined to the central nervous system (CNS) but rather extend to other physiological dysfunctions in peripheral organs. To gain insights into possible immune dysfunctions in FXS, we profiled a large panel of immune-related biomarkers in the serum of FXS patients and healthy controls.
Methods: We have used a sensitive and robust Electro Chemi Luminescence (ECL)-based immunoassay to measure the levels of 52 cytokines in the serum of n=25 FXS patients and n=29 healthy controls. We then used univariate statistics and multivariate analysis, as well as an advanced unsupervised clustering method, to identify combinations of immune-related biomarkers that could discriminate FXS patients from healthy individuals.
Results: While the majority of the tested cytokines were present at similar levels in FXS patients and healthy individuals, nine chemokines, CCL2, CCL3, CCL4, CCL11, CCL13, CCL17, CCL22, CCL26 and CXCL10, were present at much lower levels in FXS patients. Using robust regression, we show that six of these biomarkers (CCL2, CCL3, CCL11, CCL22, CCL26 and CXCL10) were negatively associated with FXS diagnosis. Finally, applying the K-sparse unsupervised clustering method to the biomarker dataset allowed for the identification of two subsets of individuals, which essentially matched the FXS and healthy control categories.
Conclusions: Our data show that FXS patients exhibit reduced serum levels of several chemokines. This paves the way for further study of immune phenotypes in FXS patients.
Geographic Availability to Optometry Services Across Canada: Mapping Distribution, Need and Self-Reported Use
Authors: Shah Tayyab , Milosavljevic Stephan , Bath Brenna
Published: March 2020

Background: This research investigates the distribution of optometrists in Canada relative to population health needs and self-reported use of vision care services. Methods: Optometrist locations were gathered from provincial regulatory bodies. A geocoding approach converted descriptive data into geographic coordinates. Utilizationof vision care services was extracted from the Canadian Community Health Survey (CCHS) 2013-2014 question regarding self-reported contacts with optometrists or ophthalmologistsproviders. Data from the 2016 Statistics Canada census were used to create three population ‘need’ subgroups (65 years and over; low-income; and people aged 15 and over with less than a high school diploma). Optometrist-to-population ratios, expressed as number of providers per 10,000 people at the health region level, were then calculated.Three classes: low (< -1.5 standard deviation (SD); -1.5 to -0.50 SD), moderate (-0.5 to 0.5 SD), and high (0.50 to 1.5 SD, > 1.5 SD) were used as a cut-off for demonstrating distributionof optometrists across health regions). Cross-classification mapping compared optometrist distribution to self-reported use of vision care services in relation to need. Results: A total of 5,959 optometrists working across ten Canadian provinces were included in this analysis. The nationwide distribution of optometrists is variable across Canada and they are predominantly concentrated in urban areas. The mean ratio of optometrists across Canada was 1.70 optometrists per 10,000 people (range = 0.13 to 2.92). Out of 109 health regions (HRs), 26 were classified as low ratios, 51 HRs were classified as moderate ratios, and 32 HRs were high ratios. Thirty-five HRs were classified as low utilization, 39 HRs were classified as moderate, and 32 HRs as high utilization. HRs with a low optometrist ratio relative to eye care utilization and a high proportion of key sociodemographic characteristics (e.g. older age, low income) are located throughout Canada and identified with maps indicating areas of likely greater need for optometry services. Conclusion: This research provides a nationwide overview of vision care provided by optometrists identifying gaps in geographic availabilityrelative to “supply” and “need” factors. This examination of variation in accessibility to optometric services will be useful to inform workforce planning and policies.
Organ/space infection is a common cause of high output stoma and outlet obstruction in diverting ileostomy
Authors: Hara Yutaro , Miura Takuya , Sakamoto Yoshiyuki , Morohashi Hajime , Nagase Hayato , Hakamada Kenichi
Published: March 2020

Aim: The objectives of this study are to identify causes of high-output stoma (HOS) and outlet obstruction (OO), which are major complications of diverting ileostomy. Methods: A retrospective analysis was performed in 103 patients who underwent colorectal surgery and diverting ileostomy between December 2015 and November 2018. Results: HOS was found in 32 patients (31.1%) and OO in 19 (18.4%). Organ/space surgical site infection (SSI), anastomotic leakage and OO were significant HOS-related factors in univariate analysis, and OO (odds ratio [OR] 3.39, p=0.034) was a independent HOS-related factor in multivariate analysis. Organ/space SSI and male were significant OO-related factors in univariate analysis, and organ/space SSI (OR 3.77, p=0.018) was a independent OO-related factor in multivariate analysis. The white blood cell (WBC) count on postoperative day (POD) 3 was significantly higher in the HOS group compared to the non-HOS group (9765 vs. 8130 /mL, p<0.05), and the WBC count (9400 vs. 7475 /mL, p<0.05) and C-reactive protein level (6.01 vs. 2.92 mg/L, p<0.05) on POD 6 were significantly higher in the OO group compared to the non-OO group.Conclusion: Organ/space infection is involved in the common pathology of HOS and OO. Decreased intestinal absorption due to intestinal edema caused by organ/space SSI and relative stenosis at the abdominal wall-penetrating site are major causes of HOS and OO.