bluuebunny/crossref_metadata_2025 huggingface dataset:
Conscious capitalism to help people with hearing disability in developing countries
Authors: Rao Vepakomma Bhujanga
Published: August 2014

With advances in medical technology, health care has improved the longevity, quality of life, and comfort of people across the world. Unfortunately, access to some of these health care technologies in many low-income countries and for certain people in developed countries is completely curtailed due to cost. The author presents a case study of a hearing technology that failed to reduce hearing disability (deafness) among profoundly hearing impaired people in developing countries despite the availability of cochlear implant prosthesis in the market for the last three decades. The recent World Health Organization (WHO) Report, released in 2013, is also silent on this issue while discussing many prevention and rehabilitation issues of hearing care across the world. There are nearly 25 million people suffering from profound hearing disability who need cochlear implant prosthesis, but are unable to afford one as each costs around USD 60,000. Most of these people suffer from social isolation, with limited employment opportunities that, in turn, severely affects their quality of life. With a personal average annual income of well below USD 2000 in low income countries, it is almost impossible to make progress against hearing disability. In the 21st century, should we allow people to suffer from hearing disability despite the availability of reliable technology? Why should any government or society indiscriminately consider the hearing disabled as helpless, incompetent, and dependent? Can the government, corporations, non-government organizations, the WHO, the United Nations Children’s Fund, and so on, not collectively take care of the hearing disabled by making cochlear implant prostheses affordable? It is time to draw attention to the fact that people with disabilities have equal rights with others. If we want to equip every profoundly hearing disabled individual with a cochlear implant that bestows the gift of hearing, neither pure socialism nor capitalism would help. Conscientious business leaders who can embrace a higher purpose beyond making profits are required. Hence, Conscientious capitalism is the only answer wherein efforts are directed to not-just-for-profit business models or conscious popular consumerism but also socially responsible investments. We have to build upon a health care access model that is open-ended and has positive aspirations with strict policies on adoption and diffusion of new technologies. The policies should be framed such that access is not denied due to the high price of the device and to clinical and hospital budgets. I have chosen a case study of the hearing disabled to showcase the plight of poor people, especially in low-income countries, in gaining access to many life-transforming medical technologies. I present a heath care access model related to hearing disability, treating it as a global issue.
Fiction and Indexinames
Authors: Voltolini Alberto
Published: August 2014

In this paper, I will start from considering some theoretical desiderata concerning sentences that directly or indirectly involve fiction: i) the fictional use of language requires a context-shift; ii) one understands a sentence whether it is used fictionally or not; iii) one and the same proper name is, typically at least, used both within a certain work of fiction, i. e., when the sentence containing it is used fictionally, and outside that work of fiction, i. e., when, apparently at least, the sentence containing it is used nonfictionally yet in order to indirectly concern that very fiction; iv) different naming practices are to be mobilized by such different uses (independently of whether the apparently nonfictional use is actually successful as far as the reference of the name is concerned); v) independently of their really having a referent, proper names are always devices of direct reference. I will claim that once one takes proper names as indexicals of a particular sort,
How to Think About the Correctness of Theistic Belief
Authors: Szatkowski Mirosław
Published: August 2014

Truth is a value in that sense that a belief is correct just in case it is true, which is frequently expressed in the metaphor that beliefs aim at truth. But,what does it mean to say that beliefs aim at truth?There are three most prominent approaches to this issue:purposive(orcausal),teleological(orintentional), andnormative. A comprehensive discussion of these approaches is the goal of our article. We also offer the hierarchy of languages and meta-languages, which gives a fragmentary account of the concept of God’s omniscience.
I Am a Lot of Things: A Pluralistic Account of the Self
Authors: Benovsky Jiri
Published: August 2014

When I say that I am a lot of things, I mean it literally and metaphysically speaking. The Self, or so I shall argue, is a plurality (notwithstanding the fact that ordinary language takes “the Self” to be a singular term – but, after all, language is only language). It is not a substance or a substratum, and it is not a collection or a bundle. The view I wish to advocate for is a kind of reductionism, in line with some – but not all – broadly Humean ideas. In short, I will defend the view there are the experiences and mental states we have, and that’s it: no additional substances, and no bundles. This does not mean, however, that there is no Self – the Self simply is the experiences. I will try to articulate and defend this view by showing that it can accommodate what I take to be the three main desiderata for any theory of the Self to satisfy: first, that the Self is the subject of experience (a subject of mental states, in general); second, that there is a unity to the Self in the sense that our (conscious, phenomenal) experience is at least partly continuous or ‘stream-like’; and third, that we do not die when we go to sleep or when we otherwise don’t have any (conscious, phenomenal) experiences.
What Trans-World Causation Could and Could Not Be
Authors: Torza Alessandro
Published: August 2014

Eduardo García-Ramírez has offered a reductio of the counterfactual analysis of causation. The argument purportedly shows that, given a natural generalization of Lewis’ semantics for counterfactuals, statements expressing the existence of causal dependence across worlds are satisfiable. The aim of the present paper is twofold. In the first part, I show that the purported reductio is flawed, as it relies on an overly strong construal of the semantics for counterfactuals. In particular, it is assumed that we can assign a degree of similarity to any given pair of possible worlds. As it turns out, that assumption reduces to the thesis that the relations of comparative similarity featured in the standard semantics for counterfactuals define an interval scale of measurement on the set of all possible worlds. It will be argued that such a thesis is incompatible with a viable understanding of comparative similarity. The second part of the paper is devoted to a new proof of the possibility of trans-world causation. Nevertheless, the new proof does not amount to a reductio of Lewis’ account of causation per se, but rather of the conjunction of several substantive theses (the counterfactual analysis of causation, modal plenitude, the existence of mereological sums and the best theory account of natural laws).
Trapping of resonant metallic nanoparticles with engineered vectorial optical field
Authors: Rui Guanghao , Zhan Qiwen
Published: August 2014

Optical trapping and manipulation using focused laser beams has emerged as a powerful tool in the biological and physical sciences. However, scaling this technique to metallic nanoparticles remains challenging due to the strong scattering force and optical heating effect. In this work, we propose a novel strategy to optically trap metallic nanoparticles even under the resonant condition using engineered optical field. The distribution of the optical forces can be tailored through optimizing the spatial distribution of a vectorial optical illumination to favour the stable trapping of a variety of metallic nanoparticles under various conditions. It is shown that this optical tweezers has the ability of generating negative scattering force and supporting stable three-dimensional trapping for gold nanoparticles at resonance while avoiding trap destabilization due to optical overheating. The technique presented in this work offers a versatile solution for trapping metallic nanoparticles and may open up new avenues for optical manipulation.
Bayesian identification of protein differential expression in multi-group isobaric labelled mass spectrometry data
Authors: Jow Howsun , Boys Richard J. , Wilkinson Darren J.
Published: August 2014

In this paper we develop a Bayesian statistical inference approach to the unified analysis of isobaric labelled MS/MS proteomic data across multiple experiments. An explicit probabilistic model of the log-intensity of the isobaric labels’ reporter ions across multiple pre-defined groups and experiments is developed. This is then used to develop a full Bayesian statistical methodology for the identification of differentially expressed proteins, with respect to a control group, across multiple groups and experiments. This methodology is implemented and then evaluated on simulated data and on two model experimental datasets (for which the differentially expressed proteins are known) that use a TMT labelling protocol.
Bayesian modelling of compositional heterogeneity in molecular phylogenetics
Authors: Heaps Sarah E. , Nye Tom M.W. , Boys Richard J. , Williams Tom A. , Embley T. Martin
Published: August 2014

In molecular phylogenetics, standard models of sequence evolution generally assume that sequence composition remains constant over evolutionary time. However, this assumption is violated in many datasets which show substantial heterogeneity in sequence composition across taxa. We propose a model which allows compositional heterogeneity across branches, and formulate the model in a Bayesian framework. Specifically, the root and each branch of the tree is associated with its own composition vector whilst a global matrix of exchangeability parameters applies everywhere on the tree. We encourage borrowing of strength between branches by developing two possible priors for the composition vectors: one in which information can be exchanged equally amongst all branches of the tree and another in which more information is exchanged between neighbouring branches than between distant branches. We also propose a Markov chain Monte Carlo (MCMC) algorithm for posterior inference which uses data augmentation of substitutional histories to yield a simple complete data likelihood function that factorises over branches and allows Gibbs updates for most parameters. Standard phylogenetic models are not informative about the root position. Therefore a significant advantage of the proposed model is that it allows inference about rooted trees. The position of the root is fundamental to the biological interpretation of trees, both for polarising trait evolution and for establishing the order of divergence among lineages. Furthermore, unlike some other related models from the literature, inference in the model we propose can be carried out through a simple MCMC scheme which does not require problematic dimension-changing moves. We investigate the performance of the model and priors in analyses of two alignments for which there is strong biological opinion about the tree topology and root position.
Terrestrial orchids in a tropical forest: best sites for abundance differ from those for reproduction
Authors: Whitman Melissa , Ackerman James D.
Published: August 2014

Suitable habitat for a species is often modeled by linking its distribution patterns with landscape characteristics. However, modeling the relationship between fitness and landscape characteristics is less common. In this study we take a novel approach towards species distribution modeling (SDM) by investigating factors important not only for species occurrence, but also abundance and physical size, as well as fitness measures. We used the Neotropical terrestrial orchid Prescottia stachyodes as our focal species, and compiled geospatial information on habitat and neighboring plants for use in a two‐part conditional SDM that accounted for zero inflation and reduced spatial autocorrelation bias. First, we modeled orchid occurrence, and then within suitable sites we contrasted habitat characteristics important for orchid abundance as compared to plant size. We then tested possible fitness implications, informed by analyses of allometric scaling of reproductive effort and lamina area, as well as size–density relationships in areas of P. stachyodes co‐occurrence. We determined that orchid presence was based on a combination of biotic and abiotic factors (indicator species, diffuse solar radiation). Within these sites, P. stachyodes abundance was higher on flat terrain, with fine, moderately well‐drained soil, and areas without other native orchids, whereas plant size was greater in less rocky areas. In turn, plant size determined reproductive effort, with floral display height proportionate to lamina area (more photosynthates); however, allometric scaling of flower quantity suggests a higher energy cost for production, or maintenance, of flowers. Overall, habitat factors most important for abundance differed from those for size (and thus reproductive effort), suggesting that sites optimal for either recruitment or survival may not be the primary source of seeds. For plots with multiple P. stachyodes plants, size–density relationships differed depending on the size class examined, which may reflect context‐dependent population dynamics. Thus, ecological resolution provided by SDM can be enhanced by incorporating abundance and fitness measures.
Modeling spatiotemporal dynamics of outbreaking species: influence of environment and migration in a locust
Authors: Veran Sophie , Simpson Stephen J. , Sword Gregory A. , Deveson Edward , Piry Sylvain , Hines James E. , Berthier Karine
Published: August 2014

Many pest species exhibit huge fluctuations in population abundance. Understanding their large‐scale and long‐term dynamics is necessary to develop effective control and management strategies. Occupancy models represent a promising approach to unravel interactions between environmental factors and spatiotemporal dynamics of outbreaking populations. Here, we investigated population dynamics of the Australian plague locust, Chortoicetes terminifera, using density data collected between 1988 and 2010 by the Australian Plague Locust Commission over more than 3 million km2 in eastern Australia. We applied multistate and autologistic multi‐season occupancy models to test competing hypotheses about environmental and demographic processes affecting the large‐scale dynamics of the Australian plague locust. We found that rainfall and land cover predictors best explained the spatial variability in outbreak probability across eastern Australia. Outbreaks are more likely to occur in temperate than tropical regions, with a faster and more continuous response to rainfall in desert than in agricultural areas. Our results also support the hypothesis that migration tends to propagate outbreaks only locally (over distances lower than 400 km) rather than across climatic regions. Our study suggests that locust outbreak forecasting and management systems could be improved by implementing key environmental factors and migration in hierarchical spatial models. Finally, our modeling framework can be seen as a step towards bridging the gap between mechanistic and more phenomenological models in the spatial analysis of fluctuating populations.
Origin of Galactose‐Deficient Immunoglobulin G in Gingival Crevicular Fluid in Periodontitis
Authors: Komiyama Yuske , Kafkova Leona Raskova , Barasch Andrei , Shah Ging R. , Grbic John T. , Novak Zdenek , Komiyama Kazuo , Novak Jan , Mestecky Jiri , Moldoveanu Zina
Published: August 2014

Background: Periodontitis is a chronic inflammatory disease initiated by a synergistic and dysbiotic microbial community that elicits a gingival inflammatory response leading to tissue breakdown. Periodontitis shares many characteristics with other chronic inflammatory diseases, including abnormal glycosylation of immunoglobulin (Ig)G. The current authors have previously demonstrated that IgG from gingival crevicular fluid (GCF) of patients with chronic periodontitis contains galactose (Gal)‐deficient IgG.

Methods: The origin of the aberrantly glycosylated IgG was determined by measuring levels of Gal‐deficient IgG in GCF and serum from patients with periodontitis and non‐periodontitis controls using lectin enzyme‐linked immunosorbent assay. The Ig‐producing cells and the proportion of cells producing Gal‐deficient IgG were immunohistochemically determined in gingival tissues from patients with periodontitis by fluorescence microscopy. The results were statistically evaluated and correlated with clinical data.

Results: The results indicate that GCF of patients with periodontitis had higher levels of Gal‐deficient IgG compared with controls (P = 0.002). In gingival tissues, IgG was the dominant isotype among Ig‐producing cells, and 60% of IgG‐positive cells produced Gal‐deficient IgG. Moreover, the proportion of Gal‐deficient IgG‐producing cells directly correlated with clinical parameters of probing depth and clinical attachment loss (AL).

Conclusion: These results suggest that the presence of Gal‐deficient IgG is associated with gingival inflammation and may play a role in the worsening of clinical parameters of periodontitis, such as AL.
A Quasi Intelligent Flow Control Device for Water Injectors
Authors: Bowen Eddie G. , Aadnoy B. S.
Published: August 2014

According to industry wide surveys, the number of wells drilled as injectors relative to producers are on the rise. The cause being driven by the knowledge gained from industry's experience and need to maintain pressure support during the entire production life cycle of a well improving ultimate oil recovery.

One of the biggest challenges with water injectors is how to manage an efficient sweep of the oil. An early breakthrough event when attempting to manage pressure maintenance is undesirable because it leads to unwanted water breakthrough in the producing well and leaves behind valuable oil reserves. This ultimately increases the cost of production and reduces net revenues on a per well basis.

This paper introduces an innovative, cost-effective solution resulting in an efficient sweep of the producing zones and improved oil recovery. Sustaining control of where the water is distributed in vertical cased hole wells versus long open hole lateral sections requires some type of down hole mechanical mechanism directing the injected waters to the desired zones of interest. One way to accomplish this is through an expensive intelligent completion where feed through capabilities are required for production packers and wellheads. Another is to install a passive inflow control device that passively controls the outflow of water via the use of an orifice or some type of unique geometrical shape that is dependent on a pressure drop, providing the distribution along the intervals length. A third method is providing as much flow area as possible in the lower completion and allowing the water to go where it wants to go.

Laboratory testing and modeled simulated results for the quasi-intelligent flow control device will be presented in a manner that compares the different methods available along with hardware requirements to achieve an effective quasi-intelligent completion for water injectors.
Highest Reliability Provides World Class Benchmark for Permanent Downhole Monitoring Installation and Data Delivery in Malaysia
Authors: Samuel Orient B. , Khalid M. Zaidan , Raw Ian , Singh Premjit Kaur
Published: August 2014

Reservoir pressure and temperature measurements have become the cornerstone of reservoir and production management. These measurements provide improved capabilities for understanding of oil and gas reservoir characteristics, which enables greater reservoir management for increased production and improved ultimate recovery.

The reliability and accuracy of permanent downhole pressure and temperature technologies is therefore of the highest priority when planning field developments, be it green fields, brown fields, marginal fields or EOR projects. A long term Permanent Downhole Gauge and Fiber Optic monitoring contract was awarded in August 2010 with the intent to provide reservoir monitoring with the highest reliability and accuracy that was available. Since the award of the contract, the world-class milestone of 50 installations was achieved in August 2013. This milestone was enhanced by the fact that, an amazing success rate of 100% was realized.

As of June 2014, the number of installations has increased to more than 80 gauges while maintaining the 100% success. This has provided increased confidence for the operator to expand deployment of permanent downhole gauges to higher pressure and temperature environment.

This success story has been achieved by a combination of many factors, from the strong validation process for gauge selection and subsequent choice of world class technologies with the highest survivability in the oil industry, close collaboration between the project and operations teams of the oil company and service provider, project management expertise, detailed preparation and maintenance, to the philosophy of providing real time data delivery to the end user.

This paper provides an update of the remarkable success story including the technologies installed, the progression into increasingly higher pressure and temperature environments, and examples of the benefits observed from the access to reliable and accurate downhole pressure and temperature information.
Novel Integrated Hole-Cleaning Concept Reduces Well Construction By 3 Rig Days
Authors: Heitmann Norbert , Chacinet Euro , Molero Rafael , Graterol Willy , Ouali Yazid , Burgos Elias Chamat , Cisneros Agustin
Published: August 2014

A new hole-cleaning process applied in a PDVSA Servicios Drilling Project, in the Heavy Oil Orinoco Belt, Bolivarian Republik of Venezuela saved 3 rig days and reduced the stuck-pipe risk and avoided damage to the MWD/LWD BHA and PDC bit. A long sought solution for effective wellbore cleaning was validated. Applied the first time, this concept provides a novel integrated solution for hole-cleaning, is transferrable to other well construction projects, is reducing project costs, lessens lost-in-hole BHAs and significantly reduces flat drilling time & invisible lost time.

Effective hole-cleaning is the main challenge of any deviated drilling operation, with problems in cuttings and cuttings beds removal. Even optimized mud flow rates, with reciprocal and rotational pipe movements physically cannot completely remove cutting beds. The herewith presented solution constitutes to incorporate a non-rotational scraper assembly into the drill string, applied together with an engineered and optimized hole-cleaning process.

With no access to dedicated casing cleaning tools, the 9 5/8” casing was cleaned from cuttings by back-reaming inside the casing with the BHA drill string, requiring minimum 2-3 runs and 2 days, and causing excessive wear on casing, BHA and PDC bit. After drilling the 8 ½” section, the new concept was to place a non-rotational scraper assembly into the drill string, allowing only minimum POOH of DP stands as part of the scheduled final openhole wiper trip activity, followed by RIH back to TD – and as such completing the openhole wiper trip without the need of tripping the drill string to surface. The tested solution eliminated all back-reaming inside casing and ensured a full 360° casing contact cleaning prior to RIH the liner, guaranteeing the casing is free of cuttings and also eliminating any additional round nose mill trips. The scraper never moved outside the 9 5/8” casing. This first application of RIH a scraper as part of the drill string gave outstanding results with 3 rig days been saved and a smooth RIH of the liner.
Using E-Line to Restore Well Injection on a Limited Space Platform - A Case Story from India
Authors: Nayak Jyoti Prakash , Parasher Arunabh , Anand Saurabh , Sharma Anurag , Pinto Thomas
Published: August 2014

Crane, space and height restrictions often pose problems when it comes to traditional intervention methods; adding daylight requirements, which are often a result of such platform restrictions, makes interventions even more challenging.

When slickline jarring failed to remove a lock mandrel despite more than 300 attempts, an operator on a platform, offshore India's East Coast, turned to an alternative solution on electric line (e-line). The well was being converted into an injector to facilitate pressure support for producing wells in a marginal field, but injection was not possible due to a choked ‘thru tubing sand screen’ (TTSS), placed through a 3.5 in. lock mandrel set on a 3.5 in. sliding sleeve door (SSD) nipple.

Thorough risk assessment and testing was conducted onshore to prepare for this region's first operation; however, the first run revealed that the GS profile couldn't latch on to the lock mandrel due to debris settled on top of the TTSS. A readily available clean-out solution was quickly mobilized and arrived within 12 hours. This clean-out tool incorporated a high volume suction technology and bailer sections to remove debris. Around half a liter of debris was removed allowing the subsequent run with an electric-over-hydraulic stroking ram to retrieve the lock mandrel without further complications.

Using e-line with the right blend of technology provided cost-effective management for the project and thus avoided a barge-based coiled tubing (CT) or workover rig operation involving much higher risks and costs. Post retrieving the TTSS, the well was put on injection successfully with around 22,000 barrels of water per day (BWPD) injection rate against zero injectivity prior to the operation.

This paper will report the first ever attempt of releasing a lock mandrel using e-line in the Asia Pacific region. It will review the job planning, project management, trouble shooting and execution, as well as report the lessons learned to derive best practice considerations for future operations.
First Non-Retrievable Casing Drilling Technique with Automated Surface Drive System to Improve Top Hole Drilling Performance - Vietnam Offshore
Authors: Chuong Hwong Yew , I Made Budi Utama , Wang Keith Won
Published: August 2014

Casing while Drilling (CwD) technology has become a favorable drilling technique and gaining attention among operators across the Asia Pacific region due to its field proven reduction in drilling flat time and as a solution to potential downhole problems. The non-retrievable CwD technique includes a drillable casing bit and float collar assembly attached to the lower end of the casing string. The entire casing string is driven by a surface drive system. Cementing can be carried out immediately upon reaching total depth. A conventional drilling assembly is subsequently deployed to drill out the casing bit and next hole section, without the requirement of a special drill-out trip.

Previous successful CwD operations for top hole sections of offset wells in Malay–Tho Chu Basin offshore Vietnam, have encouraged the operator to further improve the drilling efficiency. The operator planned to install 13-3/8″ conductor casing utilizing CwD techniques in similar lithologies with an even more efficient, safer, and automated surface drive system. An automated surface drive system was selected to replace the conventional manually operated casing drilling spear which was used in the previous campaigns.

The automated surface drive system combines conventional casing running equipment into a single unit, allowing string rotation and push-down while running, circulating, or reciprocating. The system's integrated measuring shaft gives more precise torque readings when making up a connection.

This paper discussed the first case history of successful planning and implementation of CwD with the automated surface drive system in Vietnam. Emphasis is placed on the entire process from the pre-job engineering planning stage until project execution, as well as the improved drilling performance and outcomes.
Successful Strategy to Minimise Non-Productive Time for Drilling Deepwater Well with Newbuild 6th Generation Drillship
Authors: Prasertamporn Praisont , Rattanachan Sarit , Maheshwari Mukesh
Published: August 2014

The first PTTEPI deepwater well in 1,003m water was drilled in the Gulf of Martaban, Myanmar in 2013. The tight deepwater rig market and single well program made it difficult to secure a rig, but a newbuild 6th generation drillship was eventually contracted. Non-Productive Time (NPT) is always the major concern when using a newbuild, especially in deepwater where the operational cost was 62,500 USD/hour. This paper explains how NPT was kept to acceptable level, describing the procedures employed.

The drillship used was identical to a sister rig which had already started the operations and lessons were learned from that. Start-up NPT from the previous rig was found to be 12.4% in the first 2 wells and the majority of this resulted from drawworks, BOP and Top-drive issues. Sub-sea equipment downtime was especially damaging in deepwater due to the extended time required to pull and re-run the BOP. This area was, therefore, a primary focus.

Third party inspection of BOP systems was witnessed by company representatives and a comprehensive testing and inspection program was designed to simulate operations wherever possible. Pre-running and Post-running tests were performed per API standard 53 and all tests were completed successfully. When the rig was in operation, BOP running procedures were strictly enforced. Contractual clauses were also agreed between the contractor and operator to minimise the impact of any start-up NPT.

Logistics planning of equipment, bulk, and chemical also played important part of downtime minimization. As the turnaround time from shorebase to well location was 5 days, lots of loadings had been done before rig departed from Singapore.

At the end of the well, drilling operations were found to have been performed efficiently. Rig NPT was only 6.9%, but with the majority of this resulting from problems with a new design of diverter system. This level of NPT was impressive for a newbuild high technology drillship, being 70% lower than the figure for start-up of the sister unit.
Challenges of Casing Design in Geothermal Wells
Authors: Torres Angelito
Published: August 2014

Casing and tubing in either oil and gas or geothermal wells are designed to withstand pressure loads (burst and collapse) and axial tension - the typical parameters that should be considered in any casing design. However, in geothermal applications, temperature is a major consideration in casing design because of thermal stresses generated by the high temperature geothermal fluids. Elevated temperature reduces the yield strength of the casing which essentially reduces the burst rating, collapse resistance and tensile strength of the material.

High temperature will be experienced by the well once it is on production. The cemented casing strings will be subjected to significant cyclical axial stress caused by changes in temperature due to production of high temperature geothermal fluids that can then be followed by the injection of cold water for well kill operations to perform wellbore maintenance. During production, the cemented casing will enter a compressive state where plastic deformation occurs since the casing is not allowed to expand. When cold water is injected to kill the well, axial tensile stresses are generated. This paper will explore this thermally induced cyclical loading in geothermal wells, and discuss how to account for these loads in the design process.

Another consideration in casing design is the selection of threaded connections that can maintain strength and seals at elevated temperatures. It is also important to evaluate the potential of trapping water in the annulus between two casing strings during cementing operations. When the well is put on production the water expands due to the large increase in temperature, creating a significant amount of pressure between the two casing strings, which can lead to a collapse failure of the inner string or a burst failure of the outer string. Examples of these failure mechanisms will be discussed in detail.
Successful Utilisation of Conventional Cement System to Mitigate Shallow Water Flow Risk in Deepwater Block M11, Myanmar
Authors: Prasertamporn Praisont , Maheshwari Mukesh , Olutimehin Kunle , Vargas Bermea Jorge Andres
Published: August 2014

In 2013, PTTEP drilled a deepwater well in the Gulf of Martaban, Myanmar. The water depth was 1003m with riserless drilling over 1000m below seabed. Being exploration well without any reliable offset well, shallow hazards risk was high. Shallow hazards analysis was performed, showing the high risk of shallow water flow. Shallow water flow causes many incidents, including surface casing cement failure. It can happen during cementing, cement phase transitioning, and after the cement has set. Cementing with the shallow water flow presence is, therefore, the critical operation to achieve the well integrity. Using special cement systems, foam or ultra-lightweight, is expensive, logistically challenging, and operationally complicated. After thorough risk analysis and mitigation, conventional class G cement system was selected.

Information from 12-1/4″ pilot hole and actual 26″ hole were analysed for cementing plan. Shallow water flow occurred at 1819m in pilot hole. Pump and dump was started from 1760m in 26″ hole to prevent the flow. However, drilling to 2005m encountered another strong flow. So, the critical zone was identified from 2005m downward. For operational success, the critical zone was covered by gas tight tail slurry with API fluid loss control less than 50 mL/30 min, a SGSA transition timer shorter than 30 minutes and a short thickening time to prevent formation fluid migration. Lead slurry was designed for sufficient density and long thickening time to provide enough hydrostatic pressure, preventing fluid migration while tail slurry was setting. Not being ultra-lightweight cement, slurries were pumped with high excess and contain fibrous LCM to mitigate losses risk. Centralisation also contributed to the cementing success.

During the cement job, good returns had been observed. No shallow water flow occurred during and after cementing. Operation was continued without subsidence issue.

This paper summarises the process of assessing the risks and designing the economical cement operation to mitigate the risks, resulting in safe operation from shallow hazards.
Tackling Drilling Challenges Through Engineered BHA and Optimized Drilling Parameters: A Case Study from the Niger Delta
Authors: Okoronkwo Anayo , Ibrahim Timothy
Published: August 2014

In the Niger Delta in Nigeria, some fields are classified as tough drilling environment due to numerous challenges encountered during the drilling phase of well construction process. In the Gbaran field in the Niger Delta, the greatest challenge is encountered in top hole drilling in 16” hole size and above. From a stratigraphical standpoint, the surface hole formation down to 6000ft in this field and other fields of similar drilling challenges shared common characteristics, with the lithology ranging from soft and loose to medium and abrasive sand inter-bedded with stringers of lignites, gumbo shale, and hard streaks (cemented sand). Bottom hole assembly (BHA) failures such as wash outs, cracks and twist-offs caused by erratic torques, excessive lateral, axial and torsional vibration are regular occurrence while drilling top hole at depths between 3000ft and 6000ft. From offset well records, more than 75% of 16” and 17-1/2” surface hole drilled in the Gbaran field ended up with unplanned side-tracks due to twist-off and lost hole. In some wells, the non productive time arising from these failures is up to 100% of planned AFE time for the section with the attendant cost impact on the wells in addition to lost-in-hole charges.

To address these challenges, steps were taken to analyse the failures in the offset wells and come up with BHA design capable of withstanding the inherent down-hole vibrations and shock. This paper discusses this engineered approach which is centred on two things: Fit-for-purpose BHA design and optimized drilling parameters. It also highlights the success story of drilling the deepest 16” hole so far in the fields without BHA failure as experienced in other wells drilled in the same field. The result from field application showed a tremendous reduction in drilling days from average of 27days per well in the last three offset wells to average of 9.5 days per well. Furthermore, the MWD output of down-hole vibration chart also showed a 50% reduction in severity compared to offset wells in the field.
Torque Simulation in the Well Planning Process
Authors: Boonsri K.
Published: August 2014

As the hydrocarbon reserves are progressively depleted, the way to find hydrocarbon is much more complicated than ever by having a number of restrictions such as environmental issues, surface location, well proximity, and so forth. It is no surprise that the well planning process nowadays is very challenging. The torque limitation of the equipment is one of the constraints. During well planning, a prediction by sophisticated engineering software is required to ensure that the drilling torque would be within the limit. However, many wells drilled in the past have suffered with excessive torque, causing unusable wells or eventually unfeasible projects. This raises a disconcerting question whether the root cause originated from the software or the engineers. No matter what the answer is, the key is to understand the root cause and how to prevent it.

Therefore, first and foremost, this project will address the nature of the torque in the drilling operation in cooperation with a mathematical approach to describe torque behaviour. Secondly, torque simulation is very useful but also perilous. The difficulties lie in how much insight the engineers have into which software modelling or input is crucial in which circumstances. For this, a study of well design parameters including well architecture, drill pipe selection, BHA type, drilling fluid and tortuosity, will elaborate the extent to which these variables have influences on the torque by utilizing torque and drag software in a controlled environment together with an analysis of the actual field data. Last but not least, well planning optimization and external resources are also integrated as a guideline for future usages.
Lessons Learned from Over 20 Historical Years of Completion Practices in the Cuu Long Basin Offshore Southern Vietnam
Authors: Vu Hao Manh , Lu Vi Dinh , Le Quan Vu , Nguyen Vu Minh , Le Trung Quoc , Emiliani Gianni
Published: August 2014

Cuu Long basin is the major hydrocarbon producing basin in Vietnam with several discoveries of oil and gas in both Oligocene-Miocene and fractured basement reservoir such as H, D, A and R field in 1990s. Overall, the geological characterization to apply the well completions in the area is not too complex. However, as operation and production have caused damage, especially, the migration of reservoir sand and fines into wellbore, water breakthrough, and paraffin deposition which might shorten lifetime of wells, increase operating costs and might decrease well profitability.

The purpose of this paper will review, discuss and evaluate the well completion technologies current application in the Cuu Long basin, the methodology starts with approximately 350 wells on a total of more than 430 production and injection wells are collected. Then, the focus on case by case of the field studies cover completion design, well performance evaluation, completion improvement, completion failure diagnostics, and so on. Finally, the main target for this study is to share some lessons learned and experiences gained from the past more than 20 historical years a worthy case study for both current and future development of the fields not only in the Cuu Long basin but also in the continental shelf of Vietnam and the world.
Best Practices for Logging While Drilling Fluid Sampling of Deviated Wells in Deepwater Applications
Authors: Martin Stephen J. , Tran Pei-Chea , Marshall Steven
Published: August 2014

A deepwater operator in Asia Pacific required a large volume fluid sample from a gas reservoir in the northwest shelf of Australia for accurate non-hydrocarbon gas content analysis. This paper highlights pre-job planning and operational considerations for running logging while drilling (LWD) fluid sampling and formation pressure testing devices in two highly deviated 8 ½-in wellbores. These include risk mitigation techniques to avoid stuck pipe, accommodating rig heave associated with deepwater drill ships, oil-based mud (OBM) gas sampling issues and the prevention of geo-chemical absorption.

Because the wells reached more than 80°inclination, traditional, wireline fluid sampling required a pipe-conveyed or tractor mechanism, increasing the AFE, rig time and operational risks. To make sampling feasible required the use of a unique LWD solution. Furthermore, the planning, mobilization, and deployments were accomplished in less than six weeks by seamless cooperation between the operator and service partner.

In two runs, 26 samples were acquired containing more than 19 liters of fluid. During the pre-sample cleanup, a high- speed telemetry system provided 25 bits per second of real-time fluid analysis data to ensure the fluid properties were stabilized. Because of the improved operational efficiency of logging while drilling technology, the operator estimated savings of approximately USD10 million dollars in rig and operating costs and potentially millions more in reduced retrofitting costs of the production facility.

Fluid sampling while drilling technology represents a major change in deepwater formation evaluation capabilities. By utilizing the techniques presented in this paper, operators can collect large volumes of fluid samples in deviated wells while reducing operational risks and minimizing costs. A recap of the two wells presents best practices for prejob planning, risk mitigation and overcoming mobilization challenges in short call-out scenarios. These high-quality development well samples enable a properly designed production facility, thereby preventing costly post-production modifications.
Best Practice in the First Wireline Retrievable ESP Pilot Job in Kuwait
Authors: Bouhanna Mahfoud , Al-Shammari Menwer , Al-Fadli Ali , Mali Prasanna Vasant , Al-Jasmi Ahmad
Published: August 2014

Electrical Submersible Pump is an artificial lift method which consists of lowering a pump system on tubing string during rig workover where the power cable is clamped externally along with the tubing.

Because of the significant rig workover cost, the ESP is usually run until failure.

Wireline Retrievable ESP (WRESP) is a step change in ESP method, where the pump without electrical cable can be retrieved and reinstalled with a wireline method (as a rigless job) at any time of ESP life cycle.

A Wireline Retrievable ESP system consists of two main parts:

Permanent part: Docking station with a male connector, attached to a large bore tubing string with a power cable clamped on it and lowered in the well bore during a rig work-over job Retrievable part: Standard ESP string with a seal assembly on top and motor connector on the lower end, lowered and retrieved with Wireline inside the large bore tubing.

This technology was implemented as a trial jobs in Oman, Ecuador and Nigeria. Challenges faced during implementation were as follow:

➢ Considerable seals friction of seal assembly, resulting in a serious damage and stuck in tubing wall during pulling out of hole. ➢ Difficulties to retrieve remaining pieces of damaged seals from the docking station. ➢ Swap to CT conveyance. ➢ Swabbing effect.

During the first implementation in Kuwait, similar challenges were faced.

An Innovative Idea was designed, implemented and succeeded to overcome the above challenges. It was about adding a circulating device (operated by a slickline method) to the seal assembly configuration part, which was resulting first time (in Kuwait and worldwide) in completing a trial project smoothly and successfully.

This paper will describe the innovative idea, experience and best practices of the first WRESP application in Kuwait oilfield.
Lessons Learned from DAS and DTS in MultiCluster, MultiStage Horizontal Well Fracturing: Interpretation of Hydraulic Fracture Initiation and Propagation through Diagnostics
Authors: Sookprasong P. A. , Gill C. C. , Hurt R. S.
Published: August 2014

Fiber optic distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) have been used to monitor and diagnose the integrity of wellbores (leak detection, gravel-pack screen damage, formation subsidence, etc.), the performance of reservoirs and wells (production profile, injection profile, etc.), used for surveillance and other applications for quite some time. The application of high resolution fiber optic DAS and DTS during multi-stage hydraulic fracturing has increased in recent years.

In this horizontal tight-gas well, the fiber optic filaments were placed in a small stainless steel tube which was clamped to the casing while running in hole, and the casing was then cemented in place. Perforations had to be oriented to avoid damage to the fiber optic. In this case, perforations were place at the topside of the casing, zero degree phasing, at 5 shots per foot (1 foot per cluster).

This paper shares results from DAS and DTS techniques that allow for interpretation of fracturing treatments in multi-cluster (each stage), multi-stage horizontal well with cemented casing and ‘plug and perf’ completion process. The images illustrate the dynamics pertaining to initiation, propagation and arrest of hydraulic fractures during simultaneous stimulation of multiple clusters. First, fracture initiation appears not only during early time, as expected, but late time initiation events may develop in seemingly dormant clusters. Second, propagation of multiple fractures can occur randomly within a cluster array. Third, dominate clusters are often observed during stimulation. Further, during the treatment cycle, the position of dominate cluster(s), within a given stage, may actually change.
Case Study: High-Strength Disintegrable Tripping Balls in Hydraulic Fracturing System Application
Authors: Wibowo H. , Carrejo N. , Gaudette S. L. , Kitzman J. D.
Published: August 2014

High-strength disintegrable frac balls have provided successful isolation in multi-stage completion systems during hydraulic fracturing treatments in thousands of wells throughout North America. The multi-stage hydraulic fracturing is enabled through one avenue with the utilization of a ball-activated frac sleeves to fracture each stage. Advancements in technology permit over 40 individual stages in one wellbore. This puts a critical emphasis in the reliability of the frac ball as an integral part to the success of each treatment. The High-Strength Disintegrable (HSD) frac balls must exceed the pressures required in hydraulic fracturing, while avoiding the risk of remaining stuck on seat or collecting in the lateral. This break-thru-material is engineered to disintegrate in typical downhole brines. The combination of this unique characteristic and its high strength enables the material to actuate frac sleeves and provide flow assurance by optimizing the flow area after fracturing a stage. More than 30, 000 HSD tripping balls have been deployed downhole. This paper presents a case study on fracturing pressure requirements using this new, innovative technology, and the reliability of the tripping balls' ability to disintegrate while being exposed to downhole brines.