bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison among Fracture Calibration Test Analysis Models
Authors: Ehlig-Economides Christine A. , Liu Guoqing 
Published: January 2017

Abstract
Recent papers show new models for matching the injection falloff response to a fracture calibration test, also known as minifrac or the diagnostic fracture injection test (DFIT), one numerical and one analytical. Both models address variable compliance, but they disagree on the value for minimum stress. The analytical model provides a way to estimate the effective permeability from the after-closure response that can be compared to an existing methodology for permeability estimation from the before closure behavior.
The objective of this work is to assess where the existing interpretation models agree or disagree and the limitations on where the various approaches apply. The McClure numerical model for variable compliance results in exactly one closure instance, after which all observed behavior is matched with after closure variable fracture compliance. The Liu analytical decoupled fracture model identifies and matches multiple closure events, with variable fracture compliance and/or variable fracture surface area. The Craig model couples before and after closure behavior by treating the fracture closure as storage and matching with against a family of type curves.
The original Mayerhofer method for before closure permeability estimation has clear potential advantage over techniques that require the after-closure response. If before and after closure permeability estimates are sufficiently similar, the need for acquiring after closure data is reduced to pore pressure estimation.
Field examples are used to illustrate the application of the four models. The parameter values estimated from these analyses are essential to design of the main fracture treatment(s). Discrepancies in the value estimates may have profound impact on the treatment design and execution.
Accelerating Completions Concept Select in Unconventional Plays Using Diagnostics and Frac Modeling
Authors: Azad Ali , Somanchi Kiran , Brewer Jim R. , Yang Daniel 
Published: January 2017

Abstract
Data pads in unconventional plays have shown significant value when they are carefully designed to tackle specific problems or concerns. This includes the use of diagnostics to cross-validate development concepts such as stimulation design, well architecture, frac and well spacing, and numerous other variables. In this paper, it is demonstrated how various diagnostics technologies together with subsurface data can be used to calibrate a frac model. The model can then be coupled with a reservoir simulator to accelerate completions concept select decisions in unconventional plays. This process (a) eliminates multiple field trial costs, (b) tests different completions and stimulation designs, and (c) assists in de-risking various field development planning scenarios. This paper focuses on a real-life case-study where integrated diagnostics and modeling were applied to de-risk multiple completions scenarios. An intermediate planar frac model was calibrated and used to lower the uncertainty of key frac parameters including frac geometry and conductivity. In addition, subsurface parameters such as in-situ stresses and rock properties were tuned. The results from the integrated modeling effort were used to propose future development options for the play.
A Causation Investigation for Observed Casing Failures Occurring During Fracturing Operations
Authors: Adams N. J. , Mitchell R. F. , Eustes A. W. , Sampaio J. H. , Antonio A. O. 
Published: January 2017

Abstract
The objective of this paper is to present findings from a causation investigation of casing failures occurring during fracturing operations. The study analyzed case histories and examined post-failure laboratory results. Outcomes from casing failures include blowouts, pollution, injuries/fatalities, and loss of the well with associated costs. This work has not been previously published nor is this type of work available in the public domain literature.
This study cataloged pertinent data from fourteen (14) land-based case histories of casing failures while fracturing. The case histories were analyzed with the use of photographic evidence of recovered casing, well reports, fracturing treatment data, drilling records, and laboratory testing of recovered casing when available. Failure causes were identified. Preliminary guidelines are provided to avoid casing failures and mitigate the damages. Recovery guidelines are presented.
A model was developed to evaluate axial loads under several considerations associated with fracturing. The model accounted for the casing's in-air load, buoyancy effects from wellbore fluids, piston effect, bending, erosion, and temperature decreases. The combined loads were compared to the casing's yield strength.
The failures were not systemic but included cracking related to fatigue, hydrogen and sulfide stress embrittlement, and erosion at ERW weld lines. The failures were observed at various well depths, both in the cemented and uncemented hole sections. Results address common casing sizes and couplings involved with each failure, weight and grade, failure location and causation identification of other factors contributing to the failure. A goal of this investigation and on-going work is to develop a thorough understanding of casing failures and the myriad of contributing factors in order to develop a comprehensive predictive model for land and offshore fracturing operations.
Effect of Geological Layer Properties on Hydraulic Fracture Initiation and Propagation: An Experimental Study
Authors: AlTammar Murtadha J. , Sharma Mukul M. 
Published: January 2017

Abstract
Hydraulic fracture initiation and propagation in the presence of multiple layers with different mechanical and flow properties are investigated experimentally utilizing a novel fracturing cell. Mixtures of plaster, clay and other materials are used to cast sheet-like test specimens in layers with different mechanical properties. The specimen is placed between two transparent plates that allow us to take videos of the speckled rock sample surfaces to facilitate digital image processing of rock displacement. In order to control fracture orientation, a far-field differential stress is applied to the specimen via pneumatic jacks. Hydraulic fracture growth during the experiment is recorded using a high resolution digital camera. Key frames are subsequently analyzed using Digital Image Correlation (DIC) to reveal micro-cracks, strains and other features that are difficult to detect with the naked eye. Experiments are conducted for fracture propagation across layered porous media in different stress states.
It is clearly shown that a fracture initiating in the vicinity of a layer interface may exhibit a range of behaviors including propagation straight through the layer interface, forming secondary fractures, fracture kinking, and fracture propagation along or parallel to the interface. Straight/plane fracture propagation is observed across an interface when going from a hard to a soft layer. Conversely, crossing from a soft to a hard layer, a fracture tends to kink at a slight angle as it approaches the interface. The angle at which the fracture turns increases as the contrast in Young's modulus and fracture toughness between the layers increases and/or the differential stress decreases. Tensile stresses on the intact (hard) side of the interface can also develop a secondary fracture at an offset to the parent fracture with localized interface opening resulting in a fracture step-over. Given a choice of multiple layers, fracture propagation into a harder layer is favored over a softer layer. The effect of hard inclusions that can act as fracture barriers is also investigated. Fractures tend to initiate and propagate parallel to the bounding interfaces when the fracture initiation layer is relatively thin or in the case of an isotropic stress state and propagate along the interfaces when the bonding between the layers is weak. A fracture approaching a dipping, harder layer tends to kink towards the low side of the interface. The experiments, for the first time, clearly demonstrate and quantify experimentally the factors that control fracture propagation across geological layers. The observed turning and branching of the fractures can have a profound effect on fluid leakoff and proppant transport.
Stacked Height Model to Improve Fracture Height Growth Prediction, and Simulate Interactions With Multi-Layer DFNs and Ledges at Weak Zone Interfaces
Authors: Cohen Charles-Edouard , Kresse Olga , Weng Xiaowei 
Published: January 2017

Abstract
Commercial hydraulic fracture software are generally based on the planar 3D model (PL3D) or the Pseudo 3D model (P3D). The PL3D model is more accurate but very CPU intensive, which makes it unsuitable to simulate complex hydraulic fracture networks due to the interaction with natural fractures. The pseudo-3D model is faster but considers separately the vertical and horizontal propagation of the fractures. In recent years, a sophisticated P3D-based complex hydraulic fracture network model, the Unconventional Fracture model (UFM) was developed that can simulate complex physical mechanisms such as interaction with natural fractures, stress shadow and the proppant placement in the complex fracture network. However, one of the main challenges still faced by such simulators is to accurately predict the height growth in formations with heterogeneous mechanical and stress properties.
One assumption of the P3D model is the fracture is being initiated and extended in a lower stress layer than the adjacent layers. In practice, the assumption is not always satisfied, leading to inaccurate or unstable height growth. A comparison of these two models through examples illustrates the situations where P3D model works well and where it does not, and the difficult compromise between accuracy and computational efficiency.
A better compromise can be achieved through a new Stacked Height Growth model (SHG). This model is an enhancement to the P3D model, consisting of multiple rows of elements vertically stacked, to more precisely account for the effect of vertical stress heterogeneity, and to allow multiple horizontal propagation fronts. The width profile and stress intensity factors at the top and bottom depend on the stress and pressure profiles along the stack of elements. The theoretical background of the model is presented. Comparison shows good agreement with the PL3D model for cases that the P3D model cannot accurately simulate, and at a fraction of the computational cost of PL3D. A particularly interesting feature of the SHG model is its flexibility to transition smoothly from a 1D cell-based model such as the P3D model, to a fine scale 2D gridding in the fracture plane. This feature greatly facilitates the implementation of other modeling features into the fracturing simulator.
For example, the SHG model can be used to simulate interaction of hydraulic fractures with Multi-layer Discrete Fracture Networks (MDFN), to better model naturally fractured reservoirs. The SHG model can also be used to model offsets of hydraulic fractures through weak interfaces called ledges. The model can capture the influence of these discontinuities on the proppant placement. Another example, is how a fine 2D gridding using the SHG model can predict proppant placement as accurately as a PL3D model. These extensions of the SHG model have been implemented into the UFM model and are illustrated in this paper through several examples.
Far-Field Proppant Detection Using Electromagnetic Methods - Latest Field Results
Authors: Palisch T. , Al-Tailji W. , Bartel L. , Cannan C. , Zhang J. , Czapski M. , Lynch K. 
Published: January 2017

Abstract
Over 100 billion lbm of proppant are placed annually in wells across the globe, with the majority in unconventional reservoirs. The location of the proppant in these horizontal wells and formations is critical to understanding reservoir drainage, well spacing and stage spacing. However, for many years proppant detection has primarily been limited to near-wellbore measurements. A novel method to detect proppant in the far-field has been developed and is the subject of this paper.
The method to detect proppant that has been developed utilizes electro-magnetic methods. This technology entails using a transmitter source and an array of electric- and magnetic-field sensors located at the surface. A current signal with a unique wave form and frequency is transmitted to the bottom of the wellbore via a standard electric line unit. In addition, an electrically conductive proppant is pumped into the stage(s) of interest. The electric- and magnetic-fields are measured both before and after the detectable proppant stages, and a novel analysis method is then employed to process and invert this differenced data to create an image of the propped reservoir volume.
This technology is the product of years of development of computer models capable of forward modeling this technique. Once this modeling was completed, an initial field test was performed in west Texas, with a preliminary analysis of this work presented in a previous paper. Since that paper, however, additional processing of the data has yielded a much more detailed image of the proppant location in this Bone Springs well. In addition, a subsequent field application has been performed in a major basin in the Northeast US. Multiple stages received detectable proppant of varying stage volumes and the analysis has shown a detailed image of the proppant location in that wellbore also. In addition, the initial west Texas field test employed only electric-field sensors, while this latest test employed both electric- and magnetic-field receivers. Numerical simulations and field results indicate the percentage difference between pre- and post-frac results are two times higher using magnetic versus electric field sensors.
This paper will review the technology development and methods, it will present the latest imaging from the initial west Texas test, and it will describe the latest learnings from the most recent field test. This paper should be beneficial to all completions and development personnel who are interested in knowing where proppant is located in their fractures. This technology has the potential to assist in understanding well drainage and spacing, stage and perf cluster spacing, vertical fracture coverage as well as the impact of fracture design changes.
Nuevas observaciones taxonómicas y etnomicológicas en Psilocybe s.s. (Fungi, Basidiomycota, Agaricomycetidae, Agaricales, Strophariaceae) de México, África y España
Authors: Guzmán Gastón 
Published: January 2017

Se presenta una nueva emendación de Psilocybe zapotecorum, basada en un re-estudio del holotipo y en la descripción de los pseudocistidios, pleurocistidios y queilocistidos, antes confusamente descritos. Se discute la numerosa sinonimia de este hongo, con base en el estudio de los holotipos y su amplia distribución en el neotrópico. Se analizan sus usos tradicionales como hongos sagrados y se hace una revisión de códices y piezas antropológicas, en donde se identifica a esta especie o sus afines: P. muliercula y P. moseri. Se establece una relación entre el culto de Quetzalcóatl y el uso de tales hongos. Se analizan las palabras “teonanácatl” de Sahagún y “teotlaquilnanácatl” de Guzmán. Se discuten las relaciones de P. mairei con los murales prehistóricos de Tassili en el Desierto del Sahara. Se presenta el primer estudio de materiales auténticos de P. mairei de Argelia, de donde se designa un neotipo. Finalmente se tratan las relaciones entre un mural prehistórico en España y P. hispanica.
Afinidades florísticas y fitogeográficas de la vegetación del municipio de San José Iturbide, Guanajuato, México
Authors: Gutiérrez Jorge , Solano Eloy 
Published: January 2017

Se realizó un estudio florístico y se establecieron los patrones de distribución geográfica y ecológica de las especies que conforman la flora vascular del municipio de San José Iturbide, Guanajuato. Este municipio se ubica en el Altiplano Mexicano. El área de estudio cubre una superficie de 538 km2. Se censaron 661 especies, incluidas en 361 géneros y 101 familias. Se encontraron dos nuevos registros para el estado de Guanajuato, Osmunda regalis var. spectabilis y Anoda pentaschista. Se estimó que el inventario integra cerca de 70% de los taxa presentes en el área. El 41% de las especies son endémicas de México, 114 de ellas son propias del centro del país, siete de éstas solo se distribuyen en áreas cercanas al municipio y una es endémica del mismo. La flora vascular de la zona tiene afinidad con la de los matorrales xerófilos del centro de México, y comparte un gran número de especies con la vegetación de clima árido del Altiplano Mexicano. San José Iturbide contiene 12% de las 5500 especies estimadas para la región que abarca el proyecto “Flora del Bajío y de Regiones Adyacentes”, y 22% de las calculadas para el estado de Guanajuato, por lo tanto, su riqueza florística es alta si se considera su pequeña superficie.
Inventario micobiótico de la región de Tapalpa, Jalisco, México
Authors: Gándara Etelvina , Guzmán Dávalos Laura , Guzmán Gastón , Rodríguez Olivia 
Published: January 2017

Se presentan 233 taxa (especies y variedades) de hongos (229 macromicetes y cuatro micromicetes) de la región de Tapalpa, Jalisco. El material estudiado fue recolectado en los años 2000 al 2003, principalmente en bosques de Pinus y Quercus. Se examinaron además otros ejemplares depositados en el Herbario IBUG provenientes de dicha área. Se registran por primera vez de Jalisco 21 taxa. Doscientos cinco especies (88%) pertenecen a Basidiomycota, 22 (9.5%) a Ascomycota y 6 (2.5%) a Myxomycota. Éste constituye el primer inventario micológico de la zona.
Las plantas vasculares y vegetación de la barranca Tepecapa en el municipio de Tlayacapan, Morelos, México
Authors: Hernández Cárdenas Rodrigo Alejandro , Cerros Tlatilpa Rosa , Flores Morales Alejandro 
Published: January 2017

El área de estudio, la Barranca Tepecapa de aproximadamente 3.5 km de longitud, se ubica dentro de la zona núcleo “Las Mariposas” en el Corredor Biológico Chichinautzin del estado de Morelos. Se realizaron colectas periódicas durante un año y medio, de octubre 2009 a abril 2011. Se colectaron 1018 ejemplares de Pteridofitas y afines, Gimnospermas y Angiospermas, pertenecientes a 99 familias, 266 géneros y 434 especies. Las familias mejor representadas son: Asteraceae, Fabaceae, Poaceae, Orchidaceae, Pteridaceae, Solanaceae y Bromeliaceae. Asimismo, se registran y describen tres tipos de vegetación para el área de estudio. Dos géneros (Amyris y Dasylirion) y 16 especies son nuevos registros para el estado de Morelos.
La familia Juncaceae en México
Authors: Balslev Henrik , Duno de Stefano Rodrigo 
Published: January 2017

Se presenta un tratamiento de la familia Juncaceae Juss. para la flora de México. La familia incluye dos géneros en dicho país: Juncus L. yLuzula DC. El primero comprende 31 especies y el segundo cinco. Se proporciona una clave para la identificación de los taxones, descripciones morfológicas, notas taxonómicas e información sobre la distribución geográfica, así como ilustraciones de algunas especies. Una especie es endémica: Juncus chiapasensis Balslev crece exclusivamente en el estado de Chiapas. Otra, J. textilis Buchenau, es un endemismo local que se encuentra en el estado de Baja California y en el estado de California en los Estados Unidos de América.
Análisis florístico sucesional en la estación biológica Cerro Huitepec, Chiapas, México
Authors: Ramirez-Marcial Neptali , Ochoa-Gaona Susana , Gonzalez-Espinosa Mario , Quintana-Ascencio Pedro F. 
Published: January 2017

Se presenta una lista florística y una descripción de la vegetación de seis comunidades sucesionales: zacatonal, matorral, bosque incipiente, bosque sucesional intermedio, bosque de encino y bosque de neblina en la Estación Biológica Cerro Huitepec, San Cristóbal de Las Casas, Chiapas. El total de la flora comprende 83 familias, 186 géneros y 315 especies; 10% de ellas fueron herbáceas anuales, 50% herbáceas perennes (incluyendo bejucos y helechos), 20% arbustos, 17% árboles del sotobosque y 3% árboles del dosel. El análisis de similitud (índice de Jaccard) permitió reconocer tres grupos de vegetación: el primero definido por especies predominantemente pioneras o sucesionalmente tempranas, típicas del zacatonal y del matorral, que tienen 58% de semejanza florística; el segundo incluye los elementos del bosque incipiente y el bosque sucesional intermedio, compartiendo 52% de su flora y en el que destacaron las plantas sucesionales intermedias; el último grupo formado por el bosque de neblina y el bosque de encino, que tienen en común 57% de la composición florística, principalmente de especies sucesionales intermedias y tardías. En la Estación Biológica Cerro Huitepec está representada 32% de la riqueza florística estimada para la región ubicada por encima de los 2000 m de altitud en el centro del estado. Sin embargo, debido a la baja densidad de las poblaciones de varias especies y a las tasas elevadas de deforestación que prevalecen alrededor, es probable la ocurrencia de algunas extinciones locales en el futuro cercano, por lo que es necesario diseñar estrategias apropiadas para su manejo y conservación.
POLA PENDIDIKAN CERDAS KREATIF BERKARAKTER; PRAKSIS DI RUMAH KREATIF WADAS KELIR PURWOKERTO JAWA TENGAH
Authors: Sumiarti Sumiarti , Kuntoro Sodiq Azis , Sutrisno Sutrisno 
Published: January 2017

Tujuan penelitian ini adalah untuk mengungkapkan: (a) landasan filosofis dan konsep pendidikan cerdas, kreatif, dan berkarakter; (b) praktik pendidikan cerdas, kreatif dan berkarakter, dan (c) pola praksis pendidikan cerdas, kreatif, dan berkarakter di Rumah Kreatif Wadas Kelir (RKWK) Purwokerto. Penelitian ini menggunakan pendekatan kualitatif fenomenologis karena berupaya mengungkap pengalaman subjek penelitian dalam merumuskan konsep dan praktik pendidikan yang mengintegrasikan kecerdasan, kreativitas dan karakter. Data penelitian dikumpulkan dengan menggunakan teknik wawancara mendalam, observasi partisipan dan nonpartisipan, dan analisis dokumen. Pola praksis pendidikan yang terdiri atas konsep pendidikan dan praktik pendidikan yang bersifat dialektis yang mengintegrasikan aspek cerdas, kreatif, dan berkarakter dilaksnakan dalam kegiatan pembelajaran harian, mingguan, bulanan, tahunan dan insidental. Pola Praksis Pendidikan Kreatif-Integratif tersebut dilaksanakan dalam bentuk bermain aneka kretivitas, yaitu: bermain kreativitas angka-logika, bermain kreativitas bahasa, bermain kreativitas warna, bermain kreativitas gerak dan bermain kreativitas musik.Kata kunci: pendidikan kreatif-integratif, pendidikan cerdas kreatif berkarakter, bermain kreativitas THE PATTERN OF CHARACTERIZED CREATIVE INTELLIGENT EDUCATION: PRACTICE IN THE WADAS KELIR CREATIVE HOUSE PURWOKERTO, THE PROVINCE OF CENTRAL JAVAAbstractThe study was to uncover: (a) the philosophical foundation and the concept of characterized, creative and intelligent education; (b) the practice of characterized, creative and intelligent education; and (c) the pattern of characterized, creative and intelligent education. The study implemented the phenomenological qualitative approach because the researchers would like to uncover the subjects’ experiences in formulating the educational concept and practice that integrated the intelligence, the creativity and the characters. The data then were gathered by means of in-depth interview, participatory and non-participatory observation and document analysis. The pattern of dialectical educational practice that consisted of the aspects of intelligence, creativity and characters had been implemented in the daily, weekly, monthly, yearly and incidental learning activities. The pattern of Creative-Integrative educational practice had been implemented in the form of color creativity game, movement creativity game and music creativity game.Keyword: integrative-creative education, characterized creative intelligent education, creativity game