bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspekte einer evidenzbasierten Therapie klinischer Mastitiden
Authors: Mansion-de Vries E. M. , Hoedemaker M. , Krömker V.
Published: September 2015

Die Mastitis ist eine der häufigsten und kostenintensivsten Erkrankungen der Milchrinder. Die Entscheidung über die Therapie klinischer Mastitiden erfolgt meist ohne Kenntnis der Ätiologie und ist dadurch nur bedingt evidenzbasiert. Die evidenzbasierte Medizin beruht im Wesentlichen auf der Kombination des eigenen klinischen Sachverstands mit Erkenntnissen aus der Wissenschaft. Diese Erkenntnisse sind in der Mastitistherapie meist erregerabhängig, weshalb bei einer evidenzbasierten Therapieentscheidung die Erregeridentifizierung als Basis für die Berücksichtigung wissenschaftlich geprüfter Therapiekonzepte dienen sollte. Die Arbeit gibt auf der Basis einer Literatur-zusammenfassung Hinweise für die evidenzbasierte Therapie klinischer Mastitiden. Die Autoren kommen zu dem Schluss, dass bei der Mastitistherapie unabhängig vom Erreger immer eine antiphlogistische Therapie mit einem nichtsteroidalen Antiphlogistikum durchgeführt werden sollte. Die Wahl der antibiotischen Therapie ist jedoch sehr vom mastitisverursachenden Erreger, dem klinischen Bild und dem Tier abhängig. Grundsätzlich sollte die lokale antibiotische Mastitistherapie bei leichten und moderaten Mastitiden gewählt werden. Zu bedenken ist aber, dass der Nutzen einer antibiotischen Therapie bei Coliformen-Infektionen fragwürdig ist und es bei Kenntnis des Erregers durchaus vertretbar scheint, den Verzicht auf eine Antibiose in Erwägung zu ziehen. Bei schweren, also fiebrigen Mastitiden sollte eine parenterale Antibiose gewählt werden. Eine Verlängerung der antibiotischen Therapie über die in der Regel vom Hersteller empfohlene dreimalige Gabe hinaus erwies sich lediglich bei Streptokokken-Infektionen als sinnvoll. Die Entscheidung über eine verlängerte antibiotische Behandlung sollte deshalb erst nach Kenntnis des mastitisverursachenden Erregers getroffen werden. Bei der Wahl des Wirkstoffs sollte – hinsichtlich der Therapie von Staphylokokken oder Streptokokken – auf Schmalspektrum-Antibiotika aus der Gruppe der Penizilline zurückgegriffen werden.
Abolir o passado, reinventar a história: a escrita histórica de Hanfeizi na China do século III a.C.
Authors: Bueno André Da Silva
Published: September 2015

Na antiguidade, os intelectuais chineses acreditavam que a História continha todos os exemplos morais necessários para guiar a sociedade. Os pensadores deveriam buscar, no passado, as respostas para os desafios políticos, estratégicos e culturais. A História era, portanto, o caminho para a redenção moral. Todavia, no século III a.C., o pensador Hanfeizi, interessado em promover a teoria política da escola Legista, propôs que, sem abolir por completo o passado, seria impossível construir uma nova sociedade. Este artigo busca compreender no que consistia a proposta de Hanfeizi – abolir o passado, e reinventar a História – e os desdobramentos que ela teve para a sociedade e a historiografia chinesa.
Learner Inclinations to Study Computer Science or Information Systems at Tertiary Level
Authors: Jacobs C , Sewry D A
Published: September 2015

After the so-called “dot-com crash” of the Internet in the early 2000s, tertiary level student enrolments in IT-related

subjects began to experience a significant decline both in international countries and South Africa. The paper replicates

research done in the Western Cape, South Africa, by Seymour et al. (2005) [20], in which grade 12 learner inclinations to study Computer Science (CS) and Information Systems (IS) at tertiary level were analysed and underlying factors affecting their interest in the subjects were determined. The study analyses the “misguided” perceptions that learners and students have of these subjects; the implications of the decline in enrolments on students, educational sectors and industry; and determines a set of underlying factors that influence learners in their attitudes toward further degrees in IT, starting from the secondary level of education.

The research compares South African Eastern Cape learner perceptions with those from the Western Cape study and establishes three to four years later, that the reasons behind the decline in IT enrolments are still influenced by an underlying demographic and digital divide.
An exploration of Deaf telecommunication processes and associated social issues in South Africa
Authors: Liebenberg Marisa , Lotriet Hugo
Published: September 2015

This paper presents the results of an exploratory investigation into telecommunications practices and challenges among the Deaf in South Africa.

Telecommunication products like cell phones, TTY’s, sMessage terminals, e-mail, fax messaging, instant messaging (IM) were

some of the technologies investigated. The research shows that the Deaf considers IM as the most successful technology for both business and social communication. E-mail was rated most often used for business communication, where as e-mail and SMS were rated most used for social communication. The main drawbacks experienced by deaf users of telecommunications technologies related to connecting with and understanding of people.

The research findings indicate that the Deaf would like to see heightened public awareness of deafness and its challenges in

telecommunication.
From Procedural to Object-Oriented Programming (OOP)- Performance in OOP: An empirical study
Authors: Govender Irene
Published: September 2015

This exploratory study of introductory pre- and in-service teachers’ performance in object-oriented programming (OOP) assessments reveals important issues with regard to learning and teaching OOP, using java. The study is set against the backdrop of the country’s transition of its national IT curriculum from a procedural to an object-oriented programming language. The effect of prior programming experience and performances in different types of questions are examined. A combination of quantitative and qualitative methods is used to analyse the data. The effect of prior programming experience of a procedural kind and the type of assessments given is shown to have a marked influence on the performance in programming assessments and teaching of OOP. Many introductory OOP courses are in effect taught procedurally as courses in the small. Therefore educating teachers how to teach programming is a significant educational challenge. Some implications for teaching are therefore suggested
Challenges in Ascertaining ICT Skills Requirements in South Africa
Authors: Lotriet HH , Matthee MC , Alexander PM
Published: September 2015

World wide, a number of far-reaching decisions regarding ways to address the ICT skills shortage are made by both the public and private sectors. These are based on information obtained from various sources and in various ways including quantitative research reports commissioned by government authorities. This paper reports on findings of a systematic textual examination of existing ICT skills shortage research reports with the South African reports receiving particular attention. This analysis shows that the collection of accurate data on ICT skills availability is extremely difficult, if not impossible, as the skills categories used in a diverse, ever-changing ICT environment are ill-defined, the data collection procedures are flawed and the results are difficult to interpret. In addition, successive reports frequently note the weaknesses of the data, but then use it as the basis for their findings. A recommendation from this research is that a Research Methodologies group be formed specifically to discuss this and with the brief to suggest some guidelines and to monitor and endorse future data collection and analysis.
South African physicians’ acceptance of e-prescribing technology: an empirical test of a modified UTAUT model
Authors: Cohen Jason , Bancilhon Jean-Marie , Jones Michael
Published: September 2015

E-prescribing systems hold promise for improving the quality and efficiency of the scripting process. Yet, the use of the technology has been associated with a number of challenges. The diffusion of e-prescribing into physician practices and the consequent realisation of its potential benefits will depend on whether physicians are willing to accept and engage with the technology. This study draws on the Unified Theory of Acceptance and Use of Technology (UTAUT) and recent literature on user trust in technology to develop and test a model of the factors influencing South African physicians’ acceptance of e-prescribing. Data was collected from a sample of 72 physicians. Results indicate a general acceptance of e-prescribing amongst physicians who on average reported strong intentions to use e-prescribing technologies if given the opportunity. PLS analysis revealed that physicians’ performance expectancies and perceptions of facilitating conditions had significant direct effects on acceptance whilst trust and effort expectancy had important indirect effects. Social influence and price value perceptions did not add additional explanatory power. The model explained 63% of the variation in physician acceptance.
Self-perceived intrinsic and extrinsic differences between Information Systems and Computer Science university students
Authors: Alexander Patricia M , Lotriet Hugo H , Pieterse Vreda
Published: September 2015

Strong arguments exist that the sub-disciplines of Information Systems (IS) and Computer Science (CS) can be meaningfully distinguished, and the literature indicates that teams in which there are variety of personalities and divergent career interests are more likely to successfully complete computing projects. This paper set out to identify differences in terms of personality and career objectives between those entering universities with the intention of pursuing a career in CS and those intending to study IS. First-year students from South African tertiary institutions in 2010 and 2012 were studied in terms of self-reported personality factors (using the Five Factor Model as frame of analysis) as well as perceived environmental factors associated with career choice. Surprisingly, the only persistent significant difference found was that IS students consider well-paid employment as soon as possible after graduating to be more important than CS students do. In terms of the other factors studied no significant differences were found to occur in both years for which data was analysed. Hence, the result show that combining data collected from the students studying different sub-disciplines of computing is justified for research that specifically studies personality or factors such as interest, self-efficacy, career outcomes and how the career choice impacts on quality of life. At a practical level, the findings inform efforts in attracting, retaining and teaching students in these sub-disciplines.
Applying long short-term memory recurrent neural networks to intrusion detection
Authors: Staudemeyer Ralf C.
Published: September 2015

We claim that modelling network traffic as a time series with a supervised learning approach, using known genuine and malicious behaviour, improves intrusion detection. To substantiate this, we trained long short-term memory (LSTM) recurrent neural networks with the training data provided by the DARPA / KDD Cup ’99 challenge.

To identify suitable LSTM-RNN network parameters and structure we experimented with various network topologies. We found networks with four memory blocks containing two cells each offer a good compromise between computational cost and detection performance. We applied forget gates and shortcut connections respectively. A learning rate of 0.1 and up to 1,000 epochs showed good results.

We tested the performance on all features and on extracted minimal feature sets respectively. We evaluated different feature sets for the detection of all attacks within one network and also to train networks specialised on individual attack classes. Our results show that the LSTM classifier provides superior performance in comparison to results previously published results of strong static classifiers. With 93.82% accuracy and 22.13 cost, LSTM outperforms the winning entries of the KDD Cup ’99 challenge by far. This is due to the fact that LSTM learns to look back in time and correlate consecutive connection records. For the first time ever, we have demonstrated the usefulness of LSTM networks to intrusion detection.
An Insider Threat Neutralization Mitigation Model Predicated On Cognitive Dissonance (ITNMCD)
Authors: Padayachee Keshnee
Published: September 2015

The insider threat concern is a complex issue, as the problem domain intersects the social, technical and socio-technical dimensions. Consequently, counteracting the insider threat involves influencing the insider’s perceptions and behaviour in order to ensure compliance. When an individual’s actions and beliefs are incongruent, this induces a phenomenon known as cognitive dissonance. In order to reduce this dissonance, individuals are self-motivated either to change their behaviours or beliefs, or to rationalize their behaviour. Neutralization is a technique used by criminals to rationalize maleficence. In terms of the insider threat, it has been proposed that if the justifications for committing an offence are eliminated, then the insider is less likely to commit the offence. This process is known as neutralization mitigation. The research reported on here proposes that inducing cognitive dissonance may be a means of mitigating the neutralizations that the insider may use to justify maleficence. To integrate these concepts into a pragmatic implementable solution the Insider Threat Neutralization Mitigation model predicated on Cognitive Dissonance (ITNMCD) is proposed. A proof-of-concept was developed and the model concept was evaluated using the design science method.
Efficient Compositional Simulation with Locally Lumped EOS Characterization
Authors: Fleming Graham , Wong Terry
Published: September 2015

Equation-of-state (EOS) fluid characterization is used to model the behavior of hydrocarbon reservoirs when variation in the fluid composition has a significant influence on the recovery of hydrocarbons. Examples are miscible gas-injection processes, where mass transfer between the injected gas and in-situ hydrocarbons can result in the injected fluid developing into a fluid that is miscible with the in-situ hydrocarbons, or gas-condensate fluids, where the liquid yield varies with pressure and composition as the reservoir depletes. For many reservoirs, more than one recovery mechanism is employed. For example, insufficient supply of miscible injectant might result in part of a reservoir employing miscible injection, while part is under waterflood. In such cases, accurate prediction of recovery for the miscible injection area might require an EOS characterization with a large number of components, while the phase behavior in the waterflood area could be modeled with sufficient accuracy with many fewer components. Phase-behavior calculations become much more computationally expensive as the number of components increases, but current commercial reservoir simulators must use the same number of components everywhere in the reservoir model. Thus, the requirement to use a large number of components to model the recovery process in part of the reservoir results in a large computational penalty in regions of the reservoir where a smaller number of components would suffice.

In this paper, we describe a method whereby the fluid can be locally lumped for phase-behavior calculations so that regions that are able to maintain sufficient compositional accuracy with fewer components can use less-expensive EOS calculations. Different lumpings can be used at different times in the life of the reservoir, as compositional effects become more or less important in different regions in the reservoir. Example problems that demonstrate the flexibility, efficiency, and consistency of the method are explored.
Performance Step Change: Optimized PDC Design for Directional Drilling Application Increases ROP by 39% Drilling Difficult Hard/Interbedded Formations in Northern Kuwait
Authors: Al-Khaldy M. D. , Al Failakawi K.. , Al-Mulaifi M.. , AlRashidi A.. , Nair P.. , Hassan S.. , Ghoneim O..
Published: September 2015

Constructing the 12¼” direction hole section through approximately 3000ft of difficult interbedded lithologies (Mutriba-Lower Burgan) in northern Kuwait presents a number of distinct challenges. In the upper portion of the hole section, a PDC bit must penetrate medium to hard carbonate and shale formations with compressive strength ranging between 9-12 kpsi with peaks up to 30kpsi. Next, a challenging abrasive sand with compressive strength between 6-9kpsi requires an RSS/PDC assembly to reach TD. The operator experimented with several different bit designs attempting to efficiently achieve directional objectives and improve borehole quality with limited success. Issues with baseline designs included lack of cutting structure durability and low ROP.

To accomplish the operator's objectives, the engineering team analyzed all relevant offset data and concluded an existing 12¼” six-bladed bit with 16-mm cutters would serve as the starting point for an optimization effort. The bit's design data was fed into an FEA-based modeling system. Formation characterization software was then utilized to select the appropriate rock samples to simulate the field formations in the laboratory. Multiple simulations were run to determine the best combination of technologies to achieve the objectives. A new 12¼” directional design (616-type) would include premium cutters that can withstand impact in the interbedded carbonate/shale section and remain sharp while drilling the lower sand formations to TD. The bit also features a torque limiting feature in the blade top and TSP inserts in gauge to ensure hole quality. Next, a series of simulations were preformed to observe how different RPM and WOB values would affect vibration and torque levels. The results were plotted to create a smooth drilling parameter window to maximize the new bit's ROP potential.

The new bit design was run on RSS with PDM assist and set a new ROP record of 46 ft/hr, 39% faster than the best offset of 33 ft/hr and 68% higher than the five-well offset average (27.3 ft/hr). The bit met all directional objectives (5-6° DLS) and was pulled in excellent dull condition (0-1-WT). The authors will discuss the bit design and selection process in addition to the HTHP cutter technology which saved the operator 2.5 days of rig-time and associated costs.
Removal of Ilmenite Oil-based Filter Cake under HP/HT Conditions Using Hydrochloric Acid
Authors: Xiao J.. , Nasr-El-Din H. A. , Al-Bagoury M..
Published: September 2015

Oil-based drilling fluids using a micronized ilmenite (5 µm) as weighting materials are proved to be suitable for HP/HT drilling operations with good rheological properties, low sag tendency, and low filtration volumes, even after heating at 400°F for 16 hours. The objective of this study is to assess the efficiency of hydrochloric acid to remove ilmenite oil-based filter cake, and therefore remediate any damage that might occur during its use in drilling operations.

An oil-based drilling fluid containing micronized ilmenite with 1.9 S.G. was used for filter cake formation. A HP/HT filter press was used for the removal process of ilmenite oil-based filter cake. Prior the acid removal, a mutual solvent (10 vol%) was used to break the oil-based filter cake for 2 hours. The purpose of the use of a mutual solvent is to remove the oil-soluble components and change the wettability of oil-based filter cake. Berea sandstone cores with an average porosity of 18 vol% and an average permeability of 50 md were used. CT scan, XRD, SEM, and chemical analysis were used to examine the reaction characteristics of different concentrations of acid with ilmenite oil-based filter cake. Coreflood tests with different concentrations of HCl were also conducted to provide recommendations on how to remove the internal damage caused by oil-based drilling fluid invasion during drilling operations.

Results showed that ilmenite oil-based filter cake can be successfully removed at 300°F after soaking with 5 wt% hydrochloric acid for 4 hours, even without causing much damage to the core permeability. The filter press test showed that the retained permeability of Berea sandstone cores was more than 90%. In the core flood tests, with the increment of the HCl concentration from 5 to 15 wt%, more internal damage could be removed. There was even some stimulation effect with 15 wt% HCl. This study will provide a complete evaluation of the efficiency of hydrochloric acid in removing ilmenite oil-based filter cake for HP/HT applications.
Overcoming High-Temperature Logging Challenges While Staying Cost-Effective for a Tight Gas Project in the Sultanate of Oman
Authors: Briner Andreas , Ketabchi Iman , Nadezhdin Sergey
Published: September 2015

Data collection throughout the exploration stage is of paramount importance, especially for the unconventional projects. Since a vast amount of data is acquired through the well logging, large logging expenditures are usually incurred. In unconventional projects, marginal economics dictate particularly strict budget strategies, including expenditures for logging activities. A significant component of the logging costs is associated with the tool temperature rating. In northern Oman, the bottomhole static temperatures of the tight sandstone gas formation being explored are 175°C [347°F] or higher, which coincides with the upper limit of the conventional logging tools. It has been observed that the tool failure frequency increases dramatically when this limit is approached, leading to repeated logging jobs or regretted (missed) data. The simple way to increase the temperature rating of logging tools to perform at high bottomhole temperatures is to use ceramic electronic boards. However, the cost of this solution is roughly 10 times higher than standard tools. Slightly less costly is acquiring data with logging-while- drilling techniques; this has its own disadvantages, such as logging tool availability and data resolution. Another possible approach is careful assessment of the bottomhole temperature at particular times during logging to enable using conventional tools with lower temperature ratings. The assessment is a challenge itself. Direct measurements are difficult because the temperature gauges on logging tools are affected by heat from the electronic components. It is possible to simulate borehole conditions, but this requires extensive modeling and involves many variables such as cooling from mud circulation; heat transfer among the formation, annulus, and drillpipe; conversion of mechanical energy from drilling to heat; and the addition of hot cuttings to mud. That latter modeling has been performed and verified with the field data in various conditions: vertical and horizontal geometries and different mud types. The study established the achievable bottomhole circulating temperatures at various operations, duration of safe temperature window for less-expensive logging, and the bottomhole temperature profile in various drilling scenarios. This allowed delineating a road map for logging future high-temperature wells in the field.
Feasibility of Cyclic and Continuous Steam Injections into a Middle-Eastern Heavy Oil Reservoir: A Simulation Approach
Authors: Mongy Mohamed A. , Shedid Shedid A.
Published: September 2015

Steam injection has been applied successfully worldwide. The main objectives of this simulation study are to investigate the influences of steam quality, steam injection rates, well spacing, and well completion on the performance and oil recovery by cyclic and continuous steam injection modes into a Middle Eastern heavy oil reservoir. The ultimate goal of this study is to design a complete steam injection process capable to provide the highest cumulative oil recovery.

Screening criteria has been applied for the reservoir to select the steam injection as the most appropriate enhanced oil recovery (EOR) method. The geological and fluid models were well-established and used with other reservoir rock, fluid, petrophysical data plus production history data to develop the best history matching for the reservoir under development. The effects of different injection injection rates, well completion and well spacing have been investigated. Heat distribution profile at different injection rates is developed plus water cut curves for different time intervals over 20 years. The influence of different types of well completion of open hole and selected perforated zones are also studied for different numbers of injectors and producers. The steam quality is optimized under different conditions for all proposed scenarios.

The results indicated that the application of the open-hole well completion and the increase of steam injection rate increased the attained production rate for different steam quality and different well spacing. The optimum steam quality is determined and used for different proposed combinations of the above-listed factors in this reservoir. The results also indicated that the application of selected perforation well completion is better than open hole completion because it is proven to provide better heat distribution throughout the pay zone.

The results of this study develop a systematic approach for optimization the application of both cyclic and continuous steam processes considering heat distribution, well completion and variable parameters of the reservoir under development.
Innovative Water Control Technique for Horizontal Wells in Isotropic Reservoirs - Successful Case History From Belayim Field
Authors: El Gogary Ahmed. F. , El-Masry Hossam. H. , Kortam Mostafa. M. , El-Rayek Hany. R.
Published: September 2015

Horizontal and highly deviated wells are increasingly being used in oilfield developments worldwide. Large-bore horizontal wells can deliver significantly higher oil production rates than conventional completions, reducing field development costs by allowing reserves to be targeted with fewer wells

Rudies formation in Belayim Land field is a bottom water-drive reservoir with a strong supporting aquifer. it is characterized by its great isotropy and heterogeneity where based on the analysis of SCAL data, it was found that the vertical permeability is nearly equal to horizontal permeability raising the problem of water coning(cresting), earlier water breakthrough situation and masking the oil production by water due to the great difference in mobility

Based on calculation of the critical coning production rates and water control plots it was concluded that the horizontal wells drilled in Rudies formation which are produced with high production rates suffered from extreme water coning problems that raised the necessity for water shutoff procedure to be considered

Field cases presented on this paper explain applications of internal casing packer and blank tubing as a tail pipe in accompanied with downgrading the production rates from horizontal wells for the purpose of zonal water control in the uppermost section of open hole and slotted liner completed horizontal wells in Petrobel

Included in this paper are two different field cases for uncemented water shutoff in horizontal wells that succeeded in decreasing the water cut in the wells from the range of (90-95 %) to the range of (10-30%) implementing a huge increase in the gained net oil towards achieving the maximum recovery. Technical data including well configuration, production performance and casing string are included in the paper. Field operations and lesson learned from each application are also presentedinthispaper
The Investigation of Tight Reservoir Responses to Induced Hydraulic Fracturing – With the Use of Analytical and Numerical Analysis
Authors: Dahroug Ahmed , Cosgrove John , Bachiri Salim
Published: September 2015

Tight gas reservoir development has long been affected by 1) complex flow profiles and 2) the impact of very low permeability on reservoir productivity. Where well tests (WT) buildup is very short, interpretation becomes difficult and results often are ambiguous. Most WT of tight, dry gas wells are of short duration; thus, such tests typically lead to multiple interpretations and open-ended conclusions. Adding to the complexity, simulation software packages often fail to adequately model flow in fracture networks.

A series of well tests were conducted in tight sandstone, dry gas, naturally fractured reservoirs post-induced hydraulic fracturing. The tests were conducted for long durations: 100 hours in most cases, and 1,000 hours in two extended well-test cases. The WT responses from these tests were ambiguous.

We have investigated possible direct causes of the ambiguous results, including wellbore, geology, and specific well conditions. However, because the WT response has been found repeatedly in a variety of regions around the world, it may not be related to any of these.

After investigating in multiple manners, including the use of simulation software, we argue that the anomalies in the WT response may reflect a step in the scale-dependent properties of the fracture network.
Oil Shale in Upper Egypt and it’s Economics
Authors: Salam Mahmoud Abdel , AbdulGhaffar Mostafa
Published: September 2015

The term oil shale generally refers to any sedimentary rock that contains solid bituminous materials (called kerogen) that are released as petroleum-like liquids when the rock is heated in the chemical process of pyrolysis. Oil shale was formed millions of years ago by deposition of silt and organic debris on lake beds and sea bottoms. Over long periods of time, heat and pressure transformed the materials into oil shale in a process similar to the process that forms oil; however, the heat and pressure were not as great. Oil shale generally contains enough oil that it will burn without any additional processing, and it is known as “the rock that burns”.

Oil shale can be mined and processed to generate oil similar to oil pumped from conventional oil wells; however, extracting oil from oil shale is more complex than conventional oil recovery and currently is more expensive. The oil substances in oil shale are solid and cannot be pumped directly out of the ground. The oil shale must first be mined and then heated to a high temperature (a process called retorting); the resultant liquid must then be separated and collected. An alternative but currently experimental process referred to as in situ retorting involves heating the oil shale while it is still underground, and then pumping the resulting liquid to the surface.

This work focus on oil shale as energy resource unused in Egypt with about 8 billion bbl oil reserves, require a new technology, not existed in Egypt with high operating costs.

It answers the following questions: is the conditions and oil price suitable for start-up of oil shale project in Egypt to be accepted by Ganope (Holding company related to the Egyptian ministery of petroleum) and the investor. If not, what is the minimum oil price required for the project to be attractive, with which concession agreement terms.
Abu Madi Reservoirs-Evaluation of Level-III Remaining Gas Potential, Abu Madi And El Qara Fields
Authors: Nassar Mohamed , Matresu Justin , Talat Amr , Hasan Motaz
Published: September 2015

Nile Delta Basin is a mature gas producer in Egypt, from the early sixties till present many gas discoveries were made in both on & offshore areas in the Pliocene and Miocene reservoirs. The first gas field, Abu Madi Field, was discovered onshore Nile Delta in 1967, by AGIP (IEOC) with the drilling of the Abu Madi-1 (AM-1) well. The Abu Madi field started to be developed since 1970, it's producing wells increased to 21 and by end-1992, the field had a capacity of 400 MCF/d; being that time the biggest gas field in Egypt. Subsequently of the gas-bearing reservoir discovered in Abu Madi Formation (Late Messinian) - becomes one of the main targets in on and offshore area of Nile Delta. The stratigraphic framework of the Abu Madi Fm., was reveal through years, now a days this formation is considerate as a sedimentary infilling of a fluvial paleovalley characterized by stacked fluvial-deltaic sandstone and shale's. The classical Abu Madi Fm., lithostratigraphic layering comes from the Abu Madi/El Qaraa fields where the reservoirs sandstones levels have been named, starting from bottom, as follows: Level 3 (Lower, Main, Upper and 3A), Lev2 and Lev 1. The recently wells targeting the Lev 3 Main and Lev 3A reservoirs did not achieved the estimated remaining recoverable resources. In this study the new 3D seismic data, production history and petrophysical data were integrated in order to relocate the unachieved residual OGIP and also to find new drilling opportunities for additional potential resources.
Incorporating Lithofacies Classification and well logs into Statistical Learning Algorithms for Comparative Multisource Permeability Modelling
Authors: Al-Mudhafar Watheq J. , Mohamed Lamees
Published: September 2015

Multisource and multiscale modelling of formation permeability is a crucial step in overall reservoir characterization. Thus it is important to find out an efficient algorithm to accurately model permeability given well logs data. In this paper, an integrated procedure was adopted for modelling formation core permeability given well logs and Lithofacies classification for a well in sandstone formation in South Rumaila Oil Field, located in Iraq. The core permeability was modelled give well logs interpretation: neutron porosity, shale volume, and water saturation as function of depth, in addition to the vertical Lithofacies sequences. The statistical learning algorithms that were adopted in this paper are Generalized Linear Models (GLM) & Smooth Generalized Additive Model (sGAM) for permeability and Probabilistic Neural Networks (PNN) for Lithofacies prediction.

Firstly, the Probabilistic Neural Networks was adopted for modelling and prediction the continuous and discrete Lithofacies distribution. The classified Lithofacies were considered as a discrete independent variable in core permeability modelling in order to provide different model fits given each Lithofacies type to capture the permeability variation. Then, GLM and sGAM models were applied to build the statistical modelling and create the relationship between core permeability and the explanatory variables of well logs and Lithofacies. GLM considers the maximum likelihood function to estimate the coefficients; however, sGAM considers a sum of nonparametric smoothing functions to identify nonlinear relationships depending on the degree of smoothing. The cubic spline function provides the closest fit as it minimizes a penalized negative log-likelihood function, which represents the smooth terms, by minimizing of an internal generalized cross validation function by iteratively reweighted least squares.

In sGAM results, Root Mean Square Prediction Error (RMSPE) and the R-squared have better values than GLM especially in the reduced models. The stepwise elimination was considered to find the best predictors subset in GLM; nevertheless, the non-influential predictors in sGAM were recognized and treated as splines smoothed term to ensure rejection for the null hypothesis and ensure the confidence interval to be greater than 95%. The sGAM model has led to overcome the multicollinearity that was available between one pair of the predictors by using the smoothed terms. All the multivariate statistics analyses of Lithofacies classification and permeability modelling with results visualizations were done through R, the most powerful open-source statistical computing languages.
New Engineering Solution Applied in SUCO Gulf of Suez for Maximizing Usage of Offshore Platforms to Drill Four Times More the Number of Wells From the Same Slot
Authors: Magdy Ramy , Yosri Karem
Published: September 2015

This paper is to highlight the engineering advance method had been successfully applied in Gulf of Suez, Red Sea, Egypt, well, January 2014. This new method enables to use the same slot for several slot recovery operations rather than only one slot recovery. The Deflecting Conductor Shoe is made as a subsea diverting tool. The conventional size ranging from 24” to 30” depending on the platform's dimensions and restrictions. Using a DCS with bigger sizes designed to match the platform's levels to result in the minimum angle at seabed, and to permit for conductor movement horizontally. Also to avoid the magnetic effect at the seabed a mechanical gyro used to determine Azimuth. The spacing between the conductors at the seabed is designed in pattern to allow for best anti-collision results, and more number of wells. The modification on the DCS is by the controlled azimuth of exit, the diameter and the new conductor inclination at the seabed. The most important feature in this design is the ability to engage with a spear from the inside in the future, and turn it to the desired direction considering collision with nearby wells, and with applying the method of drill and drive the risk of hitting nearby wells had vastly decreased and the ability to correct the well path increased by using motors. Using this design will push the platform life within the increased production and in the same time saves the cost to install standalone wells or to establish new platforms extensions which enhances the investment cost for wells on old fields. This means an overall revival of old platforms and old slots whilst making the best use of reservoir potential reserves which were difficult to be achieved with minimal cost. Using this new design, each slot on the platform can be used for multiple slot recoveries, up to five. This design is a modification on the methodology of using the DCS tool which is still conventionally used by major Oil and Gas companies.
Improve Predictions of Petroleum Type and Property Distributions in Reservoirs
Authors: Bouhlel Aziza Moumen
Published: September 2015

Petroleum system modeling has mostly been the preserve of exploration departments in major oil companies, which have the specialist resources to execute these studies. However, as it is a dynamic tool for petroleum system analysis, it also has significant applications in the development stages.

It may provide information on several different aspects of the areas surrounding a discovery: show which other closures were located on the same migration pathways from the same source and highlight the likely oil and gas distributions in these closures.show which satellite accumulations were effective traps and their hydrocarbon composition.The chance that the structure has been flushed with another hydrocarbon type, breached and re-charged, or only contains residual hydrocarbon may also be predicted.

The compositional information from a 3D petroleum system model can be valuable in: Planning appraisal and satellite exploration drilling,Facilities planning where the hydrocarbon composition and the number of satellites that will contribute to the plateau are important to design vs. economic decisions, andRelinquishment decisions.

A discovery well has encountered oil and there is a significant volume of the reservoir updip of the well. 3D petroleum system modeling can be used in determining the possibility of a gas cap and the necessity of the investment in an updip appraisal well. Furthermore with multiple compartments of which only one has been tested the understanding of the effectiveness of the fault seal is critical to determine if the closure may have different hydrocarbon compositions.

The 3D petroleum system modeling can prioritize appraisal drilling to test structures that are most likely to have the desired fluid fill. Furthermore in the case of parts of the concession area has to be relinquished the 3D petroleum system modeling can be used to determine which areas has the lowest economical value in the development.

The high-resolution charge, thermal and pressure histories are important boundary conditions which are required to understand the genesis of the field and the original properties of the oils, and then to obtain an improved understanding of the conditions under which the development hydrocarbons could have taken place (e.g.biodegradation, multi-phase hydrocarbon filling, thermal maturation, water washing, gravitational segregation, hydrocarbon migration along faults, etc).

This provides the best possible definition of the charge, temperature and pressure histories, which will then be available to improve analyses of the genesis and distribution of Hydrocarbons.
Revisiting Reaction Kinetics and Diffusion Rate of Dolomitic Rock with HCl
Authors: Khalid Muhammad Ali , Sultan Abdullah , Qiu Xiangdong
Published: September 2015

Diffusion coefficient (De) is an important parameter used in both matrix acidizing and acid fracturing job design. There are two major limitations of conventional lab practices. Firstly, De is obtained at 1000 psi (or below) system pressure, which is too low to represent realistic reservoir conditions. Secondly, De obtained from conventional lab practice is based on fresh acid, which largely ignores the impact of reaction products, especially CO2.

Herein, we investigate the effects of both pressure and reaction products on De of HCl acid reacting with dolomite using fresh acid (15 wt. %) and various spent acid concentrations (12.5, 10 and 7.5 wt. %). A customized rotating disk apparatus was used to obtain the reaction kinetics data at pressure conditions of 1000 and 3000 psi at various disk rotational speeds (250 – 1250 rpm) at 150 °F. Samples of the reacted acid were collected and analyzed using Atomic Absorption Spectroscopy. In addition, the disks were scanned using X-ray micro computed tomography to characterize the 3D image of the disks.

Our experimental results showed that at equal HCl concentration levels, De was significantly decreased at elevated pressures, due to the impact of CO2 produced by the HCl-carbonate reaction. There was approximately 23% decrease in the diffusion coefficient value when compared with 1000 psi results for HCl/dolomite reaction. On the other hand, when the fresh acid was spent to 12.5 wt. %, there was a slight decrease in the diffusion coefficient results because of the slow reaction rate of dolomite. Moreover, HCl/dolomite reaction was mass transfer limited at low disk rotational speeds and surface reaction limited at high disk rotational speeds. In addition, diffusion coefficient was significantly affected by rock porosity due to variation in surface reaction area which caused increase in dissolution rates as observed by Micro XCT images of the reacted disk.

Rotating Disk experimentation have been used for many years to describe acid reactivity. Literature suggests very few have been conducted under sufficient pressure to represent reservoir conditions. Thus, in order to properly design the acid treatment jobs, the De of acid acquired from high-pressure and various spent acid conditions should be used to provide more reliable parameters estimation such as acid injection rate, volume and pumping schedule leading to more accurate production forecast.
Acidizing of High Temperature and Highly Sensitive Multilayered Carbonate Well with Aminopolycarboxylic Acid Low-pH Fluid: Field Implementation and Laboratory Validation
Authors: Reyes Enrique A. , Rispler Keith , Davis John , Stimatze Russell , Ouedraogo Martial , Beuterbaugh Aaron , LaBlanc Alyssa , Williams Wade , Rees Steve , Bungo Feliciano , Kintomba Pedro , Aguiar Inacio , Morais Elvira De
Published: September 2015

During effective acid stimulation of mature producing wells, operators often face challenges in terms of achieving sustained production increases. Such challenges in formations subjected to acid stimulation in offshore West Africa include high temperatures (305°F), low reservoir pressure (0.22 psi/ft), highly heterogeneous multilayered formations with large perforated intervals (greater than 1,300 ft net and 2,400 ft gross), and scale in the wellbore, perforations, and sometimes in the near-wellbore area (NWA). Wells in this area, when treated with conventional acid systems based on hydrochloric acid (HCl), only sustain the productivity increase for very short periods. Such conventional acid systems have been based on 7.5% HCl and 10% acetic acid (AcOH) with high loadings of corrosion inhibitor, iron sequestering agents, demulsifiers, and antisludge agents.

This approach has constraints that can potentially include the following:

Ineffective stimulation attributed to fast acid reaction rates Limited penetration of live acid Rock disintegration Damage from reprecipitation of acid reaction products, such as iron and mineral fines from wellbore scale Damage from high corrosion inhibitor loading Fluids (stimulation and reservoir) incompatibility

The use of a newly developed aminopolycarboxylic acid (APCA) based stimulation fluid provides advantages that circumvent these constraints. The introduced technology delivers a stimulation system that provides deeper stimulation treatments because of lower reaction rates and potentially a more effective wormhole type of reaction for the reservoirs' characteristics. This stimulation fluid also chelates reaction products to help enable superior cleanup of the acid system. This system also requires lower loadings of corrosion inhibitors, demulsifiers, and antisludge agents, and is more compatible with formation lithology, lowering the risk of formation damage.
Laser Drilling Using Nd:YAG on Limestone, Sandstone and Shale Samples: ROP Estimation and the Development of a Constant ROP Drilling System
Authors: Hafez Ahmed , Ibrahim El-Sayed , Omar El-Said , Seif-Eddeen Fateen , Beshay Karam
Published: September 2015

Background/Scope: Mechanical drilling, the gold standard to reach oil and gas reservoirs, is associated with drilling risks and increased time and costs. Laser drilling has emerged as a potential new drilling tool. However, studies about its practical applications are limited. This study investigates the feasibility and performance of laser technology in drilling oil wells.

Methods: Core samples from the three lithologies were irradiated with Nd:YAG laser at different power intensities and exposure times while holding other parameters constant. Some core samples were saturated with brine to investigate the effect of fluid saturation. We developed a novel laser drilling system that enables users to input the lithology of encountered formations and output the power intensity needed to be drawn from the electric source to maintain the constant ROP.

Results: The Nd:YAG laser beam fully penetrated the cores in all the study trials conducted in shale. In limestone, the laser beam fully penetrated the cores in 5/13 trials and partially penetrated them in 7 trials. The experiments could not be performed in sandstone due to rough surfaces and high porosity. The ROP values ranged between 58 and 66 ft/hr (mean 62.4 ±5.3 ft/hr) in shale and between 221.7 and 460.6 ft/hr (mean 328.5±71.5 ft/hr ft/hr) in limestone. The specific energy values ranged between 650 and 5433 KJ/cm3 (mean 2885.1±1525.8 KJ/cm3) for the limestone samples. A statistically significant inverse correlation was observed between laser energy and ROP (r=-0.952, P<0.001). The developed software was tested and validated.

Added value: The study provides further evidence that laser drilling technology is a promising new technology for oil well drilling. The current study utilized high specific power laser which has not been previously used and developed a novel computer based constant ROP laser system. The rock removal mechanism should be shifted away from melting to spallation to achieve an efficient laser drilling mechanism through the optimization of the laser specific power and decreasing the specific energy during rock removal. Laser beam reflection, sample thickness and fluid saturation were identified as potential factors that influence the efficiency and performance of the laser drilling operation.