bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Zinc Dendrites Realized by β-P(VDF-TrFE) Nanofiber Layer in Aqueous Zn-Ion Batteries
Authors: Park Geumyong , Park Hyeonghun , Seol WooJun , Suh Seokho , Jo Jiyoung , Kumar Santosh , Kim Hyeong-Jin
Published: October 2022

Uncontrollable Zn dendrite formations and parasitic side reactions on Zn electrodes induce poor cycling stability and safety issues, preventing the large-scale commercialization of Zn-ion batteries. Herein, to achieve uniform Zn deposition and suppress side reactions, an electrospun ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) copolymer, a [P(VDF-TrFE)] nanofiber layer, is introduced as an artificial solid-electrolyte interface on a Cu substrate acting as a current collector. The aligned molecular structure of β-P(VDF-TrFE) can effectively suppress localized current density on the Cu surface, lead to uniform Zn deposition, and suppress side reactions by preventing direct contact between electrodes and aqueous electrolytes. The half-cell configuration formed by the newly fabricated electrode can achieve an average coulombic efficiency of 99.2% over 300 cycles without short circuiting at a current density of 1 mA cm-2 and areal capacity of 1 mAh cm-2. Stable cycling stability is also maintained for 200 cycles at a current density of 0.5 A g-1 in a full-cell test using MnO2 as a cathode.
Blood-Brain Barrier Transport of Transferrin-Receptor Targeted Nanoparticles
Authors: Thomsen Maj Schneider , Johnsen Kasper Bendix , Kucharz Krzysztof , Lauritzen Martin , Moos Torben
Published: October 2022

The blood-brain barrier (BBB), built by brain endothelial cells (BECs), is impermeable to biologics. Liposomes and other nanoparticles are good candidates for delivery of biologics across the BECs, as they can encapsulate numerous molecules of interest in an omnipotent manner. The liposomes need attachment of a targeting molecule, as BECs unfortunately are virtually incapable of uptake of non-targeted liposomes from the circulation. Experiments of independent research groups have qualified antibodies targeting the transferrin receptor as superior for targeted delivery of nanoparticles to BECs. Functionalization of nanoparticles via conjugation with anti-transferrin receptor antibodies leads to nanoparticle uptake by endothelial cells of both brain capillaries and post-capillary venules. Reducing the density of transferrin receptor-targeted antibodies conjugated to liposomes limits uptake in BECs. Opposing the transport of nanoparticles conjugated to high-affine anti-transferrin receptor antibodies, lowering the affinity of the targeting antibodies or implementing monovalent antibodies increase uptake by BECs and allows for further transport across the BBB. The novel demonstration of transport of targeted liposomes in post-capillary venules from blood to the brain is interesting and clearly warrants further mechanistic pursuit. The recent evidence for passing targeted nanoparticles through the BBB shows great promise for future drug delivery of biologics to the brain.
Mechanisms and Outcomes of Metabolic Surgery in Type 2
Diabetes
Authors: Fazliana Mansor , Nor Hanipah Zubaidah
Published: October 2022

This review aimed at synthesizing the mechanisms and outcomes of metabolic surgery on hormones, adipokines, metabolomics, and at the molecular level. We reviewed the endocrine, microRNA, and metabolomics changes in human and animal models following metabolic surgery for the treatment of obesity and diabetes. PubMed, Science Direct, Scopus, and Google Scholar databases were searched up to February 2022. The most relevant studies in the area over the past 17 years have been considered for this review. In most cases, metabolic procedures especially those that include intestinal bypass components, showed remission of type 2 diabetes. This involves a variety of weight-independent mechanisms to improve glucose homeostasis, improving insulin sensitivity, and secretion. The miRNAs’ dysregulated expressions have essential roles in metabolic processes. Metabolic surgery is a potentially sustainable treatment that can modify a patient’s physiology and glucose regulation mechanism. The feasibility and role of miRNA are important for potential targeted genetic pathways in future obesity with type 2 diabetes management.
Evaluating Portuguese Public Hospitals Performance: Any Difference Before and During COVID-19?
Authors: Nunes Alexandre Morais , Ferreira Diogo Filipe da Cunha
Published: October 2022

COVID-19 is a well-known respiratory disease spreading worldwide since January 2020, causing many deaths and massive pressure on health systems. This pandemic’s appearance compromised the health services’ sustainability and quality as many procedures were postponed or even canceled out, with an expected increase of adverse events like nosocomial infections, in-hospital deaths, and the worsening of the patients’ clinical status. Therefore, assessing whether the healthcare providers’ performance has changed is paramount. In this case, we evaluated the public hospitals in Portugal as the leading secondary health care providers in the country, which in turn has been highly affected by the pandemic. To this end, we developed a network Data Envelopment Analysis model serially relating efficiency and effectiveness. Using 2,795 observations from public hospitals and 18 variables, we observed consistent drops in efficiency when the pandemic started, followed by a recovery to levels above the pre-pandemic ones. Regarding effectiveness, we observed a positive trend during the evaluated period. In short, these results allow us to conclude that, apart from the great resilience of public healthcare providers, the Portuguese State was not prepared for a pandemic like COVID-19, but still the actions taken (including massive vaccination) were beneficial.
FADS2 Function at the Major Cancer Hotspot 11q13 Locus Alters Fatty Acid Metabolism in Cancer
Authors: Kothapalli Kumar , Park Hui Gyu , Brenna James Thomas
Published: October 2022

The human chromosome 11q13 (HSA 11q13) genomic locus is a major cancer hotspot and has been established as the most frequently altered by amplification in a variety of human cancers. The fatty acid desaturase genes (FADS1, FADS2 and FADS3) localize to the 11q12- 13.1 region. FADS2 activity is promiscuous, catalyzing biosynthesis of polyunsaturated and monounsaturated fatty acids, including unsaturated branched chain fatty acids (BCFA) by Δ6, Δ8, and Δ4 desaturation toward at least 16 substrates. Our main aim here is to review known and putative consequences of FADS2 dysregulation due to effects on the 11q13 locus in various cancer types. We searched PubMed and Google Scholar databases for articles that showed 11q13 amplification and studies reporting FADS2 function in various cancer types. FADS2 silencing causes synthesis of sciadonic acid (ScA, 5Z,11Z,14Z-20:3) in MCF7 cells and breast cancer in vivo. 5Z,11Z,14Z-20:3 is structurally identical to the eicosanoid precursor arachidonic acid (5Z,8Z,11Z,14Z–20:4) except it lacks the internal Δ8 double bond required for prostaglandin and leukotriene synthesis, among other eicosanoids. Melanoma, prostate, liver and lung cancer cells insensitive to SCD inhibition show increased FADS2 activity leading to sapienic acid (16:1n10) biosynthesis from 16:0. Elevated serum mead acid (20:3n-9) levels were found in more than a third of hepatocellular carcinoma patients, indicative of an unsatisfied demand for arachidonic acid, likely as a substrate for eicosanoids. A highly expressed circular RNA (hsa_circ_022382) within an exonic region of FADS2 is associated with shorter overall survival in colorectal cancer patients. Similarly, in lung cancer tissues circFADS2 RNA is highly expressed. Palmitic acid (16:0) is a common substrate for SCD and FADS2. FADS2 circular RNAs are at high levels in colorectal and lung cancer tissues. The evidence thusfar supports an effort for future research on the role of FADS2 as a tumor suppressor in a range of neoplastic disorders.
The Morphological Rationality for the Expediency of Topical Application of Silver Sulfathiazole in Patients with Diabetic Foot Syndrome
Authors: Kalinichenko Aleksej , Hryvenko Serhiy , Umerov Ervin , Uzbekova Leyla , Usmanova Tamila , Izosimov Vladimir
Published: October 2022

The article presents a morphological evaluation of the effectiveness of the use of silver sulfathiazole (SST) in the local treatment of trophic ulcers in patients with diabetic foot syndrome (DFS). It has been shown that the use of SST in local therapy in DFS patients can improve the course of the wound process and stimulate regeneration processes. The quantitative discrepancies that were found in the expression levels of CD68+ macrophages, depending on the nature of the local therapy in DFS patients, are a diagnostic criterion for the clinical efficacy of using SST in the complex treatment of this category of patients.
Mitochondrial tRNALeu(UUR) Mutations in Patients with Essential Hypertension
Authors: Khan Ikram , Lizhe An , Zhiqiang Li
Published: October 2022

Arterial hypertension remains a major modifiable risk factor for cardiovascular disease. Previous studies have noted a maternal effect on blood pressure (BP). Mutations in mitochondrial DNA (mtDNA) have become an additional target of investigations on the missing BP heritability. The major objective of the present work was to investigate mutations in the tRNALeu(UUR) gene in 20 Pakistani patients with EH and compare the amplified sequences to the mitochondrial reference sequence. DNA was extracted from their saliva, and the mitochondrial tRNALeu(UUR) gene was amplified using PCR with specified primers. The present study did not find mutations in the tRNALeu(UUR) gene in Pakistani EH patients. Further studies are needed for confirmation.
Assessment of Thyroid Nodules using TIRADS Classification: Interobserver Agreement and Correlation with Histopathology
Authors: Ahmed Mohamed Omer Khider , CE Ayad , Gareeballah Awadia , Arafat Mohammed , AL Ali Ahmed , Odeh Khalil Abu , Abdallah Eshtiag
Published: October 2022

Classification of thyroid nodules (TNs) based on TIRADS category is important for predicting malignancy, avoiding unnecessary biopsy and aiding in the management of patients. A prospective nonintervention study was carried out in the period from February 2020 to February 2021 in King Fahad Specialist Hospital in Dammam (Saudi Arabia). The study included 222 patients with suspected TNs (TIRADS 3-5). The thyroid ultrasound scanning was performed with a high frequency linear array probe (9 MHz and 15 MHz). The thyroid gland and adjacent neck tissues were scanned. The diagnostic performance of the TIRADS classifications was evaluated against final histology. Three highly experienced sonographers independently rated the US features of each nodule. Each sonographer assigned points to each TN for the five separate categories (composition, echogenicity, shape, margin, and echogenic foci), according to the TIRADS protocols produced by ACR. Cohen’s kappa scale was used to measure the interobserver agreement in categorizing TNs, and then the performance of ACR TIRADS categories for predicting malignancy was assessed using fine needle aspiration (FNA) as reference standard. For estimation of the diagnostic performance of ACR TIRADS to predict malignancy, the category for each TN was assigned by the principal investigator (Observer 1). This study included only TIRADS 3-5 (mildly to highly suspicious nodules: TR3-TR5), according to ACR TIRADS classification. The agreement for all sonographic features of TN among three observers (principal Observer 1 and two sub-investigators [Observer 2 and Observer 3]) was perfect, being 0.91-1.00 (Cohen’s kappa). Out of 222 patients with TNs, the percentage of malignancy in 68 TIRADS-5 nodules was 91.2%, while in 154 TIRADS 3-4 nodules the percentage of malignancy was 29.9%. The study concluded that interobserver agreement in TIRADS classification and characterization of suspicious thyroid nodule was perfect.
Material Selection Process for Non-Metallic Flexible Buoyancy Bags Assembly in Decommissioning and Marine Salvage
Authors: Thiyahuddin Izzat , Ahamid Zulkifli , M Daud M Hafis , Abdul Rahman Azam , Sulaiman M Hairul , Abdul Hamid Ismail , Xianghai Jing , Liangbiao Xu , Wan Razali Wan M Razlan
Published: October 2022

Offshore structure decommissioning and abandonment is a critical component in the life cycle of hydrocarbon production. In Malaysia, 11% of platforms and 8% of pipelines have been in service for more than 40 years, much exceeding their intended lifespan. Conventional methods of decommissioning offshore platform are inherently very costly with the mobilization and operation of HLV (Heavy Lift Vessel).

This study developed an Offshore Flexible Buoyancy Tank (OFBT) as the buoyancy assembly to execute future small structure removal operation. This study applies the structured material selection process to determine suitable material as buoyancy assembly enclosure. According to the concept, material selection seeks to determine the lightest, pressure-sustaining, fracture-resistant and cost-effective buoyancy bags suitable for the application. This is a problem with 3 objectives: minimize weight, minimize cost, and withstand the internal pressure in above or submerged conditions.

A range of material is tested based on the parameters, and it was determined that Two layers of PET membrane is proposed for OFBT with capacity not less than 380 kN/m. An additional layer is also required to protect the buoyancy bag from puncture or tear. Yard burst test testing is implemented to determine the accuracy of FEA model. A prototype OFBT is fabricated to consist of 3-layer flexible polymer sheet to create an air-containment enclosure.

Overall, the FEA correlates well with the result from the burst test. Both burst tests indicate the failure to occur the flange area. The circumferential stiffeners were observed to fail first followed by Longitudinal stiffeners. Results from this work is integrated in the research towards the development of novel flexible offshore buoyancy tank assembly for the removal of jacket structure in decommissioning and abandonment suited to the application in Malaysia.
Understand the Unconventional Reservoir Heterogeneity via Far-Field Sonic Imaging and Chemical Tracer Evaluations: A Case Study from Wulalike Shale Gas Exploration in Ordos Basin
Authors: Cui Ziyue , Xi Shengli , Ma Zhanrong , Wang Gang , Fu Ning , Yu Gaohong , Zhao Lei , Liu Yuan , Chen Yanyan , Li Yuanhua , Qu Changwei , Wang Qing , Ma Zeren , Le Calvez Joel Herve
Published: October 2022

One of the most challenging aspects of unconventional reservoirs is their heterogeneity. Natural fissures, faults, or laminations, which are the main causes for the heterogeneity, are either measured only on the wellbore or not measured at all. In our recent work on a Wulalike shale gas exploration well, we visualized the heterogeneity with three-dimensional far-field sonic imaging technology during logging, and we evaluated the uneven production profile in the horizontal laterals with chemical tracer during production test. The result of the two methods is highly consistent, which indicated the far-field sonic imaging technology is an effective way to understand reservoir heterogeneity, particularly for unconventional resources.

High-resolution image logging and three-dimensional far-field sonic imaging technology were introduced to a newly drilled horizontal well in Wulalike Shale gas. Multilevel multi-azimuthal acoustic waveforms were acquired with long enough record length to capture the reflections from the mentioned microscopic features. The innovative ray tracing inversion and three-dimensional slowness-time coherence (3D STC) methods were utilized on the filtered waveform to quantitatively determine the true dip and azimuth as well as the distance of the features from the wellbore. And as a result, only four depth intervals were identified by 3D far-field sonic where fractures extended away from the wellbore to far field. The distance of the fractures from the wellbore was in a range of 8 to 28 m.

Chemical tracers were deployed during the fracturing and completion phase to evaluate the new findings from the logging. The uneven production profile from the chemical tracer indicated that 4 out of the 17 stages were the major contributors for more than half of the gas production. Each lateral for those four stages were accompanied with the observation of fissure or lamination signature from the far-field sonic images and resistivity image logging data. This showed that this sonic imaging technology was effective to link the reservoir heterogeneity to its production, making it a valuable tool for the future unconventional reservoir evaluations.
A Thermodynamic Model for Prediction of Solubility of Elemental Mercury in Natural Gas, Produced Water and Hydrate Inhibitors
Authors: Lim Lay Tiong , Sørensen Henrik , Leekumjorn Sukit , Pottayil Adil
Published: October 2022

When it comes to mercury (Hg) there are strict regulation around health, safety and environment, and the level of Hg in discharge water. Further, Hg can potentially compromise the integrity of materials anywhere in the flow path of the produced fluid. Real-time onsite Hg monitoring presents health hazard from exposure to Hg and can also be economically prohibitive. Therefore, it is desirable to be able to reliably simulate Hg partitioning between the vapor, liquid hydrocarbon, and water phases. It is further of interest to evaluate potential Hg condensation when the produced fluid flows from the reservoir through flow lines and passes through process equipment. Commercial compositional reservoir, process and flow simulators employ models with different levels of complexity. It is desirable to be able to make consistent simulations across various simulation platforms using the same equation of state models and model parameters.

In this work we present self-contained sets of parameters for use with the original formulations of the Peng-Robinson modification from 1978 and the Soave-Redlich-Kwong equations of state. We aim at using the lowest possible level of complexity of binary interaction parameters. We further give the acentric factors for the original Peng-Robinson equations of state from 1976 giving the same results as when using the Peng-Robinson modification from 1978. The model covers various hydrocarbon components and inorganic gases, H2O, and common hydrate inhibitors. The work is based upon and ties together the experimental and modelling work of others and supplemented with new model parameters where required. We further summarize the accuracy of the model and briefly touch upon how the model extrapolates beyond the limits of data used in this work.
Thermodynamic Modelling on Wellbore Cement Integrity During Underground Hydrogen Storage in Depleted Gas Reservoirs
Authors: Zeng Lingping , Sarmadivaleh Mohammad , Saeedi Ali , Al-Yaseri Ahmed , Dowling Claire , Buick Glen , Xie Quan
Published: October 2022

Objectives/Scope

Underground hydrogen storage (UHS) has been raising more interest to safely and cost-effectively store hydrogen at large-scale to help the transition from fossil fuel to sustainable energy and to achieve net-zero emission target. During hydrogen subsurface storage particularly in depleted gas reservoirs, the wellbore plays an important role in injection and reproduction to meet seasonal energy demand. However, it is still unclear how wellbore cement would react with stored hydrogen in the presence of formation brine, which may effect long-term cement integrity. We thus performed thermodynamic modelling on cement reactions with hydrogen and water at reservoirs conditions.

Methods, Procedures, Process

The dissolution of individual components of cement including C3S, C2S, C3A, C4AF and gypsum of Class G/H, and potential precipitation of twenty secondary minerals were simulated at an infinite time scale at reservoir temperature and pressure (representing the worst case scenario of cement degradation from geochemical perspective; in real case, the degree of cement degradation would be much less than the results from thermodynamic modelling as it is a time-dependent process). The extent of cement mineral reactions with hydrogen was compared with that of methane and carbon dioxide to assess the wellbore cement integrity during UHS compared to UGS and CCS.

Results, Observations, Conclusions

The cement hydration process would lead to the transformation of the major cement compositions C3S and C2S to C1.5SH (CSH) and portlandite. Adding hydrogen would only slightly change the percentage of C1.5SH and portlandite and generate a small fraction of new mineral mackinawite. As a comparison, adding methane would generate a considerable amount of calcite. When CO2 is involved, all CSH compounds would transform to calcite through the cement carbonation process. Overall, the compositional mineral phases of cement after cement hydration is more closed to the case involving H2 compared to CH4 and CO2, implying a relatively low risk of wellbore cement degradation during UHS.

Novel/Additive Information

Our work underlines the importance of incorporating geochemical modelling in hydrogen geo-storage evaluation when using existing old wells and new drilled wells.
Integration of Mineralogy, Petrophysics, Geochemistry and Geomechanics to Evaluate Unconventional Shale Resources
Authors: Hui Gang , Gu Fei , Chen Zhangxin
Published: October 2022

It is not entirely understood how related geological parameters vary during the thermal maturation and development of shale resources and controlling factors of shale productivity. Here, a detailed examination of mineralogy, geochemistry, petrophysics, and geomechanics-related data is conducted to explore the productivity of the Fox Creek, Alberta shale play. Experiments using X-Ray Diffraction, Tight Rock Analysis, Rock-Eval Pyrolysis, and Triaxial Compression are conducted to characterize the mineralogy, petrophysics, geochemistry, and geomechanics of the region under study. Multiple Linear Regression (MLR) is used to quantify the relationship between shale output productivity and reservoir input parameters. Using 300 core samples from 15 wells targeting the Duvernay shale, the key governing characteristics of shale potential were then examined. The Duvernay shale is dominated by quartz, clay, and calcite, according to X-Ray Diffraction measurements. Tight Rock Analysis indicates that the effective porosity of the Duvernay shale ranges from 1.56% to 6.11%, with an average value of 3.97 %, while the core permeability ranges from 0.25 to 345.5 nD, with an average value of 127.2nD. The total organic carbon (TOC) content ranged from 2.32 to 5.0 %, with an average of 3.86 %, according to Rock-Eval Pyrolysis testing. The majority of the Duvernay shale near the Fox Creek region (i.e., Fox Creek shale) was deposited in an oxygen-depleted maritime environment, whereas the Duvernay shale was in the gas generation window. The MLR technique determines the elements controlling shale productivity, including the production index, gas saturation, clay content, porosity, total organic carbon, brittleness index, and brittle mineral content as input parameters in decreasing order. Based on the MLR prediction model, the expected 12-month shale gas production per stage corresponds well with the actual value. This strategy can guide the future selection of horizontal well drilling sites and lead to the efficient and profitable development of shale resources.
Horizontal Coal Seam Gas Well Orientation Optimization: The Impact of Stress Regime
Authors: Saber Erfan , Qu Qingdong , Aminossadati Saiied M. , Chen Zhongwei
Published: October 2022

Horizontal boreholes have been routinely applied to coal seams as a cost-effective way to maximize coal seam gas production. However, these wells can encounter severe instability issues during field development due to significant horizontal stress loss and change in deviatoric stresses acting on the borehole. In this work, a general dual-porosity dual-permeability model is established and assigned to a coupled gas flow and coal deformation numerical model to investigate permeability change and borehole break-out regarding different in-situ stress regimes around a horizontal borehole. Mohr-Coulomb failure criterion is used in this model.

The results show that drilling parallel to the maximum horizontal stress direction neither achieves the best stability of the borehole nor maximizes the permeability ratio. Drilling along the minimum horizontal stress direction would maximize the permeability ratio, but it has the worst stability. The optimal drilling direction window considering both permeability ratio and borehole stability is recommended to be between 45– 60°.
Novel Feature Augmentation and Input Reshaping Strategy for Accurate Seismic-Based Elastic Property Prediction Using Deep Learning
Authors: Law May , Jaya Makky Sandra , Jones Ernest Austin
Published: October 2022

Data limitation and sparsity are considered the main source of non-uniqueness and ill-posedness in elastic property prediction on seismic data using Deep Learning (DL). The ill-posed regression problem can be solved by conducting adequate pre-processing steps through data augmentation, feature engineering and feature selection. In this paper, we develop a novel technique of reshaping the input data into various multi-dimensional shapes before using the data as an input for the DL model. This strategy can increase the spatial context and temporal data coverage which is important for regularizing the DL model during training process. We also investigate the model performance between a Convolutional Neural Network (CNN) and a Recurrent Neural Network (RNN), specifically the Long-Short Term Memory (LSTM) architecture on 2D synthetic seismic data. Our findings show that using the newly developed feature augmentation and input reshaping strategy with a simple LSTM model can help improve the elastic property prediction on sparse well data. We demonstrate the robustness and effectiveness in terms of visual inspection and relative accuracy measure of the proposed method by using the SEG SEAM Interpretation Challenge dataset Phase I and comparing our results with Mustafa et al.'s (2021) work.
Karst Mapping on Carbonate Build up Using Advanced Spectral Decomposition and Enhanced Variance Filter Technology at Offshore Malaysia
Authors: Othman Haziqah Othman , Zhao Hongwen Zhao , Mohsin Norshida Mohsin , Singh Rajput Seemant , Isa Salbiah Isa , Awang Bujang Awang Amirul Zakry Awang Bujang , Ishak M Anwar Ishak , Azmi Afifah Azmi , Wong Wong Chan , Mishra Santosh Mishra , Rosselly M Noor Afifi Rosselly
Published: October 2022

Karstification is one of the major culprits for drilling issues (e.g., mud loss/blowout/wellbore collapse) in carbonate fields. Hence, it is crucial to precisely identify and predicate paleokarst distribution before formalizing a drilling plan. In this study, an isolated Miocene carbonate buildup in the offshore of Malaysia which is covered by a 3D marine seismic survey is selected for Karst mapping. Geological study shows that the carbonate buildup is bounded by two boundary faults and carbonate bodies were altered by multiple episodes of faulting and subaerial exposure related karstification. Extensive karstification is also evident by total mud losses in wells penetrating carbonate succession. Two in-house technologies: Advanced high-resolution Spectral Decomposition (ASD) and Hessian Filter-enhanced Variance (HFV) were used to illustrate the discontinuities within carbonate bodies and map Karst distribution. Well calibration with ASD and HFV results demonstrates that 1) Carbonate buildup can be clearly distinguished from surrounding clastics by specific (bright orange-colored) boundaries against dull colored clastics in RGB blending images; 2) Karst-related cavernous systems can be depicted by dendritic pattern variation in ASD images and HFV anomalies; 3) Linear discontinuities caused by fractures/faults are also highlighted by the results of ASD and HFV. It can be concluded that the combination of discontinuities revealed by ASD and HFV and with appropriate well and core calibration is a reliable way to predicate karstified reservoirs within the offshore carbonate buildup.
Acid Stimulation Campaign in Ghana Offshore Using Riserless Light Well Intervention Vessel
Authors: Leo Giuseppe , Borra Simone , Pasquali Paolo Giovanni , Sala Gianluigi , Borri Luca , Flamminio Davide , Stocchi Donatella , Mastrocola Carlo , Lazzari Andrea , Tadini Matteo , Ferraro Lorenzo , Fiameni Antonio
Published: October 2022

Scope of this paper is to describe the acid stimulation campaigns carried out in Ghana Offshore field between 2019 and 2020. The campaigns were carried out with a Light Well Intervention (LWI) vessel using different subsea equipment which allowed to safely perform the stimulation operation connecting the vessel to the X-tree production facility.
Reducing Laverda Canyon Field Production Uncertainty with Early Lifecycle Time-Lapse 4D Seismic Data
Authors: Fairburn Maddison , Pedler Hayley Sophia , Louis Jai
Published: October 2022

A time-lapse seismic survey (4D) acquired over Laverda Canyon Field has provided significant value and reduced production uncertainty early in the field lifecycle. At time of monitor one (M1) acquisition completion in April 2020 approximately 9% of the expected ultimate recoverable volumes were produced over the initial nine months of production. Horizontal wells targeting the two high-quality, vertically adjacent, oil and gas bearing reservoirs produce via waterflood. Prior to start-up, compartmentalisation was identified as a key risk due to interpreted high stratigraphic and structural complexity however, initial production data indicated greater connectivity than predicted.

The 4D successfully shows changes resulting from production within the field. Inversion of the final data to compressibility using a wave-equation-based amplitude-versus-offset approach assisted with interpretation by reducing noise and providing a direct property to correlate the impact of changing saturation and pressure within the reservoir. Water sweep, gas evolution, gas movement and pressure increase responses were calibrated at the wells prior to extrapolating interpretation of fluid flow away from well control. These insights were used to guide updates to the reservoir model. An updated fault-framework provides additional structural connectivity via cross-juxtaposition of reservoirs. Polygons corresponding to vertical stratigraphic connectivity via erosive down-cutting channels provides additional stratigraphic connectivity. Dynamic reservoir modelling has utilised connectivity polygons as well as more traditional history-matching parameters to show an overall improvement in replicating field production. Additionally, the reservoir model has been used to simulate the observed 4D response.

Improved understanding of field behaviour unlocked with the 4D has resulted in a higher level of confidence in the model for reservoir management and forecasting. Optimisations to the field operating strategy include revisions to the waterflood strategy to improve sweep and reduce gas migration and improved flexibility in voidage management. Future strategic facility decisions regarding project end of field life, development and assessment of near field tie-in opportunities will benefit.
Innovative Technique Using High Resolution Resistivity Image in Estimating Coal Seam Gas Reservoir Permeability
Authors: Oraby Mahmoud , Luft Joao , Zhou Fengde , Kuznetsov Dan , Keogh Sean , Alboub Mohamed
Published: October 2022

Permeability is one of the important reservoir properties for oil and gas reservoirs. It directly impacts the reservoir's ability to produce and is considered a key factor to delineate reservoir sweet spots for optimum well placement and successful development strategies. However, the permeability prediction is difficult for coal seam gas (CSG) reservoirs due to the presence of complex geological conditions which cause the lateral and vertical heterogeneity on the coal seam. The objective of this study is to present a practical petrophysical approach where the estimation of coal permeability is possible under the mapping of fractures and cleats using high-resolution microresistivity image logging data. This technique provides meaningful results that can integrate better with known coal geological criteria such as ranking and lithotypes. Furthermore, it helps better analyze production data and enhance history matching calibration.

Post-processing technique using resistivity inversion model and mud filtrate resistivity allowed to calculate fractures and cleats aperture as well as porosity. Fracture and cleat properties, i.e. density, length, area, aperture and porosity, were inputs for permeability calculation using fracture permeability published equations. Also, a multilinear regression (MLR) model was built for permeability estimation by utilizing the burial depth and properties of fractures and cleats.

The coal seam obtained modelled permeability is a continuous curve capturing vertical heterogeneity in both qualitative and quantitative ways. The MLR model improved the match compared to the published permeability equations. Results show that the modelled MLR permeability perfectly matches the actual diagnostic fracture-injection/falloff test (DFIT) and wireline formation tester mini-DST permeabilities. The study showed the role of petrophysical logging in evaluating coal permeability by minimizing the uncertainty associated with the traditional permeability estimation. The technique provides denser permeability points for the static model, significantly enhancing the model properties distribution. It is important to mention the benefit of this technique in selecting the best reservoir portion of the target seam during lateral wells planning.
Study on the Labyrinth Screw Pump for Heavy Oil Production
Authors: Wang Zhuoyu , Zhu Jianjun , Cao Guangqiang , Zhu Hongwu , Zhong Ruizhi , Zhu Haiwen
Published: October 2022

As widely used in onshore and offshore oil production, the electrical submersible pumps (ESPs) suffer from significant performance degradation for producing high-viscosity hydrocarbon fluids. In this paper, a new design of the labyrinth screw pump (LSP) is proposed to facilitate the high-viscosity oil production, which may partially replace the application scenarios of ESPs for heavy oil extraction. Based on the cellular supercharging theory proposed by Golubiev, a prototype of LSP was designed and manufactured, while an experimental facility was built up to test pump's performance at different rotational speeds and viscosity fluids. A fitting function was used to summarize the influence of different operating conditions on the H-Q curves by regression analysis. The applicability of the affinity law to LSPs was verified, which is widely used in centrifugal pump performance analysis. The internal flow characteristics was investigated by computational fluid dynamics (CFD) simulations. With the obtained results, the dimensionless flow and head coefficients of LSPs were able to be correlated by a non-linear relationship. Compared to ESPs, LSPs were found to be more suitable for conveying highly viscous fluids.
Method of Characteristics Based Model for a Coaxial Borehole Heat Exchanger
Authors: Duggal Rohit , Rayudu Ramesh , Hinkley Jim , Burnell John , McGuinness Mark
Published: October 2022

Mature petroleum fields provide readily accessible wells for geothermal energy extraction in many parts of the world. Likewise, the major hydrocarbon-producing region of New Zealand, the Taranaki region, has many mature wells with high temperatures (∼150 °C) measured at the bottom. Borehole heat exchangers could be a cost-effective way of producing geothermal energy from these wells. Therefore, the purpose of this study is to present a mathematical model capable of evaluating the potential of geothermal energy production from unused wells.

We first set up our mathematical model using the Method of Characteristics for the wellbore heat exchangers. A co-axial borehole heat exchanger is selected for our study due to its simple design and popularity in use. The model is then validated against the analytical results available in the literature.

For the first time, a study utilizing borehole heat exchangers to produce geothermal energy is being conducted in New Zealand. This study will help boost interest in reusing unused wells for residential and industrial direct use applications. Based on our model, the capability of alternate fluids such as supercritical CO2 to further enhance the performance of heat exchange will be analyzed in the future.
Evaluation of the Potential of Foam Producing Microorganism Improving Heterogeneity of Permeability for Novel Microbial Foam EOR
Authors: Ito Miu , Sugai Yuichi
Published: October 2022

The foam improves heterogeneity of permeability in oil reservoir and contributes to enhancing oil recovery. Both surfactant and gas are alternatingly injected into oil reservoir in foam EOR, therefore, it has several challenges: high cost of surfactant, formation of precipitation with bivalent cations, adsorption of surfactant on reservoir rock, etc. This study proposes the microbial foam EOR which overcomes those challenges by having microorganism generate foam in-situ. We have found an ability of a microorganism belonging to Pseudomonas aeruginosa to generate foam under anaerobic conditions. This study investigated the source materials constructing the foam and capacity of the foam to improve the heterogeneity of the permeability.

The challenges of our study are the reproducibility of the foam generation and the foam stability. This study therefore examined the source materials of the foam to understand the mechanisms of the foam generation. We focused on protein, which has been suggested as a possible component of the foam in our previous studies, and examined the relationship between the amount of foam generated by P. aeruginosa and the concentration of protein in its culture solution. As a result, a positive correlation was found between them. This result indicates that the foam generated by P. aeruginosa is composed of the protein produced by the microorganism.

Next, the performance of the foam decreasing permeability of high permeability porous media was evaluated through sand pack flooding experiment. P. aeruginosa was injected into a sand pack and cultivated in-situ. The post-flush water was injected into the sand pack after three days’ in-situ cultivation to measure the permeability. As a result, the permeability of the sand pack was successfully decreased to half after the cultivation. The permeability of a sand pack in which P. aeruginosa was injected with culture medium and in-situ cultivated was successfully decreased to half of initial. The efflux of bacterial cells of P. aeruginosa was detected after injecting 1.3 pore volumes of postflush water, which shows that the postflush water flowed through areas other than the area where P. aeruginosa grew and produced the foam. These results indicate that the foam produced in-situ by P. aeruginosa is effective for improving the heterogeneity of permeability in oil reservoir.

This EOR can be operated at low cost without expensive chemicals. Because the foam produced by P. aeruginosa is induced by proteins, the precipitation will not be formed in oil reservoir. The stability of protein-induced foam is higher than that of surfactant-induced foam in the presence of oil or high saline conditions. The microbial foam EOR therefore has high potential improving the heterogeneity of permeability in oil reservoir more effectively than the conventional foam EOR.
Digital Transformation of Offshore Structure Weight Control Management into Digitally Integrated and Intelligent Analytical Tool
Authors: Alias Nur Dalila , Wong Bak Shiiun , Anas Wan Zalikha , Sulaiman Nur Amalina , Epui Mildred Vanessa , A Rahman Azam , A Rahman Ahmad Rizal , Yeoh Sue Jane , Abdollahzadeh Asaad , Ngadan Linda William , Tang Horng Eng , Chooi Wai Fun , Khan Riaz , Ng Sook Moi , Saminal Siti Nurshamsinazzatulbalqish , Ibrahim M Mujiduddin , Hamid Marklin , Suhaili Ave Suhendra , M Hisham M Said Farhan
Published: October 2022

Leveraged on the abundant weight data comprised of more than 200 offshore platforms, a smart digitalized analytical tool called i-WEIGHT, an integrated weight control tool consisting of three (3) main modules: centralized multi-discipline weight database module for all offshore platforms, seamlessly linked with Insights dashboard module in providing actionable insights, and weight predictive module supported by Machine Learning (ML) model was developed. This paper discussed the Minimum Viable Product (MVP) Phase 1 development outcome, using a close-loop weight control ecosystem for continuous update of validated weight data in Module 1, and eventually improve & enhance capability of both the EDA and Predictive module. Using a supervised machine learning algorithms, the identified target variables were observed to provide weight prediction between 16% to 38% of Mean Absolute Percentage Error (MAPE), using Extreme Gradient Boosting Regressor (XGBR) algorithm. Top 10 important features were identified for each target variable, which provide insights to the operators on critical data required for topside with identified missing equipment weight data for future i-WEIGHT improvement. Based on more than 200 integrated platform topside data gathered for this study, consolidated insights from the data enabled operators to identify the threat of current data quality and thus bringing forward a promising opportunity to enhance platform weight data management system. Having a centralized and automated platform weights data, this tool has the potential answers for United Nations’ Sustainability Development Goals, in particular Goal 9.4, where the study represents a small but crucial step to upgrade from an existing conventional process into a digitally driven operation, introducing a sustainable ecosystem in offshore structure weight management, thus fostering sustainable growth within the industry.
Berri Increment Novel Waste Heat Recovery System
Authors: Alotaibi Fahad M , Al-Dossari Faisel M , Al-Majed Fahad M , Al-Hajri Ali M , Al-Zahrani Talal A
Published: October 2022

Berri Crude Increment Project (currently in the Execution phase) will install a new oil processing facility. As part of the project, a new thermal hot oil system will be provided to heat the crude oil for the desalting and stabilization process to meet the product specifications. This heating is primarily achieved through three hot oil heaters (furnaces) fueled by natural gas in a closed heating circulation system. The objective is to maximize the energy utilization and efficiency of the oil processing facility by integrating the waste heat of the plant turbines’ exhaust with the plant process heating network.

The project added in the scope a waste heat recovery system as part of the hot oil loop to recover the energy and maximize the plant’s efficiency. The waste heat recovery consists of heat exchangers mounted on the plant combustion gas turbines to recover the exhaust heat and supply it to the plant heat demand. These turbines are fueled by natural gas to drive the water injection pumps at the facility.

This design enhancement will minimize fuel gas burning in the hot oil heaters to supply the required process heating, and will reduce combustion product emissions from the hot oil heaters’ stacks to atmosphere. The anticipated benefits are as follows:Recover energy of up to 75 MW that represent 50% of the total heating duty.Optimize lifecycle cost through Savings by reducing fuel gas burning by 50%.Reduce greenhouse gases emissions by minimizing the hot oil heaters’ fuel gas consumption.Improve equipment and plant efficiency (10% turndown of process heating can be achieved).Minimize single point of failure through the increase of plant availability with flexible process heating design.

This energy integrated design is one of a kind among conventional oil and gas surface facilities with very high energy recovery capability. The facility is expected to recover 50% of its total thermal duty needed by processes through efficient energy utilization. In addition, substantial environmental advantages are foreseen by reducing the plant combustion effluents. This is important for a processing facility located in an area that is considered a hub of several marine and environmental initiatives of Saudi Aramco.
Pigging the Unpiggable: A Case Study of Waxy Crude Oil Pigging Simulation and Field Implementation
Authors: Anuar Astriyana , A Rasib Amira , M Norpiah Rohaizad , Ali Zalina
Published: October 2022

This paper presents the various challenges faced by a 10-km waxy crude oil pipeline at Field 23, as the pipeline has not been able to be pigged for almost one year due to recurring pigging issues such as broken/damaged pigs, vibrations and high pressures that were close to trip settings. The implemented pigging frequency as per operating philosophy is every two weeks. However, the frequency has been extended based on field experience. Due to these issues, Operation team immediate action is to devise a pigging program that works and to avoid recurring issues. Flow Assurance (FA) engineers working together with Operation team devised a plan that incorporates lab analysis and conducted desktop studies which include field data analysis and application of various FA simulation tools. The main challenge is to develop a robust FA model that is reliable enough to use for detailed analysis, be able to reproduce field data and use it to develop the most suitable pigging program. Additionally, it is worth noting that the pipeline has gone through rigorous wax chemical optimization that potentially contribute towards wax incremental issues in the pipeline. It was also observed that the fluid has changed tremendously from initial design basis due to fluid blending from non-associated gas (NAG) and oil zone and production header temperature mixing effects. Therefore, the initial operating envelope was found to be no longer suitable for this pipeline. From extensive lab analysis, fluid modelling update, metocean data calibration and wax deposition tuning, the FA models were able to match the field conditions within < 10 % variance. A field tuned baseline model was developed. Several options have been proposed and analyzed such as varying pig types, pigging and chemical methods where extensive FA modeling were performed to evaluate the suitability of each method/application to develop a more suitable pigging program. A detailed workflow on the chosen program was then produced based on a progressive pigging method utilizing multiple pig types at a reduced flowrate with chemical application. Although wax dissolution effects from wax dissolver chemical was not modeled, this model-based approach was a success in that we were able to reduce pig stuck risk during actual field implementation. The success of the waxy crude oil pipeline pigging campaign has sparked an immediate interest among the Production/Operation engineers especially on the application of a robust FA models, in which when it is well calibrated, enable effective and immediate troubleshooting of issues at site. This work has set a benchmark for FA engineers to update/develop a well-calibrated FA model during operation phase to facilitate optimization and troubleshooting programs.