bluuebunny/crossref_metadata_2025 huggingface dataset:
PACIENTES CARDIOVASCULARES COM COVID-19 EM TERAPIA INTENSIVA: UMA REVISÃO SISTEMÁTICA
Authors: Lee Barbara Mayumi Sansana , Alves Winnie da Silva
Published: September 2022

Resumo: OBJETIVO: Analisar na literatura, a prevalência de doenças cardiovasculares (DCV) e o desenvolvimento de disfunções cardíacas ou vasculares, em indivíduos internados em unidades de terapia intensiva (UTI), devido Covid-19. MÉTODOS: Revisão integrativa da literatura, realizada nas bases de dados BVS: BDENF e LILACS; PuBMED: MEDLINE; Web of Science e CINAHL. Critérios de inclusão: artigos na íntegra, em português, inglês ou espanhol, publicados a partir de 2019. RESULTADOS: Foram selecionados seis artigos e elencados três temas centrais: pacientes com DCV prévia; pacientes que desenvolveram doenças cardíacas ou vasculares durante a internação; e, pacientes que cursaram com alterações de biomarcadores de lesão cardíaca e de degradação de fibrina. Observou-se prevalência de DCV entre 0 e 29% dos estudos, como doenças coronarianas, arritmias, disfunções valvares e ventriculares, e a incidência de DCV entre 2,6 e 59%, apresentando alterações elétricas, funcionais, estruturais e choque cardiogênico. CONCLUSÕES: Identificou-se percentagem importante de pacientes com Covid-19, internados em UTI, que apresentavam DCV prévias e que desenvolveram DCV. Entretanto, até a finalização do presente estudo, não havia pesquisas em que 100% da amostra possuísse DCV prévia, o que seria importante para a compreensão dos possíveis acometimentos sob ela. Assim como, pesquisas que especificassem os tipos de acometimentos desenvolvidos, nomeados apenas como “lesões cardíacas” ou aumento de biomarcadores. Como limitações do presente estudo, ressaltamos que novas pesquisas foram realizadas após a sua conclusão, que certamente agregarão melhor conhecimento. Desta forma, mantém-se a preocupação da gravidade em que a Covid-19 pode acometer pessoas com DCV prévia e suas manifestações cardiovasculares.
Kebijakan APBN Khalifah Umar bin Khattab
Authors: Jajuli Suleman
Published: September 2022

Problem keuangan negara selalu menjadi permasalahan aktual, apalagi dalam ruang lingkup Indonesia, dari mulai besarnya belanja untuk kebutuhan para pejabat negara, pemasukan yang tidak seimbang dengan pengeluaran hingga masalah hutang luar negeri yang belum juga terbayar. Kebijakan berkenaan dengan Anggaran pendapatan Belanja Negara menjadi masalah hampir di seluruh negara, demikian juga yang terjadi pada masa Kekhalifahan Umar bin Khattab di Madinah. Banyaknya permasalahan keuangan negara memerlukan adanya tindakan yang efekstif dan efisien untuk menyelesaikannya.

Khalifah Umar bin Khattab adalah seorang kepala megara dalam sejarah islam yang telah berhasil mengatur bagaimana income suatu negara dapat ditingkatkan selain juga mengatur bagaimana keuangan negara agar tidak terjadi defisit.  Di natara kebijakan yang dilakukan oleh Umar bin Khattab adalah dengan mengoptimalkan zakat, kharaj, ushur, jizyah dan pendapat negara lainnya. Sedangkan dari pembelanjaan maka Umar bin Khattab melakukan kebijakan dengan melakukan pengeluaran demi pemenuhan kebutuhan hajat masyarakat banyak, pengeluaran sebagai alat retribusi kekayaan, pengeluaran yang mengarah kepada bertambahnya permintaan-permintaan efektif, pengeluaran yang berkaitan dengan investasi dan produksi dan    pengeluaran yang bertujuan menekan tingkat inflasi dengan kebijakan inetrvensi pasar.

Inti dari kebijakan ekonomi Khalifah Umar bin Khattab adalah mendorong masyarakat untuk beraktifitas ekonomi baik secara sendiri-sendiri atau kelompok tanpa bantuan Baitul Mall. Kedua, tindakan atau kebijakan untuk mendorong pertumbuhan ekonomi masyarakat dengan bantuan dana Baitul Mall.
PENGARUH KEPEMIMPINAN KARISMATIK TERHADAP ETOS KERJA STAKEHOLDER PADA PONDOK PESANTREN MODERN MAN ANA KECAMATAN PAMIJAHAN KABUPATEN BOGOR
Authors: Ihsan Muzhir Ihsan , Firdaus Maulana , Romli Moh
Published: September 2022

Maulana Firdaus (NIM: 1415.04.003). Effects of Charismatic Leadership on Stakeholder Work Ethics

This study aims to determine the effect of charismatic leadership on stakeholder work ethics. This research was conducted at Modern Man Ana Islamic Boarding School, Pamijahan District, Bogor Regency. The research method used is a type of inferential research with a quantitative approach with research subjects are the Principals of Modern Man Ana Islamic Boarding Schools and respondents of this study are all stakeholders of the Modern Man Ana Islamic Boarding Schools. Sampling is done by non-probability sampling technique that is with saturated samples. Data collection using the questionnaire method and unstructured interviews. Analysis of the data used in this study was a descriptive analysis of respondents, a descriptive statistical analysis of variables, an assumption test using the normality test, and a hypothesis test using simple linear regression analysis, the t-test and the coefficient of determination test (∆R2).

The results of the study which were processed using the SPSS computer program version 16.0 for windows showed that the results of hypothesis testing using simple linear regression analysis showed that charismatic leadership had a positive effect on stakeholder work ethics in Modern Man Ana Islamic Boarding School, Pamijahan District, Bogor Regency. This is evidenced by the beta coefficient (β) of 0.269 and a significance value of 0.034. The contribution of charismatic leadership influence to the work ethic of stakeholders of (∆R2) 0.168 or 16.8% (significant influence) can be proven by stakeholders and students have been able to achieve achievements that boast both academic and nonacademic.

The application of charismatic leadership to the work ethic of stakeholders in Modern Man Ana Islamic Boarding School, Pamijahan Sub-district, Bogor Regency is seen from 4 aspects of charismatic leadership implemented by the leadership of Modern Man Ana Islamic Boarding School in daily life, namely among them: ability, self confidence, confidence, and environmental sensitivity.

Charismatic leadership positively influences stakeholder work ethic at Modern Man Ana Islamic Boarding School, Pamijahan District, Bogor Regency. This is evidenced by the regression coefficient of 0.269, indicating that if charismatic leadership increases by 0.269; the stakeholder work ethic increases by 0.269; t count 2,249> t table 2.059 then H0 is rejected and H1 is accepted, so it can be concluded that the charismatic leadership variable (X) influences the stakeholder work ethic variable (Y). Significance value of 0.034 <0.05 then H0 is rejected and H1 is accepted, so it can be concluded that the charismatic leadership variable (X) influences the stakeholder work ethic variable (Y).
Analisis Faktor-Faktor yang Mempengaruhi Aksesibilitas UMKM terhadap Produk Pembiayaan Di Bank Umum Syariah (Studi di Kecamatan Pamijahan Bogor, Kabupaten Bogor)
Authors: Anita  , Thantawi Tubagus Rifqy , Suryani Ermi
Published: September 2022

ABSTRAK

Di Indonesia, Usaha Mikro, Usaha Kecil dan Usaha Menengah (UMKM) mempunyai peranan yang penting sebagai tulang punggung perekonomian Indonesia. Dalam mengembangkan usahanya, UMKM dihadapkan pada beberapa permasalahan. Diantaranya faktor SDM yang rendah, terbatasnya sarana dan prasarana, teknologi, faktor utama yang menghambat perkembangan UMKM adalah kurangnya permodalan dan terbatasnya akses pembiayaan. Proses pengembangan UMKM ini otomatis membutuhkan pendanaan yang banyak, sehingga banyak UMKM yang melakukan financing melalui kredit bank. Penelitian ini bertujuan untuk menganalisis faktor tingkat pendidikan, pengalaman usaha, omzet usaha, kepatuhan membayar pajak penghasilan, total asset dan jenis usaha untuk mempengaruhi aksesibilitas UMKM terhadap produk pembiayaan di Bank Syariah. Jenis penelitian ini bersifat penelitian kuantitatif pengambilan sampel berjumlah 150 responden dengan menggunakan teknik Tabachic & Fidell, teknik penentuan sampel dengan menggunakan teknik simple random sampling. Metode analisis data menggunakan regresi linier berganda. Hasil penelitian uji t menunjukkan bahwa masing-masing variabel independen yaitu tingkat pendidikan, pengalaman usaha tidak berpengaruh positif dan signifikan. Sedangkan omzet usaha, kepatuhan membayar pajak penghasilan, total asset dan jenis usaha secara parsial berpengaruh positif dan signifikan. Hasil uji F menunjukkan bahwa terdapat pengaruh positif secara simultan antara variabel tingkat pendidikan, pengalaman usaha, omzet usaha, kepatuhan membayar pajak penghasilan, total asset dan jenis usaha terhadap aksesibilitas.

Kata kunci : tingkat pendidikan, pengalaman usaha, omzet usaha, kepatuhan membayar pajak penghasilan, total asset, jenis usaha dan aksesibilitas UMKM
ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI PEMILIK TOKO BANGUNAN UNTUK MENGAJUKAN PEMBIAYAAN DI BANK SYARIAH (STUDI DI KECAMATAN PAMIJAHAN DAN KECAMATAN CIBUNGBULANG BOGOR)
Authors: Febtianda Nadia , Trihantana Rully , Anwar Miftakhul
Published: September 2022

ABSTRACT

The purpose of this study is to know the factors affecting the building store to raise financing at the Islamic bank. This thesis is localized in promotion, confidence and environment. The respondens in this study are proprietors of building store. The sample used in this study was 30 respondents. The sampling technique used was non probability sampling with a purposive sampling method. The T test concludes that what affected the building store decision to apply a financing at the Islamic bank was confidence ( T count -2,710, sig. 0,038) and the environment (T count -2,185, sig. 0,012) while promotion no affect the building store decision to apply financing in Islamic bank because it has a value of T count -1,549 < T table +- 1,705 and sig. 0,133 > 0,05. Whereas the result of the study on the F with a value of 4,115 and significant value of 0,016 wich more than F table 2,98 and its significant value 0,05 can be concluded that promotion, confidence, and the environment together influence the building’s decision to propose financing at the Islamic bank. And The result of coefficient research determination has concluded that the impact of promotion, confidence, and environment on the hardware store decision to raise financing at a islamic bank is 22,4%.

 

Keywords: Promotion; Confidence; Environment; Decisions; The building store
STRATEGI PENGEMBANGAN WIRAUSAHA SYARIAH DI KALANGAN MAHASISWA INSTITUT AGAMA ISLAM SAHID BOGOR
Authors: Ambri Saepul , Thantawi Tubagus Rifqy , Kharis Mubarok Mohamad
Published: September 2022

Penelitian dilatarbelakangi karena angka pengangguran pada negara Indonesia semakin meningkat, cara memperkecil jumlah pengangguran yaitu dengan berwirausaha, dalam Al-qur’an Allah SWT memerintahkan berwirausaha secara syariah seperti yang dicontohkan rasulullah. Institut Agama Islam Sahid Bogor merupakan salah perguruan Tinggi yang mengharuskan mahasiswanya untuk berwirausaha syariah, namun jumlah mahasiswa berwirausaha masih sedikit karena sebagian mahasiswa tidak begitu tertarik untuk berwirausaha, dari itu dibutuhkalah strategi dalam pengembangan wirausaha syariah pada mahasiswa. Jenis penelitian bersifat deskriptif kualitatif, informan penelitian mahasiswa Kampus Institut Agama Islam Sahid Bogor dengan metode pengumpulan data observasi, wawancara dan dokumentasi adapun analisis data penelitian yaitu analisis SWOT pada kekuatan, kelemahan, peluang dan ancaman lingkungan internal dan eksternal. Berdasarkan hasil penelitian strategi yang dapat diterapkan dalam pengembangan wirausaha syariah adalah lebih meningkatkan sumber daya manusia dalam pemberian ilmu wirausaha syariah, menyediakan fasilitas penunjang dalam kegiatan berwirausaha seperti usaha yang dapat dikelola mahasiswa, serta memberikan dukungan dengan mendirikan koperasi yang dapat membantu permodalan kegiatan mahasiswa berwirausaha.
PEMBERDAYAAN USAHA KONVEKSI DAN PENGENALAN AKSES KE PEMBIAYAAN SYARIAH DI DESA GUNUNG BUNDER II, KECAMATAN PAMIJAHAN, KABUPATEN BOGOR
Authors: Oktavia Tasya Audina , Trihantana Rully , Anwar Miftakhul
Published: September 2022

The purpose of this service is to prevent the transmission of the COVID-19 virus and convection business empowerment to residents who will take part in posyandu activities in Gunung Bunder II village by distributing cloth masks and providing hand sanitizer. The method of implementing this activity begins with distributing cloth masks to residents who come to the posyandu who do not use masks, then giving directions to implement health rules for residents who come to the posyandu to avoid the virus. From this activity, it is hoped that the use of cloth masks and hand sanitizers as well as directives and guidance on COVID-19 can break the chain of transmission of COVID-19 and increase public awareness and vigilance against the COVID-19 virus by training them to get used to implementing health protocols.

Keywords: Empowerment of Confection Business, Implementation of Health Protocol, Posyandu
PENGENALAN MANAJEMEN BISNIS SYARIAH MELALUI PENGEMBANGAN USAHA MIKRO KECIL DAN MENENGAH DI DESA CIMANGGGU I, KECAMATAN CIBUNGBULANG, KABUPATEN BOGOR
Authors: Syamsul Ma’arif Muhamad , Buchori Muslim Ujang , Shiddieqy Hasbi Ash
Published: September 2022

Abstract

Spinach is a highly nutritious vegetable ingredient and is loved by all levels of society. Cimanggu I Village is one of the villages in Cibungbulang District, where most of the residents' livelihoods are in the agricultural sub-sector. One of the home industries in the area is the PKK women's group. These groups are cadres who work in the village to improve the field of business in Cimanggu I Village. The community service method is providing training to farmer groups or PKK cadres in Cimanggu I Village is a participatory method, which involves as many partners as possible in participating in discussion and practice activities that produce products. After doing this community service in the form of training on making spinach chips by partners or the community in Cimanggu I Village, they can find out that spinach that is not selling well and is still good or excessive from the harvest can be processed into spinach chips. These spinach chips can be easily managed as complementary foods and snacks, which were recently held in Cimanggu I Village. Apart from being beneficial for health because of their high nutritional content, they can also be made as souvenirs that can increase farmers' daily income. And also with this training, it is able to help create business opportunities or be able to develop businesses for the people in Cimanggu I Village.

Keywords: Spinach, Micro, Small and Medium Enterprises Development, Sharia Business Management.
MENYELARASKAN PEMBERDAYAAN BANK SAMPAH BERBASIS TEKNOLOGI DENGAN MANAJEMEN BISNIS SYARIAH DI DESA CIBITUNG WETAN, KECAMATAN PAMIJAHAN, KABUPATEN BOGOR.
Authors: Baibars Mugi Komara , Thantawi Tubagus Rifqy , Putra Bayu Purnama
Published: September 2022

Abstract

The introduction of a waste bank in Cibitung Wetan Village, Bogor Regency, West Java has been socialized in 2021. This is based on the accumulation of garbage in the village due to the public's reluctance to spend money every month for transporting waste from the cleaning service. The existence of this activity in community empowerment is to strengthen the management of the Waste Bank 'Seroja Kahuripan' so that it has a clearer structure and division of labor, the number of waste bank customers has increased to 57 people, the post for weighing the waste bank with various supporting tools and additional income of around >200,000 -300,000/year/person. The improvement in the skills of waste bank members is felt through various trainings that have been carried out such as: sorting organic and inorganic waste, training on inorganic waste management, especially the use of glass bottles and plastic crackers, training in making processed product packaging, utilizing organic waste by planting nutritious vegetable gardens and managing waste banks. manually and digitized via software. The use of technology as a result of downstream research through computerized waste bank applications makes it easier to carry out waste bank administration which is routinely carried out every two weeks. The results of the partner satisfaction questionnaire show that waste bank respondents are very satisfied with this application because it can help with various obstacles ranging from the transaction recording process, weighing waste, errors in inputting data from weighing results to avoiding suspicion between officers and customer.

Keywords : Waste Bank, Technology, Village Empowerment
Sztuczna inteligencja a godność człowieka
Authors: Kuciński Mariusz
Published: September 2022

„Sztuczna inteligencja zmienia sposób, w jaki robimy wszystko”
Rozwój i szybkie rozszerzanie się sztucznej inteligencji powoduje zmianę w postrzeganiu i poznawaniu świata. Coraz częściej rodzi to nowe problemy natury moralnej. Efekt ten związany jest z ogromnymi możliwościami innowacji technologicznych i przemiany społecznej. Artykuł ten pragnie podjąć próbę odpowiedzi na coraz częściej stawiane pytania. Co znaczy być człowiekiem w epoce obecnych zmian? Czy i jak możemy kierować rozwojem technologicznym? Czy są jakieś ograniczenia, których nie da się przekroczyć w czasach, gdy technologia zaczęła być używana nie tylko do interwencji zewnętrznych, ale i wewnętrznych na człowieku.
An Attachment Model for Assessing Suicidal Risk
Authors: Hope Keely , Smith-Adcock Sondra
Published: September 2022

A model for addressing suicidal risk utilizing attachment theory is addressed. Risk factors for suicide have generally been conceptualized at the level of individual characteristics rather than relational dynamics. Combining Shneidman’s common characteristics of a suicidal person with Bowlby’s attachment theory provides for a more relational view of suicide-related behaviors and communications. Considering high rates of suicide, especially among some population groups, it is important to have a more comprehensive framework for suicidal risk from which to treat suicidal clients.
On station performance evaluation of local honey bee colonies traits (Apis mellifera scutellata) in Gedeo zone, Ethiopia
Authors: Dinku Negash
Published: September 2022

In Ethiopia, despite the potential of apicultural resource, production and productivity are relatively low. This could be due to many factors like management, environmental factors and races of honeybees. The aim of this study was to evaluate productive potentiality trait of local honeybee colonies for further colonies multiplication purpose. We obtained 20 selected strong honeybee colonies from local beekeepers within traditional hives and transferred into movable frame hive at Dilla site. All the transferred colonies were managed properly to establish themselves and acquire uniform strength. These colonies were evaluated for different parameters such as hygienic behavior, brood, pollen and nectar area, swarming and absconding tendency at different season. The result indicated that the mean percent removal per colony varied from 86.57 (February) to 99.62 (August). The highest brood rearing activity was observed in September and March that covered up to 148.9±14.16 unit areas while the least was observed during November (1.19 ±0.43) unit area. Maximum pollen and nectar area was found in October (97.5±12.40) unit area and April (81.88±9.47) unit area. While minimum pollen area (5.25±7.13) unit area and nectar (1.10±0.1) area was occupied in November. In general, the study showed that A. m. scutellata honeybees are good in hygienic behavior and brood rearing performance under optimum management practices in the study area. On average 25% of absconding was observed at study site over the last two years of the study period at the time of pollen and nectar shortage mainly November and May Therefore, it is recommended to investigate its detail behavioral aspects whether it is due to environmental or genetically factor for future selection and improvement.
SUPER-EDGE MAGIC TOTAL LABELING IN CERTAIN CLASSES OF GRAPHS
Authors: Jegan R. , Vijayakumar P. , Thirusangu K.
Published: September 2022

Duplicate graph of a graph is constructed from a graph with vertex set V of p vertices and edge set E of q edges as a new graph with vertex set union of V, V 0 where V 0 is a set disjoint with V having p vertices such that uv is an edge in the graph G if and only if uv0 and u 0 v are the edges in its duplicate graph. Superedge magic total labeling of a graph is a bijection which labels the vertices with integers 1 to p and edges with integers p + 1 to p + q such that the induced edge sum of edges defined as “sum of labels of end vertices and label of that edge” are all same. In this paper, we provide algorithms and prove existence of super-edge magic total labeling in extended duplicate graphs of twig, comb, star and bi-star graphs.
A DESIGN OF SPECIAL PURPOSE DOUBLE SAMPLING PLAN OF TYPE DSP(0, 1) USING FUZZY PARAMETER
Authors: Priya P. Kavi , Ramaswamy A. R. Sudamani
Published: September 2022

In traditional sampling plan, the proportion defective is generally assumed to be crisp value. But, in real life parameters are vague and assumptions are too rigid. So traditional methods are inaccurate. In this paper Fuzzy set theory is applied to acceptance sampling. A procedure for designing Special Purpose Double Sampling Plan of Type DSP(0, 1) using trapezoidal fuzzy number is developed and it is based on fuzzy binomial distribution. The OC curve values are determined using fuzzy parameter while fixing the sample size. Fuzzy probability of acceptance values are calculated for different AQL ] and LQL ] values and are presented in Tables for the selection of DSP(0, 1) Plan. Optimum value of the sample size is obtained such that it satisfies both the condition of producer’s risk and consumer’s risk for given AQL ] and LQL ] values. The sample size is obtained such that it minimizes the sum of risks. Numerical examples are provided for the illustrations.
Instrumentos náuticos contidos em tratados portugueses e espanhóis produzidos entre os séculos XVI e XVIII para articulação entre história e ensino de Matemática
Authors: Batista Antonia Naiara de Sousa , Pereira Ana Carolina Costa
Published: September 2022

Nos séculos XVI a XVIII diferentes tratados foram produzidos envolvendo aspectos relacionados a astronomia, astrologia, cosmografia, a produção de instrumentos, entre outros, com vista a disseminar conhecimentos que seriam de grande utilidade na navegação astronômica. Assim, esse estudo tem como intuito apresentar alguns instrumentos náuticos atrelados a tratados português e espanhóis, que podem se tornar potencialmente didáticos para a articulação entre história e ensino de matemática. Os instrumentos destacados neste estudo, vieram à tona a partir de leituras iniciais referentes as produções de Luís de Albuquerque, Margarida Matias Pinto, Bernadete Barbosa Morey e Iran Abreu Mendes. Nelas, se pode encontrar instrumentos como, o quadrante, o astrolábio, a balhestilha, entre outros, que faziam uso em suas medições da Estrela Polar ou do sol para ajudar no direcionamento dos navios em alto mar. Partindo disso, pode-se fazer um breve levantamento de alguns tratados português e espanhóis, nos quais esses instrumentos estavam presentes. Esses documentos contêm geralmente a fabricação e/ou o uso de tais instrumentos, que se tornam ricos e complexos em sua essência porque incorporam saberes de ordem contextual, epistemológica e matemáticas do período em que se encontravam em produção, e que podem ser utilizados para dialogar com a matemática que temos no século XXI. Portanto, esse estudo visa contribuir para ampliar o conhecimento de professores sobre instrumentos náuticos que podem ser atrelados as aulas de matemática para potencializar o ensino.
Study on Cement Sheath Integrity of Shale Oil Horizontal Wells in Northeast China
Authors: Liu Penglin , Li Jun , Qi Yue , Tian Yudong , He Long , Liu Wei
Published: September 2022

Shale oil in northeast China is about to enter the stage of large-scale hydraulic fracturing. Cement sheath integrity must be ensured for horizontal shale oil wells. In this paper, the mechanical parameters of cement sheath are measured. A numerical model of casing - cement sheath - formation assembly is established to analyze the stress law of cement sheath. The integrity of the cement sheath is analyzed. The results show that the elastic modulus of cement is 6 GPa and the Poisson’s ratio is 0.17. The compressive strength and tensile strength of cement after cyclic loading are 90MPa and 7.5mpa ~ 11.25mpa respectively. The maximum radial stress of cement sheath increases with the increase of fracturing pressure, the decrease of displacement, and the increase of elastic modulus. The maximum tangential stress of cement sheath increases with the increase of fracturing pressure and elastic modulus of cement. The tensile strength of cement sheath cannot meet hydraulic fracturing requirements. The elastic modulus of cement should be reduced to 4 GPa or the tensile strength should be increased to be higher than 15 MPa. This study would guide the shale oil wells in northeast China.

1. INTRODUCTION

As hydraulic fracturing technology matures and international oil prices recover, more and more unconventional oil and gas resources are being developed, such as shale gas, conglomerate reservoirs, and shale oil. In particular, shale oil resources are becoming a new direction of exploration and development of unconventional oil and gas resources in China. Shale oil has been developed scaled in Jimsar block, in Inner Mongolia, and Tianjin district. At the same time, shale oil resources have been successfully explored in northeast China and will soon enter the stage of large-scale development.

Based on the development experience of shale gas and other unconventional oil and gas resources over the past few years, casing deformation and sustained casing pressure are the most common problems in horizontal wells during multistage fracturing (Adams, 2017; Atkinson, 2020; Chaojie Zhao, 2020; Xi Yan, 2021.). Well integrity issues have a significant impact on the safety and production of horizontal wells. Fig. 1 shows the casing deformation logging results of Wel-Wei204H39-6 in the Weiyuan block and Well-JHW033 in Jimsar Block, Xinjiang respectively. Logging results showed casing deformation in both wells. One of the wells is a shale gas horizontal well and the other is a shale oil horizontal well. Thus, shale oil wells face the same well integrity issues as shale gas wells.
An Efficient Simulator for Microseismic Mapping of Fracture Networks
Authors: Cao M. , Sharma M. M.
Published: September 2022

Microseismic monitoring has been developed to characterize fracture geometry. However, the results for fracture characterization can be incomplete due to interpretation and inversion methods that are limited by a lack of integrated geomechanical models. In the paper, a geomechanical microseismic simulator which includes natural fractures is developed to: (1) quantify the magnitude and capture the spatiotemporal distribution of induced microseismicity (MS), (2) evaluate the evolution of MS events along the vertical direction, (3) better account for the effect of noise, and (4) better interpret the MS data using a fully integrated 3-D geomechanical model. The results for spatiotemporal distribution of MS show that the locations of registered events tend to be consistent with those of planes of weakness prone to be reactivated due to failure. The vertical variation in MS events provide an efficient way to monitor vertical fracture growth. MS events generated by isolated fractures cause an over-estimation of the spatial extent of the fracture network that contributes to production. A similar effect is seen with seismic noise that can also lead to an over-estimation of the fracture network. Quantifying these over-estimations helps to improve mapping of the connected fracture network that is likely to contribute to production.

1. INTRODUCTION

Hydraulic fracturing has been successfully employed in unconventional reservoirs in pursuit of increasing hydrocarbon production. Microseismic events are generally induced during hydraulic fracturing treatments. The monitoring of microseismic events provides an effective tool to estimate the geometry of the created hydraulic fractures and the reactivated natural fractures. A model that can enable us to improve fracture diagnostics and perform it more efficiently is developed and presented in this paper.

Numerous studies have been conducted to investigate induced microseismic events during hydraulic fracturing operations over the past decades. These include, lab and field experiments, machine learning techniques, and numerical simulations.
Optimization of Reinjection Fluids of Oil-Based Drilling Cuttings
Authors: Sun Mengying , Deng Jingen , Feng Yongcun , Gui Yun
Published: September 2022

Oil-based drilling fluid will produce a large amount of oil-based drilling cuttings with complex composition and pollution factors. Cuttings reinjection technology, as an effective method to treat oilfield wastes, has gradually become a preferential choice for the treatment of oil-based drilling wastes in offshore oilfields. In order to increase the efficiency of cuttings reinjection, an oil-based drilling cutting slurry system was developed through a series of experimental studies. The final optimized cutting slurry has a formula of drilling cuttings content of 15%-35%, guar gum and Xanthan gum compounded in a ratio of 4:3 as the main additives, with 0.33% filter loss agent and 0.23% defoamer. The experimental results show that the viscosity of the cuttings slurry system is 55 mPa·s, the viscosity of the Marsh funnel is 93 s, and the suspension stabilization time can reach 24 h. The sedimentation density difference is 0.137 g/cm3. At a temperature of 70 °C, The overall performance of the optimized cutting slurry satisfies the requirement of the operator, and can overcome the issues of perforation hole blockage, cuttings bed accumulation, fracture tip deposition, commonly caused by the insufficient suspension ability of the injection slurry.

1. INTRODUCTION

Oil-based drill cuttings contain organic compounds such as diesel (white oil), polycyclic aromatic hydrocarbons, chemical additives, etc., which are complex in composition, many pollution factors, and difficult to handle. Any carelessness will affect the ecological environment such as soil, water quality, the environmental protection of oil-based drill cuttings has become one of the important tasks in the oil and gas drilling industry (Mckay et al. 1991). Solidification, bioremediation, incineration or different chemical and mechanical treatments were used in the treatment of drilling waste, but this requires a lot of storage space, a large site. It will greatly increase the costs. Therefore, there is an urgent need for an economic and sustainable treatment of oilfield waste (Arfie et al. 2005, Reed et al. 2002).
Numerical Simulation of Multi-Fracture Non-Uniformly Propagating in Shale Oil Reservoir Using a Fully Coupled THM-XFEM Model
Authors: Luo Zhifeng , Cheng Long , Zhao Liqiang , Xie Yaozeng
Published: September 2022

The multi-cluster fracturing in horizontal well has become the most effective stimulation technique for development of shale oil reservoir. The multi-fracture with uniform morphology that distributes densely along horizontal wellbore is the key to realize the high production. However, affected by the heterogeneity of stress and properties among stage, stress interference and non-uniform fluid partitioning, non-uniform propagation usually occurs in multi-cluster fracturing, which highly limits stimulating effect. In this study, multi-fracture non-uniformly propagating in shale oil reservoir is modelled using a thermal-hydro-mechanical coupling model. The non-isothermal fluid flow in matrix and fracture, slurry flow for proppant transport in fracture, thermoelastic and poroelastic deformation are taken into account. Spatial discretization and temporal discretization are conducted by extended finite element method and finite difference method, respectively. A case of multi-fracture non-uniform propagating in shale oil reservoir of Sichuan Basin is discussed. The simulations show that the non-uniform fluid partitioning will be aggravated when injecting fracturing fluid with higher viscosity. Comparing with large particle size, a uniform distribution of proppant and high propping efficiency can be obtained when using a small particle size.

1. INTRODUCTION

In shale oil reservoirs development and stimulation, multi-cluster fracturing is an efficient and widely used stimulation technique to improve oil productivity. Ideally, the multiple hydraulic fractures with relatively uniform morphology and size will be obtained. However, it is found that multi-fracture non-uniformly propagation and non-uniform fluid partitioning occur in multi-cluster fracturing in shale oil reservoirs according to the fiber optic monitoring data and coring inspection (Raterman et al., 2018). The non-uniform fracture morphology shall highly affect proppant transport and fracture conductivity later, which will influence the stimulation productivity. Therefore, it is essential to gain a comprehensive understanding of mechanism of multi-fracture non-uniformly propagating during multi-cluster fracturing in shale oil reservoirs. Numerical modelling is an accurate way to simulate the complex processes.
The Influence of Elliptical-Geometry Wellbore on Zonal Isolation
Authors: Zheng D. , Miska Z. , Ozbayoglu E. , Zhang Y.
Published: September 2022

Zonal isolation is key to the safety of drilling, injection, and production. If zonal isolation fails, significant financial losses or environmental damage can occur. Cement integrity is critical to maintain zonal isolation. The objective of this paper is to study the influence of wellbore shape on cement sheath integrity and zonal isolation. To diagnose cement sheath integrity, cylindrical wellbore models which contain circular-shape casing, cement, and formation layers have been built. However, the wellbore geometry in real drilling process is elliptical instead of circular. In this study, we built an elliptical-geometry Casing-Cement -Formation System (CCFS) analytical model by applying complex variable method. Two case studies were performed with the elliptical-geometry CCFS model and circular-shape CCFS model that does not consider the wellbore shape factor.

1. INTRODUCTION

Quality of cement is an integral part of well integrity. The change of downhole condition and post well site operation may lead to change of the stress-strain state of casingcement- formation system (CCFS) [1]. Cement sheath failure is manifested by inter zonal annular fluid movement and abnormally high annular pressure at some point behind casing up to and at the surface [2]. The detrimental effects of cement sheath failure are numerous and may cause lost revenue from lost production, potentially hazardous rig operations and producing operations. Losing zonal isolation may lead to contamination of freshwater table [3]. To understand the failure behavior of cement is significant for maintaining zonal isolation.

Previous research has built analytical/numerical models for predicting the stress distribution around the circular wellbore [4] [5]. However, wellbore geometry in real drilling process is elliptical instead of circular. The geometrical irregularities can result from a combination of geology and/or drilling/completion operations [6]. Two reasons that may cause elliptical geometry were listed here: 1) Tilt angle is the angle between the centerline of the hole and the centerline of the bit. Figure 1 is a simple sketch of tilt angle. The red line shows the plane that is perpendicular to the hole axis. The geometry for this plane is elliptical because of tilt angle.
Influence of Grain Structure Representation on Bonded Block Models of a High Porosity Rock
Authors: Chaurasia A. , Walton G.
Published: September 2022

With the increased adoption of numerical modeling in the last two decades, it is now possible to study rock mass deformation and failure using tools such as FEM (Finite Element Method), DEM (Discrete Element Method), and FDEM (Finite Difference Element Method). Bonded Block Models (BBMs) are a type of DEM that can be used to simulate rock at both the laboratory and field scales. However, limited studies have been performed on high porosity rocks (porosity > 15%) using BBMs. This research focuses on the generation of a 2-Dimensional 27% porosity BBM model for a large-scale Texas Cream Limestone specimen using two different approaches. The first approach uses the software Neper, which uses the block size distribution, distribution type, and circularity to generate a convex polygonal block structure; to achieve 27% porosity, some blocks are removed from the structure ensuring that each block has at least one contact. The second approach uses PFC to generate circular balls with a bimodal size distribution to achieve an initial 12-15% intrinsic porosity; an algorithm in MATLAB is then utilized to convert this into a polygonal structure, and the removal of additional small blocks increases the porosity to 27%. Following initial model calibration, model results are used to understand the effects of different block and pore structures on the emergent behaviors of the BBMs.

1. INTRODUCTION

Underground mine pillars provide natural stability to the mine area allowing for safe operations. If the load on a pillar exceeds its strength, it will fail and can increase the risk of subsidence, roadway blockage, worker injuries, air blast, etc. Therefore, a sound knowledge of pillar failure mechanisms is necessary to design stable pillars under different loading and geologic conditions. Empirical pillar design approaches provide a reliable and straightforward option for the preliminary design of hard and soft rock pillars. However, these empirical approaches have some limitations that need to be addressed, such as their inability to explicitly account for post-peak behavior and rock-support interaction. Large-scale laboratory tests offer a potential alternative approach to study pillar behavior, but such tests are expensive, time consuming, and difficult to conduct in practice (Bieniawski, 1968; van Heerden, 1975). With the advent of high performance computational software, it is now possible to use numerical modeling tools to study rockmass deformation and mechanical behavior in various geological conditions. This study considers a scenario where limited large-scale laboratory testing results can be used to constrain numerical models, which in turn can be used to study rock pillar failure mechanisms and rock-support interaction.
Experimental Study on the Causes and Protective Measures of Hydrogen Sulfide in Formation and Wellbore
Authors: Qi He , Guangsheng Cao , Daye Wang , Yongcun Feng , Jingen Deng , Zhiyi Zhou
Published: September 2022

The generation of H2S (hydrogen sulfide) in formation and wellbore is a significant cause that results in natural disasters, wellbore corrosion, and personal safety. It is essential to study the generation causes and precautions of H2S to avoid harmful gas damage. BSR (bacterial sulfate reduction) and TSR (thermochemical sulfate reduction) experiments have been discussed based on different reaction environments and conditions of H2S. It has been demonstrated that BSR is the primary cause and TSR is the secondary cause of the H2S generation in the studied fractured wells. The existence of SRB provides a premise for the occurrence of BSR. The pH value of solutions will affect SRB activity and H2S generation quantity. The reaction temperature will affect whether TSR occurs and the amount of H2S generation. The reaction pressure only affects the occurrence time of H2S in TSR, but hardly affects the generation quantity. Furthermore, the replacement of fracturing fluid formula, NaOH, bactericides and high temperature steam can be used to inhibit the generation of H2S in the formation and wellbore. This study has a certain reference value and suggestions on the causes, influencing factors, laws and prevention methods of H2S in oil reservoir.

1. INTRODUCTION

Hydraulic fracturing is one of the most significant technical issues to improve underground flow environment and increase the well production in petroleum engineering. It has made great achievements in the field of rock mechanics in recent decades(Atkinson, 2015; Hubbert & Willis, 1957). In the process of hydraulic fracturing, fracturing fluid needs to be injected to extend fractures and transport proppant into the fractures, so that more fluid channels can be kept open for a long time(Gandossi & Von Estorff, 2013). However, use of fracturing fluid with certain composition in some oil and gas fields may generate toxic gas and endanger personal safety(Michalski & Ficek, 2016). Taking Daqing Oilfield in China as an example, hydrogen sulfide (H2S) has been detected from some fractured wells, and the value has greatly exceeded the allowable safety range (150 mg/m3 for H2S). Furthermore, the presence of H2S will also corrode wellbore and bring environmental risk because of its sour corrosivity(Hedges, Chen, Bieri, & Sprague, 2006; Holubnyak et al., 2011). Hence, the generation source, influencing factors and elimination measures of H2S generated from the formation or the wellbore ought to be found out immediately.
A Comparison Between Field-Measured and Empirically Estimated Rock Mass Modulus Values
Authors: Lindenbach E. J. , Dalton S. C. , Bearce R. G. , Arany G. D.
Published: September 2022

Rock mass modulus, also referred to as the deformation modulus, is an important input variable for any load-deformation analysis of a foundation, such as a finite-element analysis for a dam. As the representative volume of rock is increased the rock mass will appear weaker and more deformable due to the inclusion of more discontinuities. The rock mass modulus can be measured directly downhole with a variety of devices, such as a uniaxial or radial jacking rig, a flat jack, or more commonly, a dilatometer. Modulus values can be estimated indirectly using site-specific empirical relationships.

This paper provides a comparison of field- and laboratory-derived rock mass modulus values in an effort to develop a range of likely parameters and evaluate data quality/confidence levels. The in-situ values were compared to values developed from eight commonly used empirical relationships. Results indicate that the dilatometer-measured and empirically estimated values are similar where the rock is massive and relatively intact but vary significantly where the rock is fractured or weathered. These significant variations appear to be related to how the rock deforms in unconfined/semi-confined conditions (i.e., failure occurs into open space).

1. INTRODUCTION

The deformation modulus of the underlying rock mass is an important input variable for any load-deformation analysis of a foundation, such as a finite-element analysis for a dam. The deformation modulus of a rock mass is subject to the scale effects typically found in any rock mechanics analysis. An in-situ rock mass may have a modulus that is a fraction of the intact modulus of specimens tested in a laboratory due to the heterogeneous nature of the mass and presence of discontinuities (fractures, joints, faults, etc.) that serve as planes of weakness. Variability of these rock mass properties can result in wide ranging modulus values for discrete test intervals (in-situ and laboratory). In general, as the scale of the rock mass being analyzed is increased, the number of weaknesses increases and the rock mass will appear weaker and more deformable (Wyllie and Mah, 2004). Both deformation modulus and rock mass modulus terms imply load deformations in the elastic and inelastic ranges (Ulusay and Hudson, 2006).

Developing a range of values for model inputs is important as a lower foundation modulus is not necessarily more conservative; the "softer" foundation may allow more transfer of dam load to the abutments and can also lead to increased damping during an analysis of seismic stability. Performing the load-deformation analysis with a variety of rock mass modulus inputs allows a reduction in uncertainty regarding a dam’s reaction under static or seismic loads. The sensitivity of any design to changes in the inputs is likely more critical than any discrete calculation of anticipated deformation or stability (Hoek and Diedrichs, 2006).
Analysis of Concentration Field in Underground-Storage Salt Cavern Using Two-Well-Vertical Solution Mining
Authors: Guan Yueyang , Ban Fansheng , Wang Xiaoyang , Chen Chunyu
Published: September 2022

The well spacing and the brine concentration are crucial for the volume and morphology of the two-well salt cavern gas storage by affecting dissolution rate of the cavity. However, it is hard to directly monitor the brine concentration inside the cavity. This study uses the classical method of Navier-Stokes, based on which the three-dimensional mathematical model of Two-Well-Vertical solution mining is established. Using Semi-Implicit Method for Pressure Linked Equations (SIMPLE) algorithm to solve the concentration distribution, while using Volume of Fluent (VOF) algorithm to solve the movement of boundary, so as to research the variation of cavity shape. According to the simulation results, it can be concluded that the region with the brine concentration of 210 g/L – 270 g/L is the key to enlarge the cavity volume in the connectivity stage. Compared with single-well salt cavern gas storage, two-well salt cavern gas storage mainly expands along the connection direction of two wells. The well spacing of 50 m can increase the maximum cavity diameter by nearly 78% compared to that of 10 m. With the increase of well spacing, the final cavity shape will change from cone shape to hump shape, however, the large well spacing may affect the cavity forming efficiency.

1. INTRODUCTION

There are more than 800 underground gas storage facilities in the world, and the total capacity is close to 450 billion cubic meters (Caineng Zou et al. 2020). Among them, salt cavern gas storage is the main technology for natural gas storage due to its lower permeability, higher gas injection efficiency and less gas consumption of cushion. However, Considering the number of salt cavern gas storage, the storage volume of salt cavern gas storage is much smaller than other underground gas storages. Therefore, accelerating the construction and increasing the volume of salt cavern gas storage are the most dominant approach to improve the competitiveness and economy. The construction of salt cavern gas storage mainly uses the salt layer of certain depth to dissolve. When the string reaches a predetermined depth, fresh water is injected to dissolve the salt layer, forming a storage space for natural gas.

Up to now, a series of experiments and theoretical studies have been carried out about salt cavern underground gas storage. Menezes, J. D. et al. applied mixed boundary and finite element methods to numerical simulations of salt caverns, in order to study the state of natural gas in underground rock salt (Menezes, J. D. and Nguyenminh, D. 1996). The ground subsidence and cavity dissolution were analyzed by comparing the numerical simulation results with actual data.