bluuebunny/crossref_metadata_2025 huggingface dataset:
A növénytermesztés szerkezetének optimalizálása a kockázatok figyelembevételével
Authors: Nagy Lajos
Published: March 2015

Az utóbbi években egyre élesebben jelentkeznek a globális éghajlatváltozás hatásai, és emiatt – a vitathatatlan genetikai és technológiai el?rehaladás ellenére – megn?tt a termésingadozás a növénytermesztésben. Ez az ágazat egyébként is a legkockázatosabb ágazatok közé tartozik, ezért már a tervkészítés szintjén, a döntés-el?készítési szakaszban célszer? figyelembe venni a kockázatot. A mez?gazdaságban leggyakrabban kockázatprogramozási modelleket alkalmaznak, melyek a döntéshozó kockázathoz való hozzáállását is figyelembe veszik, azaz hasznosságmaximalizáló modellek. A kockázatprogramozási modellek esetén el?ször azt kell eldöntenünk, hogy a kockázatot hogyan jellemezzük. A kockázat mértékének meghatározására – többek között – a szóródási mutatók is alkalmasak. Pénzügyi portfóliók optimalizálásakor a portfólió varianciájával adják meg leggyakrabban a kockázatot. A varianciát alkalmazzák a várható érték – variancia (E-V) modellekben is. A variancia minimalizálásakor egy kvadratikus célfüggvény? modellt kapunk. A variancia alternatívája lineáris programozási modellben az abszolút átlageltérés alkalmazása. E cikk célja a pénzügyi befektetési gyakorlatban általánosan használt portfolió modell alkalmazási lehet?ségének a bemutatása a növénytermesztési szerkezet optimalizálásban és a kockázat minimalizálásban.
Új generációs hálózati infrastruktúra szükségessége és szélessávú hálózatfejlesztések értékelése a vidéki régiókban
Authors: Botos Szilvia
Published: March 2015

Az új generációs hálózatok hatása a vidéki régiók fejl?désére egyértelm?, azonban szektoronként eltér? mértékben van szükség a szélessávú hálózaton igénybe vehet? szolgáltatásokra. Az új generációs hálózati infrastruktúra kiépítése vidéki régiókban, ezáltal a digitális szakadék csökkentése, központi cél az Európai Uniós és a nemzeti stratégiákban.Regionális vizsgálatokkal bizonyítottam, hogy a szélessávú hálózathoz köthet? infrastrukturális és használati jellemz?k (például a szélessávú hálózattal rendelkez? háztartások, az internetes vásárlás, vagy a számítógép használat aránya) összefüggésben vannak a gazdasági és társadalmi jellemz?kkel (például a regionális GDP termeléssel és a foglalkoztatottsági mutatókkal). A regionális és országos szint? adatok alapján végzett vizsgálataimés az eredmények szerint az egyes országok IKT színvonalában mutatkozó jelent?s különbségek az egyes országokon belüli régiók között is megjelennek. Az egyes országok IKT fejlettségének komplex vizsgálatára több indikátor is készült, melyek segítenek a jöv?beli fejlesztési irányok meghatározásában. Ezen fontosabb indikátorok alkalmazásával bemutatom az NGN és a ráépül? szolgáltatások jelent?ségét a vidéki régiókban, a fejlesztéshez kapcsolódó gazdasági jellemz?ket, és a szélessávú hálózatok infrastrukturális és használati jellemz?inek összehasonlítási lehet?ségeit különböz? területi szinteken.
Co-operation between Europe and some Southern and Eastern Mediterranean Countries on the use of ICT in Education: constrains and opportunities learnt from several European projects
Authors: Dumont Bernard
Published: March 2015

Based on previous experience in Southern Europe and Middle-East, potentiality and constraints in collaborative projects are presented. More specifically, a number of EC funded ICT projects, undertaking by countries of these regions and implemented the last seven years, are presented in brief. By the introduction of quality issues and carefully examining a number of constraints and difficulties appeared during the development of these projects, we propose specific recommendations for successful co-operation, especially at a moment of deep and strong changes in these regions.
Driving Web 2.0 Tool Adoption in Agricultural Education
Authors: Costopouloul Constantina , Ntaliani Maria , Sideridis Alexander
Published: March 2015

The new opportunities for collaboration, participatory content creation and communication offered through the advancements of Web 2.0, such as social networking, blogs, wikis, video sharing and other, are creating new learning models. In turn, tutors cannot ignore this trend and have to bear the responsibility of incorporating Web 2.0 tools in formal, informal, work-based and vocational education and approach their students in a very familiar and favourable way. In this context, this paper tries to highlight the need for enhancing tutors’ skills and drive Web 2.0 tool adoption in educational practice. Thus, it draws upon the successful example of a European project regarding agricultural tutors’ training on Web 2.0 tools. The challenge for all agricultural tutors is how to integrate Web 2.0 tools into current curricula and education.
Design, Implementation and Assessment of Videoconferencing Sessions in Earth and Life Sciences: The Case of the Agricultural University of Athens
Authors: Papadopoulos George , Voulgari Iro
Published: March 2015

In this paper we present the methodology employed in the Agricultural University of Athens for the delivery of specific courses with the use of video conferencing technology. Earth and Life Science higher education courses (agricultural, environmental and biomedical courses) present specific requirements relevant to the exposure of the students to practical issues, and the exchange of expertise. The employment of video conferencing seems be a valuable solution for addressing a number of these requirements. We describe these requirements as they emerged from our study, and present the implementation of video conferencing sessions (design, application, and assessment). Through this paper we aim at describing examples of meaningful employment of video conferencing, particularly in higher education, share the positive and negative aspects of our approach, and provide insights for similar interventions in education and training.
Adopting E-training and Living Labs for Collaborative Learning for Rural Public Agencies
Authors: Ntaliani Maria , Costopoulou Constantina
Published: March 2015

Rural Small and Medium Enterprises devote significant resources exclusively for finding information so as to perform public services. The current period of information technology achievements but also financial crisis necessitates a different approach by local agencies and regional public authorities so as to provide information to rural businesses. In this paper , a European project entitled “Rural Inclusion” aiming at making the life of civil servants and rural entrepreneurs easier through innovative e-government services, training tools and methods is presented. In particular, this project offers collaborative learning for public authorities on providing information and adopting and deploying innovative e-government services, aiming at reducing the administrative burdens of rural businesses. In this light, this paper presents a framework for public authorities’ training so as to model and provide information and e-government services.
Readiness to use e-learning for agricultural higher education in Sub-Saharan Africa. Results from a survey of faculty members
Authors: Zschocke Thomas , Beniest Jan , Yayé Aissétou Dramé , Chakeredza Sebastian
Published: March 2015

E-learning is likely to be an increasingly important element in teaching agriculture and related subjects at universities in Sub-Saharan Africa. The purpose of this study was to explore the factors involved in determining the readiness and intention to adopt e-learning by faculty members at member institutions of the African Network for Agriculture, Agroforestry and Natural Resources Education (ANAFE). The study was based on the decomposed theory of planned behavior (DTPB) to predict intentions on the use of e-learning. DTPB draws on constructs influencing the attitude to use technology from two frequently investigated models in this area, that is, the theory of planned behavior (TPB) and the technology acceptance model (TAM). Valid responses were collected from 70 faculty members with a survey questionnaire. Validated scales from previous research were used to measure the variables of interest. The results revealed that the majority of the respondents have only limited access to ICT infrastructure and support services. However, they perceived e-learning to be very useful in general and to have the potential to enhance their teaching-related activities.
Investigating the long memory property of the Hungarian market pig prices by using detrended fluctuation analys
Authors: Kovács Sándor , Huzsvai László , Balogh Péter
Published: March 2015

Within the scope of this study we test the Long Memory property on monthly average pig market prices including piglet, young pig, sow and slaughter pig. We also calculate the Hurst exponent using Detrended Fluctuation Analysis (DFA) method. DFA is a method for determining the statistical self-affinity of a time serie. It is a useful technique for investigating time series with long memory (diverging correlation time and power-low decaying autocorrelation function. The obtained exponent by DFA is similar to those Hurst exponents estimated by other methods such as Rescaled Range (R/S) and AutoRegressive Fractionally Integrated Moving Average (ARFIMA), except the fact that DFA may also be applied to non-stacionary time series (mean and variance is changing with time) as in our case. We study the long memory property of the market pig prices. Data consist of four time series (piglet, young pig, sow, slaughter pig) between 1991 and 2013. Before the econometric analysis all the series were seasonally adjusted by using TRAMO/SEATS method. Data preparation was followed by differencing the time series and testing the normality and stationarity of them. In the next step we divided the analysed period to four parts and determined the Hurst exponent for each sub-period with the DFA method. So as to sum it up, slaughter pig prices are random, young pig and piglet prices developed similarly and have long memory, while sow price changes have definitely short memory
Patterns and Drivers of Mobile Telephony for Sustainable Livelihood among Rural Farming Households in Kwara State, Nigeria
Authors: Animashaun Jubril Olayinka , Fakayode Segun Bamidele , Idris Kazeem Adebayo , Adedokun Khairat F
Published: March 2015

Recently, it is acknowledged that mobile phones, as an asset, exhibits multiple functionalities and diverse applications that cut across all forms of capital accumulation necessary for sustainable livelihood. However, empirical result is sparse in Nigeria as to the impact of mobile phones on asset accumulation. This study examined the socio-economic determinants of mobile phone use and intensity of use for sustainable capital formation in among farming households in Kwara state, Nigeria. Specifically, 120 rural farming households were randomly sampled and count data on the number of calls made with respect to livelihood capitals generated. Binary Logistic regression and Zero-Inflated negative Binomial regression models were used in analyzing the data. The study revealed that 73% of the respondents have access to mobile phone use. The study identifies major uses of mobile phone for sustainable livelihood enhancement activities. Significant determinants of mobile phone use are; possession of formal education, household size, age, marital status, annual farm income, diversity of crop cultivated and the number of family members living outside the community (p
Impact of territorial constraints on the optimization of forest accessibility. GIS Spatial Analysis for Quercus forests in National Park of Peneda-Gerês, northwest Portugal
Authors: Pecora Giovanni , Moretti Nicola , Dias Susana Saraiva , Póvoa Orlanda
Published: March 2015

ArcGIS software was used for timber harvesting planning in four (4) different mountainous forest areas of Peneda-Gerês National Park (PNPG), located in Northwest Portugal. Orographic characteristics, such as slope and watershed systems features were considered. The different manual and mechanical timber extraction and concentration methods were also considered. The different typologies of roads network to access forests were also introduced in the models. The analysis allowed identifying forest areas with different accessibilities and orographic restrictions. Performed analysis also allowed the planning of additional roads necessary for timber extraction optimization, considering optimized site-by-site timber extraction methods. The proposal of accessibility improvement through new roads construction was also considered important for forest fire prevention and for fire direct combat. However, the present proposal of accessibility improvement is merely an academic exercise because nature conservation restrictions severely limit the construction of new forest roads. This methodological approach should be tested in other mountainous forest regions throughout Europe.
Integrated HS and ALS Remote Sensing Data Sources to Develop Green Corridors in Sopron Mountains
Authors: Tamás János , Bozsik Éva , Riczu Péter , Bernadett Gálya , Herdon Miklós , Nistor Stelian , Fehér János , Burriel Charles , Heilmeier Herman
Published: March 2015

The green corridors are part of the European Union rural landscapes, but the regional increase in size of agricultural parcels had a significant effect on European land use in the 20th century. This effect radically reduced the coverage of natural forest. One ecological problem with the remaining forests is the partial missing of the network connecting the parts with ecological green corridors. Another economical problem is the verifiability for the payment system of agroforestry. Remote sensing methods are currently used to supervise monitoring the arable lands, plantations, natural reserve areas, as well as to help for the European Union payment system. Nowadays the airborne hyperspectral (HS) and LiDAR (Light Detection And Ranging; ALS) remote sensing technologies are becoming of more widespread use. They can be applied especially in spatial decision support system (SDSS), used in decisions about for nature, environment, forests, agriculture protection, conservation and monitoring, as well as for monitoring of biomass production. Our site selection model was the first step towards planning an agroforestry plantation which uses these integrated technologies to connect the parts with green corridors.
Training Needs Assessment on the Use of Social Media among Extension Agents in Oyo State, Nigeria
Authors: Thomas Kehinde Adesina , Laseinde Ayobami Abiola
Published: March 2015

Agricultural information exchange has been dominated by industrial media such as newspapers, television, and magazines for decades. However, social media as a form of Information and Communication Technology (ICT) method for harmonizing sustainable agriculture and natural resources provides broader agricultural community that eliminates physical distance. The study therefore examined training needs assessment on the use of social media among agricultural extension agents in Oyo State, Nigeria. All the 90 agricultural extension agents in Oyo State Agricultural Development Programme (OYSADEP) were interviewed. This includes 35 from Ibadan|Ibarapa zone, 22 from Saki, 19 from Oyo and 14 from Ogbomosho zone. Result shows that the mean age of extension agents in Oyo State was 38±2 years, (98.8%) had one form of tertiary education or the other. Majority (72.0%) exhibited high need for training on the use of social media even when the result revealed that Facebook (47.6%) was mostly used social media among the agents. The result of inferential statistics shows that there was a significant relationship between education (X2 =10.142, p
Information Flow along Catfish Marketing Channels in Nigeria: Whither the Role of Mobile Telephony
Authors: Animashaun Jubril Olayinka , Fakayode Segun B. , Ayinde Opeyemi E.
Published: March 2015

The objectives of this study were two-folds; examined the use of mobile phone technology to facilitate catfish marketing and identified the determinants of variations in the frequency of mobile phone use for catfish marketing among agents involved in the marketing chain. The study was carried out in Kwara-state, Nigeria. One hundred and forty respondents were stratified and randomly sampled and data was collected through the use of well-designed questionnaires. Descriptive and Poisson regression model were used to analyze the data. The study identified the use of mobile phone along five communication channels used for catfish marketing. Annual income generated from catfish business was significant in explaining variations observed in the frequency of mobile phone use (p
Development of a new software application for supporting research of thermo-mechanical behavior of agri-food and forest products
Authors: Weres Jerzy , Olek Wiesław , Kujawa Sebastian , Nowak Przemysław
Published: March 2015

Development of applications and services conforming to recent standards and perspectives of ICT is important for increasing productivity in agri-food and forestry sectors to deliver desired quantities of safe and quality products to end-users. Therefore a field of study combining two national curricula: informatics and agricultural engineering was developed by the Department of Applied Informatics of the Poznan University of Life Sciences. The scope of studies corresponds to the area of research conducted in the Department and focuses on development of Web-based advisory systems for agriculture and information systems supporting research in the agri-bio-engineering. In the paper two exemplary systems are presented. They support analysis of thermo-mechanical behavior of agri-food and forest products subjected to heating, cooling, drying and storing operations. Development of the systems resulted in a significant increase in accuracy and efficiency of estimating properties of biomaterials and in more accurate predictions of the processes investigated.
Aspect regarding the use of renewable energy into vegetable farms of agritouristic pensions
Authors: Bianca Oprea Oana , Popovici Cristina , Gaceu Liviu
Published: March 2015

Development of applications and services conforming to recent standards and perspectives of ICT is important for increasing productivity in agri-food and forestry sectors to deliver desired quantities of safe and quality products to end-users. Therefore a field of study combining two national curricula: informatics and agricultural engineering was developed by the Department of Applied Informatics of the Poznan University of Life Sciences. The scope of studies corresponds to the area of research conducted in the Department and focuses on development of Web-based advisory systems for agriculture and information systems supporting research in the agri-bio-engineering. In the paper two exemplary systems are presented. They support analysis of thermo-mechanical behavior of agri-food and forest products subjected to heating, cooling, drying and storing operations. Development of the systems resulted in a significant increase in accuracy and efficiency of estimating properties of biomaterials and in more accurate predictions of the processes investigated.
Preparation of a dynamic simulation model to support decision making in a sensitive rural area
Authors: Varga Mónika , Balogh Sándor , Csukás Béla
Published: March 2015

This paper focuses on the demonstration of a conceptual framework and a dynamic simulation based tool, through the example of southern catchment basin of Lake Balaton. The objective is to support the sustainable and reasonable environmental management by model based investigation of various scenarios.

In the developed hydrological model, the coherence is given by the compartmentalized dynamic network of water flows and water bodies. The completeness is solved by the complete and disjoint covering of the whole area by modeled patches, corresponding to the CORINE land cover database of natural and human built environment. The complexity of the large scale and long term processes is managed by evaluating detailed models only for one representative patch from each class, while the calculation of the similar patches is solved by simple multiplication rules. According to the first experiences, the developed framework is able to integrate the field experts’ knowledge (data, relations, empirical knowledge, etc.) for the prediction of land use effects besides different climatic scenarios. It is noted, that continuous extension and refinement of the model and of the involved data is necessary, especially through more realistic case studies.
The Sick Novel From Anemic State: Sickness As Praxis In The African Novelist’s Agenda
Authors: Afolayan Sola
Published: March 2015

The African novel, like most other literary genres from the same region, has thrived under different nomenclatures. Hence within the sub categories of the genre are critics’ labels like pre-colonial, colonial, post colonial, disillusionment, political and apolitical. Interestingly it has been discovered that the christening of the African novel has always been the directives of the self-instructive profile of the genre, adequately powered by the analogous critical idioms supplied by the critics. For instance Chinua Achebe had labeled Armah’s The Beautyful ones are not yet Born as ‘the sick book’ in his popular, and instantaneous criticism of the novel. Little did Achebe know that his emblematic utterance on Armah’s premier narrative would serve as a signature to understand what other African novelists have done in their works. In this essay, we attempt to hypothesize with the notion of ‘sick novel’ in a bid to buttress the enduring themes and tropes in selected novel.
Determination of Invasion Diameter and True Resistivity from the Induction-SFL-Rxo Combination
Authors: Mohammed Akram F.
Published: March 2015

Deep Induction-log readings are often influenced by drilling fluids. If invasion by mud filtrate is deep and Rt/Rxo is small, the Induction log gives values that are higher than the true resistivity. Some water-bearing intervals that are severely invaded could confuse the log analyst by appearing as oil-bearing during interpretation for water saturation.

This paper describes a method that allows the analyst to compute invasion diameter (di) and true formation resistivity (Rt) from the measurements made with the Induction-Spherically Focused (ISF)4 -Rxo combination tool. The ISF log has proven to be a most useful logging tool under conditions of Rxo > Rt, Rmf > Rw, and shallow invasion. The method covers mainly the conditions when Rxo is greater than Rt. When Rxo is less than Rt the Induction log becomes less accurate for Rt evaluation. An accurate invasion correction chart has been constructed to determine values of di, Rxo/Rt, and Rt. Without this correction a serious error could result in the calculation of water saturation (Sw), especially in a deeply invaded formation and with Rxo >> Rt.
Keeping up With Technological Advances - An Innovative Approach to Validate Production Test Data
Authors: Khan M.N. , Menchaca T. Felix
Published: March 2015

The technological advances in oil and gas industry are enabling the operating companies to monitor their hydrocarbon reservoirs closely. Today reservoir surveillance engineers are able to acquire more well/reservoir performance data than in the past.

Multi-Phase Flow Metering is an expedient addition in production testing domain. As per the recent statistics, globally, approximately 4000 Multi-Phase Flow Meters (MPFM) installations are providing reliable measurements under different applications. As with any new technology the philosophy behind MPFM measurements is blurry for many users, who find difficulty establishing and implementing the appropriate data validation workflows on the MPFM data. The conventional production test data validation approach can be applied to the MPFM measurements up to a certain extent, but in order to find the source of discrepancies in MPFM data, additional processes are required to be included in the workflow.

The production history of the majority of hydrocarbon reservoirs in the world was built on conventional test separator flow rate data. Introducing a new measurement technology with different set of accuracies and different working principles has been a challenge for the production data users. To standardize the data validation process, a systematic approach can be implemented to validate the production testing data from different sources, which not only will help the end users to gain confidence in MPFM flow measurements but also will assist identifying the sources of discrepancy in MPFM measurements during day to day operations.

This paper will explain the stepwise data validation approach that can benefit different production test data users in oil and gas industry.
In-Situ Generation of CO2 to Eliminate the Problem of Gravity Override in EOR of Carbonate Reservoirs
Authors: Abdelgawad K.Z. , Mahmoud M.A.
Published: March 2015

Carbon dioxide (CO2) injection into hydrocarbon reservoir is reported by many researchers to be one of the best enhanced oil recovery techniques. CO2 for enhanced oil recovery has favorable characteristics such as miscibility between CO2 and oil under most reservoir conditions, intermediate component extraction and heavy oil viscosity reduction which is named CO2 flooding process. As a result of viscous fingering and gravity override, sweep efficiency decreases and significant amounts of oil are left behind during CO2 flooding. Foaming was used to increase the injected CO2 viscosity but a lot of problems were encountered with the foaming agents such as stability and thermal stability, etc.

In this paper we will introduce a new method of generating CO2 in-situ in carbonate reservoirs during enhanced oil recovery processes. The generation process includes the injection of low pH HEDTA or EDTA chelating agents followed by sea water, high pH chelating agents, or low salinity water. First the low pH chelating agent will react with the carbonate rock and produce CO2 that will diffuse to the oil and increases the oil mobility and in turn more oil will be produced. The chelating agents used are H2Na2EDTA (pH = 4.5), H3HEDTA (pH = 2.5), and H2NaHEDTA (pH = 4). The acid part which contains the hydrogen ions will attack the carbonate rock and produce CO2 that will increase the oil recovery, and then the high pH chelating agent or even sea water can be used to displace the low pH chelating agent and CO2.

The experimental results showed that about 90% of the oil in place was recovered from the carbonate cores without using of surfactants or any other additives. The new method will eliminate the problem of gravity override which is the main problem of CO2 EOR. The chelating agent can be placed in the whole reservoir by introducing a low reactive form of these chemicals or by encapsulating these chemicals to start reacting with the reservoir after the placement is complete. The reaction of the encapsulated chemicals can be triggered by temperature or any other triggering mechanism.
Use of Technology to Enhance Sustained Gas Production in Saudi Arabian Carbonate Reservoirs — Key Enablers
Authors: Rahim Zillur , Al-Anazi Hamoud , Al-Kanaan Adnan , Kayumov Rifat
Published: March 2015

With the increase in gas demand and the need to supply additional energy to the Kingdom, Saudi Arabia is now focusing its drilling and production activities toward exploiting tight carbonate formations. The required key technology to make such reservoirs commercial is the multistage fracturing (MSF). Several drilling, completion, and stimulation techniques are being used to effectively produce the reservoirs. Using well performance as the primary determining factor, a systematic study and evaluation has been conducted for 12 vertical and 11 horizontal wells to assess effectiveness of performed stimulation treatments on the massive carbonate formation. The variants analyzed to determine impact on production include lateral length, hole direction, number of stimulation stages per well, treating fluids and their volumes, pumping rates and pressures, and some others.

The results of these analyses demonstrate that drilling horizontal wells in the direction of minimum in-situ stress (σmin) made a positive impact by achieving satisfactory post-treatment gas rates. Trends also highlight improved well performance with the increase in stimulation stage count and maintaining a positive seal with the adjacent stages in MSF completions. The influence of different fluid types and their volume on post-fracturing productivity was analyzed, and some particular recommendations regarding optimum fluid types and volumes provided. Also, post-fracturing productivity was assessed to detect optimum treatment pump rates and pressures. Some important conclusions were made regarding targeted etched fracture half-length and width. Finally, analysis showed potential benefits from implementation of specific proppant fracturing technologies, such as channel fracturing for carbonate reservoirs to keep the fracture opened at high applied drawdown pressures during production. The analyses identified the key post-fracturing production drivers in the gas reservoirs and ways to improve production of future wells drilled in various formations under similar conditions.
Far Mobility Evaluation Using Minifrac Analysis in a Deep Sandstone Formation: Case Histories
Authors: Rahim Zillur , Al-Anazi Hamoud , Waspada Dwi , Al-Kannan Adnan , Pacheco Eduardo
Published: March 2015

Hydraulic fracturing treatment is one of the major contributors to increase oil and gas production. In most areas, fracturing has remarkable impacts on gas potential and sustainability. Proper design and implementation of fracturing technology and calibration of fracturing parameters provide significant technical and economic advantages. The minifrac treatment conducted before the main hydraulic fracturing, is a tool often used to conduct some essential evaluations of the treatment properties and optimizes the design before the main treatment. Minifrac treatments are also used to understand the reservoir parameters such as well transmissibility that allow making final modifications to the actual fracture design.

The minifrac operation is part of the hydraulic fracturing process that consists of creating and propagating a small fracture using the same fluid that would be used in the main fracturing treatment to observe and measure pressure behavior and calculate hydraulic fracture parameters such as the instantaneous shut-in pressure (ISIP), fracture closure pressure, critical fracture initiation rate, fluid loss coefficient, and the rate and pressure necessary to extend and propagate the induced fracture. Minifracs are also widely used to assess formation properties, such as reservoir permeability and leakoff characteristics. These properties are important for characterizing the reservoir, conducting approximate assessments to evaluate well potential, and optimizing the main fracture treatment design.

This paper describes how minifrac data is used to compute the Nolte G time function (NGTF) and assess fracture pressure decline behavior and evaluate closure pressure and reservoir permeability. The calculated permeability from the minifrac is then compared to the well test pressure data analyses results. Calibration is performed to match the results with well test analyses, which is considered to provide the most precise information about the reservoir. Once a good match is obtained, the process is extended to subsequent wells that allow computing reservoir permeability values using minifrac only, thereby optimizing hydraulic fracture design and predicting production performance.
Evaluation and Assessment of Uncertainity in Electrical Properties for Arabian Carbonate Reservoir
Authors: Okasha T. M.
Published: March 2015

Electrical logging is the most widely used method for identifying hydrocarbon intervals in a wellbore. Standard methods relating oil saturations in clay-free reservoirs to electrical resistivities are based on the Archie equation. Accurate determination of Archie's parameters (saturation exponent, n, and cementation exponent, m) is essential for better estimation of water saturation and log calibration especially for heterogeneous carbonates reservoirs.

In this study, sixty (60) plugs recovered from different wells across an Arabian carbonate reservoir were used to evaluate Archie's parameters. Experimental measurements using state of the art equipment were done by five core analysis service companies. The test results were reviewed for consistency and measurement accuracy. Quality control and statistical analysis of electrical parameters (n and m values) and capillary pressure data addressed uncertainties and errors in measurements. Despite some differences in procedures and experimental conditions, the mean petrophysical values, standard deviations, and ranges of n and m values are consistent.

The range of the saturation exponents and statistical variations of formation factors between wells, indicate that additional petrophysical refinement based on petrophysical rock type may be needed. To assist the rock typing work flow, additional tests for these samples and for any future electrical property samples, the following tests are recommended: NMR T2 and T1 measurements for pore size distributionDual energy x-ray CT scans with maximum sample coveragePlug sample mercury Injection capillary pressure determinations
Experimental Investigation of the Influence of Nanoparticles Adsorption and Transport on Wettability Alteration for Oil Wet Berea Sandstone
Authors: Li Shidong , Torsæter Ole
Published: March 2015

Wettability alteration has been proposed as an important Enhanced Oil Recovery (EOR) mechanism for nanoparticles suspension. For better understanding nanoparticles adsorption behavior inside core and its effect on wettability, a series of wettability measurement experiments for oil wet Berea sandstone were conducted, where the core plugs were treated by different concentration and type of nanoparticles suspensions. Nanoparticles transport experiments also were performed for core plugs with injection of varying concentration and type of nanoparticles suspensions. Pressure drop across the core plug during injection was recorded to evaluate nanoparticles adsorption and retention inside core, as well as desorption during brine post-flush. Both hydrophilic silica nano-structure particles and hydrophilic silica colloidal nanoparticles were utilized in above two experiments. Contact angle between oil and nanofluids measurements also were performed to investigate the effect of nanoparticles on wettability.

The results of wettability alteration experiments indicated that hydrophilic nanoparticles have ability of making oil wet Berea sandstone to be more water wet, and the higher concentration the more water wet will be. Different types of nanoparticles have different effect on the wettability alteration process. The results from contact angle measurements were consistent with wettability index measurements. For nanoparticles transport experiments, the results showed that the nanoparticles undergo both adsorption and desorption during injection. Pressure drop curves showed that absorption and retention of nano-structure particles inside core was significant, while colloidal nanoparticles did not adsorb much. Permeability impairment was observed during nano-structure particles fluid injection, but on the contrary colloidal nanoparticles dispersion injection made core more permeable.
Innovative Rotatable Friction Reduction Tool Applies Extra Force to Deploy Longest 7 in. Liner in Saudi Arabia
Authors: Okot Mike , Dubais Jamal , Al-Hajji Ali , Chima Jude , Deschamps Benoit , Elrefaei Ihab
Published: March 2015

Offshore fields in Saudi Arabia are being developed based on optimum use of onshore drilling rigs. Rather than developing the field completely from offshore platforms, it is developed partially from man-made, interconnected drilling islands. Extended reach wells (ERWs) are necessary for optimum surface location use and maximum reservoir contact.

As the wells increase the step-out, challenges arise not only during the drilling phase but also while running liners to target depth (TD). Wellbore geometry, hole instability issues and torque and drag forces, restrict the ability to deploy the liner to planned depths, setting technical limits to the oil and gas production potential.

The main challenge of running liners through extended lateral sections is the lack of hookload to push the liner to TD, and the ability to rotate the drill pipe without rotating the liner. As more extended reach deployment becomes common practice, it is necessary to implement new running liner practices and tools that rotate the drill pipe above the liner, to break the frictional drag and make more surface weight available, to deploy the liners or completions to TD.

This paper outlines the problem faced when deploying 7 in. liners in ERWs through 8½ in. hole lateral sections, and the solution using an innovative rotatable friction reduction tool, which allows the rotation of the drill pipe without transmitting torque to the liner. A case study is presented showing the main challenges, pre-job engineering calculations, field implementation, final results and lessons learned. Ultimately, the new rotatable friction reduction tool was a key component in the deployment of the longest 7 in. liner run in Saudi Arabia so far.
Setting a New Milestone in Carbonate Matrix Stimulation with Coiled Tubing
Authors: Al-Hajri Nasser M. , Al-Ghamdi Abdullah A. , Al-Subaie Fehead M. , Mujaljil Salih , Al-BenSaad Zakareya R , Srivastava Abhiroop , Ahmed Danish , Aiman Kneina Mohammed , Molero Nestor , Barkat Souhaibe
Published: March 2015

Horizontal carbonate reservoir stimulation has attracted considerable attention in the past decade as one of the major areas for development in matrix stimulation engineering. Modern technologies have enabled technically suitable interventions in extended and even mega-reach wells. In the Middle East especially, carbonate field development strategies have used mega-reach wells as the main technique in achieving the highest possible reservoir contact. In such a case, coiled tubing (CT) intervention becomes a necessity.

With carbonate acidizing, since more than 50% of the matrix is soluble in acid, the objective is to bypass the damage and increase the productivity by creating new highly conductive channels called wormholes. The success of a treatment is a function of fluid penetration, acid reactivity, injection rate and diversion. To increase the success of the treatments, improvements have been made recently in injection rate and diversion using the latest technologies in CT intervention. The introduction of CT provides significant advantages in stimulation execution, yet imposes some challenges. Real-time downhole measurements using fiber optic telemetry have been used frequently to improve chemical diversion and fluid placement. However, pumping rates have been significantly limited to a maximum of 2.0 bbl/min when this technology is deployed.

Extensive engineering work was invested in solving this challenge. The main objective was to obtain the optimum diversion using downhole “point” and distributed measurements without sacrificing the high injection rates. In response to this need, modifications to the existing downhole measurement system were introduced enabling pumping of rates beyond 5.0 bbl/min. The key focus of the redesign was the repackaging of the downhole tools as well as the telemetry link to surface, resulting in expansion of the operating envelope of the technology.

Yard testing has been completed, and results have been encouraging. The solution has been piloted in the field, and a field case study showed remarkable injectivity improvement.
Application of Friction Reducing Rigid-Resin Centralizers Based on Silicon Carbide
Authors: Javier Urdaneta , Mauricio Tarache , Carlos Gonzalez , Luis Quiroga , Ramirez Zoraya , Silva Paula , Ingrith Villamizar , Oscar Zuleta
Published: March 2015

Market dynamics are forcing petroleum operators to undergo complex drilling operations in remote locations in search of new sources of oil. This change in approach has meant that new technologies play an important role in the planning and development of such projects.

Because of deeper well drilling construction, running casing has become a challenging operation. The use of rigs with high torque and drag capacity, pipes with premium connections, and chemical lubricants in the mud make drilling projects significantly more expensive. The complexity of well construction has led to running casing and effective zonal isolation being major challenges, wherein operational practices limit the ability of powerful rig equipment, and thus the length of each section. For this reason, reducing the friction factor has become a key to building high inclinations and extended reach wells.

Rigid-resin centralizers based on carbon fiber ceramic composites have been applied successfully for highly tortuous wells. The use of friction reducers can improve the efficiency of running casing and help secure its settlement to the desired depth, helping reduce time, lowering costs, and minimizing problems. Running centralization in different casings and liners can have the effect of raising the string off the low side of the well, reducing contact area (drag) and improving cleaning efficiency during circulation. This results in less time washing and reaming during runs through interbedded formations.

This paper presents the advantages of using friction reducers chemically bonded to the casing to help reduce torque and drag and maximize casing standoff for primary cementing operations. The knowledge, lessons learned, and field procedures described can be applied to help address zonal isolation problems in vertical, deviated, and horizontal wells with high dogleg severity, helping reduce both operational time and associated costs.
Excellence in Environmental Technology and Stewardship — Manifa Mega-Project
Authors: Arukhe James , Abdulelah Balto , Yateem Karam , Namlah Sultan
Published: March 2015

Completion of the Manifa field development mega-project marked the world's largest hydrocarbon production increment in a single phase. Just as significant as its considerably large production scale, the project involved several green initiatives, including broad-spectrum environment conservation and protection, air pollution controls, and coastal/marine protection. Manifa's coastal and ecologically sensitive location is a source of livelihood for local farmers and contains habitat for fish, shrimp, coral reefs, and endangered species. Consequent upon the richness of species in the zone, the field warranted a development solution that was a balance between environmental stewardship and operational excellence. During Manifa's field development, a critically important environmental strategy was also developed for the construction of the causeway, central processing facility, gas and oil separation, water injection, and cogeneration plants, and 15 offshore platforms for oil production and water injection, with associated subsea pipelines and power communication cables.

An environmental impact assessment (EIA) was completed and a continuous environmental monitoring program (EMP) was implemented during dredging and disposal of dredged materials, prior to and during the construction location of 27 man-made islands to achieve the EIA's mitigation criteria and guidelines. Four (4) studies were also commissioned by the King Fahad University of Petroleum and Minerals (KFUPM) in collaboration with the Spanish research institute AZTI-Technalia.

The successful grassroots development of Manifa, without sacrificing a responsibility to protect the environment, is a testimony to the careful integration of interdisciplinary approaches from project onception to completion; and from exploration to delivery of hydrocarbons to end users. Innovative solutions led to contractor partnering, a strong health, safety and environment (HSE) culture and an exemplary environmental awareness and conservation approach, which resulted in a successful project with a positive influence on Saudi Arabia, the region and other parts of the world.
Proper Planning Supported by Latest Technology Leads to Drilling the Longest 8.5-in. Section in an Extended-Reach Well: Case Study
Authors: Chima Jude , Umarin Isa , Kunhiveetil Dhanraj , Otaif Hassan , Al Dabyah Ali , Zubairi Bilal , Mayer Heinrich
Published: March 2015

Over the past years, extended-reach drilling (ERD) field development has significantly increased globally, and its benefits are well recognized. ERD techniques are increasingly used to intersect hydrocarbon targets that are difficult to access due to logistic issues. While these wells are challenging to drill, complete, and service, the benefits can be wide ranging. These benefits drive the development of technology and techniques to continuously expand the ERD envelope and increase the complexity of profiles to reach more challenging targets. The directional drilling and evaluation service supplier plays an important role.

Each ERD well has a unique set of challenges. Common to all ERD projects is that many aspects of drilling engineering principles are not only pushed to the limit, but become highly interrelated and sensitive to smaller changes than conventional wells. For this reason, a team approach to planning and executing ERD activities should be considered critical. Each team member should bring to the project relevant experience, knowledge, a range of field-proven technology, and a solid global support structure.

Drilling successful ERD wells in challenging conditions depends on various factors, which include careful planning and use of the latest technology. Planning involves understanding the geological structure, not only within the reservoir section, but also in the overburden where typically most of the time efficiency gains can be achieved. The last step in planning is designing an efficient bottomhole assembly (BHA) based on previous experiences, lessons learned and inputs from various teams. Good planning is supported by use of new technologies, especially tools that give real-time information, enabling quick and informed decisions to ensure safe and efficient drilling in a challenging environment. The paper discusses the planning and decision-making process to drill ERD wells by using latest real-time technologies in drilling challenging wells. This paper will describe the experiences and huge success of drilling the longest 8.5-in. hole section in an ERD well, drilled and cased smoothly through challenging formations.