bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pengaruh Kinerja Mengajar Dosen Terhadap Kepuasan Belajar Mahasiswa Program Studi Pendidikan Teknik Bangunan Fakultas Teknik UNJ
Authors: Listyaningrum Devita , Handoyo Santoso Sri , Murtinugraha R. Eka 
Published: January 2019

Penelitian ini bertujuan untuk mengetahui pengaruh antara kinerja dosen dengan kepuasan belajar mahasiswa terhadap program studi Pendidikan Teknik Bangunan Fakultas Teknik Universitas Negeri Jakarta. Penelitian dilakukan di Program Studi Teknik Bangunan. Jurusan Teknik Sipil FT UNJ pada bulan April-Mei 2016.
Metode penelitian ini menggunakan metode deskriptif korelasional. Populasi dalam penelitian ini adalah 232 orang dan sampel ditentukan dengan metode simple random sampling yang dihasilkan 90 orang. Instrumen yang digunakan adalah kuesioner untuk mengumpulkan data tentang kinerja dosen pengajar dan kepuasan mahasiswa PTB UNJ FT. Pengolahan data valid dan dapat diandalkan. Nilai reliabilitas sangat tinggi dengan nilai r11 = 0,97 pada kuesioner kinerja dosen pengajar dan r11 = 0,91 pada angket kepuasan belajar mahasiswa dengan pertanyaan sebanyak 30 item.
Berdasarkan penelitian ini disimpulkan bahwa ada pengaruh antara kinerja dosen pengajar terhadap kepuasan belajar mahasiswa yang didapat dari t hitung 6.955 lebih besar dari t tabel adalah 4,463 dan nilai siginifikasi adalah 0,00 yang berarti nilainya kurang dari 0,05 kemudian menyatakan variabel independen mempengaruhi variabel dependen yang berarti bahwa kinerja dosen mempengaruhi kepuasan belajar mahasiswa. Kinerja dosen pengajar bukan merupakan faktor mutlak yang mempengaruhi kepuasan belajar mahasiswa untuk tingkat keberhasilan mahasiswa tetapi dilihat juga dari mahasiswa dalam melaksanakan kewajiban belajar sebagai mahasiswa.
Evaluasi Pelaksanaan Program Prakerin Berdasarkan Pedoman Prakerin di SMKN 3 Depok Program Keahlian Batu & Beton
Authors: Anugerah Dwi , Daryati Daryati , Saleh Rosmawita 
Published: January 2019

Penelitian ini bertujuan untuk mengetahui kesesuaian pelaksanaan prakerin terhadap pedoman dan kendala yang terjadi pada pelaksanaan program praktik kerja industri berdasarkan fakta lapangan di SMKN 3 Depok yang mencakup: (1) pelaksanaan persiapan prakerin: (a) penandatanganan MoU, (b) pengajuan surat DUDI, (c) pendataan siswa diterima prakerin, (d) pembekalan prakerin; (2) pelaksanaan prakerin peserta didik: (a) tugas dan kewajiban peserta didik, (b) tugas dan kewajiban pembimbing; (3) pelaksanaan evaluasi prakerin: (a) penyusunan laporan prakerin, (b) uji karya tulis laporan prakerin; (4) mengidentifikasi kendala yang ada dalam pelaksanaan praktik kerja industri.
Penelitian dilakukan di SMKN 3 Depok keahlian teknik batu & beton. Subyek penelitian sebanyak 39 peserta didik, 8 orang panitia prakerin, 8 pembimbing teknis dan 6 pembimbing sekolah. Metode pengumpulan data yang digunakan adalah angket dengan pertanyaan tertutup, wawancara, dan studi dokumentasi. Data yang terkumpul dianalisis dengan teknik deskriptif kuantitatif menggunakan presentase melalui angket (persiapan prakerin dan pelaksanaan prakerin), diperjelas dengan hasil reduksi dari data wawancara dan bukti dokumentasi.
Hasil penelitian menunjukkan bahwa pelaksanaan praktik kerja industri di SMKN 3 Depok program keahlian batu & beton secara keseluruhan meliputi: (1) pelaksanaan persiapan prakerin: (a) penandatanganan MoU dalam kategori sangat baik (91%), (b) pengajuan surat permohonan DUDI kategori baik (86%), (c) pembekalan prakerin dalam kategori sangat baik (91%) untuk panitia prakerin dan kategori baik untuk peserta didik (84%); (2) pelaksanaan prakerin berdasarkan angket peserta didik: (a) kinerja peserta didik yang terdiri dari tugas dan kewajiban selama prakerin masuk dalam kategori baik (83%), (b) kinerja pembimbing praktik kerja industri dari sekolah dalam kategori cukup (75%) kinerja pembimbing dari DUDI masuk dalam kategori cukup (75%); (3) Berdasarkan hasil wawancara dan analisis dokumentasi pada penerapannya kegiatan evaluasi berjalan sesuai dengan petunjuk pedoman dengan kategori baik.
Skin-Factor Equations for Anisotropic Wormhole Networks and Limited-Entry Completions
Authors: Schwalbert Mateus Palharini , Zhu Ding , Hill A. Daniel 
Published: January 2019

Summary
It was recently shown that anisotropic wormhole networks might arise from the acidizing of anisotropic carbonates. In openhole or cased and densely perforated completions, where in isotropic formations the wormhole network would be expected to be radial around the well, the actual stimulated region might be elliptical in anisotropic formations. An analogy would be in completions where the limited-entry technique is used and the wormhole network is expected to be spherical in isotropic formations, but it might actually be ellipsoidal in anisotropic formations. This has an effect on well performance and should be considered when designing the acidizing treatment and the completion. At the same time, using a limited-entry technique might result in better stimulation coverage and also longer wormholes, but it might also result in a partial-completion skin factor, impairing the productivity from the stimulated well. This should be considered when estimating the stimulated well productivity.
In this study, two main topics are analyzed: the effect of wormhole-network anisotropy and the effect of a limited-entry completion. Both radial and spherical wormhole-propagation patterns are considered, to be applied in openhole and limited-entry completions. The differences in well performance are studied for each case, and analytical equations for the skin factor resulting from each scenario are presented.
The anisotropic wormhole networks are obtained from numerical simulations using the averaged continuum model, and the results are validated with experimental data. The analysis of the well performance is made through simulation of the flow in the reservoir with the different stimulated regions.
The results show that for highly anisotropic formations, the wormhole-network anisotropy might have a significant effect on the acidized well performance, and this should be considered in the acidizing treatment design. It was observed that the anisotropic wormhole networks present lower productivity than equally sized isotropic stimulated regions. Hence, equations such as the Hawkins (1956) formula should not be used for estimating the skin factor from anisotropic wormhole networks, and the equations proposed in this work should be used instead.
Specifically, the effect of anisotropic wormhole networks is large when the limited-entry technique is used. It is shown that for this type of completion, there is an optimal stimulation coverage of approximately 60 to 70%, and the perforation density required to obtain this for a given acid volume strongly depends on the wormholes’ anisotropy. The skin-factor equations proposed in this work for the stimulation with limited-entry completion should be used for obtaining the optimal perforation density for a given scenario.
Can Proppant Transport be Negatively Affected by Too Much Viscosity?
Authors: Galindo Tanhee 
Published: January 2019

Abstract
The use of high viscosity friction reducers (HVFR) as alternatives to guar-based fluids to improve proppant transport and lessen formation damage has increased rapidly. While several product options are available, the criteria for selection of a product has focused on viscosity at 300 RPM (511s-1) that meets or exceeds that of linear gel fluids. However, there has been limited data available on what the target viscosity should be, how it influences the fluid's ability to transport sand, and the potential for damage to proppant conductivity. This study presents methodology used to screen HVFR's and results on product performance, which identified a need for alternative specifications to viscosity to achieve maximum performance.
The proppant transport capacity in dynamic conditions was evaluated for twenty commercially available friction reducers and HVFR's in field waters which could have up to 20,000 TDS. A slot flow apparatus was used to mimic fluid flow through a fracture under different shear and flow rate conditions. Viscosity and elasticity measurements were also obtained using an advanced rotational rheometer. For comparison, linear gel and crosslinked guar fluid were also evaluated.
While viscosity at 300 RPM (511s-1) and more recently high viscosity at lower shear rates, have been used for selection of HVFR's, these parameters alone do not indicate proppant carrying capacity. The authors did not find a correlation between higher viscosity and better proppant transport, rather they propose that too high a viscosity can negatively impact transport. The results provided insight into the effect of flow rate on proppant transport, with some HVFR's that exhibited higher viscosities at low shear, losing their transport capacity at the same low shear. Elasticity testing of those same products suggested that HVFR's have a critical elasticity range at which they will provide optimal performance. Polymer residuals were also evaluated on proppant post-test and compared to traditional linear gels and crosslinked fluids. Results suggested potential for damage if HVFR's are used without breakers. Different viscosity targets should be set when selecting a HVFR and coupled with other testing criteria such as elasticity and dynamic proppant transport.
This paper provides insight into the need for development of standardized test criteria for HVFR selection. Further testing and screening of HVFR's will help increase the understanding of key factors influencing sand transport and their effect on proppant pack conductivity.
Dynamic Fracture Volume Estimation using Flowback Data Analysis and its Correlation to Completion-Design Parameters
Authors: Moussa Tamer , Dehghanpour Hassan , Fu Yingkun , Ezulike Obinna 
Published: January 2019

Abstract
Hydraulic fracturing combined with horizontal drilling is the key to unlocking vast unconventional reservoirs. However, understanding the relationship between fracturing/completion-design parameters and the process efficiency remains challenging. The objectives of this paper are 1) to estimate initial fracture volume and its variations during the production by using flowback data and 2) to investigate the existence of correlations between completion-design parameters and induced fracture volume process optimization. We analyze flowback data and completion-design parameters of 16 shale-gas completed in the Eagle Ford Formation. First, we estimate ultimate water recovery and initial fracture volume by using harmonic-decline model, and fracture volume loss during flowback by using a new iterative approach that accounts for fracture-porosity changes with time. Then, we conduct a multivariate analysis to develop empirical correlations of completions-design parameters with initial fracture volume and fracture characteristic-closure rate (FCR).
The results show that harmonic-decline model could be used to estimate initial fracture volume with an average absolute percentage error (AAPE) of 7%. The correlations developed between initial fracture volume and completion-design parameters show that the proppant concentration has the most significant effect on fracture volume, followed by gross perforated interval (GPI) and shut-in time, respectively. Total vertical depth (TVD) and fluid injection rate have insignificant effects. The results indicate that increasing choke size during early flowback leads to a relatively-sharp decrease in fracture volume, while changing choke size during late flowback has negligible effects. The proposed correlation between FCR and completion-design parameters demonstrates the significant effect of proppant concentration on fracture closure during flowback, while GPI and TVD have negligible effects.
Fracture Geometry Control Technology Prevents Well Interference in the Bakken
Authors: Vidma Konstantin , Abivin Patrice , Fox Derek , Reid Mark , Ajisafe Foluke , Marquez Aleida , Yip Wilson , Still John 
Published: January 2019

Abstract
The increasing trend of drilling infill wells (more than 60% of new wells in 2017) comes with the significant risk of well interference, or "frac hits". Frac hits occur during hydraulic fracturing operations when there is direct pressure communication between the well being treated and adjacent, pre-exisiting wells. In extreme cases, the fracture may fill the adjacent wellbore with sand, which requires expensive cleanup intervention. Fracture geometry control technologies aim to reduce the likelihood of well interference by deploying far-field diversion techniques. This paper presents a unique field experiment that demonstrates the value and effectiveness of these technologies.
In the Bakken, two child wells were drilled 1,300 and 800 ft, respectively, on each side of an existing, partially depleted parent well. Each child well treatment comprised 50 stages of slickwater, completed in zipper frac style. Treatments in the farther well did not utilize any fracture geometry control technology. In the nearer well, 20 of 50 stages (one every 5 stages) included far-field diversion material. All other parameters of the pumping schedules were the same between the two treated wells. Pressures were monitored in all three wells (parent and two child wells) at high frequency during all operations.
The parent well was not damaged during the operation. However, during the first 35 stages of the child well treatments, the parent well's pressure increased in spurts, until it stabilized near expected reservoir pressure. In this paper, each instance of well interference is quantified and attributed to a treatment stage in one of the child wells. Interestingly, not all stages contributed to the pressure buildup. Significantly, various levels of frac hits were observed, as determined by the magnitude and steepness of the pressure increase. The correlation of frac hit with the absence of far-field diverter is striking. The results clearly demonstrate that fracture geometry control technologies reduce the occurrence of direct well interference by containing fracture growth.
The operations in these wells created a unique opportunity to design a field experiment to assess the effect of fracture geometry control technology on well interference during infill well stimulation. The results demonstrate that such technologies reduce the occurrence of direct frac hits in depleted parent wells.
Validating Refrac Effectiveness with Carbon Rod Conveyed Distributed Fiber Optics in the Barnett Shale for Devon Energy
Authors: Attia Ahmed , Brady Jared , Lawrence Matthew , Porter Robert 
Published: January 2019

Abstract
This paper presents a diagnostic-driven method of evaluating refracturing (refrac) techniques in unconventional wells. Detailed analysis across the lateral, using intervention based distributed fiber optic (DFO) measurements, allows for a comprehensive understanding of the refrac performance.
While there are various approaches to refracing an unconventional well, there is a categorical division of two main strategies: iterations of limited interval re-stimulation or re-stimulate the entire lateral at once. Stage-by-stage refrac, via casing-in-casing or coil tubing with isolation-type packer tool, offers potential control over stimulation distribution but often incurs heavier cost compared to refracing the entire well simultaneously. The economically favorable simultaneous refrac of all stages (Bull head) can be executed at a lower price but at the cost of not knowing the extent of lateral distribution.
With several possible approaches for refracing an entire lateral at once, further questions arise regarding which method provides the most laterally uniform re-stimulation and whether the resultant production improvement is from re-stimulated existing or newly created fractures. A major hurdle in both executing and evaluating the success of an all stage simultaneous refrac is the uncertainty of creating new fracture initiation points; furthermore, with complex heterogenic rock, different fracture designs, and different well completions, it is difficult to develop a comprehensive understanding of how well the refrac design worked. Diagnostic validation of the success of a refrac operation, as well as iterative improvements based on those learnings, is fundamental to determining a cost-effective strategy. A strong data set takes the guesswork out of refrac and is the best method for understanding how effective the refrac designs performed.
Well Trajectory, Completion and Fracture Design Changes Improve Execution for Deep Unconventional Tight Gas Targets in the Cooper Basin, Australia
Authors: Johnson Raymond L. , Zhong Ruizhi , Nguyen Lan 
Published: January 2019

Abstract
The Cooper Basin of Australia is challenged by strike-slip to reverse stress regimes, adversely affecting hydraulic fracturing treatments. In drilling, the high deviatory stress conditions increase borehole breakout, affect log acquisition and impact cementing job quality. The non-favourable stress conditions in conjunction with natural fracturing result in: complex fracturing (with shear and sub-vertical components); high near-wellbore pressure loss (NWBPL) values; and stimulation of lower permeability, low modulus intervals (e.g., carbonaceous shales, interbedded coals) in preference to the targeted and higher modulus, tight-gas sandstones. Typically, vertical wells have been employed in past completions of the Cooper Basin as well as in the offsetting areas to the case study in the Windorah Trough, Southwest Queensland.
We will present the results from two case study wells offsetting a previous vertical well where well trajectory, completion and fracture design changes were employed in an ongoing experiment to improve job execution for Patchawarra tight gas reservoir treatments in the Cooper Basin. The two wells were directionally deviated at 31° and 25° final inclinations from vertical with azimuth &lt;10 deg from the maximum horizontal stress direction, as determined from offsetting well data. To better define sections with limited, poor or missing log data (because of difficult hole conditions), drilling data, logging while drilling (LWD) gamma ray data, openhole conventional and dipole sonic logs, along with prior 1D stress data were used with a machine learning model to improve stress profiling and reservoir characterization. Next, perforations were shot 0 and 180° phased along the wellbore and initial fluid viscosity was increased to better align the hydraulic fracture and reduce NWBPL, respectively. Finally, diagnostic fracture injection tests (DFIT) were performed in sections of varying moduli below and in the zone of interest in order to verify the horizontal strains and calibrate the final 1D stress profile prior to stimulating both wells.
The improved well and perforation alignment to the maximum horizontal stress direction has improved reservoir connection, lowered NWBPL in some cases, and in some cases improved fracture containment. Decreasing injection rates and minimizing perforated intervals has improved targeting of desired intervals; however, overall fracture widths remain low and continue to be sensitive to proppant sizing and concentrations with several screen outs experienced. This experimentation has resulted in short-term production improvements in the wells using 4- and 3-stage treatments relative to the offsetting vertical well where a 5-stage treatment was executed.
Refracturing Technology Restores Profitability of Older Unconventional Wells in Southeast New Mexico
Authors: Athavale Amrut , Onafowokan Adebayo , Kasdano Carl , Lakshminarayanan Sunil , Sousa Lisset 
Published: January 2019

Abstract
This paper covers four case histories of refracturing technology applied to under-stimulated wells, along with the benefits and well economics of returning these older wells to profitable production. Refracturing candidate selection criteria, operational execution, and well results for the four full-lateral refracturing projects are discussed.
Refracturing candidate selection criteria were developed based on several parameters tied to improved production and project economics. Liner refrac methods were evaluated to select wells and field trials were performed to verify each method provided both ease of execution and isolation. Cemented liners and several expandable liner systems were evaluated. With effective mechanical isolation, highly effective modern frac designs can be applied successfully to refracs.
The refracturing candidate wells outperformed the expected type curve and yielded positive economics. One cemented liner refrac showed poor isolation during treatment. Expandable liners showed good isolation, but some expandable technologies were better than others were. Rigorous planning and engineering were considered crucial to ensure trouble-free operational execution and to deliver an optimum wellbore for refracturing purposes.
The criteria for refracs included in this paper are directly applicable for evaluating refrac candidates. The experience with isolation methods enables engineers to select the proper technology to seal old perforations.
A Novel Technology for Hydraulic Fracture Diagnostics in the Vicinity and Beyond the Wellbore
Authors: Stolyarov Sergey , Cazeneuve Eduardo , Sabaa Karim , Katz David , Yang Junjei 
Published: January 2019

Abstract
Despite modern technological advancements in well drilling and completion, our understanding of hydraulic fracture geometry remains virtually the same as it was at least a decade ago.
A critical approach to fracture treatment diagnostics involves an accurate evaluation of near-wellbore perforations efficiency and detection of hydraulic fractures away from the wellbore. The main limitation of currently available fracture diagnostic techniques is that they provide no information about the propped and conductive fractures beyond the wellbore.
A cross-dipole acoustic tool and deep shear wave imaging (DSWI) processing are able to detect hydraulic fracture-induced changes within the vicinity and beyond the wellbore. In the near-wellbore region, the acoustic wave transit time increases substantially through the frac sand. The increase in transit time is a function of frac sand porosity. In the mid-field region beyond the wellbore (at approximately one hundred feet), changes in acoustic wave's reflection amplitude between pre- and post-frac measurements illustrate the induced (conductive) fractures and are a strong indicator of the presence of the fracture network away from the borehole.
In addition, a three-dimensional fracture radius network model generated from DSWI data can provide greater insight, compared to seismic imaging methods for example, about the presence, location, and characteristics of natural and hydraulically induced fractures. The three-dimensional fracture network model created via DSWI can be more readily used in workflows or tools associated with reservoir modeling and fracture modeling.
A novel hydraulic fracture diagnostic technology based on acoustic measurements enables efficient evaluation of the completion and quick, cost-effective hydraulic fracture mapping in the mid-field region. The ability to run a single tool before and after the hydraulic fracture treatment makes this tool a unique solution that helps customers make smart decisions to improve well economics.