bluuebunny/crossref_metadata_2025 huggingface dataset:
Usury, statutory avoidance and the Court of Chancery 1680-1800
Authors: Swain Warren , Fairweather Karen
Published: December 2014

Article by Dr Warren Swain and Karen
Fairweather, School of Law, Durham University published in Amicus
Curiae - Journal of the Society for Advanced Legal Studies. The
Journal is produced by the Society for Advanced Legal Studies at
the Institute of Advanced Legal Studies, University of
London.
A Neumann problem involving the p(x)-Laplacian with
p = ∞ in a subdomain
Authors: Karagiorgos Yiannis , Yannakakis Nikos
Published: December 2014

In this paper we study a Neumann problem with non-homogeneous
boundary condition, where the p(x)-Laplacian is involved and p = ∞
in a subdomain. By considering a suitable sequence pk
of bounded
variable exponents such that pk
→ p and replacing p with pk

in the original problem, we prove the existence of a solution uk
for each
of those intermediate ones. We show that the limit of (uk
) exists and
after giving a variational characterization of it in the part of the domain
where p is bounded, we show that it is a viscosity solution in the part
where p = ∞. Finally, we formulate the problem of which this
limit function is a solution in the viscosity sense.
Extended Unemployment Insurance and Job Search: Evidence from Time Use Data
Authors: Regmi Krishna
Published: December 2014

In this paper, I investigate the effect of extended unemployment insurance (UI) coverage in the United States in recent years on job search. The U.S. government extended UI benefits in several phases in 2008–2009, increasing the duration of the benefits to a maximum of 99 weeks, up from the regular 26 weeks. Using the American Time Use Survey (ATUS) data, I find that women are more sensitive to the extended UI benefits than men. Difference-in-differences estimation shows that the average effect of the UI extensions for women is over a 10 percentage points decline in the probability of job search. However, I do not find any statistically significant effect on men.
How Close Is a Fractional Process to a Random Walk with Drift?
Authors: Larsson Rolf
Published: December 2014

In this paper, we investigate how close a fractional process can be to a random walk with drift in terms of the sample path. Given the innovation sequence, we calculate the distance to the closest random walk with drift in the sum of squares sense. We also derive the expected distance between the processes under the assumption of white noise normal innovations. A local approximation formula for this distance is given in terms of the sample size, showing that it increases with the sample size more rapidly than the square of the number of observations. Two empirical examples illustrate the results.
H2A.Z in Neuron: Implications in Pain-Related Social Defect
Authors: Wang Xian
Published: December 2014

Cumulating evidence indicated that chronic pain-associated cellular and molecular changes play an essential role in contributing to the development of social defect symptoms, and more recent findings implicated the critical role of epigenetic mechanisms in chronic pain-related sensitization. Histone variant exchange, in which canonical histones are replaced with their variant counterparts, is an entire branch of epigenetics that has received limited attention in the brain and has never, to our knowledge, been studied in relation to pain-related social defect. Here we hypothesize that H2A.Z, a variant of histone H2A, is actively involved in the regulation of chronic pain related social defect symptoms, probably through downstream effects on gene expression. We hope the histone variant H2A.Z regulation may contribute to the molecular basis of cognitive function and serve as a potential therapeutic target for associated social defect.
Possibilities of best practices method application in agricultural organizations
Authors: Gargasas Audrius , Juodis Deividas
Published: December 2014

Agricultural organizations (companies, farms) trying to increase operational efficiency with the lowest cost. To achieve this, their can use the "benchmarking" or best practice (BP) approach – this is a comparison of one business organization versus the other, which should be guided by the best solutions, the latest technology, improved business processes and product quality, operate at the lowest cost, increase business productivity, encourage creativity, innovation and meets the consumers demands as well as higher business performance levels. The aim of the article is to analyse theoretical aspects of the BP achieving methods and to present possibilities and features of its application to agricultural organizations. Research methodology – analysis of Lithuanian and foreign scientific literature its generalization, grouping and structuring. In the article is proposed the methodology of BP method application in agricultural organizations; the methodology consists of four phases of the ten stages.
Modernization of developmental agricultural holdings of Podlasie province
Authors: Koloszko-Chomentowska Zofia
Published: December 2014

In this paper, the effects of modernization activities in developmental agricultural holdings in the Podlasie voivodeship are analyzed. The research material was constituted by agricultural holdings participating in FADN. Analysis of agricultural holdings in the years 2011–2012 indicated an advancing process of strengthening of units with high production potential and capable of expanded reproduction. Growth of the technical development of land and work at these holdings took place during the studied period. In 2012, a reduction of most economic indices took place as a result of worsening of production conditions. The value of completed investments and the structure of their financing indicates a renewal of investment activities. Preferential loans were the most important external source of financing and the main stimulator of modernization. All studied holdings took advantage of this option. Supporting them with public funds is very much justified.
Bioenergy: impact of rural development support measures in Latvia
Authors: Melece Ligita , Krieviņa Agnese
Published: December 2014

The Latvian RDP 2007–2013 targets renewable energy production from biomass of agricultural and forestry origins, where a total investment of EUR 45 million is predicted; besides, there are also additional opportunities for support of renewable energies in the farm modernization measures. The purpose of the study presented in the paper is to evaluate the support under the RDP 2007-2013 measures provided for the bioenergy production in Latvia by studying its tools, results and impacts. The main materials used for the studies are as follows: published and unpublished data from Central Statistical Bureau of Latvia (CSB) and Latvian Rural Support Service (RSS). The results show the support granted to biogas plants has been significant as it constituted almost half of the total support paid to the rural economic diversification measures in Latvia by 2014. Moreover, biogas plant projects were realized by the wealthy agricultural producers and are located in most productive agricultural Latvian regions, which contradict the aim of RDP. Despite the rapid increase in the amount of biogas (bioelectricity) produced, mainly due to the generous public support, as well as the fast development of the production of biomass (fuelwood), the total bioenergy consumption in Latvia is still below the target. Furthermore, the development of fuelwood production mainly contributes to meeting the RES targets in other countries, not Latvia, as it is mostly export oriented.
The expediency of vertical integration: synergy approach arguments
Authors: Shukalovych Vasyl
Published: December 2014

Deciding on vertical integration is caused by the need to increase the company's competitiveness in the market. At the same time, under conditions of intense transformation processes in the market environment, the choice of organizational strategy is very complicated. This requires the development of recommendations on its feasibility taking into account the stage of market evolution. Accordingly, the aim of the work is the definition of expediency of vertical integration by use methodological instruments of synergetic approach. Results of the study were obtained using a methodology that includes theoretical synchronization of synergy tools and economic phenomena at the macro and micro level; simulative modeling stages of development of the market system which includes parameters of the value added, value of enterprises, number of enterprises; forming conclusions based on a comparison of probability estimates. As a result, it is determined that vertical integration is more doomed to success in conditions close to the stability of the market, rather than in terms of active transformations on it.
Mental health and spirituality
Authors: Bagdy Emőke
Published: December 2014

A téma-összefoglaló tanulmány a Magyar Pszichológiai Társaság XXIII., 2014. évi Marosvásárhelyi Nagygyűlésén elhangzott előadásnak szerkesztőségi felkérésre megírt, kibővített változata. A címben megjelölt fogalmak történetileg változó jelentésének nyomon kísérését követően elemzi a spiritualitás helyét a mentális egészségkoncepciókban. Határt von a vallásosság és a spiritualitás között, kiemelve a lényegi különbözőségeket. Rávilágít arra, hogy a (teljes) egészség szerves részét alkotó spiritualitás mint az egyedi, személyes filozófia meghatározója jelentős szerepet játszik az egészség megőrzésében, a prevencióban és egészségpromócióban egyaránt. Megkülönbözteti a spirituális szemlélet és életgyakorlat bizonyítékokon alapuló eredményességét, valamint a vallási rendszer(ek)nek elkötelezetteknél igazolható egészségmegőrző szerepét. A feltárt bizonyítékok alapján az a konklúziója, hogy a spiritualitás egészségvédő faktor, pszichológiai vagyon.
Interactional aspects of healing
Authors: Varga Katalin
Published: December 2014

Az előadás a gyógyítás néhány interakciós vonatkozását taglalja, összekapcsolva az affektív pszichológia és a hipnózis alapkutatás fejleményeit két alkalmazott területtel: az orvosi kommunikációval és a perinatális tudományokkal. Amellett érvel, hogy az emberi kontaktus, a mély egymásra hangolódás, az érzelmi jelenlét a modern orvoslás kulcseleme lehet, illetve kellene, hogy legyen. A gyógyítás során tekintettel kell lenni a páciens „valahova tartozás” szükségletére. Ez a megközelítés kedvezőbb a gyógyító számára is.
Processing of the emotional value of words in an emotional stroop task by late Hungarian-Serbian bilinguals
Authors: Grabovac Beáta , Pléh Csaba
Published: December 2014

Az érzelmi információ feldolgozása kétnyelvűeknél az utóbbi években több kutatás fókuszpontjává vált. A vizsgált csoportok között vannak korai és kései kétnyelvűek is, a nyelvi dominancia és a nyelvek kombinációi is variálódnak. A kognitív nézőpont képviselői sok esetben a kétnyelvűek végrehajtó funkcióira helyezik a hangsúlyt és ez a trend megfigyelhető az affektív információ feldolgozásában is, amit a végrehajtó funkciókat affektív szinten mérő feladatok megjelenése jelez.Kutatásunk célja az volt, hogy megvizsgáljuk, mennyire dolgozzák fel az érzelmi információt Stroop-feladatban magyar-szerb kései kétnyelvűek a magyar és a szerb nyelvben. Az érzelmi információ a feladat szintjén irreleváns disztraktorként volt jelen.Eredményeink szerint a második nyelvet alacsonyabb szinten ismerő személyeknél nyelvtől függetlenül megjelenik az érzelmi Stroop-hatás, a negatív információ lassúbb feldolgozása a semlegessel szemben, valamint a nyelvi dominancia is kirajzolódik az anyanyelvi gyorsabb válaszadáson keresztül.
What gets healed due to healing imagery? Effectiveness of the Simonton method among Hungarian cancer patients
Authors: Rohánszky Magda , Prezenszki Zsuzsanna , Katonai Rózsa , Konkolÿ Thege Barna
Published: December 2014

Absztrakt
Turning-points in history of Hungarian psychology In Transylvania
Authors: Séra László
Published: December 2014

A tanulmány az erdélyi magyar pszichológia, s különösen a kísérleti megközelítés és az oktatás alakulásával foglakozik a kezdetektől 1989-ig. A kezdeteket a kolozsvári Ferenc József Tudományegyetem alapításától (1872) a felszámolásáig (1919) tartó időszakban Parádi Kálmán, első erdélyi „Physiológiai lélektan”-a (1887), Lechner Károly pszichiáterprofesszor, Palágyi Menyhért filozófus reakcióidő-vizsgálatai (1906) és Böhm Károly filozófiaprofesszor tevékenysége illusztrálja. A két világháború között Erdélyben csak a kolozsvári román I. Ferdinánd Király Egyetemen volt lehetőség pszichológiát és filozófiát tanulni; a pszichológiai érdeklődést egyesületek, folyóiratok tartották fenn. A második bécsi döntés utáni időszakban (1940–1944), a Szegedről Kolozsvárra visszaköltözött egyetem Lélektani Intézetében (professzor: Várkonyi Hildebrand Dezső), majd 1945–1959 között létrejött Bolyai Tudományegyetem Pszichológiai Tanszéke (vezetője 1946–1947-ben Harkai Schiller Pál, majd Zörgő Benjamin) tevékenységéhez kapcsolódik a képzés és kutatás. A következő fejlődési szakasz a kényszeregyesített Babeş-Bolyai Egyetem Pszichológiai Tanszéke magyar tagozatának munkájához (Zörgő Benjamin, Fodor Katalin, Kulcsár Tibor) kapcsolódik. 1982 és 1989 között a romániai pszichológia teljes betiltása következik be, és csak Ceauşescu diktatúrájának 1989-es megdöntése után szerveződik újra.
Edge strength model for structural glass based on the mirror zone depth
Authors: Vandebroek Marc , Louter Christian , Caspeele Robby , Ensslen Frank , Belis Jan
Published: December 2014

A reliable assessment of the edge strength becomes an important issue when designing structural glass elements in buildings. However, in the literature the edge strength of glass, dependent on the edge quality, is not well documented. Therefore, in this study an edge strength model was established and validated for commonly used edge finishings, namely ground, arrissed and cut. After testing at a high stress rate, the fracture mirror zone depth and the flaw depth were measured. For every edge finishing a reliable ratio between the fracture mirror zone depth and the initial flaw depth was found. A strength model based on the measurement of the mirror zone depth was established and validated, as the measurement of the mirror zone is much easier than the measurement of the flaw depth. Also, the mirror zone depth is independent of the loading rate and can be useful for forensic engineering.
Clinical, Microbial, and Immune Responses Observed in Patients With Diabetes After Treatment for Gingivitis: A Three‐Month Randomized Clinical Trial
Authors: Raslan Suzane A. , Cortelli Jose R. , Costa Fernando O. , Aquino Davi R. , Franco Gilson C.N. , Cota Luis O.M. , Gargioni‐Filho Antonio , Cortelli Sheila C.
Published: December 2014

Background: Although patients with diabetes are frequently affected by periodontitis, only a few investigations have focused on gingivitis in this at‐risk population. This randomized placebo‐controlled clinical trial compared the response to a gingivitis treatment protocol that combined mechanical procedures and daily use of an essential oil (EO) mouthrinse between patients with and without diabetes.

Methods: The whole‐mouth periodontal probing depth (PD), gingival index (GI), and plaque index (PI) were monitored in gingivitis cases among systemically healthy patients (n = 60) or those with diabetes (n = 60) at baseline and 3 months after treatment. Levels of Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and total bacterial load were determined by a real‐time polymerase chain reaction in intrasulci plaque samples. The volume of gingival crevicular fluid (GCF) was quantified, and interleukin‐1β (IL‐1β) levels were determined in GCF samples. After a full‐mouth ultrasonic debridement, patients were randomly assigned to an EO or a placebo rinse for 90 days (40 mL/day). The data were analyzed through repeated‐measures analysis of variance and multiple comparisons Tukey tests (P <0.05).

Results: GI was more severe in the diabetes group. Diabetes impaired GI and reduced GCF volume. PD, bacterial levels, and IL‐1β improved similarly in both systemic conditions. The adjunctive use of EO provided greater reductions of PI, GI, total bacterial load, T. forsythia, A. actinomycetemcomitans, and GCF volume.

Conclusions: Response to gingivitis treatment in patients with diabetes can slightly differ from that in patients without diabetes. Daily use of an EO mouthrinse after ultrasonic debridement benefited patients with and without diabetes.
A Unique Rectus Femoris Injury in an Adolescent Professional Soccer Player
Authors: Huri Gazi , Dubin Justin M. , Ozgonen Kerem , Kaya Defne , Doral Mahmut Nedim
Published: December 2014

Case:

A sixteen-year-old professional soccer player presented with persistent pain in the right thigh of two years’ duration and the inability to return to play. Evaluation revealed a chronic rupture of the rectus femoris muscle. Because physiotherapy and rehabilitation failed to help, a surgical repair was performed. He returned to his previous activity level within nine months after surgery.

Conclusion:

Rupture of the proximal part of the rectus femoris should be acknowledged in the differential diagnosis, especially when presenting with persistent pain in the anterior aspect of the thigh lasting more than one year. Delayed repair might be recognized as a reasonable option for chronic rupture of the proximal part of the rectus femoris.
Chemical and Mechanical Aspects of Wellbore Stability in Shale Formations: A Literature Review
Authors: Al-Arfaj Mohammed K. , Amanullah Md , Sultan Abdullah S. , Hossain Enamul , Abdulraheem Abdulazeez
Published: December 2014

Drilling a shale formation with no borehole problems can be a challenging task. With high content of clays, shale formations are prone to swelling, dispersion, tight hole and other problems. Those problems are well-documented in literature. Different types of clays give different types of problems. For example, when it is exposed to water, a shale sample with a high percentage of smectite tends to swell while another shale sample with a high percentage of kaolinite tends to disintegrate and disperse. The mechanism that destabilizes reactive shale when it comes in contact with water differs from on shale sample to another. It is important to know which mechanism is taking place in order to be proactive and inhibit the drilling fluid with the appropriate inhibitor. It is also important to characterize the shale sample in terms of its geological structure, mineralogical composition and interaction potential.

Shale characterization and testing methods include but not limited to the following: X-ray analysis, degradation and reorientation evaluation using scanning electron microscope (SEM), cation exchange capacity (CEC) determination, swelling test, dispersion test, slake durability test, bulk hardness test, accretion test, shale membrane test, inhibition durability test and uniaxial and triaxial compression tests.

Different types of shale inhibitors and stabilizers have been used in the industry such as: potassium chloride, calcium chloride, silicates, polyamines, glycol and lignosulfonate. Each of them has a mechanism by which it can inhibit the hydration, disintegration and dispersion of clays in the presence of water.

This paper discusses the physio-chemical and chemico-mechanical effects of shale-drilling fluid interactions and the associated drilling problems that are most frequently encountered while drilling shales formations. It also reviews the most common shale testing methods used to evaluate the interaction potential of various shale-drilling fluid systems. Moreover, the paper describes different mechanisms by which shale can be inhibited and wellbore stability problems can be mitigated.
Multi-Lateral Well Design Advisory System; an Inverse-Looking Solution
Authors: Al-Mousa Talal S.
Published: December 2014

The shifting trend towards drilling multilateral wells has motivated engineers and researchers to investigate ways to improve their decision-making when designing multilaterals. The problem becomes more challenging in unconventional reservoirs, where tighter and highly heterogeneous and discontinuous reservoirs are targeted. Achieving the right design of a multilateral well configuration is a complex problem due to the vast possibilities of well forms (i.e., number, location, length and orientation of laterals) that need to be evaluated. Accordingly, arises the need for an inverse-looking approach to come up with a sound decision.

Conventional ways in designing multilaterals involves investigation of different possible scenarios using a reservoir simulator model and comparing results against an objective function. However this addresses the problem only from a forward-looking point of view. This procedure is time and labor intensive and tremendously increases the computational cost. This paper illustrates the utilization of the artificial neural network (ANN) concept to develop an advisory system for designing multi-lateral well configurations for a given target reservoir performance in fraction of the time, cost and effort required by a numerical simulator. From that point onwards an engineer can improve on the recommended design or modify it to adhere to certain field, cost or operational constraints.
Reservoir Connate Water Chemical Composition Variations Effect on Low-Salinity Waterflooding
Authors: Shehata Ahmed M. , Nasr-El-Din Hisham A.
Published: December 2014

Extensive experimental work has indicated that Low-Salinity Waterflooding (LSW) is an enhanced oil recovery technique that improves oil recovery by lowering and optimizing the salinity of that injected water. Most of the LSW studies focused on the injection of brine salinity and composition. The question remains how does the salinity and composition of reservoir connate water affects the LSW performance. Therefore, in this paper different connate water compositions were used (TDS varies from 1550 up to 174156 ppm) to investigate the role of reservoir connate water on the performance of LSW.

Nine Spontaneous Imbibition (SI) experiments and six coreflood experiments were performed. Two sandstone types (Bandera and Buff Berea) with different clays contents and stock-tank crude oil samples were used in all the experiments. This work describes experimental studies of SI of oil by low-salinity and high salinity brines using 20″ long outcrop sandstone samples. This study focused on the effect of connate water composition and temperature, 77 and 160°F, on the performance of LSW. The coreflood experiments have been conducted using 6 in. outcrop Buff Berea sandstone cores at 150°F and 500 psi. Oil recovery and pressure drop were observed and analyzed after each coreflooding experiment to examine the effect of the connate water composition (Na+, Ca+2, and Mg+2) on the performance of the LSW in secondary recovery mode.

Reservoir connate water composition and salinity have a dominant influence on the oil recovery rate. The Ca2+, Mg2+, and Na+ ions play a key role in oil mobilization in different sandstone rocks. Reservoir cores saturated with connate water contained divalent cations of Ca+2 and Mg+2 showed higher oil recovery for cores saturated with monovalent cations Na+. Low-salinity waterflooding showed a high potential to improve oil recovery in the SI experiments at different temperature levels. For high permeability Buff Berea cores, the SI oil recovery ranged from 38 to 69% OOIP, while oil recovery of the low permeability Bandera cores ranged from 17 to 45% OOIP at 77°F and 14.7 psia. As the temperature increased from 77 to 160°F, an additional oil recovery up to 4.2% of OOIP was observed by SI for Buff Berea cores. From the coreflood experiments, low-salinity brine had a significant positive effect on oil recovery for sandstone cores saturated with divalent cations (Ca+2 and Mg+2). The magnitude of incremental oil recovery increased from 51.9 to 58.9% OOIP when the reservoir connate water salinity increased from 3,420 to 36,350 ppm. On the other hand, increasing the monovalent cations (Na+) from 1,550 to 137,670 ppm resulted in slight increase in oil recovery (1.2% OOIP). The oil recovery from the coreflood runs for the Buff Berea cores ranged from 58.9 to 35.9% OOIP. The oil recovery decreased when the salinity of reservoir connate water decreased.
New Approach for Formation Evaluation Using Advanced Mud Gas Analysis of Conventional and Unconventional Reservoirs: A Case Study from Onshore UAE
Authors: Farouk Atef , Pinna Giovanni N. , Ahsan Syed Asif , Mahmoud Gehad , Heard Stephanie , Al Hanaee Ahmed , Kingsley Kanu , Al Shehhi A.
Published: December 2014

The formation evaluation of any wildcat, exploratory and/or appraisal well is challenging due to scarcity of information with respect to reservoir presence, its characterization and the expected pressure. It is expected that hydrocarbon bearing reservoirs, especially those located in low resistivity zones and without core for calibration of physical properties, might possibly be overlooked as these are difficult to interpret from petrophysical logs for the presence or absence of hydrocarbons.

An advanced surface mud gas acquisition and analysis system, based on membrane technology, was utilized for the first time in the United Arab Emirates. Advanced mud gas analysis and interpretation of conventional and unconventional carbonate reservoirs sections identified interesting hydrocarbon bearing zones which were subsequently confirmed by integration of core, electric log and well-test data.

An exploratory well was drilled to explore the hydrocarbon potential of unconventional reservoirs and appraise the conventional carbonate reservoir. Reliable results were achieved in a highly challenging environment including petrophysical uncertainty and a variety of reservoir fluids present. The results from the advanced mud gas analysis were confirmed by down hole sample testing results.

The approach developed can be modified or customized to explore/appraise a prospect to capture any hydrocarbon zones, including by-passed zones, and subsequently optimize logging and testing programs resulting in a reliable data set and cost savings.
Planning, Execution and Delivery of First Saudi Arabian Red Sea Deepwater Well: Project Management and Execution Case Study
Authors: Adewuya Opeyemi , Tiwari Shrikant , King Steve , Brown John , Luquetta Helmut , Mansouri Mohammed , Abdelwahed Abdullah , Arafa Ibrahim , Taher Ahmed
Published: December 2014

The first deepwater well in the Saudi Arabian side of the Red Sea was going to be a rank wildcat well. Saudi Aramco Upstream leadership assembled a team of experienced, knowledgeable and dedicated professional staff across the Exploration Geology, Geophysics, Reservoir and Exploration Drilling organization to undertake the challenge of safe and successful well delivery. Contemporary frontier exploration projects utilize project development processes with long inter-nodal phasing schemes that follow traditional lateral cascade workflow methodology or the common waterfall process.

Published works on project development best practices cite project development and management processes that are ostensibly an adoption of product development processes with stage gates and decision points. In order to meet the Saudi Aramco leadership challenge for project delivery -- speed, scale and a safe delivery mandate, non-negotiable parameters established for the project -- innovative project interface management tools and strategies devised to enable multidisciplinary resources both internal and external to recognize vertical and lateral impacts of decision, specification and system dependencies, compatibility, boundaries and critical path sensitivities was developed.

The pervasive cohesion and shared sense of responsibility by the core project team and service partners, seamless communication protocols among stakeholders though fraught with complex and diverse perspectives was also a source of robust decision making. Several industry first technologies for well construction were successfully deployed and the meticulous engineering motions undertaken to ensure hitch-free deployment are noteworthy. The strategies for selection of service contractors along service and product lines, capabilities and compatibility for performance management are also described.

This paper describes drilling engineering and operations preparation, front end engineering and design activities, and the project delivery success of Saudi Aramco's first deepwater exploration program in the Red Sea. The validation of the potency of the strategies, tools and systems employed is embodied in the drilling to record regional total depth of the first deepwater well of Saudi Aramco's Red Sea Deepwater Exploration Campaign Program
Impact of Surfactants on Fracture Fluid Recovery
Authors: Palla Chandra , Weaver Jim D. , Benoit Denise , Lu Zheng , Vera Noe
Published: December 2014

One of the many challenges of unconventional reservoirs is maximizing the recovery of fracturing fluid following hydraulic fracturing treatments. Effective fracturing fluid recovery reduces water saturation of the fractured network and fluid invasion into the formation, enabling better hydrocarbon production from the reservoir. Each chemical component present in complex fracturing fluid systems should first be carefully formulated to achieve the stimulation design requirements for the well and second to help ensure complete or maximum recovery of the broken fracturing fluid.

To help achieve maximum fracturing fluid recovery, it is necessary to understand the complex, multistep processes that occur during the fracturing fluid breaking chemistry (gel degradation) and to incorporate this understanding into the fracturing fluid design. Considerable attention has been given to insoluble residue, breaker concentration, break time, and broken fluid viscosity, all which are crucial for fluid recovery, but these do not address the tendency of insoluble materials contained within the fluid or formed during the polymer degradation process to aggregate, which can result in a significant loss of proppant pack permeability. Polysaccharide-based polymers are typically degraded by breakers composed of enzymes, oxidizers, or acids. These breakers are designed to reduce viscosity of the fluid to enable easy flowback, but they generally do not degrade the polymer completely to the monosaccharide state; rather they leave fairly long chained oligomers. These broken polymer fragments tend to aggregate, forming malleable flocs. The nature of these oligomeric fragment aggregates, such as type, size, and strength of the association, affect the efficiency of fluid debris recovery following a fracture stimulation treatment.

Surfactants added to the fracturing fluids, if properly chosen, can also act as inhibitors to the formation of the oligomeric aggregates and prevent flocculation, thus helping to avoid a significant loss of proppant bed permeability. This paper demonstrates the importance of surfactants in preventing permeability damage resulting from oligomeric polysaccharide aggregation. Selection of the proper surfactant helps prevent flocculation and enhances the recovery of broken fluids from proppant packs.

Fracture design engineers can use these strategies to maximize both the rate and efficiency of fracturing fluid recovery following the fracture stimulation of a well. This can lead to improved hydrocarbon recovery and is particularly important for the stimulation of extremely low permeability, unconventional reservoirs.
Interaction between Multiple Injections Using Tightly Coupled Fluid-Structure Interaction Computational Algorithm
Authors: Bai Jie , Lin Avi
Published: December 2014

Recent technologies developed for drilling, completion, and fracturing in horizontal wells have allowed the oil and gas industry to effectively use multistage fracturing stimulation treatments to help improve production in tight and unconventional gas and oil reservoirs. The fracturing process usually involves placing multiple perforation clusters exposed to the injected fluid in each treatment's stage. It has been shown that very strong interactions occur between the fractures propagating from the clusters, which further influence the effectiveness of production following a fracturing treatment. This paper presents a computational methodology to simulate and analyze the major physics associated with the interactions between multiple injections using a tightly coupled fluid-structure interaction (FSI) numerical model for hydraulic fracturing. This approach uses the finite element method (FEM) to computationally evaluate the stresses and deformation of elastic rock blocks. Nonpenetration contact conditions between adjacent solids, coupled with tensile and shear failure models, are developed to describe fracture evolution and its interaction with the rock blocks. The fluid flow in opened fractures is modeled using the cubic law formulation. The proposed coupling computational method leads to an integrative algebraic system for a set of variables that fully describes this multiphysics phenomenon, including rock block corner displacements and Lagrange multipliers for cases where the blocks are in contact, along with the fluid's pressure at junctions of the opened fracture network. The suggested algorithm solves all of the unknowns simultaneously and in a tightly coupled manner. This algorithm is not limited to the specific study of the interactions between hydraulically induced fractures from different perforation clusters, but it can also be used to properly describe the interactions between hydraulically induced fractures and natural fractures. Yet, because of the existence of natural fractures, the interactions between multiple injections become more complicated than the interactions between only hydraulically induced fractures. In these cases, the natural fractures between multiple injections provide a stronger interaction and pathways for injected fracturing fluid between multiple injections. The spacing of injection clusters is studied for its effect on fracture length and the width of fractures for each injection cluster.
Topside Installation by Float over – Engineering Challenges
Authors: Cherian Litty Dani , Suresh P. K. , Takieddine Oussama Halim
Published: December 2014

In recent years there has been a significant rise in heavy integrated Topsides for the new offshore fields in the Arabian Gulf. The Topside designs are increasingly becoming more complex and heavy. Installation of these decks through float over philosophy is the most sought after method. With its proven efficiency and cost effectiveness in installing those heavy topsides, this method has become well known in the Arabian Gulf. The significant savings in time and cost of offshore hook up and commissioning and the relatively reduced risks offshore makes it the preferred option in comparison to modularized lifting of the topside.

Float over is an operation of mating of a topside structure, carried on a cargo barge, to a fixed (jacket) substructure. Normally the layout of the jacket and topside are designed such that it will be suited for a specific barge size in mind. The selection of barge size (dimension) corresponds to the target weight of topside and center of gravity location. Although the method appears simple, it requires meticulous planning from very early stages of the FEED design. Float over installations are comparatively weather sensitive and responses (motion behavior) of the float-over barge, carrying the topside, in waves are crucial and must be determined. The impact loads due to barge motions during mating are extremely important for jacket and topside design.

The involvement of experienced Naval Architects from the FEED stage of design to carry out all installation studies leading up to float over is an absolute necessity to ensure good platform design. Awareness of potential challenges during float over design and installation shall help in the design of the platform and thereby avoid surprises later.

This paper presents the float over philosophy, method of performance, systems used, technical aspects and various parameters to be considered during engineering for float over installation in the Arabian Gulf from a Naval Architect's perspective. This includes discussion on the importance of weight control of topsides, selection of barge for float over installation, finalization of support heights for topsides on barge, typical float over installation aids etc. The paper also discusses the typical technical analyses required to be performed for the design. The discussion in this paper is limited to float over installations using conventional load transfer method (by ballasting) and using normal spread mooring arrangement.
An Operator Feedback on the Installation of a Pipeline Intrusion Detection System
Authors: Audouin Grégoire , Rupert Serge , Popineau Dominique , Minto Chris
Published: December 2014

"Third Party Interference", whether intentional or accidental, is responsible for more than half of the pipeline failures in the world. The consequences can be catastrophic for people, the environment but also for facilities availability. The project presented here considers the use of a communication optical cable, laid with the pipeline, in order to detect intrusions and also leaks. Field data from an operational test was acquired at the Balhaf LNG facility in Yemen in December 2012.

The LNG plant operations had been subject to numerous sabotage actions, impacting the pipeline feeding gas to the plant, and therefore the plant availability. A security review concluded that there was a need to implement specific security measures to allow early detection of potential threats. The requirement was to minimize new equipment installation in the field, so as to avoid personnel exposure, by making use of the already installed communication optic fiber communication cable.

A fiber optic based detection system was selected. Such systems detect acoustic signals via the optical pulses sent within an optical fiber, known as Rayleigh scattering. For example repeated and regular impacts on soil will trigger an "excavation" alert and a security team can be sent to stop intruders before they reach the pipeline. The advantage of this technology is that it makes use of one of the optical fibers within the communication cable, already installed in the pipeline trench. There is no need to install additional new cables alongside the pipeline.

Since its resulting installation, the system has demonstrated that this technology can reliably contribute to pipeline security by enabling operators to detect and listen to pipeline external threats. Fiber optics can also be used for leak detection. Such detection is based on the continuous measurement of the temperature gradient between the fluid transported and the surrounding ground, the environmental effects on the ground of the escaping product or the multiple acoustic signatures of a leak. This functionality is being tested and evaluated. This technology has the potential to drastically improve operational safety and security for pipelines deployed within challenging environments.
Ageing Offshore Well Structural Integrity Modelling, Assessment and Rehabilitation
Authors: Ramasamy Ramesh , Aljaberi Manea , Aljunaibi Hamad
Published: December 2014

Zakum Development Company (ZADCO) is operating Upper Zakum (UZ) Field offshore Abu Dhabi consisting several offshore wellhead platform towers (WHPT) which have been in service for over 30 years and evidence of severe corrosion has been found on majority of these well's conductors and casings.

A major challenge faced by ZADCO is to repair corroded well's conductor casing to prevent well structural collapse and extend the life further to allow for safe and planned retirement. The challenges faced during the assessment includes the absence of design basis, well age, data accuracy and drilling quality for 30 years, the challenges takes another dimension when factoring the number of wells and possible different configurations. They way forward was to categorise the wells into several groups with close design configurations and then reverse engineer the design basis to a build a structural model for that fits the various wells configuration to establish the minimum thicknesses to assure well's structural integrity, and the requirement for life extension by suitable repair method.

This paper outlines the activities undertaken to design and implement an effective process for evaluating the structural integrity of aging well conductors considering over 6000 possible well configuration scenarios. The paper describes the engineering methodology involved in the integrity assessments for well conductor evaluation using analytical methods to assess the present strength and stability states of the conductor/casing assembly based on corrosion inspection data and the knowledge of existing cement elevations and operating conditions of the well. Operability guideline plots are generated to present the available safety margin of the aging conductor/casing system, and to enable well conductors with unacceptable structural integrity to be identified. Where safety margins are poor, repair solutions and mitigation methods are also developed for implementation on the affected conductors and casings.

A detailed rehabilitation flow-chart is also developed to assist engineers in the repair/replace decision-making process, with comprehensive guidelines for assessing and executing the rehabilitation steps for extended safe operations of ageing conductors, hence prolonging the well operating life.
Customizable Synergistic Dual Breaker Technology Improves Fracture Fluid Cleanup
Authors: Cortez Janette , Singh Dipti
Published: December 2014

Natural and synthetic polymers are commonly used within the oil and gas industry as viscosifying agents in hydraulic fracturing applications. Hydraulic fracturing involves pumping of a highly crosslinked fluid into a formation to create fractures. The viscoelastic fluids are used to provide sufficient viscosity for proppant suspension, transport, and enhanced fracture width. Breaking the crosslinked polymers after the fracturing operation is a crucial step that can greatly impact hydrocarbon production. Conventional breakers, such as oxidizers, are most commonly used for breaking fracturing fluids; however, these breaker packages sometimes show inferior regained permeability at lower temperatures (100 to 160°F). Regained permeability studies with fracturing fluid compositions tested in low-perm cores show that persulfate-type oxidizing breakers do not always adequately degrade the polymer; furthermore, higher concentrations do not always show improved breaking. This paper presents an alternative breaker solution that is superior to conventional breakers in terms of improving regained permeability.

Recently it was shown that in situ acid-generating hydrolytically degradable polymers, in combination with oxidizing breakers, dramatically improved the regained conductivity of the proppant pack without the detrimental effects associated with the use of higher breaker concentrations at lower temperatures. For example, test results show that, even at temperatures as low as 150°F, the synergistic phenomenon of this dual breaker system provided multiple and beneficial functions. The hydrolysis rate of degradable polymers to generate acid in situ is dependent on several factors. The wide variety of degradable polymers containing ester-linkages that are available permits one to select a polymer that will result in a desired break profile for the given conditions, making this chemistry customizable.

In addition, these acid-generating self-degradable polymers are biodegradable, potentially minimizing health, safety, and environmental (HSE) concerns.

Conductivity improvement as compared to using a breaker system based on individual components are attributed to the improved cleanup provided by the synergy between the degradable polymer and the oxidizing breaker (even at lower temperatures). This represents a significant improvement to current technology.
Effect of Sequence Stratigraphy-based Facies Modeling for Better Reservoir Characterization: A Case Study from Powder River Basin
Authors: Odezulu Christopher , Olawole Seun , Saikia Kalyan , Mento Dean
Published: December 2014

The integration of high quality sequence stratigraphic analysis plays an important role in the 3D modeling of reservoir facies and petrophysical properties. It provides a better characterization of complex geology and helps to reveal hidden pays that may not have been found with conventional techniques. This paper demonstrates the benefits of effective sequence stratigraphic interpretation in creating a holistic 3D reservoir model and in identifying probable hydrocarbon traps in the study area.

The paper establishes a sequence stratigraphic framework, consisting of two lowstand system tracts (LSTs), one highstand system tract (HST), and one transgressive system tract (TST), using integrated interpretation of well logs and seismic data. Studies of the depositional pattern of the framework revealed three main sedimentary facies (marine, flood plain, and fluvial) with complex lateral and vertical relationships. In conventional approaches, a global facies average calculation is assumed, creating an unrealistic model with a stationary condition. In this study, layer-wise facies trend maps were generated, using lithotype proportion map (LPM) and vertical proportion curves (VPC), to capture the geological inhomogeneity. While making the model geologically more realistic and non-stationary, facies boundaries from the sequence framework are honored by constraining the final 3D facies simulation through customized lithotype rules. Next, a petrophysical property modeling technique is used to populate individual litho-groups for porosity, saturation, and total organic carbon (TOC) by interval and constrained by facies. This process leads to a holistic, geology-controlled 3D reservoir model that reveals hidden pockets of LSTs with high porosity values in the reservoir, which provide promising exploration sites for future development. This study also shows that the TST has an abundance of high value TOC; consequently, it is more likely to be genetically related to the source sediments. In conclusion, the integration of sequence analysis played a significant role in the development of a realistic 3D distribution of reservoir facies, providing a better prediction of reservoir properties, increasing recovery, and reducing uncertainties in field development.