bluuebunny/crossref_metadata_2025_split huggingface dataset:
Convergencia de normas contables internacionales entre México y Estados Unidos: evidencia empírica
Authors: Polo Jiménez Sergio Demetrio , Palacios Manzano Mercedes , Martínez Conesa Isabel 
Published: May 2016

El objetivo de este trabajo es examinar si la adaptación de la normativa contable mexicana a las IFRS ha convertido los principios mexicanos en unas normas de mayor calidad, incrementando su comparabilidad con los US GAAP y reduciendo la manipulación de los resultados. A su vez, nos cuestionamos, de acuerdo con la Teoría de la Agencia, si las diferencias entre las variables contables calculadas bajo la normativa mexicana y americana pueden ser debidas a la interpretación oportunista de los estándares mexicanos por los managers más que a las diferencias en la normativa contable de ambos países. Los resultados sugieren que los esfuerzos para converger las normas contables han incrementado la comparabilidad del resultado contable, si bien esta convergencia se debe también al uso oportunista de la elección de los métodos contables en función de la distinta coyuntura económica.
Aseguramiento del informe de sostenibilidad en España y Latinoamérica
Authors: Zorio Grima Ana , García-Benau María A. , Sierra García Laura 
Published: May 2016

Este trabajo presenta un estudio sobre el aseguramiento de los informes de sostenibilidad emitidos en España y Latinoamérica. Sobre una muestra de 783 empresas que envían su informe de sostenibilidad al Global Reporting Initiative, se identifican en primer lugar las características corporativas que conducen a las empresas a someter a aseguramiento dicho informe. En segundo lugar, se analiza la evolución del mercado de aseguramiento y su distribución que se evidencia dominado por firmas auditoras. En tercer lugar, se estudia el contenido del informe de aseguramiento para observar las diferentes tendencias en su confección, así como para crear un índice sobre la calidad del mismo. Las conclusiones señalan que las variables de la empresa tamaño, sector, pertenencia a sector sensible, país, nivel de aplicación del GRI y se sigue o no el suplemento GRI para ciertos sectores son significativas sobre la decisión de asegurar el informe de sostenibilidad. Por otro lado, se evidencia un crecimiento del mercado de aseguramiento que se encuentra dominado por las Big4 y algunas empresas certificadoras, como AENOR con gran presencia en España. Por último, se observa que la calidad de los informes de aseguramiento presenta un grado de variabilidad considerable, dependiendo de quién firma el informe.
Práticas de orçamento de capital predominantes na literatura internacional
Authors: De Souza Paula , Schnorrenberger Darci , João Lunkes Rogério 
Published: May 2016

Este artigo tem como objetivo identificar as práticas de orçamento de capital predominantes na literatura internacional. Para atingir esse objetivo, foram realizadas três etapas: i) construção de um portfólio bibliográfico das práticas de orçamento de capital com enfoque na análise de investimentos, por meio da utilização do instrumento de intervenção denominado ProKnow-C; ii) análise bibliométrica e iii) elaboração de uma representação pictórica das práticas de orçamento de capital contidas no âmbito internacional. A análise bibliométrica permitiu analisar os artigos quanto aos autores, às palavras-chave e aos periódicos que mais publicaram sobre o assunto em discussão. A análise sistêmica dos artigos constatou que: i) os métodos para análise de investimentos predominantemente citados são: Valor Presente Líquido, Taxa Interna de Retorno, Taxa Interna de Retorno Modificada, índice de Rentabilidade, Payback, Taxa de Retorno Contábil e Opções Reais; ii) os métodos mais utilizados para definição da taxa de retorno são: Custo Médio Ponderado do Capital, Custo do Capital Próprio e Custo da Dívida; iii) deve-se estabelecer uma taxa mínima de retorno aceitável para cada investimento realizado e iv) os métodos de análise de risco evidentes nos estudos são: Análise de Cenários, Análise de Sensibilidade, Simulação de Monte Carlo e Árvore de Decisão.
Bacterial Diversity Analysis of Upper Lake, Bhopal (M.P) India, Using Metagenomics
Authors: Prasad Bhupendra , Choudhury Tilottama , Antony Reena 
Published: May 2016

<p>Diversity analysis in reference to current methodology offers advantage over existing methodology such as biochemical characterization etc. Present study is carried out in order to establish diversity pattern using metagenomic procedure. The water body situated in Bhopal has its own recreation and water supply potential. Any water body is entertained by biological activity preferably predominant in sediment, as sediment represent site of various biological and geochemical activity. The protocols combine the application of mechanical (Beads and Sonicator ) and soft lysis (SDS and enzyme) method for the isolation of total DNA from sediment of Upper lake of Bhopal followed by its quantification and purity assessment. The quality and purity of metagenomic DNA was quite consistent and reliable, although it contained residual concentration of humic acid. The methods have wide applicability in investigating molecular diversity and exploring functional genes.<br />The methodology used showed supportive observation of sediment habitat as use of extracted DNA when amplified using 16s rDNA region. Phylogenetic relationship was established. Dendogram was prepared using NTSYS ( software for clustering of the data) which is based on unweighted Pair Group Method with Arithmetic Averaging (UPGMA). The dendogram showed deviation of initial two groups at 27% as well as 42% similarity. Sample B1 and B13 from Boat club site falls with absolute similarity, B4 and B10 also shows absolute resemblance in relation to pattern of amplification.</p>
Drillable PDC Casing Bit Defies Challenging Onshore Drilling Environment and Sets Longest Single Trip Drilling with Casing Record
Authors: Utama Budi , Won Keith 
Published: May 2016

Abstract
Orubadi formation in Permit PRL 21 at Western Province Papua New Guinea(PNG) was known for its challenges to drilling and casing-running operations on the surface section. A waterflow event occurred when drilling the offset well through the formation, consequently requiring the flow to be diverted. In addition, the surface casing-running operation was time-consuming due to tight-hole conditions, which led the operator to perform extra trips to reamthrough the ledges.
An approach using the drilling-with-casing technique was presented and identified as the most suitable drilling method for setting the 13 3/8-in. surface casing safely and improving drilling efficiency through trip-time reduction and elimination of conventional drilling BHA handling. A unique, reliable and easily operated top-drive casing-running and drilling system, which had been used regularly for surface casing-running operations, has contributed to the first successful drilling-with-casing operation on the rig. The casing-bit selection has appeared to be an important process in this challenging project. Ultimately, a newly-developed polycrystalline-diamond-compact (PDC) drillable casing bit with PDC cutters was selected based on the estimated hard formation rock strength characteristic of the field, in order to achieve the targeted total depth in a single trip.
The drilling-with-casing system was deployed through the problematic zone and mitigated the expected borehole problem with variations in the drilling penetration rate. Recommended drilling parameters were used to achieve optimum performance in combination with sufficient mud properties to maintain good hole cleaning and bit hydraulic performance until total depth.
This paper presents the drilling-with-casing project in the field, covering the planning stage, equipment selection, preparation, implementation, and operational aspects of the longest nonretrievable 13 3/8-in. drilling-with-casing project performed in the world to date.
New Offshore Sidetrack Practices Reduced Significantly Stuck Pipes in KSA
Authors: Al-Dossary Abdulla 
Published: May 2016

Abstract
This paper demonstrates the causes of the major issue of stuck pipes in offshore sidetracks in Saudi Aramco & also explains the new drilling practices implemented to reduce the number of stuck pipes while drilling or running completion systems. Out of three wells sidetracked, two stuck pipes occurred. Year after, this number of stuck pipe has declined significantly after revised and corrected drilling practices. In year 2005, oil demands went up and therefore, Saudi Aramco converted vertical and deviated wells to horizontal in order deliver more oil to the oil market. Sensitive shale instability problem was present almost in every well where drill pipe got stuck. Also, it is worth mentioning that development of humps while drilling contributed to inability of cleaning the hole very efficiently. Typically, every single well is sidetracked and drilled across shale formations of different pressures up to the productive zone. After drilling the horizontal section, the whole well is reamed with stiff assembly during which obstructions and tight spots are cleared. Then, ICD system is deployed to TD. This paper will highlight the main causes of stuck pipe and following that, successful solutions will be presented and explained in detail.
Casing While Drilling (CwD): Surface Hole Optimisation in Mature Field of Offshore North West Java
Authors: Taufiqurrachman H. , Tanjung E. 
Published: May 2016

Abstract
Offshore North West Java (ONWJ) is one of Indonesia's mature fields. Mature field developments in this level require a simple, fast and cheap well design to be economically interesting. The highlight in this paper is drilling top-hole section optimization by applying Casing while Drilling (CwD).
The main 2 challenges in drilling top-hole section in ONWJ are gumbo attack and loss circulation. Past mitigation was drilled a small pilot hole to reduce cutting amounts then enlarge the open-hole by hole opener. However it did not solve the problem completely. The gumbo attack still occurred, some associated non-productive rig times still happened and safety concern to clean the plugged flowline still existed. KCl Polymer mud system was not an option due to loss circulation existence, where hole will collapse when seawater is displaced to keep hydrostatic.
CwD were executed successfully at 2 exploration wells in Q3 2011 by implementing Vertical-CwD (VCwD). First trial of VCwD was run only in surface section with a simple cutters casing shoe mounted on the end of a casing string. Further improvement in drillshoe, BHA and mud design was made on the second trial to extend the interval and improve overall ROP. The second trial of VCwD managed to safely drilled almost 3000ft of combine surface and intermediate vertical section with overall ROP of 60fph, where at surface section CwD was performed blindly due to total loss circulation and it was successfully cemented (no annulus pressure trap so far). The second trial has saved the company over 1MMUSD compared to conventional drilling.
In 2012, numerous trials of Vertical Casing while Drilling (VCwD) have been performed for exploration and development wells in offshore North West Java. CwD is heralding the way to the future of drilling in mature fields of Offshore North West Java.
Carbonate Rock Types Matrix, the Ultimate Rock Properties Classification Catalogue
Authors: Al-Farisi Omar , Belhaj Hadi , Ghedan Shawket , Negahban Shahin , Gomes Jorge , Yammahi Fatmeh , Amr Mohamed , Khamissa Hocine , Ibrahim Khalil , Al-Shamsi Abdullah 
Published: May 2016

Abstract
The heterogeneity in carbonate rocks, made it hard for Geoscientists and Reservoir Engineers to define a universal classification methodology that is able to honour the critical reservoir static properties. Most classifications, like, lithofacies, capillarity and textural methods have based their rocktyping concept on one or two static properties, then tried to find an analog to other static properties to cluster or group them, then worked to populate the rock types across the whole field. However, from field observations and experiences of utilizing these conventional techniques, it was obvious that they suffered from several gaps, like inability to have the properties analog consistent throughout the whole reservoir. Moreover, the groups or clusters have big dispersion that produced overlaps, and then theoretically they could not fully honour the physics and rock properties links.
Therefore, in this study, rock typing is made to honour static properties all together through changing the classification concept to resolve the gaps of the traditional methodologies. The ultimate objective of all reservoir characterization and rock classification is to enable building geological and simulation models, with optimum honouring of rock properties. To achieve this objective, the established framework in this research is based on analyzing the effects of each of the rock properties on another and the value and impact that each can add to the models most critical parameters. By this technique, the gap of pore and pore-throat network is resolved through Multiple Properties Intersection.
This Integrated Carbonate Rock Typing technique starts with capturing the heterogeneity of carbonate rock by generating matrix of core permeability, capillary pressure (end point, threshold pressure and Plateau), pore-throat size distribution and porosity. Then intersecting this matrix to construct weighted links between these properties and identify unique groups. Resulted classes are novel carbonate rock type classes that entered to feedback analysis node to explore and validate the logic of linked physics to tune the classes'thresholds and assure no overlap between any of classification properties. Finally for utilizing this technique in non-cored wells, an analog with logging data is structured through novel permeability, capillary pressure and saturation function called the C-Function to be the replacement of the J-Function in Carbonate.
Unlock Shale Oil Reserves Using Advanced Fracturing Techniques: A Case Study in China
Authors: Liu Hai , Luo Yin , Zhang Ning , Yang Dong , Dong Wanbai , Qi Dunke , Gao Yinjun 
Published: May 2016

Abstract
Development of unconventional resources has become major focus in China in the recent years as the growth of energy demands. Many pilot projects on shale oil reservoirs have been initiated to seek for economic development with modern hydraulic fracturing technologies. Fracturing these reservoirs is quite challenging and requires not only large reservoir contacts but also high fracture conductivity in both primary fracture and fracture networks since oil viscosity is several magnitudes higher than natural gas. Vertical fracture connectivity is also an issue in many cases due to lamination of shale-rich layers with thin siliceous and calcareous beds. This typical sedimentary feature may result in either short fracture height or pinch-point in vertical fracture profile due to proppant embedment in shale-rich layers.
The paper presents a shale oil case study in Northern Songliao Basin in China in which many fracturing treatments have been attempted in the past without success. Two existing vertical wells drilled in 1989 were used to study appreciate fracturing techniques and demonstrate the possibility of economic production before evaluating horizontal well completion. The paper illustrates optimization of treatment strategy and design by integrating detailed reservoir characterization, fracture simulation using unconventional fracture model and numerical reservoir simulations. It also introduces an innovative fiber diversion technique for improved vertical fracture coverage and proppant placement together with real time fracture monitoring for treatment optimization.
After increased understanding from the treatment on the first well, the treatment on the second well was quite successful and the well produces 30 bopd after the treatment, which is the first ever economic production in the field. The first month production history also matches with the forecast very well, which increases the confidence of extending the practice to the entire field as well as subsequent horizontal well evaluation.
Assessing Unconventional Resources Using an Integrated Petroleum Systems Approach
Authors: Roy Ananda Shankar , Neber Alexander , Kadir Zailani Abdul 
Published: May 2016

ABSTRACT
Petroleum system modeling has matured in the past few years and is now a valuable component in conventional exploration. It has become best practice to mitigate risks by using petroleum system modeling to predict the presence, types, and volumes of hydrocarbons in prospective areas or structures before drilling. An adaptation of this methodology has been successfully applied to unconventional resource plays. Petroleum system modeling may be applied to predict: the type and quantity of hydrocarbon remaining in the source rock, proportion of adsorbed gas, porosity, and geomechanical properties of potential unconventional reservoirs.
A new methodology has been developed to integrate trap, reservoir, charge, seal, and other risk (sub-) elements to evaluate play risk. Chance-of-success (COS) maps are created by transforming the physical propertiy maps to maps with probability units. As data, interpretations and related COS maps are in the same software system, the evaluation can be kept alive and dynamic as new data interpretations become available. Within the same application, prospect COS can be evaluated using a consistent approach
This paper illustrates this methodology using examples from shale plays in North America, data-rich plays from the North Slope of Alaska and data-poor plays that are more representative of many Asia-Pacific basins from the north-eastern and southern regions of the United States. The examples demonstrate the application of the methodology in both frontier and mature areas, either in quick data-room reviews or for delineating prospects.
Oil-Based Fracturing Fluid: First Results in West Africa Onshore
Authors: Perfetto R. , Melo R.C.B. , Martocchia F. , Lorefice R. , Ceccarelli R. , Tealdi L. , Okassa F. 
Published: May 2016

Abstract
Hydraulic fracturing operations in West Africa are not as common as in the US, Latin America and the Middle East. In the Republic of Congo fracturing technology is spreading and has overcome more than few difficulties since the practice began. The most significant challenge has been the formation, which has shown through laboratory testing to be soft and water-sensitive.
The fracturing project started in the laboratories, identifying critical issues, such as formation heterogeneity, hardness, water sensitivity, clay content and particularly the risk of proppant embedment.
The fracturing fluid chosen for the project was a water-based, borate-crosslinked guar fluid, with specific chemicals added to minimize formation softening and clay swelling issues. A specific pumping strategy was implemented when using water based fracturing fluid to limit the effects of proppant embedment. Several wells were treated with this system.
In an effort to improve well productivity, a pilot test was designed with oil-based fracturing fluid. This fluid was pumped in two wells, resulting in improvements in terms of cleanup time and economics, compared to the water-based treatment fluids in the same field.
Part of the economic benefit was gained because of the reduced hydrostatic head of the oil-based fracturing fluid, which eliminated the need for a coiled tubing gas lifting operation. Economics were also improved by minimizing rentals of well cleanup equipment because the broken fracturing fluid can be sent directly to production facilities. In this paper, design and application results for the oil-based fracturing fluid operations are presented with all the operational and logistical challenges overcome.
Imaging Earth
Authors: Zhu Hejun , Luo Yang , Bozdag Ebru , Peter Daniel , Tromp Jeroen 
Published: May 2016

Abstract
Harnessing high-performance computers and accurate numerical methods to better constrain physical properties of Earth's interior is becoming one of the most important research topics in structural and exploration seismology. We use spectral-element and adjoint methods to iteratively improve 3D subsurface images ranging from continental to exploration scales.
The spectral-element method, a high-order finite-element method with the advantage of a diagonal mass matrix, is used to accurately calculate three-component synthetic seismograms in a complex 3D Earth model. An adjoint method is used to numerically compute Frechet derivatives of a misfit function based on the interaction between the wavefield for a reference Earth model and a wavefield obtained by using time-reversed differences between data and synthetics at all receivers as simultaneous sources. In combination with gradient-based optimization methods, such as a preconditioned conjugate gradient method, we are able to iteratively improve 3D images of Earth's interior and gradually minimize discrepancies between observed and simulated seismograms. Various misfit functions may be chosen to quantify these discrepancies, such as cross-correlation traveltime differences, frequency-dependent phase and amplitude anomalies as well as full-waveform differences.
Various physical properties of the Earth are constrained based on this method, such as elastic wavespeeds, radial anisotropy, shear attenuation and impedance contrasts. We apply this method to study seismic inverse problems at various scales, from continental-scale seismic tomography to exploration-scale full-waveform inversion. Two examples are utilized to illustrate the applications of this method, namely, 1) application of adjoint tomography in improving 3D elastic wavespeeds of the European crust and upper mantle, and 2) application of the impedance gradient in elastic reverse-time migration for a 2D salt dome model.
First Horizontal Openhole Gravel Pack Installation in a Clastic Gas Reservoir: KM Field
Authors: Izzat M. , Nizam M. , Azmi Mahadi K. , Ogbonna C. , Jadid M.B. , Chen Y. , Chia I. 
Published: May 2016

Abstract
The KM field is part of the KM cluster development project, which plans to deliver 100 MMscf/D of gas to liquefied natural gas (LNG) from five horizontal wells. Four of the wells were completed with 4 1/2-in. production tubing using horizontal openhole gravel packs (HZOHGPs) as sand control, which was the first application of this technology for the operating company. Based on geomechanical modeling, the KM field is an unconsolidated clastic gas reservoir that requires active sand control. The particle size distribution (PSD) suggests that the KM clastic formation is a poorly sorted sand with a high uniformity coefficient and very high fines content; thus, justifying the need to use a gravel pack completion rather than a screen-only completion. The conventional internal gravel packed (IGP) technique has been widely applied because it provides a reliable means of abating sand production. However, it does not provide the same productivity as a HZOHGP. IGP is also highly prone to increasing skin throughout the production life of the well. Nodal analysis indicates that HZOHGP would give the highest production index (PI) with low production drawdown compared to a cased-hole gravel pack completion, in addition to potential cost savings realized from the elimination of the casing, cementation of the casing, and perforation of the casing. Running a screen in conditioned, solids-free mud, avoiding premature bridging during the job execution, proper removal of the mud filter cake, and limiting flow to below critical drawdown pressure (CDP) play important roles in the successful implementation of a HZOHGP completion in the KM field. This paper describes the planning of the first openhole gravel pack installation for an unconsolidated gas formation while highlighting the risk assessment, the lessons learned, and the excellent production performances achieved. Use of OLGA® transient simulators for estimating drawdown during well cleanup is also briefly discussed.