bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconocimiento de sentencias extranjeras de divorcio en Perú
Authors: Monge-Talavera Luz
Published: October 2022

La eficacia extraterritorial de las sentencias extranjeras constituye un tema de importancia mayor del Derecho Internacional Privado. Este artículo presenta el régimen legal establecido en el derecho peruano haciendo constate referencia a su aplicación jurisprudencial en materia de reconocimiento de sentencias extranjeras de divorcio. Si bien se constata esfuerzos legislativos destinados a simplificar el trámite del proceso judicial, el análisis de la norma y su aplicación por la jurisprudencia, revelan ciertos rezagos y contradicciones que podrían poner en peligro el principio de tutela judicial efectiva.
MARÍA JOSÉ AZAUSTRE FERNÁNDEZ. Determinación de la residencia habitual y foros de competencia: del Derecho romano al Reglamento europeo de sucesiones
Authors: Carrascosa González Javier
Published: October 2022

Este artículo reseña: María José Azaustre Fernández. Determinación de la residencia habitual y foros de competencia: del Derecho romano al Reglamento europeo de sucesiones. Editorial Aranzadi, Navarra, ISBN 9788413455099, 2021
N. C. RODRIGUES (Editor). Extraterritoriality of EU Economic Law: The Application of EU Economic Law Outside the Territory of the EU
Authors: Rinaldi de Barcellos Nicole
Published: October 2022

Este artículo reseña: N. C. Rodrigues (Editor). Extraterritoriality of EU Economic Law: The Application of EU Economic Law Outside the Territory of the EU. Cham, Switzerland, Springer, 2021, 385 pp. ISBN 978-3-030-82290-3
Oral microbiota in oral cancer patients and healthy individuals: A scoping review
Authors: Sufiawati Irna , Piliang Alamsyah , Ramamoorthy Vatchala Rani
Published: October 2022

Background: Oral microbiota has been suggested to have a role in the etiopathogenesis of oral cancer; however, the oral microbiota diversity in patients with oral cancer compared to healthy individuals remains unclear. Purpose: This scoping review aimed to provide an overview of the current evidence regarding the oral microbiota composition colonized in oral cancer patients and its comparison with healthy individuals. Reviews: This study was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Eligible studies were searched in PubMed, Scopus, Web of Science, and ScienceDirect databases from January 2015 to March 2022. A total of 20 relevant studies were included according to the inclusion and exclusion criteria, including 14 cross-sectional studies and 6 cohort studies. All studies have identified various oral bacteria, but only one study has detected viruses and parasites diversity. A variety of oral microbiota found were 6 phyla of bacteria, 6 phyla of viruses, 7 phyla of fungi, and 7 phyla of parasitic. Seventeen studies proved that oral microbiota compositions were statistically significant differences compared to healthy controls, but not in 3 studies. Conclusion: The majority of studies showed various oral bacteria in oral cancer patients which were statistically significant difference compared to healthy controls. This study indicates the need for more research to evaluate viruses and parasites composition and diversity in oral cancer patients. Moreover, future research should focus to clarify whether the changes of oral microbial composition as a community may play a critical role in the etiopathogenesis of oral cancer.
Role of supportive periodontal management in patient with metastatic cancer
Authors: Neo Kevin Chee Pheng , Mohamad Nurul Syahirah , Rath Avita , Wong Melissa Li Zheng , Wai Myint , Fernandes Bennete
Published: October 2022

Background: Treatment of head and neck cancers may cause sequelae affecting patients’ quality of life during and after treatment. As a result, periodontal management of a patient with parotid gland adenoid cystic carcinoma, particularly in advanced stage 4, can be challenging for dental practitioners, especially if the patient is on active oral molecular therapy and undergoing long-term radiotherapy and chemotherapy. Purpose: This report was intended to describe the conservative non-surgical management of tooth 27 with poor prognosis owing to grade II mobility in a patient on active Lenvatinib therapy – where the extraction was not advisable to lessen the risk of osteonecrosis. Case: A 52-year-old female patient was referred by an oncologist to our dental clinic for noncarious toothache. Five years ago, the patient was diagnosed with adenoid cystic carcinoma (ACC) and had a treatment history of radiotherapy, chemotherapy and surgical removal of the left parotid gland to manage the malignancy. Oral examination revealed characteristic findings of periodontitis. Case Management: Ultrasonic scaling, antimicrobial mouth rinses and reinforcement in oral hygiene instructions manage the tooth 27 conservatively. Conclusion: A cautious approach by the dental surgeon, together with the multidisciplinary team caring for cancer patients, is fundamental and helps with the palliative periodontal management of this patient to enhance oral health-related quality of life. With a lack of reports on conservative periodontal therapy in ACC patients, this report highlights the combination of smoking cessation, reinforcement of oral hygiene instructions and conservative periodontal treatment.
Hepatocellular carcinoma in Hepatitis B and Human Immunodeficiency Virus coinfection in Africa: a focus on surveillance
Authors: Wan Qian , Anugwom Chimaobi , Desalegn Hailemichael , Debes Jose D.
Published: October 2022

Human immunodeficiency virus (HIV) and hepatitis-B virus (HBV) infections are weighty public health challenges, especially in the African continent. The direct carcinogenic effect of HBV means that it remains a potent cause of early-onset hepatocellular carcinoma (HCC) in Sub-Saharan Africa (SSA), where it causes significant morbidity and mortality. The presence of HIV infection in HBV-infected patients poses a complicating factor, as coinfection has been shown to hasten the progression of liver disease to cirrhosis and HCC, and often resulting in early-age hepatocarcinogenesis with consequent late diagnosis and lower survival. In this review, we discuss this unique conundrum, the epidemiology of HIV-HBV coinfection in SSA, its effect on liver disease and development of HCC, as well as practices and barriers to HCC surveillance in this distinct population. We propose a way forward to curb this considerable health burden focusing on reduction of disease stigma, the need for easy-to-measure biomarkers, and implementation of large prospective studies in this population.
Gamma Irradiation Processing on 3D PCL Devices - A Preliminary Biocompatibility Assessment
Authors: Guedes Fernando , Branquinho Mariana V. , Biscaia Sara , Alvites Rui D. , Sousa Ana C. , Lopes Bruna , Sousa Patrícia , Rêma Alexandra , Amorim Irina , Faria Fátima , Patrício Tatiana M. , Bugalho António , Alves Nuno , Maurício Ana C.
Published: October 2022

Additive manufacturing or 3D printing applying polycaprolactone-(PCL)-based medical devices represents an important branch of tissue engineering, where the sterilization method is a key process for further safe application in vitro and in vivo. In this study, the authors intend to access the most suitable gamma radiation conditions to sterilize PCL-based scaffolds in a preliminary biocompatibility assessment, envisioning future studies for airway obstruction conditions. Three radiation levels were considered, 25 kGy, 35 kGy and 45 kGy and evaluated as to their cyto- and biocompatibility. All three groups presented biocompatible properties, indicating an adequate sterility condition. As for the cytocompatibility analysis, devices sterilized by 35 kGy and 45 kGy showed better results, with the 45 kGy showing overall improved outcomes. This study allowed to select the most suitable sterilization condition for PCL-based scaffolds, aiming at immediate future assays, by applying 3D-customized printing techniques to specific airway obstruction lesions of the trachea.
Feed Efficiency, Tissue Growth and Energy Budget Changes during the Molting Cycle of Juvenile Mud Crab, Scylla Serrata: Effects of Dietary Proteins, Fishmeal versus Soy Protein Concentrate
Authors: Nguyen Ngoc Thi Bich , Wantiez Laurent , Lemaire Pierrette , Chim Liet
Published: October 2022

Three isoenergetic diets differing on their fishmeal/ soy protein concentrate (SPC) ratio were assessed on tissue growth and energy budget of juvenile crabs Scylla serrata in postmolt stages (PMolt) and in intermolt stages (IMolt). The average growth rate on dry matter basis, were 2.064 ± 0.324% and 0.492 ± 0.08% initial BW.day-1 during PMolt and IMolt stages respectively. The efficiency in feed conversion (FCE, %), protein retention (PRE, %) and energy retention (ERE, %) were similar for the 3 experimental diets. However, FCE, PRE and ERE in PMolt stages were 4 to 5 times higher than in IMolt stages. Feed intake, energy and protein required for growth in PMolt stages were obviously higher than in IMolt stages. The energy budgets (%total energy intake) were marginally affected by diet but were significantly affected by the molt stage. Maintenance energy was lower in PMolt stages (49.84 ± 4.9%) than in IMolt stages (83.33 ± 2.45%). The excess of maintenance energy in IMolt stages represents the portion set aside for next molt: shell energy content (4.97 ± 0.31%) and energy for ecdysis (± 28%). Conversely, recovery energy was significantly higher in PMolt stages (34.39 ± 0.99%) than in IMolt stages (8.33 ± 1.7%). In conclusion SPC sustained good tissue growth and good feed utilization and can be used as a main source of dietary protein for crab juveniles in captivity.
Распространение вариантов вируса SARS-COV-2, вызывающих озабоченность (VOC) на основе количества их геномов, депонированных в базу данных GISAID за неделю с 08.10.2022 г. по 14.10.2022 г.
Authors: Дмитриева Людмила , Краснов Ярослав , Чумачкова Елена , Осина Наталья , Зимирова Анастасия , Иванова Александра , Карнаухов Игорь , Караваева Татьяна , Щербакова Светлана , Кутырев Владимир
Published: October 2022

В обзоре представлена информация по циркулирующим в настоящее время вариантам вируса SARS-COV-2 вызывающих озабоченность (VOC), геномные последовательности которых размещены в международной базе данных GISAID с 08.10.2022 г. по 14.10.2022 г.
Evaluation of the Discrimination between Beta-Thalassemia Trait and Iron Deficiency Anemia Using Different Indexes
Authors: Elshaikh Rabab Hassan , Amir Rawaa , Ahmeide Awadia , Mohamedahmed Khalid Abdelsamea , Alfeel Ayman Hussien , Higazi Hassan , Hussein Salah Eldin Omar , Babker Asaad MA
Published: October 2022

Background: Iron deficiency anemia (IDA) and beta-thalassemia trait (BTT) are the most common types of microcytic hypochromic anemias. The aim of this study was to evaluate the reliability of different RBC indices for discrimination between IDA and BTT in Sudanese patients. Methods and Results: This cross-sectional laboratory-based study was conducted among 200 patients (100 patients suffering from BTT and 100 from IDA) who attended the public health hospitals of Khartoum State (Sudan), from Jan 2021 to Feb 2022. The diagnosis of BTT was based on CBC and hemoglobin electrophoresis, and was confirmed by PCR. The diagnosis of IDA was based on complete blood count, reduced serum iron levels, and ferritin levels. Pregnant women, patients who had received a blood transfusion within three months of the study, and patients with thalassemia coexisting with IDA or other hemoglobinopathies were excluded from the study. A series of red blood cell indices were analyzed to differentiate IDA and BTT. The sensitivity, specificity, positive predictive value, negative predictive value, and Youden index (J) were calculated for each index. In BTT and IDA patients, mean values of Hb, hematocrit, and mean corpuscular volume were 10.9g/dL, 33.96%, 59.11fL, and 8.5g/dL, 26%, 68fL, respectively. All RBC indices were decreased in BTT and IDA. Mean RBC count was increased in BTT while showing normal values in IDA. In BTT patients, hemoglobin electrophoresis showed high HbA2 (6.4%) and HbF (1.95%) but a decreased HbA (78.2%). Conclusion: The best discrimination index according to J was Mentzer index (0.85), followed by Sidrah index (0.83), Ehsani index (0.81), RBC count (0.80), RDWI (0.79), Green and King index (0.76), MDHL (o.76), Srivastava index (o.76), and England and Fraser index (0.7). The lowest J was presented in Ricerca index (0.45), Shine and Lal index (0.01), and MCHD (0).
An Innovative Solution for Sour Service Offshore Pipeline Design Utilizing Multiphase Transient Simulation Modelling and Topsides Sour Gas Treatment Selections
Authors: Awang Bakar Dyg Amalina Azyyati , Mustaffa Norlelawati , M Norpiah Rohaizad , M Nazori Qurratuaini , Mukhtar Nur Izyan , Jamil Zurina , Rahman Nurain
Published: October 2022

An offshore gas field uses a membrane acid gas removal unit (AGRU) to remove H2S from the sales gas and condensate stream to meet low specification and operate reliably. A stringent pre-treatment specification is a must to ensure reliability and integrity of the system. With high H2S concentration in condensate from the pre-treatment regeneration cycle, it is imperative to treat both gas and condensate stream to meet gas sales specification. This paper covers process engineering and flow assurance design implemented for gas and condensate H2S removal system and determining sour service operating envelope necessary for pipeline material selection utilizing multiphase transient simulation modelling.
A Simplified Approach to the Analysis of Commingled Wells Whose Layers Have Contrasting Skins
Authors: Last Nicholas Charles , Jongkittinarukorn Kittiphong
Published: October 2022

It has been well documented in the literature that commingled wells in which the different layers have different levels of formation damage – also known as skin – yield anomalous values of formation transmissibility (kh) when they are tested. Specifically, the apparent transmissibility resulting from pressure transient analysis of such wells is typically lower than the arithmetical sum of the transmissibilities of the individual layers. The objective of this study is to present a simple method to quantify this kh reduction effect that is applicable to cases with unlimited numbers of layers that may have different layer pressures as well as different skins.

The methodology starts with the quantification of each layer's productivity index (J), as a function of its kh and skin, during transient inflow conditions. During this transient period, J is not constant but decreases with time, and the apparent kh of the well is then calculated as a function of the evolution with time of the productivity indices of the individual layers. The method is applied to cases where layer skins are different but initial layer pressures are the same, as well as to cases where both skins and pressures differ between layers. The method is then extended again to the case of stabilized inflow conditions, at which time J is conventionally considered to be no longer changing.

The outcome of the study is a simple equation that allows the apparent transmissibility of the commingled well to be calculated, for any number of layers with differing pressures and skins, under transient or stabilized inflow conditions. The quantification of the apparent transmissibility then allows the apparent total-well skin to be easily calculated. It is shown that, for certain combinations of layer skins and layer pressures, the transmissibility reduction effect is significantly smaller than expected and, in some circumstances, might not be observed at all. This result is at odds with the current understanding as set out elsewhere in the literature.

The results of this study point towards alternatives to the conventional methods that are used for testing and analyzing commingled wells, and also have implications for the design of well stimulation programs.
Evaluating In-Situ Gelation Property for Conformance Improvement
Authors: Wang Jinxun , AlSofi Abdulkareem M. , Alzahid Yara A. , Boqmi Abdullah M.
Published: October 2022

Gel-based deep conformance control is a potential method for improving sweep efficiency and facilitating contact with the remaining oil in heterogeneous reservoirs. When using an in-situ gelling system for in-depth treatment, gel strength gradually increases during and after the gel placement in reservoir. Understanding the in-situ gelation properties is essential for screening reliable gelling systems to achieve successful field treatment results. In this study, we performed in-situ gelation evaluations on an organically crosslinked polymer gel system at 95°C. The gel consisted of a low molecular weight polyacrylamide polymer and a polyethylenimine (PEI) crosslinker. Bulk gel properties were assessed through bottle tests and rheological measurements. Results showed that the gelation time of the studied gel system can reach up to 10 days at 95°C. The oscillatory measurements demonstrated the dominance of its elastic nature and remarkable stretch ability. This indicated the potential of the studied organically cross-linked gel for deep conformance improvement applications. Coreflooding experiments of both the bidirectional displacement and continuous injection were conducted for in-situ gelation assessment. In the bidirectional displacement test, the polymer solution was alternately injected from both ends of a three-plug composite core with gel pre-placed in the middle plug. In the continuous injection test, a slug of gel was kept at dynamic flow condition in a slim tube by continuously injecting the polymer solution. The pressure responses from these displacement tests were used to assess the in-situ gelation behavior. Results showed that the in-situ gelation times from both tests were almost the same for a same gel. The in-situ gelation time from the displacement tests also corresponded very well with the transition time from moderately flowing gel to strong gel observed in the bottle test. This demonstrates that both displacement methods can be used to effectively evaluate the in-situ gelation property, and the conventional bottle test can be calibrated as a very efficient way to assess in situ gel performance.
Analytical and Experimental Study of Oil/water Emulsion in Multi Stage Electric Submersible Pump
Authors: Ridlah Muhammad Rasyid , Zhu Haiwen , Zhang Hong-Quan
Published: October 2022

The non-Newtonian behavior of oil/water emulsion in the ESP stage is still not well understood. The industry relies on existing empirical correlations, which only valid for production pipelines without considering the effect of shear force acting on the system. This paper will present the analytical modeling of emulsion rheology in the ESP stage and its effect on ESP boosting pressure. An extensive experimental data set validates the analytical model accuracy.

The Brinkman empirical correlation is the baseline of the analytical model development. Emulsion rheology in the ESP stage depends on many factors. Dimensionless analysis by the Buckingham-Phi theorem indicates that at least three parameters play an essential role in the emulsion rheology at the pump stage. Those parameters are concatenated and applied as the modified function of Brinkman empirical correlation. In addition, the pump boosting pressure performance observed experimentally to study the emulsion rheology effect at the ESP. More than a thousand experiment data points employed to test the proposed model, and its comparison is studied statistically.

The dimensional analysis prevails that the turbulence effect at the stage condition reflected by the Reynolds number, the droplet size effect represented by the Weber number and the Strouhal numbers relates to the shearing effect due to impeller rotation. The analytical model and experiment perform with two different oil viscosity, 45 cp and 70 cp. The results reveal that the higher oil viscosity reaches the inversion point at a lower water fraction since the turbulence decreases with higher oil viscosity. The emulsion rheology from the experiment result shows a significant increase of emulsion viscosity at water fraction close to the inversion point since the increase of hydrodynamic forces due to a higher number of water droplets. The emulsion rheology model aligns with the experiment results for the inversion point at around 35% and 32% water-fraction, respectively. The emulsion rheology model shows a good agreement with the experimental data with a 15% standard deviation of relative error. Increasing water fraction up to the inversion point deteriorates pump boosting pressure since the high friction loss occurs due to higher emulsion viscosity. Nevertheless, as the water fraction passes theinversion point, the boosting pressure starts to rebound as the water turns into the continuous phase. The formation of oil/water emulsion in the ESP is inevitable during production operation and consequently affects the pump boosting pressure. The inversion point phenomena occur at a different range of water fractions for different oil viscosity. A better understanding of emulsion rheology at the pump stage will lead to an accurate artificial lift design and eventually avoid operation failure during production well operation.
The Practical Design of a Carbon Storage Injection Well Completion Using In-Line Flow Control Devices to Maintain Injection Stability
Authors: Konopczynski Michael Robert , Petitt Anna Helene
Published: October 2022

While depleted oil and gas fields can provide important storage capacity for Carbon Capture and Storage (CCS), injection of carbon dioxide into extremely pressure depleted hydrocarbon fields can be problematic due to the phase change of CO2 that can cause flow instability and result in adverse physical phenomena, such as the cooling associated with the latent heat of vaporization and Joule-Thomson cooling which could damage the completion equipment, reduce the hydrostatic head of CO2 and make it difficult to inject carbon dioxide.

Thus far, most completion solutions to this problem have focused on multi-string designs, either parallel or concentric, using flow conduit friction to maintain sufficient back pressure to prevent CO2 flashing. These methods can restrict the amount of carbon dioxide which can be injected and/or are costly or technically prohibitive. An alternative solution is proposed using variable, autonomous or surface-controlled, flow control devices strategically placed in the injection tubing string to provide stepwise pressure drops with depth.

This paper builds on the CCS simulator examined in SPE-209705 (Petitt and Konopczynski, 2022) by comparing three case studies modelled by altering the aperture of the wellhead choke and the inline control devices to maintain the CO2 in liquid form. These real-life scenarios were modelled with a variety of injection and reservoir pressures thus mimicking the varying conditions over the life of a well.

Using a purpose-designed CCS wellbore flow simulator that honors the thermodynamics and heat transfer of CO2 injection, we have modelled the flow performance of CCS well completions with multiple downhole flow control devices placed at strategic depths, the size and number of devices chosen to achieve the desired pressure distribution and CO2 injection rate.

The modelling shows that the multi-flow control device concept can maintain the carbon dioxide in a dense phase over anticipated operating conditions and provides a greater injection rate capacity and turndown range than multi-string solutions inside the same casing size. Depleted reservoirs and restricted CO2 injection rates require the greatest number of flow control devices, while maximum injection rates at maximum reservoir pressures require the fewest number of devices, introducing the potential for completion designs that permit retrieval of the in-line devices with minimal intervention as the reservoir is charged through project life.
Optimising the Jansz-Io Trunkline Next Project Using Integrated Production Modelling
Authors: Barzi Mohammad , Sze Ewen Siu Ming
Published: October 2022

The Chevron-operated Gorgon asset is the largest single resource project in Australia, with a portfolio of offshore gas fields to supply gas via two trunklines (Gorgon and Jansz-Io) to a three-train, 15.6 MTPA LNG plant and a 300 TJ/D domestic gas plant on Barrow Island. Gorgon will be a legacy project, with decades of production anticipated from the development of backfill fields gas resources. To realise the value of the asset, it is critical to select the right projects and execute them at the right time. Greater Gorgon Integrated Production Modelling (IPM) has been developed by Chevron Australia's gas supply team on behalf of the Gorgon Joint Venture (Australian Subsidiaries of Chevron, ExxonMobil, Shell, Osaka Gas, Tokyo Gas and JERA) to specifically enable optimisation of both the subsurface and surface value chain. It integrates reservoirs, wells, and subsea production networks to enable rigorous assessment of various portfolio-level development and planning scenarios.

The focus of this paper is on the Jansz-Io trunkline, which is initially supplied by the massive depletion drive Jansz-Io field, and the key decision of how to maintain production post development of the Gorgon Stage 2 (GS2) project. To inform this key decision, extensive evaluation was conducted using coupled INTERSECT (IX) IPM model to assess Jansz-Io Compression (J-IC) concepts (floating platform vs subsea compression). The IX-IPM model includes either detailed IX dynamic simulation or simplified material balance (MBAL) reservoirs, and a detailed production system that captures the full pressure hydraulics and their complex interactions. Using this IX-IPM model, a systematic staircase approach was applied, starting with a minimum facility concept, before sequentially adding more functionalities (power, capacity, phasing and backfill fields tie-in) and quantifying their incremental benefits. This enabled comprehensive understanding of the compression model's pressure hydraulic performance and various value trade-offs at each step. A fit-for-purpose, fixed power compression model was implemented to commence the staircase assessment. Once subsea compression was selected, and as the assessment matured, vendor compressor performance curves were adopted for more rigorous modelling.

Overall, the Greater Gorgon coupled IX-IPM model has proved to be invaluable in the assessment of the J-IC concept select and supported the Final Investment Decision (FID) on J-IC in 2021. The coupled IX-IPM model is continually refined with greater engineering resolution and additional production history to support the wider Gorgon asset decisions.
A Lab-to-Field Approach and Evaluation of Low-Salinity Waterflooding Process for High-Temperature High-Pressure Carbonate Reservoirs
Authors: Sarma Hemanta Kumar , Singh Navpreet , Belhaj Ahmed Fatih , Jain Adarsh Kumar , Gopal Giridhar , Srivastava Vivek Raj
Published: October 2022

Low-salinity waterflooding (LSWF) process has gained great attention over the years as a promising enhanced oil recovery (EOR) method with its superior performance over high-salinity water waterflooding. This study presents a rigorous and systematic lab-to-field approach involving research, discovery and validation using experimental and simulation components. Impact of various ionic compositions on LSWF was determined including a fundamental understanding of water geochemistry and likely geochemical reactions. The roles of crude oil/brine/rock (COBR) interactions and resulting rock-surface charges were investigated as well. Both experimental and simulation components were treated as complementary to each other. Experimental components included: reservoir-condition high-pressure high-temperature (HPHT) displacement tests in composite cores using brines of different salinities and specially-designed ionic compositions; investigation of wettability alteration - presumably a key LSWF mechanism - in a unique and specifically-designed HPHT imbibition cell; Zeta potentiometric studies were conducted using a Zeta potentiometer capable of more representative evaluation in brine-saturated whole cores rather than with pulverized samples. Simulation involved: proposing likely geochemical reactions during LSWF; incorporating oil/brine/rock interactions, and then, simulation studies linking laboratory data to data from the candidate reservoir on complementary basis. The findings of the coreflooding experiments proved conclusively that LSWF with certain specific ionic composition yield a higher oil recovery. HPHT imbibition tests yielded both visual and quantitative estimations and monitoring of how the wettability alteration took place during LSWF and how it was impacted by the degree and magnitude of both temperature and pressure as the vivid variations in the contact angles were clearly captured. Using a whole reservoir core rather than pulverized samples, Zeta potentiometric studies enabled an investigation of the charging behavior at the rock-water interface at various salinities. A new method to estimate Zeta potential in high-salinity environment was developed and validated, and it conclusively proved that rock-surface charge played a vital, if not a more dominant role, in the LSWF process. The simulation studies included incorporation of experimental data generated during the study, identification of a set of likely geochemical reactions during the process and complementary field data to study the LSWF performance under various conditions and constraints. A conceptual "lab-to-field" approach that can contribute to designing a more efficient LSWF process with optimized ionic chemistry has been proposed based on results and analysis from this study.
New Approach for Reducing Investment Risk Through the Development of a Permeability Delineation Strategy in Coal Seam Gas Reservoirs
Authors: Caro Diana Olarte
Published: October 2022

The intrinsic heterogeneous nature of Coal Seam Gas (CSG) reservoirs can significantly diminish the expected return. This paper presents a new method to decrease inherent investment risk by delineating permeability and provides illustrative case studies. The approach identified riskier reservoir areas to effectively place delineation wells and optimise the number of fracture wells, all with an aim to reach economic gas rates with minimum expenditure and maximum value during development phases.

This work characterises high-mid-low permeability and coalbed gas saturation areas through a novel methodology that uses normalised production rates and net coal measurements. As a result, a comprehensive risk map is generated, from which new development locations near high-risk areas are proposed for permeability delineation. The data acquired from delineation defines which development wells need to be fractured to minimise risk. Additionally, the effect of dewatering on gas production is investigated, along with the impact of fractured wells on mitigating risk. The approach also incorporates a decision trees analysis to predict incremental value resulting from applying the new approach.

A reliable qualitative characterisation of permeability and coalbed gas saturation was obtained after using normalised production rates and net coal measurements in a particular CSG reservoir. Probabilistic distributions of actual production trends show a detrimental effect of low permeability in dewatering and, subsequently, gas recovery. This condition worsens as gas saturation decreases. The above findings are crucial to categorising risk and generating a risk map. An effective delineation well placement is determined based on the existing high-risk area's size and location. Overall, this methodology provides an effective placement of delineation and fracture wells to identify and mitigate risk, respectively. According to economic risk assessment in an illustrative case, the expected return is projected to increase by more than five times from implementing the new delineation approach.

This approach fits the current industry needs very well, as it is reliable, maximises return and can be easily integrated into the development strategy of any CSG reservoir. The novelty of the methodology relies on the qualitative identification of permeability and gas saturation to capture reservoir heterogeneity and categorise risk, all to optimise delineation and fractured wells placement. It can be applied to reservoirs where heterogeneity characterisation through traditional tools is not economically feasible.
Assessment of CO2 Emission and Reduction Technologies in Offshore Oil and Gas Fields
Authors: Mohd Pangi Syahirah , Md Yusof Muhammad Aslam
Published: October 2022

The offshore oil and gas industry is an energy-intensive process that contributes to one of the prominent carbon dioxide (CO2) emission sectors in Malaysia. The CO2 is obtained from the hydrocarbon (HC) flaring, HC venting, fuel gas and diesel combustion and CO2 venting. The pressing need to achieve net zero carbon emissions by 2050 goal, has encouraged the implementation of more energy-efficient and CO2 emission reduction solutions, of which four are assessed in this paper: (i) implementation of surge gas recovery, (ii) application of flare gas recovery, (iii) conversion of vent to flare, (iv) re-injection of CO2 for enhanced oil recovery. This paper provides a comprehensive assessment to evaluate the ongoing initiatives to reduce CO2 emissions from offshore oil and gas fields and address the pain points that need to be solved to ensure that the net zero carbon emission can be achieved in 2050. Data from 18 offshore fields in South China Sea is taken as the case study. This study started with the analysis of the overall CO2 emissions trend and narrowed it down to each type of emission and field to analyse the impact of the technologies implemented while modelling the efficacy of the solutions. Finally, the developed model was used to predict the possibility of the current approach to achieving the desired goal of net zero carbon emissions by 2050. Overall CO2 emission analysis highlighted that fuel combustion contributes the most with an average of 1.3 MMtCO2e per year which takes up 53% of the total emission followed by HC flaring and HC venting that takes up the remaining 24% and 23%, respectively. The results indicate the benefits of all the implemented technologies. The surge and flare gas recovery projects have started to reduce the emissions significantly since 2020 and will prohibit any CO2 release from flaring and venting in 2025 once the project is fully completed. Moreover, the vent to flare conversion technology gives a positive impact to the total flaring with a drastic reduction from 2024 onward where there will be only 6 fields that will continue to flare beyond 2035 but with low emissions. However, there is an urgent need for a cleaner technology to solve the continuous emissions by fuel gas combustion because it remains high even after 20 years of forecasting. This paper is the pioneer to address the impact of implemented CO2 reduction technologies in offshore oil and gas fields in the Southeast Asia region.
High Performance and Recyclability of WBM on the GWF-3 Project
Authors: Nasiri Zahed Masoud , Punler Alastair , Purkis Clare , Boase Aaron , Smillie Steven , Duff Mark , Park Fraser , Cobb James
Published: October 2022

The four well GWF-3 development project offshore Western Australia has used Water Based Mud (WBM) in the 12 ¼ in. section to drill through the same reactive clay formations which, on off-set wells, were historically drilled with Synthetic Based Mud (SBM).

The GWF-3 project well design was based on the learnings from the GWF-2 development project completed in 2017. The typical well design required a 36 in. conductor, 13 ⅝ in. casing, highly deviated 12 ¼ in. section through the Muderong shale interval and then completing the well in an 8 ½ in. hole section.

This paper describes the approach to the drilling fluids design and reviews the performance of the WBM on these wells, focusing on its salinity and recyclability.

As part of the change from SBM to WBM, a fundamental re-design of the Solids Control Equipment on board the drilling rig was also carried out. The SBM cuttings treatment system was removed from the rig, a Big Bowl Centrifuge was installed, and modifications were made to the surface flow lines. The installation of the Big Bowl Centrifuge was a waste minimisation initiative, and the surface flow line modifications were made to assist in the reduction of rig time spent on the displacement and re-conditioning of the drilling and completion fluids.
Swelling Mechanisms Assessment of Water-Based Drilling Mud by Polyvinyl Alcohol
Authors: Poungui Danielle , Sugai Yuichi , Sasaki Kyuro , Nguele Ronald
Published: October 2022

Swelling control is an elaborated balancing of solid-liquid ratios in the mud, influencing crucial physio-chemical features. Mechanical swelling control methods showing limitations drove recent researchers to consider chemical agents, including polyvinyl alcohol (PVOH). PVOH is known to have a swelling ability to improve mud rheology. The present study investigates the synergy of PVOH and Bentonite in an aqueous environment by analyzing the effluents samples. Three types of PVOH were selected: a standard PVOH and two modified PVOHs (a non-ionic group PVOH and a cationic group PVOH-3 attached to the carbon backbone. Except for the control sample (sample without polymer), PVOHs were added to different mud samples at ranging concentrations of 0.1 wt.% to 0.5 wt.%; each has a bulk volume of 400 ml. Each mud sample was filtrated at room temperature under an applied pressure of 1.28 MPa for 5 hours. The samples’ effluents were then analyzed for polymer adsorption. Preliminary filtration tests revealed further effluent production reduction with increased PVOH concentration. Compared to the control sample, samples containing standards PVOH-1, Non-ionic PVOH-2, and Cationic PVOH-3, respectively, had their mud cake mass increase of 48%, 36%, and 38%, while respectively having filtrate recovery reduction of 21%, 19%, and 43%. Adsorption tests showed mud swelling owes primarily to hydrogen bonding which is counteracted by the presence of a charged group. Mud swelling is, therefore, dependent on the rate of hydrogen bounding in a system.
Influence of Activators and Admixtures on Rheology of Geopolymer Slurries for Well Cementing Applications
Authors: Omran Mohamed , Khalifeh Mahmoud , Saasen Arild
Published: October 2022

Geopolymers are considered an alternative to Ordinary Portland Cement due to various reasons regarding some of its shortcomings and the high carbon dioxide footprint associated with its production. Superplasticizers are admixtures that plasticize and fluidize the cementitious slurry by means of steric electrostatic mechanisms that apply repulsion forces between the slurry particles. They are commonly used to improve the workability of cement and geopolymer pastes. However, the most developed superplasticizers are for Ordinary Portland cement. Electrokinetic potential measurements of the ingredients can be used in the evaluation of superplasticizers. Therefore, the effect of the utilization of two hardeners and the effect of the electro-kinetic potential of four admixtures, on the rheological properties of a rock-based geopolymer slurry are presented. These four admixtures are examined to investigate their applicability to being superplasticizers for conventional geopolymers. The results show that naphthalene-based admixtures could be considered effective superplasticizers for the rock-based geopolymer slurry. Although they reduce the slurry's yield stress and API gel strength by showing the highest absolute zeta potential value, the viscous behaviour of the geopolymer slurries showed an increase. Hence, electro-kinetic potential measurements could be used to evaluate the applicability and performance of the admixtures on the rheological properties of the geopolymer slurry.
Reliability Improvement of Auxiliary Boiler Feed Water Pump Caused by Vibration Issue and Capacity Oversized by Pump Upgrading Using Frequency Response Function Inspection Test Method Basis
Authors: Permadi Kemal , Firdauzi Athena Anatolia , Syamsuddin Syamsuar , Waluyo Sabdo
Published: October 2022

Two Auxiliary Boiler Feed Water Pump (ABFW) serve as a fluid supplier into the boiler to support the operation for steam system in Floating Storage and Offloading (FSO) Gagak Rimang. During FSO Gagak Rimang operation, steam system is produced through 2 unit boilers to run Cargo Oil Pump (COP) intermittently during lifting activity. In order to maximize boiler operation, the fluid has to be inside the envelope of design parameter specification. Therefore, the reliability of the ABFW pumps are very essential to ensure smooth and stable lifting operation.

Historically, the performance of this ABFW pump was degraded due to vibration issue and capacity oversized resulted from changing boiler operating mode.

This paper will explain how to improve pump reliability by solving the 2 factors mentioned above by redesigning the impeller which reduced pump vibrations and return the pump condition back into desired operating points.
Estimation of Rock Permeability Scores Using Machine Learning Methods
Authors: Qalandari Roohullah , Zhong Ruizhi , Salehi Cyrus , Chand Nathaniel , Johnson Raymond Leslie , Vazquez Gonzalo , Mclean-Hodgson Jack , Zimmerman Joel
Published: October 2022

Permeability is an important parameter that describes the flow characteristics of rocks (hydrocarbons in the oil and gas reservoirs or groundwater in aquifers). Currently, laboratory experiments using cored samples and well testing are the main methods to determine rock permeability. However, these methods are time-consuming and/or resource-intensive. This paper proposes a novel machine learning approach to predict permeability scores. Field drilling and wireline data are acquired from 80 wells in the Surat Basin, Australia. The permeability scores are based on petrophysical interpretations from wireline logs. Before applying machine learning modeling, some preprocessing steps are conducted, including the elimination of non-numerical values and outliers. In this study, artificial neural network (ANN) and extreme gradient boost (XGBoost) are used to predict the permeability scores. There are 7 permeability scores in the original data and additional groupings (3 or 4 permeability groups) are conducted. As the data is highly imbalanced (i.e., almost 90% of samples are labeled with permeability score 0), the undersampling technique and oversampling technique (SMOTE) are used to enhance the model performance. Finally, the confusion matrix is used as an evaluation metric to quantify the model performance of this multiclass classification task.

Results show that machine learning models have skewed performance (predicted permeability scores are lower than actual permeability scores) due to imbalanced data and have the best performance on the 0 permeability score samples (>99% accuracy). The implementation of undersampling and oversampling techniques can balance the model performance and improve the performance on high permeability score samples. Among all simulations, XGBoost with undersampling technique can achieve over 80% accuracy for the 3 permeability classes. The proposed machine learning approach provides a fast and cost-effective way to estimate rock permeability. It can be used to identify high and low permeability zones (e.g., identification of sweet spots).
Drilling Riser Affecting Shallow Water Wellhead Fatigue
Authors: Lee Jia Hui , Lim Tze King , Young Laurence , Porter Mika
Published: October 2022

The use of a semi-submersible drilling vessel in relatively shallow water (<100m) wells, can expose the wellhead, conductor and surface casing to significant wave-induced fatigue loading. A short length of drilling riser connecting the drilling vessel and the subsea well allows for a significant portion of the vessel and riser motions to be transferred directly to the wellhead and conductor system. Thus, screening of drilling vessel and drilling riser parameters that reduce the transfer of wave fatigue loading to the subsea stack is critical to ensure that the well has sufficient fatigue performance to accommodate expected drilling and completion operations, as well as provide margin for future workover and P&A operations. This paper provides the effects of drilling riser system parameters such as riser tension, BOP stack size and weight, riser joint hydrodynamics and flex-joint stiffness on fatigue accumulation. A parametric study is performed to determine the individual effect of each parameter mentioned above, on the fatigue performance of a shallow water well. Values considered from each parameter are selected based on drilling vessels that are available in the Australian region. The analysis is performed using irregular wave analysis with an industry standard riser analysis software. Based on wave fatigue analysis performed for the subsea wells, the riser telescopic joint hydrodynamic diameter and stiffness of the upper and lower flex-joints are identified to have significant effect on fatigue performance of the wellhead and conductor system in shallow water depth. This differs from wells in deeper water, where riser tension and BOP stack size and weight have a larger effect. Learnings from the parametric study will benefit future wells by allowing screening of acceptable drilling vessels and riser systems to be performed up front to ensure acceptable fatigue accumulation at the shallow water wells. In addition, it is envisaged this information can be fed back to drilling contractors to enable equipment configuration to be selected that is suitable for various water depths.
A Case Study of Design and Installation of Upper Completion System for a Deepwater Gas Field in South China Sea
Authors: Huang Yi , Meng Wen Bo , Jiang Dong Lei , Wang Xue Peng , Chen Hai Ning , Su Jian Bo , Ruescher Nigel , Xu Fei , Diao Huan , Wang Heng , Xiao Tan , Wang Ying Hao , Yu Yi
Published: October 2022

The urgent demand to replace the rapidly declining conventional reserves is driving China's operators to accelerate the development of deepwater reservoirs. SHENHAI Project is the first deepwater project operated by CNOOC China Ltd., locates in water of 1220m to 1546m in South China Sea.

Deepwater completions differentiate themselves not only by unique technical challenges, but also by their high cost, risk, and long project cycles. A sound project management process is essential to ensure flawless execution. By reviewing the key steps of the SHENHAI deepwater completion campaign, such as upper completion design, critical equipment selection, interface management, workshop preparation, and final project execution, lessons learnt, etc., this paper provides both a job cycle of completion design-to-execution and a methodology to manage a complex project by addressing the challenges inherent in the deepwater completion process.

As a result, the well completion campaign was completed ahead of schedule. A total of 11 deepwater wet-tree wells were successfully delivered as designed including two dual-zone hydraulic controlled intelligent wells. The upper completion design has been proven to be safe and reliable with first applications of several critical upper completion tools in the region, such as Nitrogen-Charged Surface Controlled Sub-surface Safety valve (SCSSV), Hydrostatic-Setting production packer and quartz-based permanent downhole pressure gauge.

This success demonstrates the completion design and practices are applicable for this deepwater project and can be extended to further offset deepwater projects in this area. This paper describes case details of successful upper completions of SHENHAI project aiming to provide information and experiences for engineers who may face the similar challenges.