bluuebunny/crossref_metadata_2025 huggingface dataset:
Travma iz otroštva kot dejavnik samomorilnega vedenja tekom življenja pri odraslih otrocih staršev s škodljivo rabo alkohola
Authors: Šrajner Martina , Zadravec Šedivy Nuša , Poštuvan Vita
Published: March 2022

Slovenija predstavlja t. i. »mokro kulturo«, kjer je alkohol splošno sprejet. Najpogosteje zaradi škodljivega pitja posameznika trpi njegova družina, predvsem otroci, ki predstavljajo ranljivo skupino s povečanim tveganjem za duševne in telesne težave. Namen pričujoče raziskave je bil preveriti, ali prihaja do razlik v težavah v duševnem zdravju, v različnih oblikah samomorilnega vedenja in v pogostosti pojavljanja travme v otroštvu med posamezniki, ki so odraščali ob staršu s škodljivo rabo alkohola, in posamezniki, ki niso odraščali ob staršu s škodljivo rabo alkohola. Hkrati je bil namen preveriti odnos med samomorilnim vedenjem odraslih otrok staršev s škodljivo rabo alkohola in pogostostjo pojavljanja travm iz otroštva ter proučiti morebitne napovednike samomorilnega vedenja tekom življenja pri odraslih otrocih staršev s škodljivo rabo alkohola. Vzorec je zajemal 216 udeležencev; 106 posameznikov je bilo uvrščenih v skupino odraslih otrok staršev s škodljivo rabo alkohola, preostalih 110 pa v primerjalno skupino. Odrasli otroci staršev s škodljivo rabo alkohola so v primerjavi s primerjalno skupino pogosteje poročali o poskusu samomora v preteklosti ter o pogostejšem doživljanju fizične in čustvene zlorabe ter zanemarjanja. Ugotovljena je bila pozitivna povezava med čustvenim zanemarjanjem in občutkom, da je oseba drugim v breme, in sicer pri odraslih otrocih staršev s škodljivo rabo alkohola. Doživljanje travme v otroštvu se je izkazalo kot najpomembnejši napovednik poskusa samomora v preteklosti pri odraslih otrocih staršev s škodljivo rabo alkohola, medtem ko je misli o smrti najmočneje napovedoval občutek, da oseba drugim predstavlja breme. Na splošno rezultati nakazujejo, da travma, doživeta v otroštvu, lahko pomembno prispeva k poskusu samomora pri odraslih otrocih staršev s škodljivo rabo alkohola.
Modelamiento y diseño del sistema de alcantarillado sanitario, utilizando la metodología del Cepis en el centro poblado compañía baja, distrito Sivia, provincia Huanta, región Ayacucho
Authors:   ,   Universidad San Ignacio de Loyola, Pacheco Huamani Karen Emperatriz
Published: March 2022

La presente investigación corresponde al modelamiento y diseño del sistema de alcantarillado sanitario, utilizando la metodología del CEPIS en el Centro Poblado Compañía Baja, Distrito Sivia, Provincia Huanta y Región Ayacucho. En la actualidad la comunidad no cuenta con los servicios básicos, su población actual es de 380 habitantes, al no contar con dicho servicio básico y por la importancia de mejorar la salud pública se realizó el presente estudio. Se realizó un diseño No experimental, Descriptivo y Transversal; se utilizaron técnicas como la observación, datos estadísticos del Instituto Nacional de Estadística e Informática, encuestas, procesamiento de datos, diseño y cálculo de la red de alcantarillado. Para elaborar el diseño del sistema de alcantarillado se inició con el levantamiento topográfico en el Centro Poblado Compañía Baja y las características de la zona pudieron definir los parámetros hidráulicos fundamentales según la Metodología del CEPIS. Una vez definido el trazo de la red de alcantarillado y los respectivos cálculos de las bases de diseño, se procedió a realizar el modelamiento hidráulico y diseño en el programa SewerCad V8i. En el sistema de alcantarillado sanitario la tubería a usar será PVC NTP-ISO 4435 S-25 de diámetros de 6” de una longitud de tubería 848.3ml y tuberías de diámetro de 8” de una longitud de 1539.7ml; así como, 22 buzonetas y 66 buzones de altura variable. Para el tratamiento de las aguas residuales se plantea una cámara de rejas, dos desarenadores de flujo horizontal, dos lagunas facultativas y una laguna de maduración . La remoción de contaminantes lograda por el sistema cumplirá con los límites máximos permisibles de descarga a los cuerpos receptores para aguas residuales. El presupuesto referencial para el sistema de alcantarillado sanitario y planta de tratamiento de aguas residuales asciende a la suma de S /. 1,379,460.31
Simplified Procedures for Managing Insecticidal Wastes; A Case of KCMUCo-PAMVERC Vector Control Product Testing Facility in North-Eastern Tanzania
Authors: Msapalla Agness , Azizi Salum , Jangu Menan , Mbewe Njelembo Joshua , Matowo Johnson , Shayo Magreth , Kaaya Robert , Mawa Benson , Joram Amandus , Kirby Mathew , Rowland Mark , Mosha Franklin
Published: March 2022

Insecticide testing facilities that evaluate a variety of vector control products may generate large amount of hazardous wastes from routine operations. These wastes originate from degraded technical grade materials, sprayed substrates, redundant stock or working insecticidal solutions. The washing of Long-Lasting Insecticidal Nets (LLINs) during preparation for laboratory and experimental hut trials also contribute to waste water with insecticide content. Human and environmental exposure to insecticidal waste can occur during transport, categorization, storage and disposal in resulting in environmental pollution and potential health effects. Various national and international guidelines have been devised for safe disposal and should be strictly followed to avoid adverse effects on humans or environment. The current paper describes a case study from insecticide test facility in north-eastern Tanzania in management of insecticidal waste.
Taking a Closer Look: Clinical and Histopathological Characteristics of Culture-Positive versus Culture-Negative Pulmonary Mucormycosis
Authors: Spallone Amy , Moran Cesar A , Wurster Sebastian , Axell-House Dierdre B , Kontoyiannis Dimitrios P.
Published: March 2022

Cultural recovery of Mucorales from hyphae-laden tissue is poor, and the clinical implications of culture positivity are scarcely studied. Therefore, we compared clinical and histological characteristics of culture-positive and culture-negative histology-proven pulmonary mucormycosis cases among cancer patients. Histology specimens were blindly reviewed by a Thoracic Pathologist and graded on four histopathologic features: hyphal quantity, tissue necrosis, tissue invasion, and vascular invasion. Twenty cases with a corresponding fungal culture were identified; five were culture-positive, and 15 culture-negative. Although no statistically significant differences were found, culture-positive patients were more likely to exhibit a high burden of necrosis and have a high burden of hyphae but tended to have less vascular invasion than culture-negative patients. In terms of clinical characteristics, culture-positive patients were more likely to have acute myeloid leukemia (60% vs. 27%, p=0.19), a history of hematopoietic cell transplant (80% vs. 53%, p=0.31), severe lymphopenia (absolute lymphocyte count ≤500/µL, 100% vs. 73%, p=0.36), and monocytopenia (absolute monocyte count ≤100/µL, 60% vs. 20%, p=0.11). Forty-two-day all-cause mortality was comparable between culture-positive and culture-negative patients (60% and 53%, p=0.80). This pilot study represents the first comprehensive histopathological scoring method to examine the relationship between histopathologic features, culture positivity, and clinical features of pulmonary mucormycosis.
Factors Influencing Clinical Nurse’s Intention for Acquiring Coronavirus Disease 2019 Vaccination
Authors: Choe YeonHui , Cha Jieun
Published: March 2022

Objectives: This study investigated psychosocial factors that influence nurse’s intention to receive a COVID-19 vaccine. We focused on factors including COVID-19 knowledge, attitudes and beliefs related to COVID-19 vaccines, social contexts, and demographics.Methods: Data were collected from 200 nurses at five hospitals in Daegu between 12 April and 19 June 2021. We assessed COVID-19 knowledge, perceived susceptibility, severity, benefits, barriers, safety concerns, COVID-19 exposure, demographics, and the intention to get COVID-19 vaccines. Data were analyzed using descriptive statistics, t-tests, ANOVA, Pearson correlation, and hierarchial multiple regression.Results: Of 200 participants, 180 (90.0%) reported an intention to obtain a vaccination against COVID-19. Among four health beliefs towards COVID-19 vaccines, perceived severity was the highest. Perceived benefits (r = 0.42, p< 0.001) were positively associated with vaccination intention, while perceived barriers (r = -0.32, p< 0.001) and safety concerns (r = -0.20, p< 0.001) negatively influenced vaccination intention. There were differences in the scores for vaccination intention according to hospital grade and work department. According to the regression analysis, perceived benefits and barriers were discovered to account for 21% of the variance in vaccination intention.Conclusions: This study offers a timely overview of psychosocial factors that are related to nurses’ intention to get vaccinated for COVID-19. The vaccines’ benefits need to be highlighted in campaigns and educations, and it is imperative to remain transparent and truthful in communications about the vaccine safety.
Распространение вариантов вируса SARS-COV-2, вызывающих озабоченность (VOC) и интерес (VOI) на основе количества их геномов, депонированных в базу данных GISAID за неделю с 05.03.2022 г. по 11.03.2022 г.
Authors: Дмитриева Людмила , Краснов Ярослав , Чумачкова Елена , Осина Наталья , Зимирова Анастасия , Иванова Александра , Карнаухов Игорь , Караваева Татьяна , Щербакова Светлана , Кутырев Владимир
Published: March 2022

В обзоре представлен анализ геновариантов вируса SARS-CoV-2, вызывающих озабоченность (VOC) и интерес (VOI) на основе их геномов в базе GISAID за неделю с 05.03.2022 г. по 11.03.2022 г.
Elective Inpatient Total Joint Arthroplasty Case Volume in the United States in 2020
Authors: Heckmann Nathanael D. , Bouz Gabriel J. , Piple Amit S. , Chung Brian C. , Wang Jennifer C. , Mayfield Cory K. , Stambough Jeffrey B. , Oakes Daniel A. , Christ Alexander B. , Lieberman Jay R.
Published: March 2022

Background:

Despite known surgical volume reductions in 2020 during the height of the COVID-19 pandemic, no study has fully quantified the impact of the pandemic on the number of elective inpatient total hip (THA) and total knee arthroplasty (TKA) cases. The purpose of the present study was to analyze THA and TKA case volumes in the United States during the COVID-19 pandemic.

Methods:

The Premier Healthcare Database was utilized to identify adults undergoing primary elective THA or TKA from January 2017 to December 2020. The National Inpatient Sample was cross-referenced to provide nationwide representative sampling weights. Patients undergoing revision total joint arthroplasty (TJA) or non-elective surgery were excluded. Two quantitative models were created from both databases to estimate TJA case volume in 2020. Descriptive statistics were utilized to report monthly changes in elective TJA utilization throughout 2020. Univariate analyses were performed to compare differences between subgroups.

Results:

From 2017 to 2019, it was estimated that 1,006,000 elective inpatient TJAs (64.2% TKA and 35.8% THA) were performed annually. In 2020, an estimated 526,000 to 538,000 cases (62.0% TKA and 38.0% THA) were performed, representing a 46.5% to 47.7% decrease in nationwide volume from the prior 3-year average. Moreover, the elective TJA case volume for April 2020 was 1.9% of the average for that month from 2017 through 2019. Subsequently, case volumes for May and June increased compared with the volumes for those months from 2017 through 2019. There was then a decrease in cases for July, corresponding with the “second wave” of COVID-19, followed by an additional steady monthly decline through December, corresponding with the “third wave.” Finally, the elective TJA cases for December 2020 represented only 41.0% of the average case volume for that month from 2017 through 2019.

Conclusions:

In the midst of the 2020 COVID-19 pandemic, approximately 526,000 to 538,000 elective inpatient TJA cases were performed, representing a 46.5% to 47.7% decrease compared with the 3 previous years. The effects of the COVID-19 pandemic persisted through the end of that year, with decreased case volume through December 2020.
The Foreign Exchange Rate Prediction Using Long-Short Term Memory
Authors: Haifa Zahrah Hasna , Sa’adah Siti , Rismala Rita
Published: March 2022

The foreign exchange market is a global financial market that is influenced by economic, political, and psychological factors that are interconnected in complex ways. This complexity makes the foreign exchange market a difficult time-series prediction. At the end of 2019, the world was faced with the COVID-19 pandemic that has not only affected public health but also the foreign exchange market, which makes the trading behaviour affected. Long Short-Term Memory network (LSTM) is a type of recurrent neural network (RNN) that can solve long-term dependencies and is suitable to be a financial time-series model. This study implemented the LSTM model to predict the foreign exchange rate at a timeframe of 1 hour and daily in 2020 to get the best hyperparameter based on the RMSE evaluation results. Furthermore, with the obtained hyperparameters, the prediction result of 2020 was then compared with the 2018 and 2019 prediction results. The best RMSE result was obtained in 1-hour timeframe and when 2020’s RMSE result was compared to 2018’s and 2019’s RMSE result, the prediction of 2019 gave the best RMSE result. The LSTM model is able to achieve good results in the 2020 prediction, proven by the RMSE result which is 0.00135.
Seismic Drill-Bit Tracking for Improved Well Positioning
Authors: Houbiers Marianne , Bussat Sascha , Schopper Florian , Hansteen Fredrik
Published: March 2022

The lateral well position uncertainty of magnetic/gyro measurement-while-drilling (MWD) measurements can often exceed the requirements regarding anticollision, for optimal placement of infill wells between existing producers, or for hitting targets with limited geological extent. The positional uncertainty can be significantly reduced by implementing high-precision drill-bit localization using passive seismic data. Consequently, not only drilling risks can be reduced, but optimal reservoir drainage is ensured as well.

By using passive seismic recordings from the seafloor, we can “listen” to the noise generated by the bottomhole assembly (BHA) while drilling. Despite various noise sources in the vicinity (e.g., vessels and rigs), advanced data processing and the combination of hundreds of seafloor receivers spread above the ongoing drilling enable us to detect the drilling signal and locate the drill bit. Whereas the magnetic and gyro MWD tools have errors that accumulate with measured depth (MD), each bit position derived from seismic (usually every 90 seconds) is completely independent. For horizontal sections, the error does not increase with MD and hence can provide improved lateral accuracy. No additional BHA tool is required, and the measurements are neither dependent on the magnetic nor gravitational field. Moreover, the passive seismic measurements can be used to obtain an improved lateral well position estimate. This is done by optimizing the azimuth information of the well trajectory in the minimum curvature method. A lateral uncertainty measure can be derived from the residuals between the passive measurements and the updated well path. Since 2018, we have used the continuous stream of passive data from permanent seafloor sensors at the Grane Field, with its reservoir depth of around 1800 m true vertical depth subsea (TVDSS) to follow all wells with this drill-bit tracking scheme. Lateral deviations from the official well path based on magnetic/gyro measurements are mostly within ±30 m. The lateral position uncertainty can be as low as a couple of meters under optimal conditions.
Steam Additives to Reduce the Steam-Oil Ratio in SAGD: Experimental Analysis, Pilot Design, and Field Application
Authors: Nejadi Siavash , Ortiz Julian , Sanchez Javier , Yang Xiaomeng , Kalaei Hosein , Abbas Sayeed
Published: March 2022

Producing bitumen using SAGD requires a significant amount of water and energy, resulting in a large amount of greenhouse gas emissions. Therefore, reducing the steam-oil ratio (SOR) in SAGD is critical to make the oil recovery process profitable and sustainable in a carbon-constrained world.

This paper presents the potential benefits of co-injecting water-soluble volatile additives with steam in SAGD. The objective of the process is to decrease the SOR while maintaining SAGD-like oil production rates at economical chemical additives concentrations.

Through a comprehensive experimental study, multiphase behaviour of the additive-water-bitumen system, mixture's viscosity, additive thermal stability, adsorption, emulsion stability, and recovery performance were evaluated. Extensive coreflooding experimental tests quantified the potential for improved oil recovery and SOR reduction. The experimental variables included additive concentration, water-oil ratio, and temperature. The studies showed that the additives improved oil recovery by promoting the formation of oil-in-water emulsions at the producing SOR.

A series of reservoir simulation studies were also conducted for a field pilot design and evaluation of key performance indicators. Two different methodologies, equilibrium and non-equilibrium, were used to model the steam additive behaviour under both transient and steady-state conditions. Data obtained from coreflooding and viscosity measurements were the primary inputs of the reservoir simulation models. The fine-tuned reservoir simulation model quantified the technology uncertainties using multiple equally probable realizations of the reservoir to design and optimize the field pilot's injection scenarios and operating conditions.

The simulation results showed SOR reduction of up to 25% with steam additives co-injection for the designed concentrations. Different phenomena such as additive transportation, condensation, additive degradation, and adsorption in a growing steam chamber were included in the numerical model. Based on the experimental and reservoir simulation results, a 4-well pair field pilot was designed, built, and put in operation at the Surmont SAGD project.
A New Method for Determination of Rock Fabric Number from Well Logs in Unconventional Tight Oil Carbonates
Authors: Azuara Diliegros Brenda , Aguilera Roberto
Published: March 2022

This paper develops a new method for estimation of rock fabric number (RFN) from well logs in unconventional tight oil carbonates with less than 0.1 md. The objective is to investigate the oil potential of a Middle Cretaceous tight carbonate in Mexico. Development of a method for these conditions is challenging as the current approach developed by Lucia (1983) has been explained for carbonates with more than 0.1md.

The method is calibrated with data from cores and cuttings and allows estimating the presence of grainstone, packstone and wackstone rocks in unconventional tight carbonates from well logs. A crossplot of RFN vs rp35 (pore throat radius at 35% cumulative pore volume) permits delimiting intervals with good production potential that is supported by well testing data. Information for analysis of the Mexican carbonate comes from well logs of 9 wells and 2 re-entry wells, four buildup tests and a limited amount of core and drill cuttings information. All data were provided by a petroleum company and have been used, for transparency, without any modifications.

An unconventional tight carbonate as defined in this paper has a permeability smaller than 0.1 md. The unconventional tight oil carbonate reservoir considered in this study includes 95 percent of data with permeabilities smaller than 0.1 md and only 5% with permeabilities larger than 0.1 md. The method introduced by Lucia (1983) and Jennings and Lucia (2003) for determining RFN is powerful, but they explained it only for permeabilities larger than 0.1 md. Thus, the need for a methodology that allows estimating from well logs the presence of grainstone, packstone and/or wackstone in unconventional tight carbonate reservoirs with permeabilities smaller than 0.1 md.

Results indicate that the RFN provides a useful approach for distinguishing grainstone, packstone and wackstone rocks in unconventional tight carbonate reservoirs. Furthermore, rock fabric can be linked with Pickett plots to provide an integrated quantitative evaluation of RFN, porosity, water saturation, permeability, pore throat radius, and capillary pressure. This integration indicates that there is good oil potential in the Middle Cretaceous unconventional tight carbonate in Mexico.

The novelty of this paper is the use of rock fabric (RFN) in unconventional tight carbonates with permeabilities smaller than 0.1 md for estimating the presence of grainstone, packstone and wackstone rocks from well logs. In addition, a crossplot of RFN vs rp35 provides a good indication of intervals with oil production potential.
Distributed Temperature Sensor Analytics: Estimating SAGD Depletion from Temperature Fall Off Data
Authors: Nguyen Anthony , Hematillake Dylan , Glover Robert , Diaz-Goano Carolina
Published: March 2022

This paper outlines an end-to-end case study from ideation through to the development and deployment of a novel method to estimate SAGD depletion along a producing SAGD horizontal well from temperature fall off (TFO) events, from any temperature measurement point along the well. The methodology combines reservoir engineering first principals, analytics, simulation modelling and digital product delivery components. The outputs of this work are expected to drive rapid, data-driven, and standardized approaches to subsurface optimization of SAGD well pairs through quantified estimation of remaining oil in place opportunities that could be economically exploited through operations, re-completions, re-drills and technology applications.
Estimating Leak-Off Characteristics Due to Hydraulic Fracture and Natural Fracture Interaction Utilizing XFEM-Based 3D Hydraulic Fracture Model
Authors: Leem Junghun , Musa Ikhwanul Hafizi , Tan Chee Phuat , Che Yusoff M Fakharuddin , Zain Zahidah Md , Kear James , Kasperczyk Dane , Chen Zuorong , Salimzadeh Saeed
Published: March 2022

Leak-off characteristics during hydraulic fracturing operation are difficult to determine but yet critical in developing conventional and unconventional reservoirs with natural fractures and other weak structural planes (e.g. micro-faults, weak beddings). When hydraulic fractures interact with natural fractures, they will either be arrested or transect the natural fractures depend on the leak-off characteristic of the natural fractures. The effective leak-off characteristic in a naturally fractured reservoir is an essential input for hydraulic fracturing simulation and consequent completion design as well as reservoir simulation (e.g., dual porosity and dual permeability) and consequent production optimization.

A novel method of estimating the effective leak-off characteristic in a naturally fractured reservoir is developed directly from hydraulic fracturing diagnostic tests such as minifrac and DFIT utilizing eXtended Finite Element Method (XFEM)-based 3D hydraulic fracturing model. Complex behaviors of hydraulic fractures interacting with natural fractures are simulated in the XFEM-based hydraulic fracturing model and history-matched with minifrac/DFIT data (i.e., treating pressure), in order to estimate effective leak-off characteristics of naturally fractured reservoirs.
Effect of Temperature on Gas/Oil Relative Permeability in Viscous Oil Reservoirs
Authors: Kumar Saket , Sarma Hemanta , Maini Brij
Published: March 2022

Oil displacement tests were carried out in a 45-cm long sand-pack at temperatures ranging from 64 to 217 °C using a viscous oil (PAO-100), deionized water and nitrogen gas. It was found that the unsteady-state method was susceptible to several experimental artifacts in viscous oil systems due to a very adverse mobility ratio. However, despite such experimental artifacts, a careful analysis of the displacement data led to obtaining meaningful two-phase gas/oil relative permeability curves. These curves were used to assess the effect of temperature on gas/oil relative permeability in viscous oil systems.

We employed a new systematic algorithm to successfully implement a history matching scheme to infer the two-phase gas/heavy oil relative permeabilities from the core-flood data. We noted that at the end of the gas flooding, the "final" residual oil saturation still eluded us even after tens of pore volumes of gas injection. This rendered the experimentally determined endpoint gas relative permeability (krge) and Sor unreliable. In contrast, the irreducible water saturation (Swir) and the endpoint oil relative permeability (kroe) were experimentally achievable.

A history-matching technique was used to determine the uncertain parameters of the oil/gas relative permeability curves, including the two exponents of the extended Corey equation (N° and Ng), Sor and krge. The history match showed that kroe and Swir were experimentally achievable and were reliably interpreted. The remaining four parameters (i.e., Corey exponents, true residual oil saturation and gas endpoint relative permeability) were obtained from history matched simulations rather than from experiments. Based on our findings, a new correlation has been proposed to model the effect of temperature on two-phase gas/heavy oil relative permeability.
Design of a Solar Parabolic Trough Capable of Producing Steam for Enhanced Oil Recovery in Trinidad and Tobago
Authors: Gajadhar Ahiliah , Hosein Raffie
Published: March 2022

Enhanced oil recovery by steam injection requires the burning of natural gas, a finite and expensive resource for steam production. However, solar energy can be harnessed for steam production via solar parabolic troughs. In this study, the design and application of a solar parabolic trough, in tandem with a heat exchanger for producing steam for Enhanced Oil Recovery (EOR) in Trinidad and Tobago is presented. Excel spreadsheets were developed to perform the calculations and to optimize the size and design of the parabolic trough collector for maximum heating efficiency. The parabolic trough designed was 36 m in length and consisted of a parabolic aluminum reflector, stainless steel receiver tube, and a glass envelope that surrounded the receiver tube. The heat transfer fluid used was Therminol VP-1, a synthetic oil, which was heated up to 403 °C. Once heated, the heat transfer fluid was then transferred to a heat exchanger whereby steam was produced at 300°C. Overall, 4 of the parabolic trough collector systems were required to heat enough fluid to fill the calculated 343 tubes of the heat exchanger, which were 0.091 m in diameter and 4.9m in length. The total cost of the parabolic troughs and the heat exchanger tubes was calculated to be USD 119,562. By having a mass flow rate of 46 kg/s for the water within the heat exchanger, approximately 1630 barrels of oil were economically produced at a maximum steam oil ratio of 4.5 after one day of steam injection. A cash flow projection was completed using both operational and capital expenditure of the parabolic trough collector. From this study, the parabolic trough system was shown to generate a profit of USD 1.8 MM after six months of steam injection. Profit calculation considered both capital and operating expenditure as well as the income gained from oil recovery due to the parabolic trough collector. The spreadsheet developed can be used to design similar systems of steam generation for enhanced oil recovery projects of different scales.
Fluor Solvent Offers Significantly Lower GHG Intensity CO2 Removal from Natural Gas Than MDEA for Horn River
Authors: Rodwell Morgan
Published: March 2022

As natural gas demand increases through the energy transition, due to shifts away from coal-fired power generation and increased hydrogen utilization, production and processing of high CO2 natural gas sources, such as the Horn River Basin in Northern British Columbia will become more economic and important. The capture process should be energy efficient and provide the lowest GHG intensity possible to ensure the maximum decarbonization benefit. The propylene carbonate-based Fluor SolventSM process provides CO2 capture from natural gas sources at up to 97% lower GHG intensity when compared to the use of a formulated MDEA solvent which was used at the largest plant constructed to date in this field.
Coupling a Thermal Reservoir Simulator with a Dynamic, Multiphase Wellbore Flow Simulator to Rigorously Model Complex SAGD Well Geometries and Completions
Authors: Rivero Jose A. , Istchenko Christopher , Nascimento Carlos , Cao Jia-Ming , Aghabarati Hossein , Bergen Michael
Published: March 2022

In this paper, we propose a methodology to iteratively couple a wellbore simulator and a reservoir simulator in order to model the complex flow regimes that exist in a producing SAGD well while still taking into consideration the fluid movement and distribution within the reservoir. The process was successfully tested and implemented in two SAGD pads and the results were compared with those obtained using a commercial, fully-coupled reservoir-wellbore model. This method addresses the modeling limitations encountered in typical thermal reservoir simulators that use source/sink or discretized formulations to describe wellbore flow.

SAGD producers exhibit overly complex flow regimes caused by the presence of a steam phase that can condense within the wellbore and promote significant variations in temperatures and pressures along the tubulars. Therefore, standalone wellbore simulators are necessary to predict performance as accurately as possible; however, using a wellbore simulator alone will neglect the effects caused by varying inflow conditions from the reservoir. With these variations occurring both in time and in space (along the wellbore), it is necessary to include the dynamic input of a reservoir simulator, hence the rationale for coupling both models.

The algorithm devised to integrate the wellbore and reservoir simulators was coded into a standalone GUI-driven computer program called a coupler. The coupler was used to evaluate the performance of new SAGD pairs and new infill producers featuring flow devices and slanted trajectories.

In this work, we will present the results of field case studies with the proposed coupling approach to evaluate the effect on ultimate recovery of drilling new SAGD pairs and SAGD infills using toe-up or toe-down trajectories as well as fitting these wells with inflow control devices. When applying the coupling workflow to the case studies, we determined that despite challenging conditions, it is possible to have inclined SAGD wells properly transition from preheating to production as well as allowing access to previously untapped parts of the reservoir resources, which increased ultimate recovery.
The Effects of Asphaltene Precipitation on Bitumen Recovery during Non-Thermal Cyclic Solvent Injection in Cold Lake Oil Sands- An Experimental Study
Authors: Yuan Lin , Yousefi Mohammad , Dehghanpour Hassan
Published: March 2022

The non-thermal solvent-based processes for bitumen extraction consume less energy and water, and thus, have less impacts on the environment compared with the steam-based thermal processes. The objective of this paper is to investigate the mechanisms responsible for propane transport into and bitumen production from oil-sand core samples during the cyclic solvent injection (CSI). We use a state-of-the-art high-pressure and high-temperature (HPHT) visualization cell to investigate non-equilibrium propane-bitumen interactions during CSI. We inject propane into the cell containing a bitumen-saturated core plug representing in-situ reservoir conditions. Three sets of tests with different propane vapor (C3(v)) to liquid (C3(l)) ratio are conducted (set 1 with C3(l), set 2 with C3(l)-C3(v) mixture, and set 3 with C3(v)). After the CSI tests, the final bitumen recovery factor is calculated by the weight-balance method and the precipitated asphaltene content caused by propane-bitumen interactions is also measured using a distillation apparatus.

When the core is fully immersed in C3(l), the cell pressure rapidly declines during the early soaking process, and then, it declines gradually. However, no obvious pressure decline can be observed when C3(v) is present in the system. This can be explained by the higher compressibility of C3(v) compared to C3(l), leading to a less significant pressure decline during the soaking period. A light hydrocarbon phase is produced from the core at the end of the depletion process, indicating the extraction of light components of oil by propane even at low-temperature conditions. The bitumen recovery factor is the lowest (11.93%) in set 1 when the core is soaked in C3(l), while that is the highest (14.73%) in set 3 when the core is soaked in C3(v). Also, the bitumen production stops quickly at the early soaking period in set 1. This is because asphaltene precipitation is more significant when the C3(l) is present in the system. The propane density in liquid state is higher than that in vapor state, leading to more bitumen-propane interactions and more asphaltene precipitation. The precipitated asphaltene blocks the pore network and inhibits bitumen production. Our results show that increasing C3(v) to C3(v) ratio decreases the amount of asphaltene precipitation, and in turn, increases bitumen recovery factor.
CO2 Mineral Trapping in Basaltic Formation During CO2 Storage
Authors: Hamdi Zakaria , Raja Zainal Raffik Raja Zuhaili Aimran , Talabi Oluwole , Patel Urval , Mackay Eric , Bataee Mahmood
Published: March 2022

The rise in global warming is due to the high emissions of greenhouse gases (GHG) around the world. Carbon dioxide (CO2) gas emissions, a by-product from the petroleum industry, is contributors to climate change. One technology that may help curb CO2 gas emissions is injecting the gas into the subsurface reservoir. In this study, CO2 mineral trapping behaviour and its reactions within a wet basaltic rock containing Olivine mineral are captured and simulated in a full field numerical simulation model. A 2-stage approach was planned to develop the full field numerical model. In the first stage, a single cell model was developed, assessed and matched to the literature experiments with several assumptions considered and applied. Following this, the second stage involved developing a full field model to observe and analyse the distribution and concentration of CO2 during injection, as well as its sequestration as a solid phase (i.e., mineral trapping). The overall volume ratio of injected CO2 versus water was also assessed to ensure enough CO2 were injected into the basalt rock ensuring clear distribution of CO2 in the rock either in dissolved, trapped, or mobile state. In this study, the injected volume covered 4% of the total water volume. Results show that mineralization occurs faster than expected when CO2 gas was introduced to the wet basaltic rock especially near the CO2 injector wellbore. The mineralization speed depends on the reaction rate, modelling (cell) surface area and volume as well as the reaction rate coefficient where it was tuned to match the experimental results. The time required for the CO2 component to travel within the rock was also assessed to give a clear picture of the CO2 distribution where it took 10 years to reach 1000 ft away from the injector wellbore within a 440 ft thick reservoir.
Study of Carbon Capture in Oilsands Production and Upgrading
Authors: Isley Jon , Gutscher Matthew , Henezi Benjamin
Published: March 2022

Canada's oilsands production and upgrading industry has plans for a regional CO2 pipeline, enabling carbon capture and sequestration (CCS) solutions for reducing industry CO2 emissions. In order to evaluate the relative merits of carbon capture solutions, a case study is developed of three hypothetical carbon capture facilities: one post-combustion from a SAGD facility, a second post-combustion from an upgrader hydrogen plant, and a third pre-combustion from an upgrader hydrogen plant. All cases are based on process configurations of commercially proven technologies. Capital costs are developed for each of the cases based on Fluor process expertise and historical cost data for the oilsands region. Process and utility balances are developed to inform net carbon intensity reductions along with operating costs. The study includes a discussion of the influencing factors to CCS economics, including looking at the carbon footprint balance of production and upgrading operations, the existing utility profile, economies of scale, and carbon lifecycle impacts of choices. In addition to net carbon avoidance from a $CAD/ton CO2 perspective, the results also inform on relative merits of carbon intensity reduction of produced liquid fuels which generate carbon credits and revenue under the Canadian Clean Fuel Standard (CFS). Consideration of both carbon tax avoidance and fuel carbon intensity need to be considered to justify capital investment.
Steam-Solvent Process: A Gamechanger in Cutting Emissions in In-Situ Recovery of Oil Sands
Authors: Chowdhuri M. A. K. , Filstein Alex , Huang Haibo
Published: March 2022

Due to extensive energy requirements and the volume of emitted greenhouse gases associated with burning natural gas to generate steam in the SAGD process, there has been always a strong motivation to develop oil recovery processes for bitumen reservoirs with lower energy and emissions intensities. A hybrid steam-solvent co-injection process, which is to synergize the advantages of both SAGD and VAPEX processes and minimize their drawbacks is the subject of ongoing research and field piloting since early 2000. Most of the past efforts of the steam-solvent process were primarily focused on improving the oil rate or improving the process's economic benefits. However, due to Canada's ambitious greenhouse emission reduction target (net zero emission by 2050) along with the significant increase of carbon tax ($170 by 2030), the primary focus of the oil industry is shifting towards reducing steam injection and cutting the GHG emission drastically. This study revisited the steam-solvent process to find a suitable combination of solvent type and operating strategies that can reduce the steam injection and GHG emission significantly, and without significantly compromising the oil production. Two hydrocarbon pure solvents, propane and butane were recommended in this project to cut the steam injection drastically and without having a significant negative impact on the oil production. Among the two solvents, butane may be preferred. However, to reduce the cost further and cut energy input, propane may be a better choice than butane. Propane is cheaper than butane and it requires less energy to vaporize propane. The process should start with steam-only injection (as SAGD) and next inject solvent after the chamber is somewhat developed. The solvent may not be effective if the oil production is already in the natural decline stage. At later stages, the solvent retention in the reservoir could also be high. During the solvent injection period, a small amount of steam could be continuously injected with the solvent or steam could be intermittently injected as needed to keep enough energy in the reservoir. This will help to vaporize the solvent and prevent the chamber from being cooled down significantly.
Powering Offshore Installations with Wind Energy
Authors: MacDougall Blair , Nash Phil , Doyle Bruce , Hudson Joshua , Murphy Rick , Meyers Justin
Published: March 2022

The offshore Oil and Gas industry continues to explore and develop oil and gas fields using installations powered by generators burning either natural gas or marine gas oil (MGO), similar to diesel. There is increasing pressure on the industry to explore and produce hydrocarbons responsibly, cost effectively and with the lowest emissions. By employing renewable sources of power, Waterford Energy Services Inc.'s (WESI) methodology provides a possible solution using Floating Offshore Wind Turbine (FOWT) to power offshore installations. Various methods are being proposed and developed to maintain production while bringing down overall greenhouse gas emissions (e.g. CO2, NOx, SOx).

This paper outlines the methodology used for a conceptual design of a "Plug and Play" hybrid power solution in the Canadian Offshore Oil and Gas Industry. FOWTs are electrically connected to offshore installations such as Mobile Offshore Drilling Units (MODU), Floating Production Storage and Offloading (FPSO) and fixed production platforms in a harsh environment to replace large portions of the onboard power generation. Battery Energy Storage Systems (BESS) are incorporated to transition from wind power, increase efficiency, provide safety backup and enhance emissions reduction. The plan includes considerations for the optimal electrical and battery storage topology and the electrical equipment necessary to connect the FOWT Array to the offshore facility.

For the purposes of this paper, a representative location was chosen offshore Newfoundland and Labrador, Canada to assess both local conditions and design requirements. WESI has evaluated additional global locations for this FOWT solution.

The conceptual design considers the wind turbine power output and examines the components required to deliver the power to the installation's electrical system (e.g. transformers, batteries, switchgear, static and dynamic cables, disconnects, communications/monitoring and required safety systems).

Although there have been incremental improvements in emissions via advancements in fuel standards and engine exhaust abatement modifications, the only approach to have a significant step-change improvement in emissions is through replacement of onboard power generation with renewable sources. It anticipated that the installations’ greenhouse gas (GHG) emissions can be reduced in excess of 70% by combining wind power and battery supplementation.

Oil and Gas operations are ideal applications of this decarbonization approach, presenting an opportunity to mature FOWT technology which can readily adapt to other grid isolated applications such as Remote Communities, Aquaculture and near-shore Industries.
Pore-Scale Modellings on the Impacts of Hydrate Distribution Morphology on Gas and Water Transport in Hydrate-Bearing Sediments
Authors: Li Zhuoran , You Jiahui , Qin Guan
Published: March 2022

Gas and water transport behavior, which is controlled by the pore characteristics and capillarity in hydrate-bearing sediments (HBS), is one of the key factors affecting the gas production. Hydrate distribution morphology (HDM) can significantly influence the pore structures of HBS, affecting the relative permeabilities of gas and water. To elucidate the impacts of HDM in microscopic scale, a phase-field lattice Boltzmann (LB) model is developed to describe the gas and water transport in HBS.To simulate the transport of immiscible fluids, which exist obvious density and viscosity contrasts, a phase-field LB model with the conservative form of interface-tracking equation is developed to suppress the spurious currents at phase interfaces. To describe the fluid-solid interactions, the bounce-back condition is applied for both solid phases (hydrate and grains) to achieve the non-slip condition and the wettability condition is applied for grains and hydrate to describe the wettability behavior. To improve the numerical stability, the multi-relaxation-time (MRT) collision operator is applied and the discretization schemes with 8th order accuracy for the gradient operator are selected. In this work, we first validated our model by applying several benchmark cases aiming at fluids with obvious density contrasts such as the layered Couette/Poiseuille flows, Rayleigh–Taylor instability. Then the synthetic geometries of the pore-filling and grain-coating HBS with several hydrate saturation (Shyd) were constructed by guaranteeing the same extent of connectivity. Then the steady-state relative permeability measurement and drainage capillary pressure measurement processes were simulated by the LB model for two HDM cases under several Shyd. The results showed that in the hydrophilic HBS, the relative permeability of gas in the pore-filling case is obviously larger than that in the grain-coating case at the same Shyd, and larger capillary pressure can be obtained in the pore-filling case. In addition, as the Shyd increased, it would notably enhance these differences of fluids relative permeability and capillary pressure between two HDM cases. Because the HDM can not only influence the pore space structures but also the wettability of the porous medium by creating solid surfaces of varying wettability, the distribution and transport of fluid phases in different HDM cases can be obviously affected. The phase-filed LB model applied in this study is capable to handle and suppress the spurious currents at phase interfaces, ensuring a satisfactory numerical stability and accuracy. Thus, the real density and viscosity contrasts between the water and gas under the in-situ thermodynamic conditions can be considered in the simulation. The impacts of HDM on the gas and water transport were quantitively analyzed by simulating multiphase flow processes in HBS.
Organic Weighting Hydraulic Fracturing Fluid: Complex Interactions between Formate Salts, Hydroxy Carboxylate Acid, and Guar
Authors: Liao Zihan , Chen Fu , Deng Yu , Wang Kuntai , von Gunten Konstantin , He Yuhe , Zhong Cheng
Published: March 2022

Hydraulic fracturing has extended to both deep-terrestrial and deep-sea reservoirs because hydrocarbons in shallow subsurface are depleting. However, the density of common inorganic weighting agents may not give sufficient column pressure, which may compromise the efficiency of hydraulic fracturing fluids (HFF) and present potential risks to facilities and the environment. Here, we investigated hydroxypropyl guar (HPG)-based HFF (HPG-HFF) using potassium formate (PF) as a weighting agent with and without a hydroxy carboxylate acid (citric acid, abbreviation FW was used througout this study) as an additional dispersion stabilizer. Analyses included stability investigations, macro- and microrheology assessments, Fourier transform infraredspectroscopy (FTIR) analyses, molecular dynamic simulations, and screening of crosslinking points. Our results showed that increased concentrations of PF substantially reduced the stability and viscosity of HPG solutions, but adding citric acid mitigated these drawbacks. Molecular dynamic modeling suggested that formate acid ions formed hydrogen bonds with HPG and water, resulting in reduced hydrophilicity and coiling of the HPG molecular chain. When citric acid was added, less formate ions surrounded the HPG molecule, and the forming FW ions primarily interacted with the HPG molecule through hydrogen bonding. Besides, the hydroxyl group of the citric acid may improve the hydrophilicity of the whole complex. Thus, the original nature of the HPG molecular chain could be compensated. Atomic force screening showed more crosslinking points with stronger intensity and an even distribution in the HPG-PF-citric acid gel system, compared to that in the HPG-PF gel system (without citric acid). Furthermore, thermal stability tests showed that the proposed PF-citric acid-HPG-HFF system could resist temperatures up to 120°C. Our study demonstrates the potential application of formate-based weighting agents, highlighting the effects of hydrogen bonding in complex HFF. This benchtop study provides a foundation for future research to understand the application of formate-FW-based weighting HPG-HFF in downhole high temperature conditions.