bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimalisasi Pemanfaatan Mata Air Jagasatru untuk Layanan Sistem Penyediaan Air Minum (SPAM) di Desa Manggis
Authors: Pamungkas Tri Hayatining , Soriarta I Ketut , Wiratnata I Wayan Astu , Astariani Ni Kadek
Published: October 2023

Desa Manggis memiliki sistem penyediaan air minum dengan memanfaatkan mata air Jagasatru. Dalam pemanfaatanya mata air Jagasatru baru melayani dua dusun yaitu Dusun Belong dan Yehpoh sedangkan untuk debit mata air Jagasatru yaitu 10 liter/detik memiliki berpotensi untuk dapat melayani seluruh Desa Manggis yang memiliki 12 Dusun. Mata air Jagasatru jika dimanfaatkan sangatlah menguntungkan karena memiliki elevasi 169 m di atas permukaan laut. Berdasarkan kondisi tersebut maka dilakukan penelitian yang bertujuan untuk mengoptimalkan pemanfaatan mata air Jagasatru. Metode analisis dilakukan untuk mengetahui dusun yang dapat direncanakan sistem gravitasi, sistem jaringan dan biaya yang diperlukan. Analisis memproyeksikan pertumbuhan penduduk dan kebutuhan air sampai 10 tahun. Hasil dari survei topografi dusun yang dapat dijangkau sebanyak 10 dusun kecuali Dusun Bakung dan Pegubugan karena elevasinya lebih tinggi dari sumber mata air. Analisis jaringan sistem perpipaan menggunakan metode modeling Epanet 2.2 menghasilkan dimensi pipa, spesifikasi pipa, dan skema jaringan yang memenuhi syarat untuk dioperasikan. Mengacu pada hasil analisis jaringan sistem pemipaan didapat rencana anggaran biaya untuk pelaksanaan proyek tersebut sebesar Rp. 1.529.239.000.
EVALUATING THE INTEGRATION OF WORD PROBLEMS, WORLD EXPERIENCE, AND MATHEMATICAL KNOWLEDGE IN YOUNG CHILDREN
Authors:   Department of Psychology, The Education University of Hong Kong, Hong Kong, Yuet Ling Linda Kwan
Published: October 2023

This study arose from research conducted in a school where students aged seven to nine struggled to solve mathematical problems. The study's goal was to find out how children make sense of their problems. Students were given a few simple arithmetic problems and then individually interviewed to determine and comprehend the difficulties that the students were experiencing. The problems' stories involved a quantity being increased by or combined with another quantity to form a total. The quantities were small natural numbers that did not exceed 20. The findings revealed a number of problems with mathematics learning. The results were derived from how students understood the word problems, the relationship between the word problems and real-life experience, the relationship between real-life experience and mathematical knowledge, and the integration of word problems, world experience, and mathematical knowledge. How students work and verify their answers in order to better understand their thinking was observed. The usefulness of word problems in school can be realized only if students' understanding of a particular situation can be elicited, enriched, or embellished with their experience before that experience can be re-examined in light of the theory that is applied to the real-life situation.
Flexible tactile sensor with an embedded-hair-in-elastomer structure for normal and shear stress sensing
Authors: Cao Yudong , Li Jiacheng , Dong Zihao , Sheng Tianyu , Zhang Deyuan , Cai Jun , Jiang Yonggang
Published: October 2023

Endowing robots with multi-directional tactile sensing capabilities has long been a challenging task in the field of flexible electronics and intelligent robots. This paper reports a highly sensitive, flexible tactile sensor with an embedded-hair-in-elastomer structure, which is capable of decoupling normal stress and shear stress. The flexible tactile sensor is fabricated on a thin polyimide substrate and consists of four self-bending piezoresistive cantilevers in a cross-shaped configuration, which are embedded in an elastomer. The sensor can decouple the tactile information into a normal stress and a shear stress with simple summation and differencing algorithms, and the measurement error is kept within 3%. Moreover, the sensitivity and detection threshold of the sensor can be adjusted by simply changing the elastic material. As a demonstration, the flexible tactile sensor is integrated into a robotic manipulator to precisely estimate the weight of the grasped objects, which shows great potential for application in robotic systems.
Barrier options pricing under stochastic volatility using Monte Carlo simulation
Authors: Jerbi Yacin , Bouzid Rania
Published: October 2023

The aim of this paper is to evaluate barrier options by considering volatility as stochastic following the CIR process used in Heston (1993). To solve this problem, we used Monte Carlo simulation. We studied the effects of stochastic volatility on the value of the barrier option by considering different values of the determinants of the option. We illustrated these effects in twelve graphs. We found that in general, regardless of the parameter under study, the stochastic volatility model significantly overvalues the in-the-money (ITM) barrier options, and slightly the deep-in-the money (DIP) options, while slightly undervaluing the near-out-the money (NTM) options.
ANALISIS FUNGSI INSTRUMEN MUSIK SEBAGAI PRODUK TERAPEUTIK BAGI ANAK DENGAN ADHD
Authors: Hairunnas Hairunnas
Published: October 2023

Attention Deficit Hyperactivity Disorder (ADHD) adalah kelainan yang cukup sering terjadi di Indonesia. Ketidakmampuan anak untuk memusatkan perhatian biasanya ditangani dengan pemberian medikasi dan terapi psikis maupun fisik. Terapi musik adalah terapi yang menggunakan rangsangan suara untuk meningkatkan kualitas fisik dan mental anak. Gelombang suara yang dihasilkan oleh musik dapat merangsang perkembangan otak anak dan dapat menjadi alternatif pengganti medikasi. Banyaknya jenis terapi yang dilakukan pada seorang anak dengan ADHD tidak akan maksimal ketika tidak dilakukan secara konsisten. Konsistensi terapi pada anak dengan ADHD sangat bergantung pada orangtua yang juga berperan sebagai terapis bagi anaknya, namun kondisi orangtua saat ini memiliki wawasan yang kurang untuk membantu konsistensi terapi. Penelitian bertujuan untuk mengkaji fungsi-fungsi instrumen musik sebagai sarana terapi musik. Metode pada penelitian ini adalah kualitatif, dilakukan dengan menguji interaksi jenis-jenis instrumen musik pada anak ADHD dan wawancara terhadap terapis ADHD untuk mencari variabel-variabel yang dapat menjadi acuan penggunaan instrumen musik sebagai sarana terapi ADHD. Hasil dari penelitian ini menunjukkan adanya hubungan antara desain instrumen musik dengan kegiatan terapi. Hasil ini dapat menjadi pertimbangan dalam perancangan produk instrumen musik  sebagai media terapi anak ADHD.
Optimal MIS weights in case of mixing 3 strategies for bidirectional MCRT with photon maps
Authors: Ershov Sergey Valentinovich , Kopylov Mikhail Sergeevich , Pozdnyakov Sergey Georgievich , Voloboy Alexey Gennadievich
Published: October 2023

Bidirectional Monte Carlo ray tracing with photon maps is a powerful method for rendering images. But stochastic noise is inherent in it. However, this noise can be reduced using the multiple importance sampling technique which combines the weighted results of different strategies. The optimal weights allow you to minimize the noise functional and, thus, render the image of the best quality. In this paper, we determine the optimal weights using a system of integral equations derived and solved by us. This system has several qualitative differences from the case of mixing two strategies investigated previously. But further increasing the number of strategies does not change the qualitative features of the system. The system can be solved in a closed form, i.e. as an algebraic formula that includes several integrals of known functions. They can be calculated during ray tracing. Therefore, application of the optimal weights in Monte Carlo ray tracing results in faster rendering of high quality realistic images.
Subchondral Insufficiency Fractures of the Knee
Authors: Musbahi Omar , Waddell Lily , Shah Nehal , Smith Stacy E. , Chen Antonia F. , Bisson Leslie , Katz Jeffrey N.
Published: October 2023

» Subchondral insufficiency fractures of the knee (SIFKs) are subchondral plate fractures with a prevalence of 2% to 4% of all knee injuries.

» Magnetic resonance imaging is the gold standard for evaluating SIFK, while plain radiographs have limited the use in the diagnosis of SIFK.

» Among patients with SIFK, 50% to 100% have meniscal pathology.

» Medical therapies and standard treatments traditionally used in the management of knee osteoarthritis differ from recommended management of SIFK patients.

» Randomized controlled trials and cohort studies with long-term follow-up are needed to determine the optimal rehabilitation protocol, interventional therapy, and prognosis of SIFK patients.
Hydroponic vegetable business strategy development in PT. XYZ
Authors: Hasibuan M Fariz Afif , Harianto Harianto , Baga Lukman Mohammad
Published: October 2023

PT XYZ is an agribusiness company. Currently, its potential is still not optimized. To support sustainable and competitive agricultural development and the sustainability of the industry in running a business, professional and efficient business plans and strategies are needed to achieve the business targets that have been set. This study aims to 1) analyze the business model run by PT XYZ, 2) analyze the internal and external conditions of PT XYZ, and 3) formulate an improvement plan for the business model of PT XYZ. The data used in this study are primary data and secondary data. Primary data was obtained through field observations, in-depth interviews with informants (purposive sampling), and distributing questionnaires. In contrast, secondary data came from various kinds of literature, both from books and the internet, regarding the results of data publications from relevant institutions and agencies relevant to the research. The method of analysis with research objectives are Business Model Canvas (BMC), SWOT (Strength, Weakness, Opportunity, and Threat) analysis, and qualitative and quantitative descriptive. The results of the Business Model (BMC) mapping at PT XYZ show that there is still a need for changes in business strategy because there are still potential customer segments to be developed. After using the SWOT analysis, there are several formulations of strategy development, namely a new alternative strategy focusing on several operational support components to reach broader consumers, integration between products and services, and a sound marketing management system.
THE EFFECT OF INSTAGRAM VIDEO ON STUDENTS’ SPEAKING SKILL IN GIVING OPINION
Authors: Wijipratiwi Siti , Lolita Yuri
Published: October 2023

Technology growth in the field of education has resulted in significant changes, particularly in the field of English learning in higher education. Instagram could be one of the alternative instruments for supporting the practice of teaching high school students English as Foreign Language (EFL). Instagram's implementation, which has amassed a large user base over the last decade, could be a valuable teaching tool to aid the learning process. The purpose of this research is to see if using Instagram video as a learning media can help ESL high school students enhance their speaking skills. The subjects of the study consisted of 49 high school students who applied the Cambridge Curriculum. A quasi experimental research design was used in this study. The pre-test and post-test score were obtained by requiring the students to speak monologue giving opinion. Then, the pre-test and post-test data was analyzed by Independent Sample T-test. Based on the test results, significance value (2-tailed) of post-test was .000 lower than .05. Moreover, the researcher found that the post-test mean score of experimental group was 89.92 whereas the control group was 82.71. In short, there was a significant difference in Instagram video usage on senior high school students’ speaking skill. Cohen's d was used to determine the magnitude of the effects, and it showed 2.6. It was discovered that the effects were significant. Thus, the findings suggest that using Instagram video as a learning tool for senior high school students could be beneficial.
Pulsed Neutron Logging Technique to Detect Bypassed Oil and Edge Water Encroachment in Complex Multilayered Reservoir in Caspian Sea
Authors: Zhangaziyev Zhandos , Hashem Mohamed , Rouis Lamia , Kontarev Roman , Mollaniyazov Eldar , Blanco Andres , Jafarov Ramin
Published: October 2023

This case study focuses on an offshore brown field in the Caspian Sea. The field is multilayered terrigenous sequence characterized by more than three kilometers of gas, condensate and oil reservoirs with changing formation water salinity. The conventional methodology adopted for producing stacked clastic sands has been to produce the deeper sands first, deplete these, and to then continue perforating stratigraphically shallower sands. This strategy is not without risk on this field because the rotated flower structures and rapid burial history often means there is high potential to miss potentially productive zones. This has a cost and production impact with additional infill wells, workovers, and near well sidetracks the result. By better understanding reservoir heterogeneity and ‘production baffles’ present within the structures as part of an active surveillance program it is possible to produce a more robust model to optimize infill well production and existing well performance. To achieve this a continuous pulsed neutron logging campaign is ongoing and this paper will demonstrate the added value the logging program brings to the field development in terms of production and reducing the number of inactive wells requiring re-completion. Proposed case study explains the workflow and result of extensive reservoir surveillance campaign performed with pulsed neutron logging tool. This data combined with open hole and production logs provided good information to understand the remaining potential of the field. Secondary gas cap expansion, edge water encroachment, bypassed oil bearing zones and current water saturation investigation allowed successful recompletion and intervention of inactive or low producing wells. The above-mentioned cased hole logging campaign resulted in significant oil production increase (more than 200%) and water rate decrease (30%) compare to initial results.
Modeling Heterogeneity of Glacial Reservoir Using Geostatistical Approach: A Case Study, Southwest Libya
Authors: Bergigh F. A. , Meddaugh W. S. , Alkhemri T. M.
Published: October 2023

The main challenge of modeling the glacial sandstone deposits is capturing the property pattern in the reservoir, because of the abrupt changes from one depositional environment to another. This reservoir heterogeneity impacts the infill well planning and production performance of the field. In this research, a comprehensive workflow is presented to model the spatial distribution of porosity and permeability within the Mamuniyat sandstone in the Murzuq Basin, Onshore Libya, using geostatistical techniques. Geostatistical techniques in combination with the available information from six wells using geological information, petrophysical analysis, and seismic interpretation were used to construct a 3D model for the reservoir. The structural input included the main interpreted horizons, with a total of 34 faults. Six facies were identified in the reservoir, dominated mainly by the Outwash Fan and Submarine Channel. To categorize reservoir quality, four rock types were defined based on the observed relationship between porosity and permeability. Variogram analysis was performed to describe the spatial relationship between all reservoir layers. Sequential Gaussian Simulation was utilized for porosity modeling and Gaussian Random Function Simulation for Permeability were both constrained to facies. Water saturation was modeled based on the height function method for each rock type. The final model revealed significant variation in reservoir characteristics; this variability is attributed to the diagenetic process that affects the reservoir quality of the sandstone. The best reservoir characteristic was encountered in structural highs, where the most productive wells had been drilled in the area. The incorporation of more data such as core analysis, seismic attributes, and the engineering information in the model will be useful to better understanding of reservoir quality, thus improves future development decisions for the field.
Exploration and Practice of Composite Temporary Plugging Fracturing Technology for Deep Shale Gas Horizontal Wells: A Case Study from X2 Well in Southeastern Sichuan
Authors: Hu Zheyu , Zhao Jinzhou , Ren Lan , Lin Ran , Hu Dongfeng , Li Zhenxiang , Lin Chen
Published: October 2023

The deep shale gas formation that has a burial depth of more than 3,500m covers nearly half of the area of entire Wufeng Formation-Longmaxi shale gas formation in the Southeastern Sichuan Basin, and more than 50% of the shale gas resources are reserved in this burial depth range. Deep shale gas is buried deep with high temperatures, high formation stress, and strong rock plasticity. It is difficult to form and maintain a complex fracture network underground. The deep shale gas fracturing technology is important to promote the overall development of shale gas in the Sichuan Basin. Well X2 is a pre-exploration well in the Southeastern Sichuan Basin. The maximum vertical depth of this well is 4,343.8 m, the average clay mineral content of the high-quality shale interval is 26.2%, the average siliceous mineral content is 48.1%, the average salt mineral content is 14.9%, the elastic modulus is 45.6 GPa, and the maximum and minimum horizontal principal stress of the reservoir is 115.5 MPa and 98 MPa, respectively. Then the horizontal stress difference is 16.8~18.5 MPa. The reservoir is characterized by a high horizontal stress contrast and a low brittleness, which severely restricts the formation of an effective complex fracture network. A composite temporary plugging fracturing of inner-fracture + inlet fracture is proposed, and the fracture net pressure is increased to improve the fracture network complexity and balance the propagation of multiple fractures by adjusting the inlet flow rate of each fracture to achieve high-efficiency fracturing. The 1,503 m horizontal well interval is hydraulic fractured 30 stages with 3 clusters in each stage, cluster spacing is 8~10 m, and the average stage length is 47.33 m. The total injected fracturing fluid volume is 89,736.6 m3 (fluid strength 63.19 m3/m), and the total amount of proppant injected was 3,477 m3 (sand strength 2.45 m3/m). The average overall sand-fluid ratio is 3.88%, the pump rate is 14~18 m3/min, and the daily test production of this fractured deep shale well reached to 41.2×104 m3. The fracturing performance is remarkable. We proposed a deep shale gas fracturing technology with "more stage & less cluster, dense cluster perforation, large fluid volume, high pump rate, medium proppants amount, double plugging, and variable viscosity slippery water alternating injection". It makes an exploration breakthrough of the deep shale gas buried more than 4,000 m and promotes the development of deep shale gas fracturing technology in China.
Flowing Bottomhole Pressure During Gas Lift in Unconventional Oil Wells
Authors: Jin Miao , Emami-Meybodi Hamid , Ahmadi Mohammad
Published: October 2023

We present artificial neural network (ANN) models for predicting flowing bottomhole pressure (FBHP) of unconventional oil wells under gas-lift operations. Well parameters, fluid properties, production/injection data, and bottomhole gauge pressures from 16 shale oil wells in Permian Basin, Texas, are analyzed to determine key parameters affecting FBHP during the gas-lift operation. For the reservoir fluid properties, several PVT models, such as Benedict-Webb-Rubin, Lee, Gonzalez, & Eakin, and Standing, among others, are examined against experimentally tuned fluid properties, i.e., viscosity, formation volume factor, and solution gas-oil ratio, to identify representative fluid (PVT) models for oil and gas properties. Pipe flow models, i.e., Hagedorn & Brown, Grey, Begs & Brill, and Petalas & Aziz, are also examined by comparing calculated FBHP against the bottomhole gauge pressures to identify a representative pipe flow model. Training and test data sets are then generated using the representative PVT and pipe flow models to develop a physics-based ANN model. The physics-based ANN model inputs are hydrocarbon fluid properties, liquid flowrate (qL), gas-liquid-ratio (GLR), water- oil-ratio (WOR), well depth (TVD), wellhead pressure (Pwh), wellhead temperature (Twh), and temperature gradient (dT/dh). A data- based ANN model is also developed based on only TVD, Pwh, qL, GLR, and WOR. Both physics- and data-based ANN models are trained through hyperparameter optimization using genetic algorithm and K-fold validation and then tested against the gauge FBHP. The results reveal that both models perform well with the FBHP prediction from field data with a normalized mean absolute error (NMAE) of around 10%. However, a comparison between results from the physics- and data-based ANN models shows that the physics- based model accuracy is higher at the later phase of the gas-lift operation when the steady state pipe flow is well established. On the other hand, the data-based model performs better for the early phase of gas-lift operation when transient flow behavior is dominant. Developed ANN models and workflows can be applied to optimize gas-lift operations under different fluid and well conditions.
Engineered Materials and Machine Learning for Carbon Storage Well Integrity
Authors: Pollock Jacob , Elshahawi Hani
Published: October 2023

Carbon capture and sequestration is an effective short-to-medium term option for reducing net carbon emissions into the atmosphere. The prevention, monitoring, and prediction of carbon dioxide leakage points and pathways are critical to the success of carbon capture and sequestration. The success of carbon dioxide injection operations and the endurance of long-term storage are partially dependent on well design and the materials used for well construction. We have developed a stack of technologies which enable enhanced well robustness, monitoring of carbon storage facilities, and modeling of their performance. They improve well integrity through better cement bonding with the casing pipe and enhanced measurement of cement condition and additionally provide critical information for intervention and remediation.

Nanocomposite surface treatments improve cement-to-casing bonding, reduce channeling, and prevent annular fluid migration while acoustically responsive metamaterial cements enable monitoring cement integrity, mechanical load, and chemical environment. The materials are sufficiently robust thermally, chemically, and mechanically for use in carbon storage wells and other types of downhole construction or remediation operations. The composite cement materials possess unique acoustic signatures that allow their distinct detection as well as measurement of local chemical and mechanical conditions.

The acoustic and physical properties of these novel materials were characterized in the laboratory as well as field trials. The improved acoustic contrast provided by these technologies enhanced log analysis and substantially improved discernment of cement location and mechanical loading. Machine learning was used to quickly identify cement and reservoir condition based on acoustic signals and to interpret sensor responses. The combination of these technologies enables the tracking of downhole and subsurface fluid distribution and flow. They can furthermore be used to exploit remaining reservoirs while preventing carbon dioxide plume migration. These metamaterials and nanotechnologies are highly scalable, which has been demonstrated in multiple manufacturing and deployment trials.
Dynamic Characterization of Pore Structures in Hydrate-Bearing Sediments During Hydrate Phase Transition
Authors: Chen Mingqiang , Li Qingping , Zhou Shouwei , Pang Weixin , Lyu Xin , Zhu Junlong , Fu Qiang , Lyu Chaohui , Ge Yang
Published: October 2023

Natural gas hydrate widely distributed in marine sediments and permafrost has brought great attention due to its large reserves. Unlike conventional reservoirs, the effective pore structures vary from time and space due to hydrate dissociation and secondary formation in the development, which produces significant impacts on gas flow and production. Therefore, figuring out the evolution of dynamic pore structures is of great importance for the efficient development of hydrate deposits.

In this work, excess-water hydrate formation method was combined with micro-computed tomography to study hydrate transition effects on the evolution of dynamic pore structures. Gas state equation and chemical reaction dynamics were combined for separating the representative 3D images at different stages of hydrate formation into four phases, which are respectively hydrate, water, gas and solid skeleton. Hydrate pore habit evolution, formation characteristics, spatial distribution heterogeneity and its effect on the effective porosity variation were studied in detail. Afterwards, a modified maximal ball method was employed to extract hydrate-bearing pore networks at different stages of hydrate phase transition. Hydrate phase transition effects on the effective pore and throat radii distributions, pore and throat cross-sections, throat lengths and distance among connected pore bodies, as well as pore topology were further investigated based on the extracted networks.

Results show that hydrate pore habit varies in porous media during hydrate formation with the main pore habit of pore filling mode. Hydrate spatial distribution exhibits some heterogeneity, causing diverse hydrate saturation at different layers during hydrate phase transition. Hydrate disrupted pore integrity to some extent, resulting in more extracted pore bodies and throats with increased hydrate saturation. In addition, hydrate phase transition reduces pore-throat radii and distribution regularity to different degrees, and results in more irregular pore-throat morphology, decrease of throat length and distance among connected pore bodies as well as poorer connectivity at the same time. This study provides a novel insight in better understanding the evolution of dynamic pore structures and lays a good foundation for the effective development of natural gas hydrate deposits.
Extended Aquifer System Pressure Behavior Under Carbon Storage
Authors: Mukhtar Muhammad Haseeb , Hatzignatiou Dimitrios Georgios , Ehlig-Economides Christine
Published: October 2023

Most reported carbon storage projects have involved inexpensive CO2 capture from gas processing plants or ethanol refineries. However, widespread carbon capture and storage application must avoid any risk that high capital investment cost for carbon capture from stationary point sources leads to unanticipated issues related to the aquifer storage. This paper reviews successful and unsuccessful carbon storage projects and explains simple extended aquifer system fundamentals that must be considered in selecting a storage aquifer.

This study begins by evaluating reported carbon storage projects in the context of an extended aquifer system with specific attention to initial formation pore pressure and potential or known hydraulic vertical or lateral communication with hydrocarbon accumulations and/or fresh water. Further study focusses on how the contrast between injection well and aquifer pressure evolution enables understanding of the overall aquifer material balance. Finally, we consider implications of brine migration during and after long term CO2 injection in unconfined aquifers.

Experience in the petroleum industry with aquifer behavior include presence or lack of water influx and production from hydrocarbon reservoirs that share a common aquifer. Of particular importance is the observation that hydrostatic initial formation pressure indicates the possibility that a petroleum system, or an extended aquifer system without hydrocarbon accumulation(s), connects to atmospheric pressure through an unconfined aquifer. In such cases indefinite injection will never increase the regional aquifer pressure. Further, initial formation pressure that exceeds hydrostatic pressure implies a petroleum system or an extended aquifer system that is volumetrically limited. In such cases injection will increase the system pressure, and pressure monitoring can detect leakage from the system. Finally, CO2 injection into an aquifer will displace brine in the direction of lower pressure that could relate to distant production from the same aquifer or from hydrocarbon reservoirs with which it communicates.

Reasons for known carbon storage project interruptions have included unexpected lateral plume migration or aquifer pressure increase during CO2 injection that might have been anticipated with attention to straightforward consideration of aquifer enabled hydraulic communication. Such extended aquifer dynamics must be included in long term models for permanent CO2 storage during and after injection.
Downhole Electric Heating to Maintain Wellbore Temperature Above the Wax Appearance Temperature
Authors: JIM SHEN , ERIC KLOTZ , ROD EWACHA
Published: October 2023

Optimizing Waxy Oil Production is challenging due to paraffin deposition. Crystallization of waxes in crude oils leads to non-Newtonian flow characteristics as described by Zheng et al in SPE paper OTC-26914 (Zheng, 2006). This crystallization may cause complete blockage of tubing and other flowlines by wax. These problems will lead to decreased flowrates and well intervention. Shutting in a well for workover increases the operation cost. The most common intervention to remove paraffin deposits is hot oiling and chemical injection. When comparing an alternative of circulating hot oiling down the annulus to melt paraffin or chemical injection; downhole heater is a good option. Downhole heating allows operators to maintain production by increasing the tubing temperature above the paraffin precipitation point. Stabilized reservoir inflow, reduced pump intake pressure and potentially dangerous and expensive hot oil and chemical batch interventions can be avoided. The aforementioned was achieved in a Provost Alberta waxy oil well with the resultant completion described and the field data recorded.
Sedimentary Analysis Via Automatic Image Segmentation and Clustering with the LWD OBM Resistivity Image: A Case Study from Gulf of Mexico
Authors: Yang S. , Wang Y. , Shrivastava C.
Published: October 2023

Microfacies analysis is the first step for depositional environment interpretation and sand body prediction. Textural details from borehole images are building blocks for facies analysis, representing different paleo sediimentation conditions. Associated workflows have been applied on high resolution borehole images by geologists and log analysts manually. Automation via machine learning solutions provides an opportunity to improve the working efficiency and accuracy. Such an approach has given satisfactory results with post-drilling wireline images. In this paper, the improved workflow for sedimentary analysis was applied and validated with a logging-while-drilling (LWD) resistivity imager in oil-based mud environment (OBM).

The OBM LWD resistivity image in oil-based mud provides 72 data points at single depth from 4 different frequencies of electromagnetic measurements with a patented processing. The non-gap resistivity image gives more confident texture characterization. The continuous histogram and correlogram derived from image data were used for image segmentation. In each image segmentation, multiple vector properties were extracted from image data representing different texture features including adoptive variogram horizontally. Agglomerative clustering was selected for its stability and repeatability. The internally built dendrogram allows to automatically determine the number of clusters by finding a stable distance between the clusters’ hierarchy branches. In addition to the features extracted from image data, optional petrophysical logs with variable weights may be fed to the algorithm for a better classification.

A case study from Gulf of Mexico is being used to demonstrate this workflow with Hi-Res LWD image. More than 10 different sedimentary geometries were classified automatically from image and petrophysical logs. The microfacies were named manually from sedimentary geometries with the related geological concept accordingly. The fluvial channel and delta sedimentary environment were interpretated finally from microfacies association. The interpretation results were compared and validated with published dips-based solution as well.

This is the first time for the automatic borehole image segmentation with LWD OBM images. The working efficiency was improved a lot through this workflow and the accuracy of microfacies interpretation was guaranteed by machine learning solution.
Quantitative Mapping of Methane Emissions in Oil & Gas Facilities
Authors: Andrews A. Ballard , Boucher Christopher , Chakrabarti Aditi , Dauphin Mathieu , Doshi Manasi , Rashid Kashif , Speck Andrew , van Pelt Aaron , Yuan Junyi , Zielinski Lukasz
Published: October 2023

Methane is an invisible greenhouse gas predicted to account for over 30% of global warming over the next decade. A substantial portion of the methane emissions from oil and gas (O&G) facilities arise from events that are intermittent. Continuous monitoring using methane emissions detectors installed permanently at a site offers a cost-effective way to identify, quantify, and repair intermittent emissions. Due to the wide variety of O&G sites, we have developed two different continuous monitoring solutions for quantitative mapping of methane leaks, i.e., methane point sensors and methane light detection and ranging (LiDAR) cameras. The methane point sensors use proprietary inversion algorithms minimizing false positives and the methane LiDAR cameras offer a unique capability of continuously scanning an entire O&G facility for direct measurement of leak rates. A single blind-study at the Methane Emissions Technology Evaluation Center (METEC) at Colorado State University confirms that both systems perform well at leak detection with methane point sensors being better suited for small to mid-sized simple facilities while the methane LiDAR camera is a better choice for larger and more complex sites. Continuous monitoring of the facilities is possible with both systems using a digital platform to track emissions which aids operators to manage their emissions abatement.
Solved: ESP Shutdowns and Restart Issues—Novel Pump Protection and Active 3D Dispersion System Improve ESP Performance in Multiple Wells
Authors: Bhattacharjee A. , Dikshit A. , Tullier B. , Mouget S. , Tripathi A. , Gupta S. K.
Published: October 2023

In North American land unconventional completions, operators are pushing production limits to keep up with global energy demand. Uninterrupted production with minimal operational expenditures is vital to deliver a quicker return on investment, and electrical submersible pump (ESP) performance plays a critical role. Aggressive production, inadequate wellbore cleanouts, and corrosive production fluid can result in unplanned shutdowns, restart issues, and the erosion of ESP parts. This paper presents a novel pump protection system that enhances ESP run life by significantly improving restarts, actively managing corrosive chemicals, and reducing scale buildup in addition to the design, development, and field installations results.

The system comprises a 3D filter, an intake control valve, a novel 3D chemical dispersion system, and a novel sand fallback protection system (SFPS) above the ESP. This paper focuses on the dispersion system and the SFPS. The 3D chemical dispersion system was developed to counter scale, paraffin, and sulfide deposition over time. This active dispersion system uses a novel injection manifold for effective downhole chemical treatment at the filter level. The SFPS was designed to ensure that the suspended solids on the ESP as a result of a shutdown, planned or unplanned, do not pose a risk to restart. The unique coil-based design vibrates with ESP pressure head, breaks down the sediments, and effectively disperses the solids back into the production fluid.

The pump protection system has been installed successfully in more than 50 wells in North America. The data show that the SFPS has enabled an improvement of more than 6% in the uptime, defined as the ESP run time as a percentage of the well's total operating time. It has also resulted in a 58.9% reduction of the average time required to restart the pump following an ESP stop event. In all of the wells, the new ESP systems are still running and in one case has already exceeded the run life of the previously installed equipment that did not include an SFPS. The number of ESP stop events, particularly those resulting from particle-related overload issues, has decreased significantly, by 75.5%. Furthermore, the average amperage during pump restart has decreased by 32.5%. The use of the active chemical dispersion system ensured that various chemicals were uniformly injected downhole per the well environment, and such wells had lower scale buildup compared to those in which no system was installed. no system was installed.

The novel SFPS and 3D dispersion system have been developed, qualified, and field installed, and the system designs as well as the results from more than 50 field installations are presented. The systems and the methodology are unique in design and have helped several operators in North America improve ESP pump performance and run life.
Estimating the Permeability Field Using the Bayesian Inference and Principal Component Analysis
Authors: Zhang Zhen , He Xupeng , Li Yiteng , Alsinan Marwa , Kwak Hyung , Hoteit Hussein
Published: October 2023

Surrogate modeling is essential in reducing computational costs for history-matching applications. Yet, traditional deep learning-based surrogate models cannot cope with high dimensional input parameters, such as the permeability field. This work introduces a robust method to automate the history matching process utilizing the Bayesian inversion assisted by a hybrid convolutional neural network and long short-term memory (CNN-LSTM) model and principal component analysis (PCA) method. The method includes five main steps. Step 1: Generate a high-spatial permeability field using a geostatistical approach. Step 2: use the PCA to reduce the dimensionality of the permeability fields, followed by using PCA to generate permeability fields and perform simulations. Step 3: construct the CNNLSTM to map the nonlinear relationship between the extracted features from PCA and the sequential outputs, such as the pressure response. Here, Bayesian optimization is employed to automate hyperparameter tuning. Step 4: perform the Bayesian inversion to inverse the high dimensional inputs, e.g., permeability field, in which the CNN-LSTM serves as the forward model to reduce the computational cost. The inversed PCA features are then fed into the PCA to recover the high dimensional inputs. Step 5: check convergence and if the errors are significant between the inversed high dimensional permeability field and the ground truth, revisit the construction of the CNN-BiLSTM and the prior information for the uncertainty parameters. A 2D reservoir model demonstrates the proposed history-matching method. We can inverse the high dimensional inputs (e.g., permeability field) with minor errors between the prediction and ground truth. We propose a Bayesian inversion assisted by a hybrid CNN-LSTM model and PCA method for high-dimensional parameter inversion, which is superior to the traditional models regarding accuracy and efficiency. This method enables us to perform history matching for reservoir simulation with high dimensional inputs and significant uncertainties.
Assessment of DFIT Analysis Using Laboratory Experiments
Authors: Ye Zhi , Ghassemi Ahmad
Published: October 2023

Reliable knowledge of the magnitudes and orientations of in-situ stress is crucial for conducting scientific and engineering activities in the subsurface, especially with regards to subsurface energy and storage applications. A commonly used technique for determining the minimum principal stress is to interpret the fracture closure pressure from the pressure decline transient during the shut-in phase of a minifrac test or a diagnostic fracture injection test (DFIT). However, current minifrac or DFIT analysis methods for interpreting fracture closure pressure often yield inconsistent results, leading to large uncertainties in determining the minimum principal stress. This paper presents a series of small-scale laboratory hydraulic fracturing experiments conducted under true-triaxial compression. The injection scheme consists of a hydraulic fracturing cycle followed by a few fracture propagation cycles and several injection/falloff (DFIT) cycles. The wellbore pressure and acoustic emission (AE) activities of each cycle were concurrently measured to monitor fracture initiation, propagation, and closure during fluid injection and shut-in. The pressure data were used to interpret S3 using different hydraulic fracturing-based methods. The results illustrate that the spatial-temporal evolution of AE activities is well associated with fracture propagation. In relatively low permeable rocks (Test 1 and Test 2), fracture reopening pressure generally provides a reliable estimate of the minimum principal stress (S3). ISIP consistently provides a relatively higher estimate of S3 and can be used as an upper limit for constraining S3. Fracture closure was observed using the so-called "tangent" method in all injection/falloff cycles. However, the "tangent" method using a signature close to the peak GdP/dG tends to significantly underestimate S3. The "compliance" method offers a relatively objective (yet still low) estimate of closure pressure. The signature associated with the change in system stiffness or compliance is observed but not consistently in every DFIT cycle. In the relatively high permeable Scioto Sandstone test (Test 3), the G-function plots exhibit a "normal" leak off behavior, and the "tangent" method provides a good stress estimate, and the compliance method lacks a clear signature for determining fracture closure. The stress interpretation results demonstrate that the process of fracture closure is highly impacted by rock properties, such as permeability and elastic moduli, and cyclic injection operations.
Ensuring Effective Downhole Corrosion Control Management Through the Newly Integrated Corrosion Monitoring Surveillance System
Authors: Abdulghani Ahmed , Muailu Husain , Bukhamseen Ahmad , Haque Mohammad
Published: October 2023

Corrosion challenges in production and injection wells are common in the oil and gas industry. The detrimental outcomes of corrosion affect the service life of a well. The necessity of dependable corrosion management solutions that can precisely measure corrosion rates is essential when taking into consideration the expense of maintenance and repair because of corrosion and material failures. In this paper, a successful deployment of a newly re-designed downhole corrosion monitoring tool with a custom-designed Downhole Coupon Holder Assembly (DCHA) is discussed.

Electrical resistance (ER) corrosion probes are widely used in the petroleum industry for corrosion rate surveillance. To keep track of metal loss, the ER probes measure the electrical resistance, which rises as the size of the consumable test coupon reduces. The weight loss corrosion coupons, one of the oldest and most well-known corrosion monitoring techniques, are still widely used to this day. Examining the Mils-Per-Year (MPY) rate of corrosion on a used coupon can give an indication of the material's durability.

The integrated innovation, the ER+ tool, was equipped with a specially configured resistivity probe to measure downhole temperature and metal loss data and hosted with a set of six metal coupons in a single coupon holder. It was deployed in a water supply well for a period of 83 days. After a successful retrieval of the tool, the downhole data was downloaded and the metal coupons were analyzed for metal loss profiling, surface profilometry, X-Ray Fluorescence (XRF), and Scanning Electron Microscopy (SEM) imaging analysis.

The results conclude that the ER+ tool offers an excellent platform allowing downhole screening of multiple tubing metallurgies for future tubing materials selection and design in a single deployment, i.e., shortening the overall well downtime. In addition, the ER+ tool enables the evaluation of corrosion inhibitor efficacy for different metallurgies. The results will be further used to design an effective and timely downhole inhibitor injection batch treatment schedule and doses for better downhole integrity maintenance. In the long run, the operational and maintenance costs are foreseen to be reduced significantly.

The deployment of the integrated ER+ tool showed an excellent understanding of the recorded corrosion rate, and temperature data and establishes the effectiveness of corrosion inhibitor treatments with improved battery life for better surveillance monitoring.
Real-Time Drilling Fluid Measurements Provide Value Via Data-Driven Decision Making for Cost-Sensitive Unconventional Environments
Authors: Petty W. , Offenbacher M. , Jara R. , Rabb C. , Unrau S.
Published: October 2023

A new approach to real-time automated drilling fluid measurement systems leads to enhanced collaboration and decision making between field and remote operations personnel. The approach is based on straight forward technology that can easily be understood by all, operated by field personnel, and robust enough for fast paced unconventional operations. The sensor information offers real-time actionable data without the demand to replicate the traditional daily mud report, streamlining wellsite activities for drilling fluid treatment as fluid conditions change.

The automated drilling fluid measurement system (mud skid) was designed for reliability and simplicity. The idea is to use trending data over the single data point mud check to drive real time decision making across teams. Rather than replace the fluids specialist on location it enhances their role to drive operational excellence and consistency in their day-to-day rig support. Everyday across multiple rigs, drilling fluids specialists use the data to adjust treatment schedules, optimize activities, and capture unplanned events as early as possible to lower treatment cost with the support of the remote operations center (ROC). The ROC's monitoring activities drive fluid enhancements across multiple locations via data transparency and analysis, sharing of best practices, and event detection. With a few proven and fit for purpose sensors, the mud skid adds value within the cost limits of the unconventional well market.

There is an opportunity for value generation via the use of economical drilling fluid sensors where costs traditionally limit full-scale automated drilling fluid measurements. The mud skid unit provides sufficient data to generate value without prohibitive expenses. The mud skid unit and the data collected are now part of standard operations across multiple rigs and basins. The data streams, available in real-time to everyone from the derrick hand to the drilling engineer, have created a new workflow for decision-making, fluid maintenance, trouble-shooting, and early event detection. As more events are captured by the sensors, there are additional opportunities to train machine learning algorithms and develop predictive models.

This paper will review the development process, deployment, and delivery of the mud skid unit with case histories demonstrating the advantages and opportunities for simple, real-time data streams.