bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Impact Of Using Digital Library Resources On The Productivity Of Researchers At The State Islamic Institute Of Purwokerto
Authors: Nurohman Aris 
Published: June 2023

Abstract: Digital library resources are invaluable in assisting universities in research. The academic community recognizes that digital resources improve their research results. Much research has also confirmed the link between the utilization of digital resources and research output. The researchers analyzed the utilization of digital library resources by researchers at the Purwokerto State Islamic Institute to validate the evidence. The study takes a descriptive-analytical approach, employing the purposive sampling method to collect data from various circles of researchers at various levels. The conclusion is that digital information sources are valuable sources of information that should be evaluated and exploited in the research process, beginning with creating ideas, study design, reference sources, and data collection. Researchers have benefited from digital resources due to the ease and speed of access to information, support for improving research performance, improving the quality of scientific work, supporting creativity to continue working, and increasing awareness about the importance of publication and authentication of scientific papers.Keywords: digital library resources, library, researchers, research productivity. Abstrak: Sumber daya perpustakaan digital sangat berharga dalam membantu perguruan tinggi dalam penelitian. Civitas akademika menyadari bahwa sumber daya digital mempengaruhi peningkatan hasil penelitian mereka. Beberapa penelitian juga telah mengkonfirmasi hubungan antara pemanfaatan sumber daya digital dan hasil penelitian. Para peneliti menganalisis pemanfaatan sumber daya perpustakaan digital oleh para peneliti di Institut Agama Islam Negeri Purwokerto untuk memvalidasi bukti. Penelitian ini menggunakan pendekatan deskriptif-analitis, dengan menggunakan metode purposive sampling untuk mengumpulkan data dari berbagai kalangan peneliti di berbagai tingkatan. Kesimpulannya, sumber informasi digital adalah sumber informasi berharga yang harus dievaluasi dan dimanfaatkan dalam proses penelitian, dimulai dengan penciptaan ide, desain studi, sumber referensi, dan pengumpulan data. Para peneliti telah mendapatkan manfaat dari sumber daya digital karena kemudahan dan kecepatan akses informasi, dukungan untuk meningkatkan kinerja penelitian, peningkatan kualitas karya ilmiah, mendukung kreativitas untuk terus berkarya, dan meningkatkan kesadaran akan pentingnya publikasi dan otentikasi karya ilmiah.Kata kunci: sumber daya perpustakaan digital, perpustakaan, peneliti, produktivitas penelitian
Durability of Polymer-Based Wellbore Sealants in a Corrosive Environment
Authors: Todorovic Jelena , Stroisz Anna Magdalena , Duda Marcin Ireneusz , Agofack Nicolaine , Lange Torstein , Nilsen Nils-Inge , Aas Per Gunnar , Sefidroodi Hamidreza , Ringe Thomas 
Published: June 2023

Abstract
Development of wellbore sealant alternatives to cements is a topic of high relevance for production and injection wells, permanent plugging and abandonment, and remediation of leakage behind the casing. Some examples of alternative sealants are epoxy-based sealants, geopolymers, and bismuth-based alloys. Depending on the application, sealing materials are expected to encounter challenging downhole conditions, such as corrosive environments (e.g., CO2, H2S) and pressure or thermal cycling. This is especially significant for permanent plugs, where long-term perspective needs to be considered.
In this work, we conducted long-term exposure of three polymer-based wellbore sealants (labelled as A, B and C) to an artificial seawater water environment with dissolved H2S gas. The polymer-based sealants are compared to each other and to a Portland G cement blend that was subjected to the same testing procedure. The experiments reported here are a part of a more extensive campaign that aims to study the behaviour of these materials after up to 12 months exposure to H2S. The aging tests were performed as batch-exposure conditions in a pressure cell at 100 °C and 10 bar. Cylindrical (core) samples of the same material were submerged together in artificial seawater in a glass beaker, and a mixture of H2S and nitrogen was dispersed into the seawater. We characterized mechanical properties before and after H2S exposure by unconfined compressive strength (UCS) tests. X-ray micro-computed tomography (CT) was performed to visualize changes potentially induced by the reaction with H2S.
After H2S exposure, sealants A and B displayed significant axial and radial deformation during UCS tests (ductile behaviour), which is a very different behaviour compared to a typical wellbore cement. Sealant C exhibited ductile behaviour during compression but without considerable deformation. For comparison, strain at the peak stress was in the order of 200-300 mm/m for sealants A and B, whereas for C it was approximately 60 mm/m, after one month of H2S aging. For all three materials, a decrease of UCS and Young's modulus was observed after H2S exposure. For sealant C, the UCS was still relatively high after three months of aging, at around 70 MPa, which was about 50 % decrease from the reference value. CT results revealed no obvious progression of a reaction front for sealants A, B and C, however, different effects (e.g. change of porosity, precipitation, cracking) were observed throughout the volumes.
The unique behaviour of these materials under stress and the possibility of tuning the physical and chemical properties hold vast potential for different applications. One of the long-term goals is to optimize the material properties to make them more suitable for the permanent plugging of both petroleum and CO2 wells.
Opportunities and Uncertainty Mitigation Base on Survivor Bias in a Mature Field: Cañadón León, San Jorge Basin, Argentina
Authors: Legarreta Andres Esteban , Barberis Rosina Cristina , Schein Florencia Tercila , Martino Luis ángel , Gandi Silvana 
Published: June 2023

Abstract
Survivorship bias is a well-known tendency to overweight available data and underestimate the missing information. Cañadón León in San Jorge basin, Argentina is a waterflooded field with a current water-cut of 95% where innovative recovery strategies such as Chemical Enhanced Oil Recovery (cEOR) become a condition for further development. Data acquisition is often biased towards the best reservoirs, leading to major uncertainty in assessing opportunities in mature fields.
After 70 years of primary oil production and water injection, the study aims to evaluate the remaining opportunity, which leads to a double challenge: Estimation of bypassed oil during the inefficient waterflooding process because of poor mobility ratio and the potential of marginal reservoirs. Initial stage field exploitation and data acquisition at early stages of development aimed mainly to characterize the higher oil-saturation zones with better petrophysical properties, leading to a lack of data on marginal reservoirs which become critical targets for mature reservoirs analysis. The data interpretation within a semi regional geological framework to build the static model, allowed a representative construction of poorly characterized reservoirs due to survivorship bias effect.
Several hypotheses were evaluated with dynamic simulation to avoid assuming recoverable oil based on survivorship bias due to missing information in secondary targets. Integration of what-if scenarios, both static and dynamic, and assessment of uncertainty provided a better understanding of critical constraints and optimum ranges of variability to analyze cEOR with polymer injection. A wide variety of fluid saturation scenarios, mobility ratios and reservoir properties were considered to quantify the field potential.
Sensitivity analysis helped to identify the most relevant uncertainties in history matching and reliability in forecast: Primary gas cap contact and its expansion, water-oil contact, the transition zone (oil-water system), fluid mobility ratios and polymer characteristics.
A major benefit from polymer injection is CO2 emissions reduction per barrel of oil by more than 40% compared to water injection, reducing project carbon footprint. Development strategy achieves a short-term incremental recovery factor of 10% with a total of 68 wells in 20 injection patterns (considering a period between 3 to 6 years due to oil production acceleration). This methodology allowed to establish the foundations for development strategies based on multi-modelling within conceptual geological frameworks reflecting the impact of the recognized uncertainties. This technique does not allow to determine the unknowns, but it does allow to estimate their impact.
Continuous Monitoring of Water Pressure Change in an Oil Reservoir
Authors: Shaker Shiran Behruz , Djurhuus Ketil , Alagic Edin , Lohne Arild , Rolfsvåg Trond Arne , Syse Harald , Riisøen Solveig 
Published: June 2023

Abstract
As oil is produced from a reservoir, the free-water-level (FWL) rises. Monitoring the FWL during oil production is of high value for the operators. This knowledge can aid placement of new wells on the field, improve the production strategy on a well level and reduce the production of water. We propose a new method for continuously measuring in-situ water pressure in an oil reservoir and investigate, both experimentally and by simulations, how this information can be used in reservoir monitoring.
Laboratory experiments with Berea sandstone and Mons chalk core samples were performed using mineral oil and synthetic brine in a test setup designed for this study. The pressure in the water phase is measured with hydrophilic probes at five locations on the core during drainage and imbibition processes. Data including temperatures, pressures, resistance, water production, and pump logs were continuously collected in a cloud solution for live monitoring during the experiments. The experimental results were interpreted using a numerical simulator (IORCoreSim) to identify key mechanisms behind probe response and upscaling to reservoir scale.
A new setup with 5 internal pressure probes for measuring in-situ water pressure with higher oil pressure was successfully designed and tested. An advanced watering system to inject water to the probe tips was included in the test setup and can be operated automatically. Experimental results showed that the water-wet probes can measure low water pressure inside high pressure oil column. The change in water pressure during drainage of low permeable Mons core and medium permeability Berea core was continuously measured. The probes were able to measure water pressure in different sections of the core with change of water saturation in the core. After the drainage process, the water pressure at one side of the core was increased. The propagation of water pressure at low water saturations were then detected in the 5 probes along the core sample.
This paper presents a revolutionary technique to measure pressure in a thin film of water with low mobility. Continuous monitoring of water pressure inside the hydrocarbon phase can be used to enhance the production on a well level and improve the strategy on a field level. This results in increased production, reduced operational costs and environmental impacts.
Viscoplastic Deformation During CO2 Storage in Danish Chalk Reservoirs: Role of Petrophysical Heterogeneity and Mechanical Alteration
Authors: Amour Frédéric , Hosseinzadehsadati Seyedbehzad , Nick Hamidreza M. 
Published: June 2023

Abstract
Denmark aims at a 70% reduction in greenhouse gas emissions by 2030 compared to levels measured in 1990, with a long-term target of becoming carbon-neutral by 2050. As part of this national effort, the Bifrost project, aims at repurposing two depleted gas fields in the Danish North Sea for CO2 storage, namely the Harald West sandstone field as the primary target and the neighboring Harald East chalk field as a potential upside. The Harald East chalk is the focus of this study. The storage potential and infrastructures available within the multiple chalk fields located in the Danish North Sea represent valuable assets to fulfill the national objectives enabling a time- and cost-efficient implementation of carbon storage activities. One of the main challenges for carbon storage in chalk is the contradictory experimental results reported in literature that indicate both a strengthening and a softening effect of supercritical CO2 on the plastic and elastic properties of chalk. Such uncertainty hampers accurate prediction of the deformation response of storage sites. In this context, the study aims at assessing the impacts of two levels of uncertainty; the type of mechanical alteration induced by supercritical CO2 and the petrophysical heterogeneity on the long-term deformation behaviour of chalk reservoirs. An in-house hydro-mechanical-chemical model calibrated against experimental data on chalk is applied in a reservoir model of the Harald East field. A 16 year-long injection period is simulated assuming two scenarios. In scenario 1, supercritical CO2 has no impact on the mechanical properties of the rock, whereas in scenario 2, a 30% and 25% lowering of the pore collapse stress and elastic modulus of chalk is assumed. A systematic comparison of the flow and mechanical behaviour of low and high porosity cells located in the vicinity of an injection well indicates that the impact of CO2 on the mechanical properties of chalk, the distance of the cells from the injector, the local stress redistribution taking place in the reservoir between mechanically soft and strong cells, and the presence of natural gas in pore space before CO2 injection are key factors controlling the amount and distribution of plastic deformation occurring in the storage site. The outcome of this work enables quantifying the main risks associated with rock compaction close to and further away from injectors during and after carbon storage in chalk fields.
Permeability Estimation Using Machine Learning Techniques for a Heterogeneous Mud Dominated Carbonate Reservoir, Offshore UAE
Authors: Contreras Perez David Rafael , Sellar Christopher , Valente Alexander 
Published: June 2023

Abstract
The implementation of Artificial Intelligence and Machine Learning algorithms has introduced the opportunity for alternative techniques to estimate permeability within uncored intervals/wells. Different combinations of input data and different approaches for training values were evaluated to select a consistent predictive model able to produce permeability logs while honoring the geological concept and available core permeability measurements.
The approach presented here is deployed in a low porosity, low permeability hydrocarbon bearing carbonate reservoir with a limited dataset, aiming to estimate a permeability log from available wireline log and core data. The geological description from core in Reservoir 3 indicates the presence of oil saturation in mud-dominated carbonate rocks with a moderate degree of calcite cementation. After a rigorous quality check of the available permeability measurements from conventional core analysis data, a high confidence database of porosity and permeability measurements were combined with existing wireline logs (e.g. GR, Resistivity, Neutron Porosity and Archie Water Saturation). The resulting structured dataset was used for permeability prediction using Random Forest regression (from scikit-learn in python).
Three cases of permeability logs were generated from this methodology at well log resolution to be used in static reservoir modeling and saturation-height-modeling with J-functions. The permeability and saturation height models are key inputs for dynamic modelling to generate production forecasts in this undeveloped reservoir. Three different permeability models were trained using 144 high quality core plug measurements from six cored wells. Even though the number of available samples can be considered low for a machine learning workflow, an oversampling approach with point repetition was adopted to overcome data insufficiency for this dataset.
From an E & P point of view, accurately predicting reservoir permeability in hydrocarbon reservoirs has been one of the major challenges facing the industry for decades. The approach outlined here reduces uncertainty in permeability prediction in the uncored interval. Furthermore, since permeability is part of the estimation of water saturation, this approach reduces uncertainty in water saturation interpretation, the potential deliverability of flow units and the volumetrics.
Numerical Investigation of the Primary Mechanisms Leading to Complex Fracture Morphology in the Near-Wellbore Region
Authors: Kryvenko Serhii , Moridis George Julius , Blasingame Thomas Alvin 
Published: June 2023

Abstract
This paper presents the results of numerical simulations of hydraulic fracturing in the immediate vicinity of the wellbore. This research aims to identify the primary mechanisms underlying the complexities in both the fracture morphology and propagation of longitudinal fractures. The study shows that the perforation attributes and characteristics, the cement quality, and the reservoir heterogeneity have a significant impact on the resulting morphology and the trajectory of the propagating hydraulic fracture.
The study is based on properties and conditions associated with a field study conducted in the Austin Chalk formation, and concludes that the pattern and the dimensions of the perforations are essential factors controlling the fracture initiation pressure and morphology. The results of the simulation studies provide insights into the principles and mechanisms controlling fracture branching and the initiation of longitudinal fractures in the near-wellbore region and can lead to improved operational designs for more effective fracturing treatments.
Novel Acid Stimulation Technique for Production Improvement – Austrian Eocene Case Study
Authors: Smith Fraser Troy , Hadziavdic Ina 
Published: June 2023

Abstract
A new approach to acidizing is presented where an inert dry chemical is hermetically sealed inside a metal carrier and deployed downhole via E-line or slickline. The tool is spotted in front of the zone of interest and an exothermic reaction is initiated generating hot acid vapour. A depleted Eocene sandstone reservoir with a 2 7/8″ tubing inside 6 5/8″ casing was successfully treated leading to sustained production enhancement in addition to significant carbon footprint reduction when compared to a conventional treatment. The treatment approach, production results and description of the CO2 reduction is presented. A rigorous well candidate selection process was done as part of the treatment design which analyzed information including damage mechanism, well completion architecture, mineralogy, well deviation, formation type and compatibility. Based on this analysis, the tool type and tool placement sequence were determined to optimize the stimulation. For this well, two 2″ HCl and two 2″ 12:3 HCl/HF tools were used to treat a 5.5 m perforated interval. The HCl tools served as pre-flush treatment and removed any scale. This was followed by 12:3 HCl/HF tools which stimulated the near wellbore matrix and ultimately improved the reservoir fluid influx. After each tool was ignited, a drop in the fluid level was observed. This was positive indication that the acid vapour was enhancing connectivity to the reservoir. When pulled to surface, it was observed that all four tools had ignited and had undergone a complete chemical burn.
The well had several tubing and pump changes throughout its long production history. More recently, the well was treated by bullheading EDTA and solvent to re-establish the oil production rate with unsatisfactory long-term production results. Prior to the novel treatment, the well had been producing at 9 – 11 m3/d (gross rate) and 1.8 m3/d of oil. After the application of the novel technique, the production results showed a return to the historical rate of 1.8 m3/d of oil (100% increase). Eighteen months post-treatment, the oil production is sustained and producing between 1.5 - 1.6 m3/d. Flow-back equipment was eliminated from the operation since the highly reactive hot acid is fully spent and dissipated. The operation was rigless and the only equipment required was a wireline unit, a crane, and a small fluid truck. The entire stimulation was completed in less than one day and the well could be put immediately back on production.
A secondary benefit was a notable reduction in CO2 associated with this treatment method versus a conventional acid treatment. This was achieved by reducing the heavy equipment requirements and the associated diesel consumption.
Research on Multiple Coal Seams Relative Permeability Calculation Method Based on Production Data Inversion
Authors: Huang Tianhao , Wang Zhiming , Zeng Quanshu 
Published: June 2023

Abstract
To obtain the actual gas-water relative permeability of the coalbed methane (CBM) reservoir and further deepen the cognition of the gas-water production law of multiple coal seams, a relative permeability calculation method based on production data inversion is constructed. Based on production data, historical fitting is carried out through the multiple coal seams whole process coupling flow model, and the basic physical parameters of each layer are inversed. Based on the obtained physical parameters, the productivity prediction of the whole production cycle is carried out. By calculating the average water saturation and gas-water relative permeability in each iteration time step, the average gas-water relative permeability curve of the reservoir in the target period is finally obtained. The results show that the calculation method proposed in this paper can realize the acquisition of the relative permeability curve in the given period. Compared with the input relative permeability curve, there is a reverse point on the output relative permeability curve that can represent the continuous production of desorption gas. Gas production is affected significantly by different types of initial input relative permeability curves, and is mainly influenced by the input relative permeability curve at the initial production stage. Under ±30% deviation, the average difference in cumulative gas production is 16.92% (3 years). During the production of CBM wells, the average water saturation was maintained at a high level. At the end of the production of multiple coal seams commingled production well, the average water saturation change is less than 15%. Restricted by high water saturation, the average relative permeability of the gas is always maintained at a low level, less than 0.1 at the end of production of actual production wells. The fundamental technical difficulty in realizing the initial high production and subsequent sustained and stable production of CBM wells lies in how to reduce the reservoir water saturation effectively and improve the relative permeability of the gas, so as to promote the desorption of adsorbed gas and the sustained CBM production.