bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature Distribution of Shallow Medium during Deepwater Drilling
Authors: Li Chaowei , Fan Honghai , Wang Zhiming , Deng Song , Ren Weiyan , Yan Bo , Liu Weichao , Kang Bo , Zhang Ming , Peng Qi 
Published: April 2015

Abstract
Since depth of shallow layers in the deep water is general 1500 ft or more, the temperature is approaching the freezing point of water at this depth. Moreover, Drilling Fluid always has a high temperature which can lead the originally stable gas hydrate, shallow flow and shallow gas to disorders, for example, corrosion and deformation of drilling strings, blowout and pipeline jam can be induced by shallow flow, shallow gas and natural gas hydrate respectively. This paper conclude a new method to describe the complex temperature gradient in the shallow layers.
A new model of heat transmission about shallow layers including shallow flow, shallow gas and wellbore is established. Thermodynamics and heat transfer are used in this paper either. Meanwhile, assuming the heat transfer among surface casing, formation and shallow flow is stable, whereas the transfer among drilling fluid, drilling strings and casing is unstable, a temperature simulation in the shallow could be done. Furthermore, this paper adopts an infinitesimal control body as a research object and establishes nonlinear partial differential systems. A fully implicit finite volume method is adopted to discrete the control equations. Then through the equation integral in the control domain, the discrete equations of conservation are obtained. Meanwhile, the alternating direction method is used in order to improve the solution efficiency, stability, and convergence.
This paper also cities a well data in South China Sea as an example. Through the analysis of different displacement, wellbore and shallow water distance, the new model calculation results are accurate compared with the classical model validation. It can be concluded that the drilling fluid temperature has a great influence on the shallow. The greater heat transfer coefficient of shallow flow, the faster the temperature rises. Some new solutions to solve geological hazards are obtained in the shallow in which the special temperature profile can trigger natural hazards.
Safety becomes the biggest concern during drilling in the shallow of deep water. This paper mainly focus on the temperature prediction in the shallow. On one hand, the complex temperature changes can cause numerous geological hazards during drilling or cementing process. On the other hand, the narrow density window of safe drilling fluid demands high standard of techniques. So the accurate temperature distribution of shallow layers in deep water has great significance in drilling works.
Pore Pressure Calculation Method for Deepwater Shallow Layers with Log Data
Authors: Deng Song , Fan Honghai , Zhou Yuyang , Zhang Ming , Liu Jinge , Niu Jun 
Published: April 2015

Abstract
Deepwater drilling practice faces numbers of geological hazards which happen in shallow area due to abnormal pore pressure, and these phenomenon go worse, even affect the drilling process, combining with shallow flow, shallow gas, and gas hydrate conditions. However, applicable pore pressure calculation methods were not established in last decades.
Formation pore pressure change closely with SDT, especially the reaction more obvious mudstone formation. In this paper, based on shallow soil attributes, two kinds of logging-based calculation methods are put forward. One is a comprehensive interpretation method, in which porosity, shaliness and effective stress are taken into account. The other is a multi-regression method with the consideration of P-wave velocity, affected by shallow gas velocity and shallow flow velocity, and mathematical model is established by multi-regression.
Two wells in Yingqiong basin are exampled to verify above two methods. Meanwhile, calculation results are consistent with testing data, and geological hazards can be detected. Results shows that the multi-regression method is more suitable for fast prediction, and the comprehensive interpretation method is more accurate.
Pore pressure calculation in deepwater is different from the shallow case due to soil attributes. How to accurately analyze it still has a long way to go. The methods proposed in this paper have been applied in many wells in the South China Sea, and provide reasonable references to drilling practice.
Novel Anchoring Solutions for FLNG - Opportunities Driven by Scale
Authors: O'Loughlin C.D. , White D.J. , Stanier S.A. 
Published: April 2015

Abstract
FLNG facilities present a more onerous anchoring requirement than existing floating structures. Optimisation of the anchoring technology through improved design or through novel anchor types offers potential cost and risk benefits. These benefits may also be applicable to smaller moorings for MODUs and FPSOs. This paper uses concept–level design calculations of anchor capacity to compare different anchor technologies in the context of FLNG and MODU/FPSO applications. Also, new observations from physical modelling of chain–soil interaction are presented. Opportunities are identified for significant cost and schedule savings by adopting the alternative plate anchor technologies that are either suction or dynamically installed. Considering fabrication alone, the estimated costs are reduced by 70% for FLNG and 80% for MODUs relative to the conventional suction caisson option. When installation vessel costs are considered, the absolute cost saving could be far higher than from fabrication alone because installation could be from an anchor–handling vessel rather than a construction barge with a heavy lift crane. Torpedo anchors have also been considered, but are less attractive. Centrifuge model data and calculations of the shape and capacity of the embedded anchor chain suggest that there may be over–looked capacity from the mooring chain both on and within the seabed. At the same time, upscaling of embedded plates to the scale required for FLNG applications increases the amount of chain slack that would be released into the mooring during in service loading, and this effect requires consideration in the overall mooring system design. Research and development activities aligned with the opportunities for reduced cost and risk in anchoring design are set out.
Environmental Consequences of Engineered Nanomaterials: An Awareness Campaign to Promote Safe Nanotechnology and Dispel Related Misconceptions
Authors: Pavan M. V. Raja , Khabashesku Valery N. 
Published: April 2015

AbstractNanomaterials comprise a wide range of material compositions, existing in the form of particles or aggregates that have at least one dimension in the nanoscale regime. They have several unique characteristics such as high surface area, customizable chemical functionalities, and unique electrical, magnetic, and mechanical properties. Examples of synthetic nanomaterials and nanostructured materials include carbon nanotubes, silver nanoparticles, nanoporous silica, and polymeric nanocomposites. Nanomaterials have been extensively studied in relation to applications such as sensors, coatings, and composites, in a wide range of industrial sectors.Thus, it is safe to assume that the application potential for nanomaterials is expanding. This is particularly true in the case of the oil and gas industry wherein several new technological developments are anticipated in relation to nanomaterials and nanotechnology – it is in a relation to a growing need for high-performance materials capable of functioning under adverse field conditions. High-strength polymer nanocomposites come to one's mind as a prominent example of a nano-related application in the oilfield sector.This paper presents an overview of the existing literature on the general impact of engineered nanomaterials from the perspectives of first, human health and the environment, keeping in mind the need to foster safe and responsible use of these materials, and considering the numerous benefits they offer in relation to various applications. In-vitro studies have shown that nanoparticles could potentially inhibit the growth of mammalian cells while in-vivo studies have shown adverse effects of nanomaterial exposure on various organs such as skin, lungs and corneas. In-vitro (on mammalian cells) and in-vivo (on laboratory animals) studies are meant to safely simulate the biological impact of the nanomaterials. However, these studies may not reveal the complete picture, and it cannot be stated that nanomaterials are generally harmful to all life forms. Microbial interaction studies have demonstrated mixed results in that carbon nanotubes were not found to inhibit the growth of E. coli in certain instances where a biofilm was formed. These trends highlight the need for each category of nanomaterial to be understood in the context of its properties, and its application or exposure route.Similar to the case of conventional / commonly used industrial chemical substances, the reviewed results serve to create an awareness of "nano-safety". They point to the need to develop appropriate measures to mitigate any potentially adverse effects of nanomaterials on human health and the environment. This is accomplished through measures such as secure containment of related wastes, choice of appropriate environmentally benign nanomaterials, and a well-planned procedure to handle unintended release of nanomaterials, etc.
Extending Anchor Handling Vessel Capabilities and the Technical Innovations that Make it Possible
Authors: Miller Jonathon D. , O'Driscoll Michael A. , Farrow Mark 
Published: April 2015

Abstract
As more structures are installed in offshore deepwater locations, the demands on the fleet of vessels that support the work increase. Deeper installation depths require the employment of emerging technologies and novel installation practices to safely accomplish installation and commissioning of the station keeping system. Deepwater operations can be costly and operators often enter extended contracts with vessel owners to support a variety of offshore operations as a cost reduction measure. In the autumn of 2014, the Delta House floating production system (FPS) was connected to its pre-set taut-leg mooring system in approximately 4,500 feet of water. Mooring installation costs were reduced by utilizing an anchor-handling vessel (AHV) already on long-term contract with the Operator's drilling department.
The Delta House hull and mooring designs were created by EXMAR Offshore, and the mooring components were specified and ordered knowing that the components exceeded the handling capacity of the selected installation vessel. This created unique challenges as the normal handling practices and equipment could not be employed. This paper summarizes the challenges and solutions found during the installation of the Delta House FPS for LLOG Exploration. It highlights innovations that extended the installation vessel's capacity and compares the size of the Delta House mooring components with those installed for LLOG's previous OTPI-Ex hull (Who Dat) in 2011. It describes enabling technologies that made installation possible with the specified asset.
An Experimental Study of Paraffin Deposition under Two-Phase Gas-Oil Slug Flow in Horizontal Pipes
Authors: Rittirong Ake , Panacharoensawad Ekarit , Sarica Cem 
Published: April 2015

Abstract
Paraffin or wax deposition under two-phase gas-oil slug flow in horizontal pipes was studied experimentally. The experiments were conducted using a 2.067-in large-scale multiphase flow loop under an operating pressure of 350 psig. Testing fluids were Garden Banks condensate and natural gas. Hydrodynamic experiments were performed prior to the wax deposition experiments to verify the flow patterns and examine the flow behavior. The hydrodynamic and heat-transfer variables were estimated using the unified mechanistic model (Zhang et al., 2003). Wax deposition experiments were conducted under single-phase and slug flows with parametric variation of oil and gas superficial velocities and testing durations of 4, 12, and 24 hrs. The bulk fluid and initial pipe wall temperatures at a removable spool piece were kept below WAT and relatively constant to control the initial concentration driving force. In this study, unprecedented detailed measurement and analysis of the circumferential local samples were conducted. A new pigging tool was designed and constructed for selective wax sampling at top, side, and bottom quarters of the circumference of the removable spool piece. Local deposit thicknesses were calculated from the direct measurements of deposit mass and density. Wax samples were analyzed by using DSC and HTGC for wax content and composition. The impact of the physics of the slug flow on wax deposition was investigated.
The results indicated that deposit thickness, wax content, and wax mass were affected by the change in superficial velocities or the flow rates of the phases. It was found that the deposit thickness increased with time. The thickness decreased with increasing superficial liquid velocity; whereas, it increased with increasing superficial gas velocity. The trends of the thickness were found to crossover each other at a certain time for different superficial gas velocities. In slug flow, circumferential variations of the deposit characteristics were analyzed. The deposit at the top wall was thicker, softer, and contained more oil than the bottom. Wax fraction increased with time reflecting the aging. Moreover, wax fraction increased with higher superficial liquid and gas velocities at a given time. The crossover of the wax fraction trends with different superficial gas velocities occurred. In slug flow, deposit at the top wall always had lower wax fraction than the bottom. Average carbon number and WAT of the deposit relatively increased with wax fraction. Wax deposits under slug flow had longer chain paraffins compared to the single-phase flow with the same wax fraction. Wax mass at the top wall was higher than the bottom. This new set of experimental data can be used as a verification tool for further development of wax deposition mechanistic model under such conditions.
Stationkeeping Technology for Frontier Deepwater Floating Systems
Authors: Duggal Arun S. , Izadparast Amir H. , Pothuganti Vijay K. 
Published: April 2015

Abstract
This paper provides an overview of the challenges associated with the stationkeeping of floating systems in frontier deepwater, and the range of solutions to address them. The paper presents the use of existing technologies, materials and components, and compare and evaluates them to the use of novel materials, new and possibly not field proven technologies, and design approaches.
The paper provides a high-level design basis and strategies for the stationkeeping system design, identifying key drivers in the selection of the stationkeeping system. The paper then utilizes an example of an FPSO system moored in a range of water depths to illustrate the current capabilities of conventional technologies and strategies to improve performance.
CFD-Based Numerical Wave Basin for Offshore Floater Design
Authors: Kim Jang Whan , Jang Hyunchul , Kyoung Johyun , Baquet Aldric , O'Sullivan Jim 
Published: April 2015

Abstract
Technip recently has developed new cost-effective and riser-friendly Semi-submersible hull forms adapted to various operation sites, with considerable saves in design cost and time. This achievement is greatly in debt to Technip's numerical wave basin, which has been developed and validated through previous projects and collaborative R&D efforts with clients. Validation of the numerical wave basin against the model test and full-scale measurement data has proven that the numerical wave basin can provide more realistic and reliable prediction of the wave- and vortex-induced motion than the physical model test. The validated numerical wave basin has been applied to develop a new semi-submersible hull design for a given design environment, partially replacing the role of the physical model test in the traditional design spiral. The new design spiral based on numerical wave basin provides optimized hull design more expeditiously and efficiently than the traditional design spiral based on physical model test. Review of the development, current status and future prospects of numerical wave basin for offshore platform design is presented in this paper.
Pastorale bediening van skuldbelydenis en versoening deur liturgiese handelinge
Authors: De Klerk Barend J. 
Published: April 2015

God se gawe, naamlik sy Seun, deur Wie verlossing van sonde en versoening met die mens bewerk is, staan sentraal in die Christelike belydenis. In die bediening van pastorale sorg en in die liturgiese handelinge is die gemeenskaplike doel die herstel van verhoudings, die versoening met God, met mekaar en met die self. Dit lei tot die vraag wat in hierdie artikel ondersoek word, naamlik wat die verhouding tussen die pastorale bediening van skuldbelydenis en versoening en die liturgiese handelinge daarvan is. Die aspekte wat aandag kry, is die pastorale sorg wat die gemeenskap aan mekaar behoort te bied, die verhouding tussen die pastorale sorg en die liturgie, die krag van rituele en ’n oorsig oor die ritueel van skuldbelydenis en versoening, enkele voorbeelde van sonde wat ’n gemeente kan bely en daarna die pastorale bediening deur rituele van berou en verootmoediging, sonde- en skuldbelydenis, vergifnis, absolusie en versoening. Die konklusie is dat die kommunikatiewe handeling van skuldbelydenis en versoening as ’n selfstandige handeling in die liturgie van die gemeente ’n kragtige pastorale bediening vir die gemeente as ’n geheel en vir die lidmate afsonderlik kan wees.Pastoral ministry on the confession of guilt and reconciliation through liturgical acts. God’s gift of his Son, through Whom he established redemption of sins and reconciliation with man, is central to the Christian confessions. In the ministry of pastoral care and in the liturgical acts the common goal is to re-establish relationships, reconcile with God, the other and the self. This leads to the question examined in this article, viz. what the relation between the pastoral ministry of confession or guilt and reconciliation and the performing of liturgical acts is. Attention is given to the following aspects: the pastoral care the community should give to each other, the relationship between pastoral care and liturgy, the power of rituals and an overview of the ritual of the confession of guilt and reconciliation, a few examples of sins a congregation may confess and subsequently the pastoral ministry through rituals of contrition and humiliation, confession of sin and guilt, forgiveness, absolution and reconciliation. The conclusion of this article is that the communicative act of confession of guilt and reconciliation as an independent act in the liturgy of the congregation, could be a powerful pastoral tool to the congregation as a whole and to members individually.
Surgical Outcome and Complications of Nasal Septal Perforation Repair with Temporal Fascia and Periosteal Grafts
Authors: Virkkula Paula , Mäkitie Antti a. , Vento Seija i. 
Published: April 2015

Aims Surgical treatment of nasal septal perforation remains a challenging field of rhinology. A large variety of techniques and grafts with promising results have been introduced for perforation repair. However, the use of fascia or fascia with periosteum has not been previously evaluated for a large sample of patients. Methods During the years 2007–2014, 105 operations were performed and 98 patients were treated for nasal septal perforation at the Department of Otorhinolaryngology–-Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland. We performed a retrospective review of closure rates and complications. Follow-up time ranged from 1 to 62 months. Results Bleeding was the most common early complication (9%), followed by postoperative infection (5%) in the whole series. Our main technique, bipedicled advancement flaps with fascia or fascia and periosteum, was performed for 81 patients. We obtained successful closure in 78% of these patients with this operative technique and the rate increased to 86% during the last 3 years of the study period. Conclusions Perforation repair with temporal fascia or fascia with periosteum requiring only one donor site seems to be a reliable option for nasal septal perforation repair.
Arithmetic of Degenerating Principal Variations of Hodge Structure: Examples Arising From Mirror Symmetry and Middle Convolution
Authors: da Silva Genival , Kerr Matt , Pearlstein Gregory 
Published: April 2015

AbstractWe collect evidence in support of a conjecture of Griffiths, Green, and Kerr on the arithmetic of extension classes of limiting mixed Hodge structures arising from semistable degenerations over a number field. After briefly summarizing how a result of Iritani implies this conjecture for a collection of hypergeometric Calabi–Yau threefold examples studied by Doran and Morgan, the authors investigate a sequence of (non-hypergeometric) examples in dimensions 1 ≤d≤ 6 arising from Katz's theory of the middle convolution. A crucial role is played by the Mumford-Tate group (which isG2) of the family of 6-folds, and the theory of boundary components of Mumford–Tate domains.
Categorical Aspects of Quantum Groups: Multipliers and Intrinsic Groups
Authors: Daws Matthew 
Published: April 2015

AbstractWe show that the assignment of the (left) completely bounded multiplier algebra Mlcb(L1()) to a locally compact quantum group , and the assignment of the intrinsic group, form functors between appropriate categories. Morphisms of locally compact quantum groups can be described by Hopf *-homomorphisms between universal C*-algebras, by bicharacters, or by special sorts of coactions. We show that the whole theory of completely bounded multipliers can be lifted to the universal C*-algebra level, and that the different pictures of both multipliers (reduced, universal, and as centralisers) and morphisms then interact in extremely natural ways. The intrinsic group of a quantum group can be realised as a class of multipliers, and so our techniques immediately apply. We also show how to think of the intrinsic group using the universal C*-algebra picture, and then, again, how the differing views on the intrinsic group interact naturally with morphisms. We show that the intrinsic group is the “maximal classical” quantum subgroup of a locally compact quantum group, that it is even closed in the strong Vaes sense, and that the intrinsic group functor is an adjoint to the inclusion functor from locally compact groups to quantum groups.
Littlewood–Paley Characterizations of Second-Order Sobolev Spaces via Averages on Balls
Authors: He Ziyi , Yang Dachun , Yuan Wen 
Published: April 2015

AbstractIn this paper, the authors characterize second-order Sobolev spaces W2,p(ℝn), with p ∊ [2,∞) and n ∊ N or p ∊ (1, 2) and n ∊ {1, 2, 3}, via the Lusin area function and the Littlewood–Paley g*λ -function in terms of ball means.
A Note on 3-choosability of Planar Graphs Related to Montanssier’s Conjecture
Authors: Zhang Haihui 
Published: April 2015

AbstractFor a given list assignment L = {L(v) : v ∈ V(G)}, a graph G = (V, E) is L-colorable if there exists a proper coloring c of G such that c(v) ∈ L(v) for all v ∈ V. If G is L-colorable for every list assignment L having |L(v)| ≥ k for all v ∈ V, then G is said to be k-choosable. Montassier (Inform. Process. Lett. 99 (2006) 68-71) conjectured that every planar graph without cycles of length 4, 5, 6, is 3-choosable. In this paper, we prove that every planar graph without 5-, 6- and 10-cycles, and without two triangles at distance less than 3 is 3-choosable.