bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluación de la hipótesis déficits gemelos en el Perú, durante el periodo 2006–2019 mediante el análisis keynesiano
Authors:   , Napuri Kolich Ursula Melissa , Pella Murgueytio Kimberly Gabriela
Published: April 2021

El presente estudio buscó corroborar la existencia de una relación causal entre el déficit presupuestario y déficit de la balanza en cuenta corriente, conocido como hipótesis de déficits gemelos, en la economía peruana durante el periodo 2006–2019, bajo el enfoque Keynesiano. Para ello, se trabajó con data trimestral de las variables, incluyéndose en estas al tipo de cambio como variable exógena, aplicándose técnicas econométricas de series temporales. Dentro de las herramientas utilizadas para la evaluación de las variables, destacan el test de Dickey-Fuller Aumentado, con el fin de verificar la estacionariedad; y el test de Granger, para examinar la existencia de una posible dirección causal. Asimismo, se optó por elaborar un modelo de vectores autorregresivos (VAR) trivariado, permitiendo analizar la importancia relativa de cada perturbación existente en los movimientos de las variables endógenas. Entre los principales hallazgos se encontró la existencia de una relación causal unidireccional tanto a corto como a largo plazo entre ambos déficits, lo cual valida la hipótesis de déficits gemelos en el Perú, y por ende una incidencia positiva entre las variables objeto de estudio.
Politika hotelskog proizvoda
Authors: Berc Radišić Branka
Published: April 2021

Politika proizvoda što ga hotel nudi tržištu, bitan je dio njegove poslovne politike. Ta se politka oblikuje na temelju dobrog poznavanja tržišta, vlastitih realnih mogućnosti i ciljeva. Ona treba biti fleksibilna, lako prilagodljiva promjenama na turističkom tržištu. Presudnu ulogu u provođenju te politike ima marketing služba hotela.
Synthesis and evaluation of AlgNa-g-poly(QCL-co-HEMA) hydrogels for cartilage tissue engineering and controlled release of betamethasone.
Authors: García-Couce Jomarien , Vernhes Marioly , Bada Nancy , Agüero Lissette , Valdés Oscar , Alvarez-Barreto José , Fuentes Gastón , Almirall Amisel , Cruz Luis J
Published: April 2021

Hydrogels obtained from the combination of different polymers are an interesting strategy for the development of controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using different concentration of the components. The hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and swelling degree; betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay shown that almost all hydrogels are cytocompatibles and an increase the proliferation in both cell types after one week of incubation was observed by Live/Dead® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics and biocompatibility.
Frail Males on the American Frontier: The Role of Environmental Harshness on Sex Ratios at Birth Across a Period of Rapid Industrialization
Authors: Schacht Ryan , Hollingshaus Mike , Hanson Heidi , Bruckner Tim , Macfarlan Shane J , Tharp Douglas , Smith Ken R
Published: April 2021

While sex ratios at birth (SRB) have been shown to vary within and across populations, after over a century of research, explanations have remained elusive. A variety of ecological, demographic, economic, and social variables have been evaluated, yet their association with SRB has been equivocal. Here, in an attempt to shed light on this unresolved topic within the literature, we approach the question of what drives variation in SRB using detailed longitudinal data spanning the frontier-era to the early 20th century in a US population. Using several measures of environmental harshness, we find that fewer boys are born during challenging times. However, these results hold only for the frontier-era and not into a period of rapid industrialization. We argue that the mixed state of the literature may result from the impact and frequency of exogenous stressors being dampened in post-industrial societies.
Rethinking Digital Literacy Competencies of Indonesian Nursing Student in IR 4.0: Philosophical Context
Authors: Aspihan Moch , Pandin Moses , Kusnanto Kusnanto
Published: April 2021

Background: Industry revolution 4.0 (IR.4.0) paradigm, nurses were required to have adequate competencies to carry out their professional duties. Digital information should be mastered by the nursing student. Purpose: This study aims to explain digital literacy competencies on nursing students in the era of industrial revolution 4.0 in the Indonesian context. Methode: A literature review was conducted in this study using Rayyan Systematic Reviews Software. Results: There was 14 literature analyzed describing Student’s Information literacy competency and Internet of Thing. Conclusion: Digital literacy for nursing students today is an inevitability, and nursing students who have digital literacy competencies have the potential to be able to increase nursing knowledge and skills as ontological competencies in their learning process.
A Simple Two-Step System to Produce a Cyclic Peptide Library for Cell-Based Assays
Authors: Nguyen Diem Quynh , Kim Dogyeong , Park Hyunjae , Cho Kyoung Sang , Kang Lin-Woo
Published: April 2021

The pharmaceutical market consists mainly of chemical and biological drugs. These drugs act on different types of targets and have distinct pharmacological properties. Generally, chemical drugs bind to the active site of target enzymes and easily penetrate the cell membrane owing to their small size; however, biological drugs can bind to the protein–protein interaction site but are less stable due to their protein properties. Cyclic peptides possess the pharmacological merits of both chemical and biological drugs, such as the ability to bind to the protein–protein interaction site and penetrate cell membranes. In this study, we developed a simple two-step system to generate a cyclic peptide library using the split intein of Npu DnaE and Gateway cloning. The first step is the PCR of Ready-to-use(R) template DNA having the coding sequences of random cyclic peptides between two split intein elements NpuC and NpuN and the recombination recognition site of Gateway cloning. The second step is the transformation of the PCR products via Gateway cloning to produce colonies with expression vectors to produce cyclic peptides comprising random amino acid sequences. The expression vectors in randomly chosen transformed colonies were confirmed to have random cyclic peptide sequences and all the clones, except ones having a stop codon in the cyclic peptide coding region, showed the expected protein splicing result. This simple two-step system for bacterial expression systems may be modified to suit various expression systems for cell-based assays.
Patellar Fracture After ACL Reconstruction: Open Reduction and Internal Fixation with a Maxillofacial Plate
Authors: Holy Filip , Licano Jorge , Treme Gehron
Published: April 2021

Case:

Patellar fractures after anterior cruciate ligament (ACL) reconstruction with a bone-patellar-tendon-bone (BPTB) autograft are a rare complication with a reported incidence of 0.2% to 2.3%. Treatment has previously been nonoperative splinting, lag screws, or a tension-band construct. We present the case of a 14-year-old adolescent girl who suffered a comminuted patella fracture 4 weeks after an ACL reconstruction using a BPTB autograft who subsequently underwent successful operative fixation through a novel technique with the use of a maxillofacial plate and screw system.

Conclusion:

A maxillofacial plate and screw system is an effective and reliable treatment option for patellar fractures sustained after ACL reconstruction with a BPTB autograft.
Unusual Pattern of Traumatic Anterolisthesis at Multiple Levels (L3,4,5 Over S1) Because of Pedicle Avulsion
Authors: Gupta Ayush , Goel Akash , Bhatia Nishant , Mehndiratta Anurag
Published: April 2021

Case:

Multilevel lumbar spondylolistheses have been reported, but only secondary to degenerative processes. We describe a case where grade 4 anterolisthesis occurred (L3,4,5 over S1) because of multiple level traumatic pedicle avulsion rather than facetal/pars interarticularis/posterior ligamentous complex disruption in a 42-year-old man who presented with paraparesis after a fall from height. Decompression was performed at the L5 level, and pedicle screw fixation was performed at L3, L5, and S1 levels.

Conclusion:

Although such an injury pattern seems catastrophic, it is deemed relatively stable because of the intact posterior ligamentous complex. Restoration of anatomy with stabilization allowed early mobility and satisfactory neurological recovery.
Surgical Treatment of Pathological Tibial Shaft Fracture in Adult Patient With Gnathodiaphyseal Dysplasia
Authors: Takeda Ryutaro , Yasui Tetsuro , Kasai Taro , Matsumoto Takumi , Matsubara Takehiro , Tanaka Sakae
Published: April 2021

Case:

Gnathodiaphyseal dysplasia is a generalized skeletal syndrome characterized by frequent bone fractures in childhood, sclerosis and bowing of tubular bones, and cemento-osseous lesions of the jawbones. We present the case of a 53-year-old man with gnathodiaphyseal dysplasia who presented with pathological fracture of the tibial shaft. Internal fixation with the Ender nail was successfully performed with 2 years of follow-up.

Conclusion:

This is the first report describing the treatment of fracture in an adult patient with gnathodiaphyseal dysplasia. Internal fixation with the Ender nail was effective for the tubular bone with deformity. Callus formation was observed without delay.
Generating Missing Oilfield Data Using A Generative Adversarial Imputation Network GAIN
Authors: Andrews Justin , Gorell Sheldon
Published: April 2021

Missing values and incomplete observations can exist in just about ever type of recorded data.

With analytical modeling, and machine learning in particular, the quantity and quality of available data is paramount to acquiring reliable results. Within the oil industry alone, priorities in which data is important can vary from company to company, leading to available knowledge of a single field to vary from place to place. With machine learning requiring very complete sets of data, this issue can require whole portions of data to be discarded in order to create an appropriate dataset.

Value imputation has emerged as a valuable solution in cleaning up datasets, and as current technology has advanced new generative machine learning methods have been used to generate images and data that is all but indistinguishable from reality. Using an adaptation of the standard Generative Adversarial Networks (GAN) approach known as a Generative Adversarial Imputation Network (GAIN), this paper evaluates this method and other imputation methods for filling in missing values. Using a gathered fully observed set of data, smaller datasets with randomly masked missing values were generated to validate the effectiveness of the various imputation methods; allowing comparisons to be made against the original dataset. The study found that with various sizes of missing data percentages withing the sets, the "filled in" data could be used with surprising accuracy for further analytics.

This paper compares GAIN along with several commonly used imputation methods against more standard practices such as data cropping or filling in with average values for filling in missing data. GAIN, as well as the various imputation methods described are quantified for there ability to fill in data. The study will discuss how the GAIN model can quickly provide the data necessary for analytical studies and prediction of results for future projects.
Carbon Dots Stabilized Foam for Enhanced Oil Recovery
Authors: Sakthivel Sivabalan , Kanj Mazen
Published: April 2021

Foams are the divergent fluids that are employed in the upstream oil and gas industry to reduce fluid channeling and fingering in the high permeability region. Foams are usually generated in the high permeability reservoirs (e.g. glass beads) by the alternative injection of surfactant and gas. Conventional foaming systems exhibit stability issues at the high temperature and high salinity reservoir conditions. In this investigation, we study the stability and efficiency (in terms of both enhanced inflow performance and added oil recovery) of foams formed using surfactant solution with and without carbon Nanodots (CND). The study involved using different brine salinities, CND concentrations, temperature and pressure conditions, and types of surfactants. A multifaceted interrelationship of the various influencing mechanisms is demonstrated. Foams are examined using foam analyzer, HP/HT coreflood and microfluidic setup. In trace amounts (5-10 ppm), CND contributed to 60-70% improvement in foam stability in high salinity brine. The improvement is attributed by the reduction of the drainage rate of the lamellae and a delay of the bubble rupturing point. Both microfluidic and core-flood experiments showed noticeable improvement in mobility control with the addition of the CND. This is contributed to an improved foamability, morphology, strength, and stability of the foam.
Will Carbon Dioxide Injection in Shale Reservoirs Produce from the Shale Matrix, Natural Fractures, or Hydraulic Fractures?
Authors: Fakher Sherif , Elgahawy Youssef , Abdelaal Hesham , Imqam Abdulmohsin
Published: April 2021

Enhanced oil recovery (EOR) in shale reservoirs has been recently shown to increase oil recovery significantly from this unconventional oil and gas source. One of the most studied EOR methods in shale reservoirs is gas injection, with a focus on carbon Dioxide (CO2) mainly due to the ability to both enhance oil recovery and store the CO2 in the formation. Even though several shale plays have reported an increase in oil recovery using CO2 injection, in some cases this method failed severely. This research attempts to investigate the ability of the CO2 to mobilize crude oil from the three most prominent features in the shale reservoirs, including shale matrix, natural fractures, and hydraulically induced fracture. Shale cores with dimensions of 1 inch in diameter and approximately 1.5 inch in length were used in all experiments. The impact of CO2 soaking time and soaking pressure on the oil recovery were studied. The cores were analyzed to understand how and where the CO2 flowed inside the cores and which prominent feature resulted in the increase in oil recovery. Also, a pre-fractured core was used to run an experiment in order to understand the oil recovery potential from fractured reservoirs. Results showed that oil recovery occurred from the shale matrix, stimulation of natural fractures by the CO2, and from the hydraulic fractures with a large volume coming from the stimulated natural fractures. By understanding where the CO2 will most likely be most productive, proper design of the CO2 EOR in shale can be done in order to maximize recovery and avoid complications during injection and production which may lead to severe operational problems.
Unconventional Optimized Development Strategy Workflow
Authors: Morsy Samiha , Menconi Mauro , Liang Baosheng
Published: April 2021

A comprehensive workflow was developed to support short and long-term unconventional Midland and Delaware Basin development strategy. The workflow is applied to every new pad to ensure child wells are targeting more of the virgin rock. The developed workflow considers pressure and stress changes around parent wells, landing strategy, completion optimization, frac order design, etc. A 3-D reservoir model was developed to estimate the depletion and the induced stress changes around the parent wells. Hydraulic fracture modeling is coupled with the flow simulation model to assess child wells fracture propagation under different scenarios. Different landing strategies were investigated to reduce depletion effects on Child wells. Child wells fracture and proppant fluid intensity was optimized to provide the optimum fracture interference. Certain technologies were successfully utilized to change the pressure and stress around the existing wells to properly alter child well fracture propagation towards virgin rock. Frac order was adjusted accordingly to benefit from the induced changes in reservoir pressure and stress around parent wells. The workflow was applied to areas in the Wolfcamp formation within the Midland and Delaware Basins. Results show the effectiveness of the developed workflow to maintain Basin development performance.
Tailor-Made Workflow to Understand and Forecast H2S Production Risks in Thermal Projects
Authors: Ayache Simon Victor , Gasser-Dorado Julien , Michel Pauline , Preux Christophe , Lamoureux-Var Violaine
Published: April 2021

In-situ extraction of heavy sulfured oil based on steam injection comes with a high level of risk in terms of H2S production, resulting from aquathermolysis reactions. This could lead to on-site living being casualties, environment damage, surface facilities and wells corrosion. Also, there is a strong need to understand aquathermolysis reactions and to forecast acid gases generation in such context. For that aim a tailor-made workflow was developed to estimate H2S concentration at the well-head.

To meet these challenges, a 3-steps approach combining laboratory studies and numerical predictions has been developed. It firstly consists in a fast preliminary assessment of the highest H2S risk areas, based on the measurements of sulfur characteristics of reservoir core samples using our Rock-Eval Sulfur set-up. Then aquathermolysis experiments from the previously selected core samples are conducted in order to calibrate the compositional chemical model of the reservoir simulator. The latter is eventually used to carry out thermal compositional reactive simulations at field scale. The reservoir simulator allows simulations of SAGD processes and handles H2S distribution over oil/water/gas phases and its migration in these phases.

Simulation results show that acid gases are generated within the steam chamber, before they accumulate at the chamber edges where they dissolve in the water and oil phases. This contributes to reduce viscosity, allowing the oil to flow along the steam chamber edges before it has reached the steam temperature. Therefore the H2S produced at surface is mainly carried towards the wells by water and to a lesser extent oil. This flowing oil has not reacted with the steam: its composition is close to the initial reservoir oil but enriched with dissolved gases. The steam chamber shape, the temperature distribution and the H2S produced at surface are strongly modified when heterogeneities are introduced in the reservoir model. Synthetic cases allow a deeper understanding of the effects of heterogeneities. Vertical permeability is thus found to be a key factor of H2S production variations. When steam reaches a lower permeability lithology, a delayed rise in H2S production at wellhead is observed as aquathermolysis reactions rates increase. Finally Foam Assisted-SAGD has been considered. While the foam improves the Steam-Oil ratio, no clear improvement was observed regarding the H2S production.
Prediction of Equivalent Liquid Permeability from Gas Permeability Measurements: A Recurrent Neural Network Approach
Authors: Alkinani Husam , Al-Hameedi Abo Taleb , Dunn-Norman Shari
Published: April 2021

One of the most vital reservoir properties is permeability. It is usually measured using core samples with two major measurement methods; using gas or using liquid. The purpose of this work is to use a data-driven recurrent neural network model to estimate the equivalent liquid permeability based on gas permeability. By using this model, the equivalent liquid permeability can be predicted for the permeability of core samples with rich clay minerals measured using gas (or any core sample that is measured using gas). This will give an alternative way to the currently used method (Klinkenberg method). Core sample data measurements of more than 500 cores were obtained from limestone formations. The data went through a processing step to eliminate any measurement errors. Then, the data were clustered into training, validation, and testing. After many iterations, a decision was made to have a network with four hidden layer and twenty neurons in each hidden layer, and four delays in the input and the output. The findings showed that the network had stopped training after nine epochs with a validation mean squared error (MSE) of 5.3. The model exhibited excellent performance during training, validation, and testing with an overall R2 of 0.91 which is excellent. These findings prove that the model can closely track the actual equivalent liquid permeability measurements using the gas permeability measurements data within a reasonable margin of error. With the rise of machine learning and other artificial intelligence (AI) methods as well as the potential application in the petroleum industry, these methodologies can revolutionize the industry and save time and money.
Data Science Use Case for Brownfield Optimization - A Case Study
Authors: Lal Manish Kumar , Kim Tae Hyung , Singleton Darrin M.
Published: April 2021

Data Science is the current gold rush. While many industries have benefitted from applications of data science, including machine learning and Artificial Intelligence (AI), the applications in upstream oil and gas are still somewhat limited. Some examples of applications of AI include seismic interpretations, facility optimization, and data driven modeling – forecasting. While still naïve, we will explore cases where data science can be used in the day to day field optimization and development.

The Midway Sunset (MWSS) field in San Joaquin Valley, California has over 100 years of history. The field was discovered in 19011 and had limited development through the 1960s. Since the start of thermal stimulation in 1964, the field has seen phased thermal flooding and cyclic stimulation. Recently there has been an increase in heat mining vertical and horizontal wells to tap the remaining hot oil. As with any brownfield, the sweet spots are long gone. Effort is now to optimize the field development and tap by-passed oil, thereby increasing recovery. The current operational focus includes field wide holistic review of remaining resource potential.

Resources in the MWSS reservoirs are produced by cyclic steam method. Cyclic thermal stimulation has been effective as an overall depletion process and for stimulating the near wellbore region to increase production. It is imperative to properly identify target wells and sands for cyclic stimulation. Cyclic steaming in depleted zones or cold reservoirs is often uneconomical. The benefit comes when we can identify and stimulate only the warm oil.

Identification of warm oil and short listing the wells for cyclic stimulation is a labor-intensive process. The volume of data can get so large that it may not be feasible for a professional to effectively do the analysis. In this paper, we present a case study of data analytics for high grading wells for cyclic stimulation. This method utilizes the machine power to integrate reservoir, and production data to identify and rank wells for cyclic stimulation and potentially increase success rate by minimizing suboptimal cyclic candidates.
Flow Profiling Using Fiber Optics in a Horizontal Steam Injector with Liner-Deployed Flow Control Devices
Authors: Javaheri Mohammad , Tran Minh , Buell Richard Scot , Gorham Timothy Lee , Sims Jack , Rivas Stephen , Munoz Juan David
Published: April 2021

Horizontal steam injectors can improve the efficiency of thermal operations relative to vertical injectors. However, effective in-well and reservoir surveillance is needed to understand steam conformance. Uniform steam chest development improves steam-oil-ratio (SOR) in continuous steam injection and accelerates recovery in cyclic steam injection. Conformance of the injected steam can be achieved by flow control devices (FCD) deployed on either tubing or liner. A new liner-deployed FCD was used in a horizontal steam injector in the Kern River field. The liner-deployed FCD is intended to replace the tubing-deployed FCDs while reducing capital costs, surveillance costs, and well intervention costs for conformance control.

Fiber optics was used for surveillance, which is the most promising method in horizontal steam injectors considering reliability, accuracy, and cost. Fiber optic data enables monitoring the performance of liner-deployed FCDs as well as estimating the flow profile along the lateral length. Multi-mode Distributed Temperature Sensing (DTS) optical fibers and single-mode Distributed Acoustic Sensing (DAS) optical fibers were installed in the well for these objectives. Algorithms for interpreting DTS were improved to include a new technique, Shape Language Modeling (SLM), and a probabilistic approach. The configuration of the FCDs was changed during a well intervention, and it was monitored by DTS and DAS. Data from both DTS and DAS confirms the open/closed position of the sliding sleeve of FCDs initially and after the intervention. The probabilistic estimates of steam outflow in several FCD configurations match well with the theoretical outflow that is expected from the critical flow of steam through chokes installed in the FCDs.
Creating Value for the High-Saline Bakken Produced Water by Optimizing its Viscoelastic Properties and Proppant Carrying Tendency with High-Viscosity Friction Reducers
Authors: Tomomewo Olusegun Stanley , Mann Michael Daniel , Ellafi Abdulaziz , Jabbari Hadi , Tang Clement , Ba Geri Mohammed , Kolawole Oladoyin , Adebisi Azeez , Ibikunle Omolara , Alamooti Moones , Iroko Adedayo
Published: April 2021

Since the arrival and advancement of horizontal drilling and hydraulic fracturing (hydrofracturing) technologies, developing and producing unconventional formations like the Bakken Formation have become a mystery solved for operators in North America. This has also made unconventional reservoir assets the central focus of the oil and gas/energy industry at the state, national, and global levels. However, the produced water from these activities has high salt contents (∼110,000 to 350,000 ppm) total dissolve solids (TDS) in the Bakken Formation) and poisonous if untreated and in contact with the environment. The most common disposal method in the Bakken Formation is deep injections into disposal wells. However, there have been some fears that continuous injections, in addition to contaminating the ground water, could potentially lead to seismic activities either at the time of injection or in the near future. If treated and made fit for its respective applications, this water could be reused in the hydrofracturing process, thereby reducing operator costs of water acquisition and disposal. In addition, it could be used for power generation or to support coal mining and irrigation. Previous studies have discussed various means of improving the quality of the produced water. However, none have been able to cope with the issue of wastewater and residual oil high in TDS. This paper aims to study all relevant means that allow the Bakken Formation to produce water that can be used as an alternative based fluid for use with polymers like high viscosity friction reducers (HVFRs) to make hydraulic fracturing fluids that will be stable with reservoir conditions and able to reduce environmental footprints and operating costs. This research presents an experimental investigation using the Bakken Formation's hypersaline water with HVFRs. This work includes experimental research divided into base case scenarios that serve as a standard for comparison of the effectiveness of the other cases. The results show that the Bakken water high in TDS treated with higher dosages (4–8 GPT) of HVFRs withstand the effect of hardness, salinity, and heavy metals and remain stable at various shear rates (66–330 s−1). No treatment was done on the Bakken produced water except filtration and dilution.
Nanoparticles Screening Criteria for Wettability Alteration in Carbonate Reservoirs
Authors: Deng Xiao , Kamal Muhammad Shahzad , Patil Shirish , Hussain Muhammad Shakil
Published: April 2021

Wettability alteration has been recognized as a key mechanism for enhanced oil recovery in oil-wet carbonate reservoirs. Nanoparticles can change rock surfaces from oil-wet to water-wet. However, there are multiple kinds of nanoparticles and different reservoir conditions. It is necessary to establish a screen system to guide nanoparticles selection. Temperature and salinity are two important reservoir conditions that may have a big influence on the performance of nanoparticles. Besides, divalent ions and monovalent ions can have a different impact. In this paper, different kinds of commercial nanoparticles were used as wettability modifiers on carbonate rock. Metallic oxide nanoparticles, SiO2, and titania nanoparticles were dissolved into brine solution under varying temperatures (50°C – 100°C) and salinity (2500 – 210,000ppm). Carbonate rock samples were aged by crude oil to make them oil-wet. After that, rock samples were immersed in brine and nanoparticle solutions to measure the contact angles under different temperature. Rock surfaces were then examined by scanning electron microscope (SEM) to see the adsorption and distribution of nanoparticles. Stability data shows that nanoparticles tend to be more stable under high temperature, low salinity conditions. Besides, monovalent ions have a smaller impact on nanoparticle stability than divalent ions. By monitoring contact angle with time, a quicker wettability alteration was observed with SiO2 and CaCO3 nanoparticles on carbonate rock under higher temperatures, indicating that temperature has a significant influence on the performance of nanoparticles. SEM images show that under low salinity conditions, nanoparticles tend to be more scattered. This paper showed that nanoparticles are very effective materials for carbonate wettability alteration under varying temperature and salinity. Besides, the relative performance of nanoparticles under different conditions and a screening guide according to carbonate reservoir conditions are provided
Effect of Cryogenic Treatment Thermal Shock on Rock Dynamic Elastic Properties and Permeability of Wolfcamp Core Samples – An Experimental Study
Authors: Ramezanian Mahdi , Emadi Hossein
Published: April 2021

A few researches have been conducted to study effects of cryogenic treatment (known as thermal shocking) on unconventional rock properties, while they have been extensively studied in geothermal projects. The results show that cryogenic treatment significantly alters the rock mechanical properties by creation of new cracks owing to thermally induced stresses resulting in the permeability enhancement. In this laboratory study, effects of cryogenic treatment (thermal shocking) on permeability and dynamic elastic properties of three Wolfcamp core samples (one outcrop and two downhole samples) at downhole conditions were experimentally evaluated. Permeability and dynamic rock mechanical properties were measured before and after conducting each cycle of thermal shock. Using X-ray powder diffraction (XRD) analysis, the mineral compositions of the cores were determined. The results demonstrate that implementing the thermal shock technique on the core samples results in increasing their permeability and ductility.
What are the Dominant Flow Regimes During Carbon Dioxide Propagation in Shale Reservoirs’ Matrix, Natural Fractures and Hydraulic Fractures?
Authors: Fakher Sherif , Elgahawy Youssef , Abdelaal Hesham , Imqam Abdulmohsin
Published: April 2021

Carbon dioxide (CO2) injection in low permeability shale reservoirs has recently gained much attention due to the claims that it has a large recovery factor and can also be used in CO2 storage operations. This research investigates the different flow regimes that the CO2 will exhibit during its propagation through the fractures, micropores, and the nanopores in unconventional shale reservoirs to accurately evaluate the mechanism by which CO2 recovers oil from these reservoirs. One of the most widely used tools to distinguish between different flow regimes is the Knudsen Number. Initially, a mathematical analysis of the different flow regimes that can be observed in pore sizes ranging between 0.2 nanometer and more than 2 micrometers was undergone at different pressure and temperature conditions to distinguish between the different flow regimes that the CO2 will exhibit in the different pore sizes. Based on the results, several flow regime maps were conducted for different pore sizes. The pore sizes were grouped together in separate maps based on the flow regimes exhibited at different thermodynamic conditions. Based on the results, it was found that Knudsen diffusion dominated the flow regime in nanopores ranging between 0.2 nanometers, up to 1 nanometer. Pore sizes between 2 and 10 nanometers were dominated by both a transition flow, and slip flow. At 25 nanometer, and up to 100 nanometers, three flow regimes can be observed, including gas slippage flow, transition flow, and viscous flow. When the pore size reached 150 nanometers, Knudsen diffusion and transition flow disappeared, and the slippage and viscous flow regimes were dominant. At pore sizes above one micrometer, the flow was viscous for all thermodynamic conditions. This indicated that in the larger pore sizes the flow will be mainly viscous flow, which is usually modeled using Darcy's law, while in the extremely small pore sizes the dominating flow regime is Knudsen diffusion, which can be modeled using Knudsen's Diffusion law or in cases where surface diffusion is dominant, Fick's law of diffusion can be applied. The mechanism by which the CO2 improves recovery in unconventional shale reservoirs is not fully understood to this date, which is the main reason why this process has proven successful in some shale plays, and failed in others. This research studies the flow behavior of the CO2 in the different features that could be present in the shale reservoir to illustrate the mechanism by which oil recovery can be increased.
Experimental Study and Numerical Modeling of Seawater Breakthrough Using Inherent Boron as Tracer
Authors: Wang Yanqing , Li Xiang , Lu Jun
Published: April 2021

Seawater injection is widely used to maintain the offshore oil reservoir pressure and improve oil recovery. However, injecting seawater into reservoirs can cause many issues such as reservoir souring and scaling, which are tightly related to the seawater breakthrough percentage. Accurately calculating the seawater breakthrough percentage is important for estimating the severity of those problems and further developing corresponding strategies to solve those issues. The validation of using natural ion boron as tracer to calculate seawater breakthrough percentage was investigated. Boron can interact with clays, which can influence the accuracy in seawater breakthrough calculation using boron. Therefore, the interaction between boron and different clays at various conditions were studied, and Freundlich adsorption equation was used to describe the boron adsorption isotherms. Then boron adsorption isotherms were coupled into the reservoir simulator to investigate the boron transportation in porous media, and the results in turn were further analyzed to calculate the accurate seawater breakthrough percentage. Results indicated that boron adsorption by different clays varied. pH value of solution can significantly influence the amount of boron adsorbed. As a result, the boron concentration profile was delayed in coreflood test. The results of reservoir model fit perfectly with that of coreflood test, indicating the validation of boron reaction model. Based on the reservoir simulator results, boron concentration profile in produced water was successfully used to calculate seawater breakthrough percentage by considering the clay content distribution. However, the seawater breakthrough point cannot be calculated by boron as boron concentration is still at the formation level due to boron desorption.
Minimizing Lost Circulation Non-Productive Time Using Expected Monetary Value and Decision Tree Analysis
Authors: Alkinani Husam Hasan , Al-Hameedi Abo Taleb Tuama , Dunn-Norman Shari
Published: April 2021

Lost circulation and problems related to drilling present a major challenge for the drilling industry. Each year, billions are spent to treat these problems. There is not a single solution to lost circulation because of the complexity and kind of formations susceptible to this issue. Lost circulation treatment data for the Shuaiba formation (induced fractured formation) were gathered from drilled wells in Southern Iraq (over 2000). Treatments have been grouped according to the volume of mud loss as complete, severe, and partial loss remedies. Detailed costs and probabilities calculations were conducted. The costs of three types of loss treatments (partial, severe, and complete) were handled separately since some treatments of severe, and all treatments of complete losses have to be introducing through open end drill pipe (OEDP). Expected monetary value (EMV) and decision tree analysis (DTA) were utilized to choose the optimal mud loss pathway to treat the lost circulation type.

In this study, probability and cost were both considered to select the practical and efficient strategy of stopping mud loss. Too many of the remedy scenarios were investigated. The selection of the optimum strategy for every type of loss was based on the lowest EMV and efficiency. Once both conditions were satisfied, the treatment strategies were selected to treat each type of loss. Treatment strategies were provided for complete, severe, and partial losses as flowcharts that can be utilized as a reference in the field to stop or at least mitigate this troublesome problem. The methods used in this paper have the possibility to be adopted and invested to treat mud loss based on historical data of treatments in any formation worldwide.
Flow Control Devices in Steam Assisted Thermal Applications: A Way to Optimize Both Steam Injection and Fluids Production
Authors: Zhu Da , Uzcategui Alberto
Published: April 2021

Flow Control Device (FCD) completions in steam assisted thermal applications have been implemented in several places: Canada, California, China, Oman and Colombia, among others. Such completion configurations have been more common in recent years to mitigate or avoid uneven and/or improper steam placement and steam breakthrough, which are some of the critical issues operators have experienced in these developments. This study presents different FCD technologies designed to optimize the steam injection and fluids production for diverse steam assisted applications including SAGD, CSS and Steam Flooding.

Three FCD technologies are introduced: (i) supersonic steam injection FCD, (ii) steam choking FCD and (iii) multi-directional FCD. Extensive Computational Fluid Dynamic (CFD) simulations, analytic near-wellbore simulations and flow loop testing were conducted to evaluate the performance of the three technologies: (i) the supersonic steam injection FCD showed a high pressure recovery (therefore, less upstream pressure requirements) and a reduction of the cumulative steam-oil ratio, (ii) the steam choking FCD demonstrated the highest steam choking capability for these type of devices and (iii) the multi-directional FCD showed promising results for CSS applications to allow for supersonic steam injection during the injection phase and steam choking capabilities during the production phase

Common FCD deployment risks such as erosion, scaling potential and high pressure drops were reviewed to provide the reader with a high level understanding of the factors which could induce these issues.

Finally, field data where FCD completions have been installed is presented to compare the FCD wells performance versus conventional well designs and illustrate the success of these completions strategies.

Keywords: flow control devices, supersonic steam injection, steam choking
Incorporating Economic Decisions into Reservoir Simulation to Support Accurate and Efficient Optimization and Analysis of Field Development Strategies
Authors: Browning Jim , Gorell Sheldon
Published: April 2021

Economic optimization of a reservoir can be extremely tedious and time consuming. It is particularly difficult with many wells, some of which can become non-economic within the simulated time period. These problems can be mitigated by: 1) analyzing the results of a simulation once it has run, or 2) applying injection or production constraints at the well level. An example of option 1 would be integration with a spreadsheet or economic simulation package after the simulation has run. An example of option 2 would be to set a maximum water cut, upon which the well constraints could be changed, or the well could be shut in within the simulation. Both of these methods have drawbacks. If the goal is to account for how changes in a well operating strategy affects other wells, then analysis after the fact requires many runs to sequentially identify and modify well constraints at the correct times and in the correct order. In contrast, applying injection and production constraints to wells is not the same as applying true economic constraints. The objective of this work was to develop an automated method which includes economic considerations within the simulator to decrease the amount of time optimizing a single model and allows more time to analyze uncertainty within the economic decision making process.

This study developed automated methods and procedures to include economic calculations within the context of a standard reservoir simulation. The method utilized modifications to available conditional logic features to internally include and export key economic metrics to support appropriate automatic field development changes. This method was tested using synthetic models with different amounts of wells and operating conditions. It was validated using after the fact calculations on a well by well basis to confirm the process.

People costs are always among the most significant associated with running a business. Therefore, it is imperative for people to be as efficient and productive as possible. The method presented in this study significantly reduces the amount of time and effort associated with tedious and manual manipulations of simulation models. These savings enable an organization to focus on more value-added activities including, but not limited to, accurately optimizing and estimating of uncertainty associated decisions supported by reservoir simulation.
Security Implications of IIoT Architectures for Oil & Gas Operations
Authors: Hou Bowen , Paul Donald L
Published: April 2021

Implementing the IIoT paradigm into the classical oil & gas field OT systems is one of the essential concepts for Digital Oilfield 2.0. The transition in architecture and the corresponding technology changes can create a new cyber-physical security risk profile through alterations in the digital information structure of the oilfield OT system. With the onset of IIoT implementations in the industry, it is an opportune time to review and assess the emerging cyber-physical risk landscape.

In the paper, we identified and compared the current oilfield OT logical structures with the designs emerging through the IIoT implementations. The analysis includes extensive reviews of developing standards, such as those proposed by Industrial Internet Consortium, and ongoing published experiences to find the primary points of transition. The security risks stemming from the IIoT implementation appear to raise significant concerns with regard to potentially severe cybersecurity outcomes, which could materially impact the integrity and safety of oilfieldoperations. The study concentrated on the cybersecurity threats that could pose negative physical and operational conditions resulting from loss of visibility and / or loss of control of the operational processes in field facilities.

Extensive literature reviews were the basis for identifying the implications of cybersecurity risks in the ongoing stages of integrating the IIoT into the field. The reviews identified the modified strategies for cyber-physical systems, including potential threats and counter measurements for the field IIoT model. However, these proposed strategies still miss a fundamental denominator - the assessments generally ignore that it is the fundamental nature of IIoT structure itself that creates cyber-security vulnerabilities. To investigate further, we performed a contrasting analysis based on specific case studies of field IIoT devices such as the pump-off controller and OT architectures. Three foundational threat implications emerged on the transformation of IIoT architecture into the oilfield: 1)The exponential growth of connected distributed artificial intelligence (DAI) devices enormously increases the complexity of designing the software of each facility and system. 2)The cutting-edge Machine to Machine (M2M) characteristic in the IIoT model pushes the human out of the traditional control and monitor loop. 3)The widespread scale of DAI devices with the unique IP address in the network shifts cybersecurity risks to each connected endpoint. The cornerstone of the distinctive IIoT attributes illustrated in the paper contributes to the potential loss of control, leading to potential for serious damaging operational outcomes in the field.

The goal of this paper is to aid oilfield security planning and design processes through animproved recognition of the cyber-physical security impacts emerging from the implementation of IIoT architectures and technologies integration into field OT domains.