bluuebunny/crossref_metadata_2025 huggingface dataset:
FORMATION OF BOOK HERITAGE PRESERVATION PRINCIPLES IN THE CULTURAL INSTITUTIONS OF THE RUSSIAN FEDERATION
Authors: Tarasenko E. Yu.
Published: March 2020

The article considers the personal contribution of the outstanding historian of the Russian middle ages Academician Mikhail Nikolaevich Tikhomirov to the national concept of documentary sources (book rarities) preservation. The scientist expressed a generalized view of historical science about how the work on the book heritage preservation at the national level had to be organized most effectively, systemically and “eco-friendly”. From the point of the present-day view on the practice of book rarities preservation in the Russian Federation, he justified the exceptional relevance and proposed the main principles of documents preservation, which are now basic at the law and library practice level.

The historical science development determined the establishment of conservation centres in libraries, since a serious obstacle to historical research was the problem of poorly organized and, sometimes, careless storage of historical documents in libraries, museums and archives. In accord to the brief history of scientific conservation in Russia, this time is viewed as the beginning of the most active development of scientific conservation methods and their introduction into library practice.

In the middle of the XX century, Tikhomirov proposed and formed the concept of book rarities preservation, consisting of such important components as: scientific research and popularization of book rarities and their value for the society, organization of public and state associations aimed at implementation of these tasks; search and collection of privately owned book rarities on the national scale (archeographic inspection of the territory of Russia), scientific publication of documents, catalogues of scientific descriptions compiling and forming the Union catalogue on their basis; scientific research of the material basis, conditions of ensuring physical safety and arrangement of work on book rarities preservation; legislative and regulatory support of all activities on book rarities preservation.
BIBLIOGRAPHIC SUPPORT FOR LIBRARY AND INFORMATION SCIENCE AND PRACTICE
Authors: Levin G. L.
Published: March 2020

The provision of bibliographic resources for individual branches of science and / or practical activity is traditional and now it is one of the most developed areas of bibliography. The library and information sphere, including library, bibliographic and scientific information activities and the scientific disciplines that study them needs (library and information sciences) it as well. These areas are characterized by the proximity and significant concurrency of goals, objects, processes, methods, and results of activities. At present, their further integration, transformation of traditional libraries (first of all, scientific ones) into library and information centers is underway.

The bibliography of library and information science and practice includes: 1) bibliography of literature on history, theory, methodology, organization, methodology and technology of these activities, 2) bibliography of publications and electronic resources of library and information institutions; for bibliography as such bibliography of bibliography is also of particular importance, 3) bio-bibliography of branch leaders (polybiobibliographic and monobibiographic (personal) resources).

Since the 1940s the Russian State Library is the main center of the current bibliographic registration of literature on librarianship and bibliography (until 2015 – the release of current indexes, since 1989 – the formation of a thematic abstract bibliographic database). The library prepared many printed retrospective indexes and lists on the problems of library and bibliographic science and practice, which creation not only its bibliographic, but also research, methodical and production structural units took active part in.

In the XXI century, the Library activities in the field of retrospective branch bibliography are limited to the creation of a series of indexes “Bibliography. Bibliographic science”, reflecting the scientifically significant array of native bibliographic literature in Russian since 1959. The main attention is paid to bibliographic registration of publications and electronic resources of the Library and about it, as well as works of its staff.

Electronic catalogs and bibliographic indexes are being created that take into account the products of libraries of the Russian Federation, as well as countries – the former Soviet republics. Polybiobibliographic and personal indexes are being prepared.
Science and Technology of High Performance Ferritic (HiperFer) Stainless Steels
Authors: Kuhn Bernd , Talik Michal , Fischer Torsten , Fan Xiuru , Yamamoto Yukinori , Lopez Barrilao Jennifer
Published: March 2020

Future, flexible thermal energy conversion systems require new, demand-optimized high-performance materials. The High performance Ferritic (HiperFer) stainless steels, under development at the Institute of Microstructure and Properties of Materials (IEK-2) at Forschungszentrum Jülich GmbH in Germany, provide a balanced combination of fatigue, creep and corrosion resistance at reasonable price. This paper outlines the scientific background of alloy performance development, which resulted in an age-hardening ferritic, stainless steel grade. Furthermore, technological properties are addressed and the potential concerning application is estimated by benchmarking versus conventional state of the art materials.
Darunavir Disrupts Critical Nodes in Metastable 2019-nCoV-RBD/ACE-2 Complex
Authors: Omotuyi Olaposi Idowu , Nash Oyekanmi , Ajiboye Basiru Olaitan , Metibemu Damilohun Samuel , Oyinloye Babatunji Emmanuel , Adelakun Niyi Samuel , Hurdayal Ramona , Aruleba Raphael Taiwo , Kappo Abidemi Paul
Published: March 2020

The transnational spread of coronavirus (2019-nCoV) first detected in Wuhan is causing global panic; thus, accelerated research into clinical intervention is of high necessity. The spike glycoprotein structure has been resolved, and its affinity to human angiotensin-converting enzyme 2 (ACE-2) has been experimentally validated. Here, using computational methods, a metastable conformation of 2019-nCoV-RBD/ACE-2 complex has been revealed and FDA-database of approved drugs have been docked into the interface. Darunavir has been discovered as high ligand affinity candidate capable of disrupting communication between 2019-nCoV-RBD and ACE-2. Darunavir, in addition to its previously known anti-HIV protease inhibitor is now repurposeable for the treatment 2019-nCoV disease acting via disruption of cellular recognition, binding and invasion.
Adhesion Hysteresis due to Chemical Heterogeneity
Authors: Popov Valentin L.
Published: March 2020

According the JKR theory of adhesive contact, changes of the contact configuration after formation of the adhesive neck and before detaching are completely reversible. This means, that after formation of the initial contact, the force-distance dependencies should coincide, independently on the direction of the process (indentation or pull-off). In the majority of real systems, this invariance is not observed. The reasons for this may be either plastic deformation in the contacting bodies or surface roughness. One further mechanism of irreversibility (and corresponding energy dissipation) may be chemical heterogeneity of the contact interface leading to the spatial dependence of the specific work of adhesion. In the present paper, this "chemical" mechanism is analyzed on a simple example of an axisymmetric contact (with axisymmetric heterogeneity). It is shown that in the asymptotic case of a "microscopic heterogeneity", the system follows, during both indentation and pull-off, JKR curves, however, corresponding to different specific surface energies. After the turning point of the movement, the contact area first does not change and the transition from one JKR curve to the other occurs via a linear dependency of the force on indentation depth. The macroscopic behavior is not sensitive to the absolute and relative widths of the regions with different surface energy but depends mainly on the values of the specific surface energy.
Medical Countermeasures Analysis of 2019-nCoV and Vaccine Risks for Antibody-Dependent Enhancement (ADE)
Authors: Ricke Darrell O. , Malone Robert W.
Published: March 2020

Background: In 80% of patients, COVID-19 presents as mild disease1,2. 20% of cases develop severe (13%) or critical (6%) illness. More severe forms of COVID-19 present as clinical severe acute respiratory syndrome, but include a T-predominant lymphopenia3, high circulating levels of proinflammatory cytokines and chemokines, accumulation of neutrophils and macrophages in lungs, and immune dysregulation including immunosuppression4. Methods: All major SARS-CoV-2 proteins were characterized using an amino acid residue variation analysis method. Results predict that most SARS-CoV-2 proteins are evolutionary constrained, with the exception of the spike (S) protein extended outer surface. Results were interpreted based on known SARS-like coronavirus virology and pathophysiology, with a focus on medical countermeasure development implications. Findings: Non-neutralizing antibodies to variable S domains may enable an alternative infection pathway via Fc receptor-mediated uptake. This may be a gating event for the immune response dysregulation observed in more severe COVID-19 disease. Prior studies involving vaccine candidates for FCoV5,6 SARS-CoV-17-10 and Middle East Respiratory Syndrome coronavirus (MERS-CoV) 11 demonstrate vaccination-induced antibody-dependent enhancement of disease (ADE), including infection of phagocytic antigen presenting cells (APC). T effector cells are believed to play an important role in controlling coronavirus infection; pan-T depletion is present in severe COVID-19 disease3 and may be accelerated by APC infection. Sequence and structural conservation of S motifs suggests that SARS and MERS vaccine ADE risks may foreshadow SARS-CoV-2 S-based vaccine risks. Autophagy inhibitors may reduce APC infection and T-cell depletion12 13. Amino acid residue variation analysis identifies multiple constrained domains suitable as T cell vaccine targets. Evolutionary constraints on proven antiviral drug targets present in SARS-CoV-1 and SARS-CoV-2 may reduce risk of developing antiviral drug escape mutants. Interpretation: Safety testing of COVID-19 S protein-based B cell vaccines in animal models is strongly encouraged prior to clinical trials to reduce risk of ADE upon virus exposure.
Simulating Low-Level Laser Propagation From Skin Surface To Lumbar Disc, Knee, Femur and Prostate Gland By Monte Carlo Method
Authors: Duyen Trinh Tran Hong , Tu Tran Anh
Published: March 2020

Nowadays, the uses of laser and optics in the medical areas are extremely vivid, especially low-level laser therapy. The light with the wavelength of 633 nm to 1200 nm could penetrate and propagate deep in biological tissue. To develop the low-level laser therapy device, optimizing light delivery is critical to accurately stimulate the biological effects inside the biological tissue. Nevertheless, each form of the tissues at each zone on the body had various refractive optic, absorption, scattering, and anisotropy coefficients. This paper describes the simulation results of low-level laser propagation from skin surface at the lower spine, the knee, the femur and the prostate gland with four wavelengths (633 nm, 780 nm, 850 nm, and 940 nm) by the Monte Carlo method. These simulation results are the base for developing the low-level laser therapy device, that could be used in clinical for treating the fracture, knee osteoarthritis, spinal degeneration, and benign prostatic hypertrophy.
Who Adopts Agroforestry in a Subsistence Economy?
Authors: Dhakal Arun , Rai Rajesh Kumar
Published: March 2020

Land degradation is a critical issue globally putting our future generations at risk. The decrease in farm productivity over the years is evidence of land degradation severity in Nepal. Among the many strategies in place, agroforestry, which is an integrated tree-based farming, is widely recommended to address this productivity issue. This paper thoroughly examines what influences the choice of agroforestry adoption by farmers and what discourages the adoption. For this, a total of 288 households were surveyed using a structured questionnaire. Two agroforestry practices were compared with conventional agriculture with the help of the Multinomial Logistic Regression (MNL) model. The likelihood of adoption was found to be influenced by gender; the male-headed households were more likely to adopt the tree-based farming practice. Having a source of off-farm income was positively associated with the adoption decision of farmers. Area of farmland was found being the major constraint to agroforestry adoption for smallholder farmers. Some other variables that affected positively included livestock herd size, provision of extension service, home-to- forest distance, farmers’ group membership and awareness of farmers about environmental benefits of agroforestry. Irrigation was another adoption constraint that the study area farmers were faced with. The households with means of transport and with larger family (household) size were found to be reluctant towards agroforestry adoption. A collective farming practice could be a strategy to engage the smallholder farmers in agroforestry.
Smallholder Farmers’ and the Treatment of Livestock Diseases Using Ethno-Veterinary Medicine (Evm): A Commentary
Authors: Nwafor Christopher , Nwafor Ifeoma
Published: March 2020

Often touted as an ancient and sustainable practice among indigenous livestock farmers in developing countries, the use of ethno-veterinary medicine is examined within the context of its efficacy. While there are undoubtedly positive implications for adopting knowledge and practice that align with nature, there is both prevalence and ambivalence to the adoption of indigenous plant knowledge and resources for the treatment of livestock infections and diseases. This situation is due to the lack of validation and standardization of the practice in low-income countries, requiring scholarly efforts in developing this indigenous knowledge system.
Heat-Transfer Characteristics of Subsea Pipelines Embedded in Multilayered Soils
Authors: Park Dong-Su , Shin Mun-Beom , Seo Young-Kyo
Published: March 2020

A good pipeline design must ensure that the heat loss is small enough for flow assurance despite unfavorable hydrate and wax depositions. The objective of this study is to experimentally verify a formula for the modified overall-heat-transfer coefficient (OHTC) that considers multilayered soil conditions for steady-state subsea pipelines. A laboratory-scale experiment is conducted to simulate the flows of cold seawater and hot crude oil inside the pipes immersed in multilayered soils at nine burial-depth rates. The obtained results are in good agreement with the data obtained by a previously derived OHTC analytical formula.
Modeling the Effects of Reservoir Deformation During Steam Injection Operations: from Empirical Models to a More Rigorous Geomechanical Treatment in the Numerical Simulation of SAGD
Authors: Rivero Jose A. , Li Qiuguo
Published: March 2020

The conventional approach used to account for geomechanical effects when modeling steam injection operations is based on dilation/compaction tables. These tables are mostly empirical and are usually employed as a history-matching parameter to calibrate simulation models to observed injection/production rates and pressures. In this study, we use a more rigorous workflow that couples a geomechanical simulator to more accurately model the changes in permeability and pore volume that occur during high-pressure steam injection.

This paper demonstrates a new approach for incorporating and modeling the geomechanical effects observed while injecting steam for heavy oil recovery, specifically during SAGD (Steam-Assisted Gravity Drainage) operations. This workflow does not need an explicit, empirical table relating pressure to permeability and porosity; instead it uses a mechanical simulator to determine the evolution of the reservoir's stresses and strains to calculate a new property distribution that is updated in the reservoir simulator to account for dilation and compaction phenomena.

To model the complex thermo-poro-mechanical coupling that prevails during thermal stimulation processes, we use a numerical workflow that integrates finite-difference reservoir and finite-element geomechanical simulators. This coupling technique enables a more rigorous modeling of the fluid and heat flows while predicting their influence on the reservoir deformation and stresses. Consequently, a direct link between stress/strain and porosity/permeability can be used to model the geomechanical changes that occur in the reservoir during high-pressure steam injection. We also compare the predicted behavior of SAGD models using the coupled approach against the use of empirical dilation/compaction pressure tables.

A comparison of the simulation results obtained using the proposed coupled approach versus those obtained using empirical tables (uncoupled) showed significant differences in steam injectivity and distribution as well as oil and water production.
Measurement of Concentration-Dependent Diffusion Coefficient of Gaseous Solvents in Bitumen
Authors: Khalifi Mohammad , Zirrahi Mohsen , Hassanzadeh Hassan , Abedi Jalal
Published: March 2020

A robust and reliable experimental approach was developed and implemented for measurement of the concentration-dependent molecular diffusion coefficient of gaseous solvents in bitumen mixtures. The developed methodology relies on accurate measurement of the rate of gas injection throughout the constant-pressure diffusion experiment. The experimental setup was then used for studying the concentration-dependent behavior of the diffusivity of gaseous dimethyl ether (DME) in bitumen at 2.76 MPa and 110°C. The estimated values of the molecular diffusion coefficient are in the range of ~1.79-3.72×10−9 m2/s increasing with the initial concentration of DME in bitumen. The results indicate that there exists a noticeable dependency of the molecular diffusion coefficient on the concentration of the solvent in bitumen. The developed methodology finds application in estimation of the concentration-dependent molecular diffusion coefficient of gaseous solvents in bitumen.
Case Studies of Integrated Flowback Analysis: Examples from the Montney and Duvernay Formations
Authors: Clarkson Christopher R. , Williams-Kovacs Jesse , Zhang Zhenzihao , Yuan Bin , Ghanizadeh Amin , Hamdi Hamidreza , Islam Arshad
Published: March 2020

Recently it has been demonstrated that rate-transient analysis (RTA) performed on flowback data frommulti-fractured horizontal wells (MFHWs) can provide timely estimates of hydraulic fracture properties. This information can be used to inform stimulation treatment design on upcoming wells as well as other important operational and development decisions. However, RTA of flowback data may be complicated by rapidly changing operating conditions, dynamic hydraulic fracture properties and multi-phase flow in the fractures, complex fracture geometry, and variable fracture and reservoir properties along the MFHW, among other factors. While some constraints on RTA model assumptions may be applied through a carefully-designed surveillance and testing program in the field (e.g. to constrain fracture geometry), still others require laboratory measurements.

In this work, an integrated flowback RTA workflow, designed to reduce uncertainty in derived hydraulic fracture properties, is demonstrated using flowback data from MFHWs producing black oil from low-permeability reservoirs in the Montney and Duvernay formations. The workflow includes rigorous flow-regime identification used for RTA model selection, straight-line analysis (SLA) to provide initial estimates of hydraulic fracture properties, and model history matching of flowback data to refine hydraulic fracture property estimates. The model history matching is performed using a recently-introduced semi-analytical, dual-porosity, dynamic drainage area (DP-DDA) model that incorporates primary (propped) hydraulic fractures (PHF) as well as a dual-porosity enhanced fracture region (EFR) with an unpropped (secondary) fracture network. Inclusion of both the PHF and EFR components addresses the need to incorporate both propped and unpropped fractures and fracture complexity in the modeling. The DP-DDA model is constrained using estimates of propped fracture conductivity and unpropped fracture permeability (measured as a function of stress), and unpropped fracture compressibility values, obtained in the laboratory for Montney and Duvernay core samples. Use of these critical laboratory data serves to improve the confidencein the modeling results.

The case studies provided herein demonstrate a rigorous workflow for obtaining more confident hydraulic fracture property estimates from flowback data through the application of RTA techniques constrained by both field and laboratory data.
Pressure Sink Mitigation: Effect of Preloading Parent Wells to Better Control Infill Hydraulic Fracture Propagation
Authors: Joslin Kevin , Ranjbar Ehsan , Shahamat Sadeq , Somanchi Kiran
Published: March 2020

Effective stimulation of infill (child) wells can be challenging: pressure sinks resulting from production of existing (parent) wells can impair child wells’ completions leading to a loss of production potential. Special completion techniques are required to better stimulate the new rock volume and divert the fracture energy away from the depleted zones. This study investigates pre-loading and re-fracking of parent wells as potential Pressure Sink Mitigation (PSM) techniques to minimize fracture asymmetry in child wells. The impact of these techniques on possible production uplift for both parent and child wells are also investigated.

A black-oil reservoir flow simulation model was created and history matched to production from three existing parent wells in a Montney field. Three new child wells have been drilled in close proximity (100m-200m) to the parent wells and were subjected to fracture generation and subsequent production. The fracture generation of the child wells was directly modelled in the reservoir simulator with hydraulic fracture conductivity as an exponential function of pressure. The conductivity-pressure relationship of the newly created hydraulic fractures were validated quantitatively to field history data and qualitatively to a third-party fracture creation software.

To limit the influence of the depleted zone, water was injected into the parent wells before the child well fractures are created. Since the child well fracture behavior is directly related to the pressure, a theoretical "reservoir pressure vs injected pre-load volume" relationship was generated. From the relationship, a series of simulation sensitivities were performed where the child well fracture creation and successive production were subjected to different pressure (pre-load) scenarios. The production uplift of each scenario over the non-preload base case was calculated to determine the efficacy of the technique and optimum injection volumes. Additionally, the time for the parent wells to return to their pre-child well production levels was quantified.

A practical and robust simulation workflow to evaluate a pressure sink mitigation technique was successfully developed using an actual field case in the Montney formation. As infill drilling and high well density become standard operational practice, understanding how to limit the influence of existing depleted wells is essential for optimizing recovery from hydraulically fractured formations.
An Alternative Technique for Fast Permeability Measurements of Gas Shales
Authors: Feng Ruimin , Chen Shengnan , Pang Yu
Published: March 2020

Laboratory pulse-decay techniques are effective for determining rock permeabilities ranging from 0.01 μd to 0.1 md. However, the measurement time is fairly long, reaching up to several hours to days when testing gas shales because their permeability can be as low as dozens of nano-Darcys. This paper proposes an alternative pulse-decay technique that offers accurate permeability measurements within a considerably short time frame.

A radial-flow pulse decay method with a new experimental design is developed, which employs two gas reservoirs of the same volume and two pressure pulses with the same magnitude, one "positive" and one "negative". A mathematical model is then developed to numerically verify the feasibility of the newly developed technique and analytically solved for permeability estimation. Pressure responses with time in the radial direction of the test sample are analyzed and compared with those in the axial direction by solving the mathematical model. A concentric circular cavity with a diameter of 0.51 cm is created along the core samples, which are tested to experimentally demonstrate the applicability of the technique.

The numerical results showed that the pressure pulse of the radial flow decays much faster than the axial flow and at least a 10-fold reduction in measurement time can be achieved. Numerical results indicated that the proposed technique is capable of eliminating the effects of the compressive storage and gas sorption in the permeability measurement; while great efforts need to be put to correct such effects when employing conventional transient techniques. An in-depth comparison is experimentally made between the proposed method and the conventional axial-flow method. The experimental results presented in the study confirm that fast and accurate measurements can be achieved using the proposed technique.
Analysis of Communicating Multi-Fractured Horizontal Well Production Data Using the Dynamic Drainage Area Concept
Authors: Ahmadi Hossein , Clarkson Christopher R. , Hamdi Hamidreza , Behmanesh Hamid
Published: March 2020

Reducing fracture/well spacing and increasing hydraulic fracture stimulation treatment size are popular strategies for increasing hydrocarbon recovery from multi-fractured horizontal wells (MFHWs). However, these strategies can also increase the chance of fracture interference, which not only can negatively impact the overall production, but also introduce complexities for production data analysis. To analyze the production data from two communicating wells, a semi-analytical model is developed and applied to a field case.

The new semi-analytical model uses the dynamic drainage area (DDA) concept and assumes that the reservoir consists of two regions: a primary hydraulic fracture (PHF) and an adjacent enhanced fracture region (EFR) or non-stimulated region (NSR) in the reservoir. Assuming a well pair primarily communicates through PHFs, the equations for two communicating wells are coupled and solved simultaneously to model the fluid transfer between the wells. This method is used within a history matching framework to estimate the degree of communication between the wells by matching the production data.

The model is first verified against more rigorous numerical simulation for a range of fracture/reservoir properties. These comparisons demonstrate that there is excellent agreement between the reservoir simulation results and the new semi-analytical model.

The semi-analytical model is then employed to history match production data from six MFHWs (drilled from two adjacent well pads) exhibiting different degrees of communication. First, only strong communication between pairs of wells (intra-pair communication) is considered. Then sink/source terms are added to account for intermediate degrees of communication between well pairs (inter-pair communication). Addition of the source/sink terms improves the history-matching quality of the three well pairs, while total material balance of the entire section is honored.

A flexible, yet simple, semi-analytical model is developed for the first time that can accurately model the communication between multiple well pairs. This approach can be used by reservoir engineers to analyze the production data from communicating MFHWs.
Field-Wide Review of Diagnostic Fracture Injection Tests DFIT in Montney and Duvernay Formations – Part 1: Stress and Pressure Distributions
Authors: Haghshenas Behjat , Qanbari Farhad
Published: March 2020

A straightforward test with debatable analysis methods, the diagnostic fracture injection test (DFIT) is a pressure-transient test extensively used for reservoir and geomechanical characterization of tight/shale formations. The test provides some key data and information to reservoir and well completion engineers including instantaneous shut-in pressure (ISIP), pore pressure, closure stress, fluid efficiency, reservoir flow capacity, and fracture leak-off regime. A comprehensive regional or field-wide study of the DFITs is deemed very useful for operators at any stage of exploration and development.

In this study, DFITs from a group of 174 Montney and Duvernay wells operated by more than 30 producing companies are quality checked and analyzed consistently. The results from DFITs are then compared against the standard poroelasticity equation.

The data set of the current study covers a wide range of DFIT conditions and reservoir and geomechanical properties which helps the authors develop reliable correlations for reservoir characterization purposes. True vertical depth (TVD) of the wells ranges from less than 1000m to more than 4000m leading to a wide range of pressure and stress conditions. The study also covers all the geographical areas of Montney and Duvernay. The results ofthe DFITs are used to develop usefulcross-plot betweenpore pressure and closure pressure.A relationship between closure pressure from compliance method and G-function analysis method for Montney and Duvernay is also provided. Results of example DFITs from depleted areas were also provided which gives an idea about the depletion level and the associated well performance degradation.

The current study gives field-wide understanding of the variations and distributions of reservoir and geomechanical properties in Montney and Duvernay based on DFIT analysis of a sizable population of wells.
Investigation of Cyclic Gas Injection in the Gas Condensate Window of Unconventional Reservoirs
Authors: Santiago Carla Jordana , Kantzas Apostolos
Published: March 2020

Reservoirs such as Duvernay, Montney and Eagle Ford are segmented in different areas, ranging from predominantly dry gas regions, to wet gas and oil regions. Extensive research has focused on the application of enhanced recovery methods in the oil window of such reservoirs. In this paper, we discuss the application of enhanced recovery in the gas condensate window, with the objective to investigate the impact of diffusion on liquid dropout and vaporization on a matrix level.

The Maxwell-Stefan equations were used to account for diffusion phenomena in the medium, and a phase behavior routine was implemented including nano-confinement effects. Numerical experiments were performed to evaluate the range of variability of recovery factors in a cyclic gas injection scenario. Methane was used as injection gas, and 1, 2 and 4 cyclic injection stages were modelled at the scale of a matrix block. Sensitivity was performed using a leaner and a richer gas composition, as well as two levels of permeability (50 and 100 nD). This allowed detailed investigation of time and location of occurrence of liquid dropout through saturation profile maps.

Due to molecular partitioning, the phase envelope shifts as production proceeds, generating an accumulation of heavier hydrocarbons in the medium. Since injectivity is reduced in lower permeability media, injection pressure ramp up needs to be controlled to prevent condensate blockage. As a result, longer cycles are needed in the lower permeability case to achieve equivalent recovery.

Liquid dropout is recurrent during production after each injection cycle, however, increasing the number of stages resulted in overall lower liquid saturation during subsequent production. Additionally, saturation profile maps indicate that the locus of condensate banks varies between each stage. As more injection stages are performed, a leaner gas remains in the vicinity of the fracture boundary and the condensate bank is formed further into the matrix block.

Although more cycles improved recovery of heavier hydrocarbons, faster cycles resulted in lesser penetration of the injection gas into the porous medium. This behavior is more accentuated in the lower permeability cases. Nevertheless, recovery of heavier fractions is still higher compared to the primary production base case. Sensitivity studies will dictate the optimum number of stages for a fixed timeframe.

In this work we use a combination of physics involved in flow in tight reservoirs to demonstrate how saturation profile maps can be used as a tool to improve enhanced recovery strategy.
An Automated Physics-Based Workflow for Identification and Classification of Drilling Dysfunctions Drives Drilling Efficiency and Transparency for Completion Design
Authors: Saini Gurtej Singh , Hender Donald , James Chris , Sankaran Sathish , Sen Vikram , van Oort Eric
Published: March 2020

In this paper, a new workflow for data wrangling, cleansing, processing, automated identification and classification of drilling dysfunctions (e.g. bit balling, drillstring vibrations, etc.) for any number of wells is presented. Statistically-derived baseline rock strengths were used to improve drilling efficiency and transparency in completions design. The methodology leverages commonly available rig surface sensor data and mud motor parameters. Data handling and processing across multiple databases was automated. Time-series data was converted to depth-based data, and drilling dysfunction indicator metrics (mechanical specific energy - MSE, depth-of-cut, etc.) were computed. Subsequently, the combined data set was segmented based on formation tops, bottom hole assembly (BHA) used, and hole sections. A multivariate physics-based decision tree methodology was then applied for identification and classification of drilling dysfunction. A baseline MSE was statistically derived and a subsurface rock strength database was created for every formation in every well within a given prospect.

Over 100 historical unconventional wells across two shale basins were analyzed using the new workflow, and 10 different dysfunction categories were classified. The most commonly encountered drilling dysfunctions were whirl, stick-slip, and bit balling. An algorithm generates a set of reports per well based on independent segments for individual drilling operations, including strip charts of drilling parameters and dysfunction indicators, with identification of potential (low/high) problem areas. Auto-generated scatter plots, identifying optimal control parameters for every geological formation at a given location, are used for planning future wells and improving drilling performance. The calculated MSE baselines were averaged to build a repository of baseline MSEs per formation, which in turn can be utilized as a diagnostic tool for real-time MSE surveillance. The MSE baseline information can also be used as a representation of unconfined compressive strength (UCS), and thus used to formulate a reliable rock hardness map to enhance completion design.

Manual dysfunction analysis is time- and labor-intensive, and therefore often done either incompletely or bypassed altogether. Automating this process reduces time and effort significantly. The novelty of this work lies in the translation of the qualitative understanding of MSE to a reliable quantification of rock strength through the analysis of magnitudes and trends in drilling parameters and dysfunction indicators. Screening out drilling dysfunctions enables a much better rock strength approximation to aid completion optimization.
Permeability of Tight Sand and Shale Formations: A Dual Mechanism Approach for Micro and Nanodarcy Reservoirs
Authors: Ziarani Ali S. , Aguilera Roberto , Cui Albert X.
Published: March 2020

Traditionally, viscous flow based on Darcy's law has been considered as the primary transport mechanism in petroleum reservoirs. In the micropores of tight sands and nanopores of shale, fluid transport is more complicated than Darcy flow. In unconventional gas reservoirs, in addition to viscous flow, diffusion can play a significant role in gas transport especially in ultra-low permeability reservoirs.

An easy-to-use dual mechanism approach that accounts for the contribution of both Darcy flow and diffusion to apparent permeability in tight sandstone and shale formations is developed in this paper. The study elaborates on how the traditional Darcy permeability is modified to account for the effect of diffusion. This is achieved through an additional term that accounts for diffusion contribution as a function of gas viscosity, compressibility, and diffusion coefficient. The proposed model is then applied to experimental data of tight gas and shale gas reservoirs.

For the case of tight gas reservoirs, Mesaverde sandstone data from the United States Basins are analyzed. For the shale gas case, Duvernay formation in the Western Canada Sedimentary Basin is studied. Laboratory measured permeability supplemented with petrographical SEM images and MICP data is investigated. The application of the proposed methodology is demonstrated for estimating the percentage of diffusion contribution to total gas transport in the rock matrix.

The transition from viscous flow to diffusion is identified with the use of Knudsen number. Viscous flow is usually observed in larger pores and higher pressures where continuous flow is driven by a pressure gradient. In micropores, and especially nanopores of shale formations, diffusion driven by a concentration gradient becomes the major transport mechanism.

The results indicate that in extremely tight reservoirs with nanodarcy permeability, diffusion is the dominant transport mechanism for gas delivery from matrix nanopores to natural fractures. This is important and should not be ignored in engineering applications. Practical guidelines and recommendations are provided for the proper use of the proposed methodology.
A Systematic Study of Water-Rock Reactions to Reveal the Relationship Between Total Dissolved Solids and Colloidal System Parameters
Authors: Zhang Lifu , Hascakir Berna
Published: March 2020

Understanding water-rock interactions occurring during hydraulic fracturing is vital to better engineer the hydraulic fracturing water. In this study, a systematic model of water-rock reactions is presented to mimic the interaction of reservoir rock with water.

To investigate the water-rock interaction Marcellus Formation was selected. The reservoir rock samples from the Marcellus Formation were first characterized for its mineral composition by an X-ray diffraction (XRD) and for its elemental composition by an X-Ray fluorescence (XRF). Based on XRD results 3 major minerals were found in Marcellus shale; quartz, calcite, and illite. Later, these minerals with high purity content were ordered from an external chemical company to prepare pseudo rock samples and single-, two-, and three- component mineral-deionized water systems were prepared. The supernatant of these solutions were analyzed for their pH, total dissolved solids (TDS) content, particle size of the colloidal system, and zeta potential of the colloidal systems.

For single-component mineral-water systems, it has been observed that pH and TDS in general give a linear relation with the mineral concentration. For two component mineral-water systems, these relations got weaker and for the three-component systems, only TDS gives good linear relation to the mineral concentration at room temperature. When the experiments repeated at 75 °C to see the effect of temperature on dissolution of minerals in a single-component system, no difference was observed in the linear relations, however, it has been observed that particle sizes of the colloidal systems for all single-component mineral-water system correlates with the TDS content of the water. It should be noted that while particle sizes measure in water gives an idea of the average size of the suspended particles in water, TDS provides information on the dissolved molecules or ionized particles in water. Moreover, we observed that for all experimental data regardless the temperature that we collected them, the TDS concentration decreases with the increase in pH.

Our results for the first time link dissolved matter concentration in water (TDS) with the colloidal system parameter (particle size) and provide an insight on how the colloidal system (suspended solids in water) can affect TDS concentration.
Uncertainty Quantification of an Explicitly Coupled Multiphysics Simulation of In-Situ Pyrolysis by Radio Frequency Heating in Oil Shale
Authors: Ramsay Travis
Published: March 2020

In-situ pyrolysis provides an enhanced oil recovery (EOR) technique for exploiting oil and gas from oil shale by converting in-place solid kerogen into liquid oil and gas. Radio-frequency (RF) heating of the in-place oil shale has previously been proposed as a method by which the electromagnetic energy gets converted to thermal energy, thereby heating in-situ kerogen so that it converts to oil and gas. In order to numerically model the RF heating of the in-situ oil shale, a novel explicitly coupled thermal, phase field, mechanical, and electromagnetic (TPME) framework is devised using the finite element method in a 2D domain. Contemporaneous efforts in the commercial development of oil shale by in-situ pyrolysis have largely focused on pilot methodologies intended to validate specific corporate or esoteric EOR strategies. This work focuses on addressing efficient epistemic uncertainty quantification (UQ) of select thermal, oil shale distribution, electromagnetic, and mechanical characteristics of oil shale in the RF heating process, comparing a spectral methodology to a Monte Carlo (MC) simulation for validation. Attempts were made to parameterize the stochastic simulation models using the characteristic properties of Green River oil shale. The geologic environment being investigated is devised as a kerogen-poor under- and overburden separated by a layer of heterogeneous yet kerogen-rich oil shale in a target formation. The objective of this work is the quantification of plausible oil shale conversion using TPME simulation under parametric uncertainty; this, while considering a referenced conversion timeline of 1.0 × 107 seconds. Nonintrusive polynomial chaos (NIPC) and MC simulation were used to evaluate complex stochastically driven TPME simulations of RF heating. The least angle regression (LAR) method was specifically used to determine a sparse set of polynomial chaos coefficients leading to the determination of summary statistics that describe the TPME results. Given the existing broad use of MC simulation methods for UQ in the oil and gas industry, the combined LAR and NIPC is suggested to provide a distinguishable performance improvement to UQ compared to MC methods.
Prenatal diagnosis of Duchenne muscular dystrophy and cytogenetic analysis in 303 Chinese families
Authors: Li Mengmeng , Yao Fengxia , Hao Na , Zhang Weimin , Zhou Jing , Tan Li , Qiu Zhengqing , Liu Juntao
Published: March 2020

Background: Duchenne muscular dystrophy (DMD) has showed a wide spectrum of mutations in the dystrophin gene including exon deletions, duplications and small mutations. This retrospective study was to supply information of the DMD mutational spectrum in 303 Chinese families and further offer 5-year clinical experience of DMD genetic counselling and prenatal diagnosis.Methods: In this retrospective study, 305 pregnancies in 303 pregnant women who has a birth history of DMD patients underwent prenatal diagnosis using multiplex ligation-dependent probe amplification (MLPA) followed by Sanger sequencing between 2014 and 2018. Karyotype analysis was performed to exclude fetal abnormal karyotype.Results: The detection rate of DMD gene mutation in 303 probands was 97.7% with 7 families having a negative genetic diagnosis. The mutational spectrum comprised of large arrangements in 288/303 (95.0%) and small mutations in 8/303 (2.6%). 204 pregnant women did carrier testing among whom, 108 mothers had the same mutation as family proband. Of the 305 pregnancies underwent prenatal diagnosis, 55 of 173 male fetuses were affected. We also performed karyotype analysis and found 3 abnormal karyotypes of trisomy 21. We even found a fetus with DMD gene mutation and trisomy 21 in a same fetus by further analysis.Conclusions: The distribution and mutation profile of 303 probands and 305 fetuses were demonstrated. Given the large samples provided in this study, the information is essential for genetic counselling and prenatal diagnosis in DMD families in China.
Five-year direct medical costs and comorbidities after bariatric surgery of obese patients with type 2 diabetes mellitus: A population-based propensity score-matched study
Authors: Wu Tingting , Wong Simon Kin Hung , Law Betty Tsz Ting , Grieve Eleanor , Wu Olivia , Tong Daniel King Hung , Leung David Kai Wing , Ng Enders Kwok Wai , Lam Cindy Lo Kuen , Wong Carlos King-Ho
Published: March 2020

Background: Bariatric surgery is effective in weight reduction and diabetes remission. This study aimed to estimate direct medical costs and changes of comorbidities after bariatric surgery up to five years among obese patients with type 2 diabetes mellitus. Methods: A population-based retrospective cohort of obese type 2 diabetes patients from Hong Kong Hospital Authority between 2006 and 2017 was assembled. One-to-five propensity score matching method was applied to match 401 eligible surgical patients with 1,894 non-surgical patients. Frequency of healthcare service utilization and dispense of diabetes medication were collected for both groups to estimate the direct medical costs from baseline to up to 60 months; Charlson Comorbidity Index (CCI) and number of comorbidities were measured to compare the changes of comorbidities between two groups over the 5 years. Results: Direct medical costs were US$40,889 for surgical patients and US$6,163 for controls in the index year (p<0.001), with incremental costs of US$34,726. Bariatric surgery and hospitalization were the main cost drivers for surgical patients in the year of surgery. Although surgical patients had significantly lower annual costs than control patients in the subsequent four years, five-year cumulative costs incurred by surgical patients were significantly greater than controls (US$60,174 vs US$33,374, p<0.001), regardless of subgroups. Surgical patients had better profile of comorbidities than controls, as they had significantly lower CCI after baseline and fewer percentages of them proceeded to higher CCI categories. Conclusions: Over 5 years, bariatric surgery was associated with increased medical costs in the year of surgery and cumulative costs. Although bariatric surgery is not cost-saving for type 2 diabetes patients at 5 years, it is associated with improved comorbidity profile.