bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Mechanisms and Evaluation Methods of Borehole Instabilities in Gas Drilling
Authors: Li Gao , Luo Bing , Liu Houbin , Meng Yingfeng , Han Lin 
Published: June 2014

Abstract
As a bottleneck problem, borehole instabilities have severely restricted further development and application of gas drilling technology. Here, the mechanisms of borehole instabilities in gas drilling are studied and four instability mechanisms are presented, including mechanical instability of weak rocks or crumbliness rocks because of their low mechanical strength, mechanics-chemical coupling instability caused by production or injection of fluid, rock burst of payzone and dynamically instability of overlying mudstone with pressure during hi-speed production. Because gas drilling has special operating conditions compared with conventional drilling, the experiment simulating field operating conditions is crucial to evaluation of borehole stability in gas drilling and need relate to more evaluating parameters, including formation temperature, pore pressure, overlying pressure, confining pressure, borehole pressure, types and production of formation fluid, velocity of slide wave as well as drilling operation, including dry gas drilling, foam or liquid drilling and conversion process of gas-liquid drilling operation. Meanwhile, deepening study on the mechanisms and evaluation methods of borehole instabilities, improving treating agents and treating process and advancing forecasting technique and sealing technique of formation fluid are thought of as effective approaches of enhancing borehole stability in gas drilling. This will be helpful for understanding the mechanisms of borehole instabilities in gas drilling and improving evaluation methods.
The Importance of Recognizing Hydrodynamics for Understanding Reservoir Volumetrics, Field Development and Well Placement
Authors: Green Sam , Swarbrick Richard E. , O'Connor Stephen A. 
Published: June 2014

Abstract
Hydrodynamically active reservoirs have been recognized in various parts of the world. The majority of these are termed "conventional", following the nomenclature presented in Swarbrick (2009), whereby fluid flow is driven by hydraulic head. More recently "unconventional" hydrodynamic reservoirs have been recognized where fluid flow is driven by lateral drainage, typically found in laterally extensive reservoirs.
The lateral drainage of pressure in reservoir sand units leads to a pressure gradient from higher pressured non-reservoir sediments (shales) above and below into the reservoir, leading to a focus of fluids, including hydrocarbons, within the reservoir. Within a laterally extensive reservoir fill and spill up-dip is likely to dominate the trapping of hydrocarbons, which is typically assisted by hydrodynamic flow as the aquifer will drain up-dip. Hence, secondary migration along extensive sand units is a highly effective carrier system, with little/no potential for vertical migration of hydrocarbons since there are higher pressures above and below. Hydrocarbon column heights can extend above the limits imposed by capillary entry pressures on account of the higher water pressures in the sealing rocks relative to the aquifer pressures in the sands.
Such reservoirs are present in the Miocene of the Gulf of Mexico and there are multiple sources of evidence for active "unconventional" hydrodynamics which are summarized within this paper. Furthermore, new data is presented that indicates the deeper Lower Tertiary Wilcox play is hydrodynamically active by combining direct pressure data interpretation with the geological depositional model.
Numerical Analysis of Wellbore Behaviour during Methane Gas Recovery from Hydrate Bearing Sediments
Authors: Xu Ermao , Soga Kenichi , Zhou Mingliang , Uchida Shun , Yamamoto Koji 
Published: June 2014

Abstract
Japan Oil, Gas, and Metals National Corporation (JOGMEC) conducted the first offshore methane hydrate production trial on March 2013, in the eastern Nankai Trough, Japan. Field work for the gas production trial began in early 2012. Coring and logging operations were conducted to prepare for the gas hydrate production trial. On March 12th, 2013, JOGMEC succeeded in extracting methane gas from the hydrate-bearing sediments by the depressurization method and approximately 120, 000 cubic meters of methane gas were produced totally. The production finally terminated due to the increase in sand production. It indicates the importance of evaluation the state of wellbore in order to produce methane gas safety and efficiently. It calls for an analysis to predict the stress changes and plastic strain evolution of wellbore during the life of well. Hence, a wellbore model, specifically designed for methane gas production, is necessary to assess the potential risks associated with the construction and production stage.
This paper describes a finite element approach, which mainly takes into account of (a) all the typical processes associated with wellbore construction and gas production and (b) the interaction between cement-casing-formation. Based on this approach, a finite element model, which includes the layered soil profile, cement, casing, gravel and sand screen, was developed in ABAQUS to simulate the gas production trial at East Nankai Trough in March, 2013. The Methane Hydrate Critical State (MHCS) model (Uchida et al., 2012), which was developed to simulate the geomechanical response of the methane hydrate bearing sediment, was incorporated into this finite element model. It presents results of coupled ground deformation and pore fluid flow analysis of a gas production wellbore from a methane hydrate formation. The study focused on the short- and long-term mechanical behaviour of the critical physical components at and near the wellbore by simulating the construction processes of the wellbore as well as the production stage. The interaction between cement-casing-formation was examined in detail.
How new seismic acquisition and processing technology is delivering high-resolution images
Authors: Vinje Vetle , Ratcliffe Andrew , Hoeber Henning 
Published: June 2014

Abstract
The objective of seismic acquisition and imaging is to recover the true properties of the earth. Major obstacles to obtaining this ideal goal are:the bandwith of the emitted source signals,the spatial sampling of the seismic survey and spatial aliasing,the aperture of the recorded data,the ghost effects on the source and receiver sides,the external and internal noise andthe ambiguity (nullspace) of the inversion problem (Yilmaz, 1987).
Analysis of Hurricane Winds
Authors: Vickery Peter J. 
Published: June 2014

Abstract
This effort represents a critical examination of the suitability of the models for atmospheric turbulence used in the draft API RP 2MET for describing the characteristics of hurricane winds offshore, using data collected from recent (post-2000) hurricanes. The preliminary results indicate that the current provisions are not suitable for describing hurricane winds, and hence wind loads associated with hurricanes.
Using wind speed measurements obtained from Gulf of Mexico hurricanes from a number of sources, the models for mean velocity profiles, gust factors and turbulence intensities given in the draft API RP 2MET were tested against these data. The wind speed data sources include:1.0 Vertical variation of wind speed with height using NOAA dropwindsonde data2.0 Gust factor data from NOAA data buoys and C-MAN stations3.0 Time series of wind speeds from a number of production facilities located in the Gulf of Mexico
The investigation found that the provisions of API RP 2MET do not provide a good representation of the structure of the hurricane boundary layer. A major reason that the provisions of API RP 2MET do not model the hurricane boundary layer well is that the models were developed using North Sea data, coupled with an assumption that the surface drag coefficient increases with wind speed. The net result is that at high wind speeds the API RP 2MET relations yield a mean velocity profile that increases too rapidly with height, overestimating wind speeds at typical deck height. For typical design wind speeds for structures located in the Gulf of Mexico the error associated with the API RP 2MET representation of the gust factor varies with height, overestimating the gust factor near the surface (10 m elevation or less), and underestimating it at higher elevations.
Numerical Simulation of Liquid Sloshing in Floating LNG
Authors: Agrawal Madhusuden , Rahumathulla Lubeena 
Published: June 2014

Abstract
The sloshing impact loads is one of the major design factors for tank containment system in LNG FPSO (Floating production storage and of?oading). With the development of offshore natural gas exploration and LNG transportation, the application of FLNG is growing rapidly. Sloshing of LNG cargo results in large impact loads on the containment system and the structure needs to be designed to withstand these peak loads.
Liquid sloshing is a complex phenomenon of fluid movement, showing a strong nonlinearity and randomness. Partially filled container which is subjected to external excitation can undergo intense movement, and large impacts on container wall, resulting in structure damage. The earlier sloshing study used experimental methods, but the number and size of tests are subject to great restrictions due to high cost, long period, and complicated operation. In view of this, the development of numerical simulation is necessary. CFD modeling can be reliably used to find the sloshing loads at different sea states, liquid levels and vapor properties, as well optimizing internal baffles to dampen sloshing.
The current paper proposes Computation Fluid Dynamics (CFD) method to predict the sloshing loads in FLNG during the ship motion. The proposed CFD method is validated with experiments for the free surface level and the impact pressure during the sloshing in various scenarios. Series of CFD studies were performed to investigate effect of mesh sensitivity, solver options and time step size. A separate study was performed to investigate effect of density ratio on impact pressure.
Volume of Fluid (VOF) method along with rigid body motion is used to model the liquid sloshing in a moving container. Validation case studies are chosen in accordance with literature.
SCORCH JIP - Feedback from Field Recovered Mooring Wire Ropes
Authors: Rosen Jeremy , Potts Andrew , Fontaine Emmanuel , Ma Kai-Tung , Chaplin Richard , Storesund Walther 
Published: June 2014

Abstract
Forensic investigations performed as part of the SCORCH JIP on wire ropes that were recovered from FPU mooring systems from Indonesia and Thailand are described. These wire ropes were used in tropical seawater for operating periods ranging from 9 to 14 years before being replaced for various reasons, including corrosion and fatigue concerns. The observed degradation mechanisms within the wire ropes are summarised and the severity of degradation is assessed in view of the external conditions (load duty, direct environment – sea water or mud), sustained by the rope and the rope construction (6-strand and 8-strand). Residual break tests were performed on 7 of the recovered wire rope samples. Mooring design codes pertaining to the corrosion endurance of steel wire ropes are reviewed with respect to recommendations for galvanic coating thickness and lubricant/blocking compound. The results for the recovered wire ropes from tropical waters are compared with reported zinc dissolution rates from cold North Sea waters.
Flow Assurance Indicators for the Design of Long Subsea Tiebacks
Authors: Zakarian Erich , Morgan Julie 
Published: June 2014

Abstract
Failure to model representative pipeline geometries during the design phase of new multiphase pipeline projects can result in poor pipeline operating flexibility which could lead to deferred production and reduced ultimate hydrocarbon recovery. Detailed analyses of high resolution bathymetric data and out-of-straightness pipeline surveys have revealed that indicators can be practical flow assurance tools for the modeling of multiphase pipeline profiles:The Terrain Indicator can be used to quickly quantify the roughness of pipeline topographies and to anticipate the influence of route selection on hydrodynamic phenomena such as liquid accumulation and slugging.When only low resolution bathymetry is available, regional regressions of roughness indicators can be used to create pipeline geometries that are representative of the actual seabed roughness for a better prediction of operating envelopes.Roughness indicators can be used to fingerprint the roughness of existing pipeline topographies and to characterize geomorphic features of the seafloor.
Reducing noise in raw survey data is essential for pertinent characterizations of the seafloor and pipeline profiles. Noise in data from seabed and out-of-straightness surveys can be reduced through a smoothing technique combining a moving average and a linear least squares fit. According to high resolution survey data, the span of this moving average should be equivalent to the length of one pipe joint; i.e. 40 feet or 12.2 meters. Before the completion of onerous Finite Element simulations for on-bottom roughness analyses, the same smoothing technique can be applied to the transformation of bathymetric data into representative pipeline geometry. The span of the moving average required for this transformation appears to be equivalent to the length of one double pipe joint.
Two examples are presented to illustrate the application of flow assurance indicators to the design of long subsea tiebacks.
Sediment Mobility Effects on Seabed Resistance for Unburied Pipelines
Authors: Bransby Fraser , Rodriguez Antonio Borges , Zhou Hongjie , Tom Joe , Low Han Eng , White David 
Published: June 2014

Abstract
In order to design unburied pipelines, pipeline engineers require information about lateral and axial seabed resistances (normally known as ‘friction factors’) prior to and during operation. Geotechnical engineers must provide this information based on knowledge of pipeline properties, seabed conditions and metocean conditions. Accurate prediction of the seabed resistances requires accurate prediction of pipeline embedments. This paper discusses how pipeline embedments and geometries can change from the as-laid state as the result of sediment mobility around pipelines and demonstrates how these embedment changes will change the pipe-soil friction factors using a series of numerical analyses. Sediment mobility tends to cause a general trend of increasing pipe embedment, which is beneficial for hydrodynamic stability but can be onerous for thermal buckling. Recommendations are provided to accommodate these effects in design, without unnecessary levels of over-conservatism.
Numerical Simulation on the Impact of Temperature Behavior for Cement Hydration for the World's First Offshore Methane Hydrate Production Test
Authors: Wang X. , Takekoshi M. , Kanno T. , Shako V. , Pimenov V. , Parshin A. , Yamamoto K. 
Published: June 2014

Abstract
The world's first offshore production test of the methane hydrate (MH) project was successfully carried out in the deepwater Nankai Troughin 2013. In February and March 2012, a production well and two monitoring wells were drilled and cemented to deploy temperature monitoring systems for which a combination of distributed temperature sensing (DTS) and array-type RTD (Resistance Temperature Detector) was employed.
For cement hydration, the chemical reactions are exothermic in nature so that a measureable temperature increase will be observed once the heat is released. With a typical cement system in wellbore configuration, this temperature increase could result in MH dissociation prior to the production that may have some impacts on the extraction of actual methane gas. Additionally, potential problems of thermally induced cracking are another concern.
To evaluate the thermal effect from the cement heat to MH, a 1D numerical model of cement hydration is developed based on the radial heterogeneity of thermal properties. The temperature data acquired during cementing stage is used as the input data for the model, and the parameters such as activation energies for the cement hydration heat correlation in the model are determined. It was shown that the variation of simulated temperature from different MH saturation within the upper MH zone is so small that a reliable estimation of MH saturation becomes difficult while the estimated MH saturations from temperature data inversion in the lower MH zone are relatively high. A sensitivity study is also performed to understand which parameters in the developed model most significantly influence the temperature during the different stages of the cement hydration, respectively.
Designing a Permanent Underwater Monitoring Network For Leak Detection
Authors: Strout J.M. , Sparrevik P.M. , Hayes S. , Kvistedal Y.A. , Tollefsrud D. 
Published: June 2014

Abstract
The process to design and deliver any monitoring system follows several well-defined phases: concept design and sensor selection; performance testing and verification of individual system components; detail design of the system architecture (mechanical and electrical); procurement, manufacturing and system assembly; and finally installation and commissioning. Quality control management and system documentation are common requirements throughout all phases.
This article uses a real-world design case to expound upon the needs and challenges encountered as project development progressed through all design phases. The monitoring architecture consists of a seabed broadband network servicing instrumented monitoring nodes. The primary mission for the system is leak detection, however secondary monitoring missions can be hosted using auxiliary access ports and the available power/data capacity. Although this monitoring network is implemented as an independent system, the site owner (a major energy company) required that the design be fully integrated in the design philosophy and technical requirements for a subsea modification project.
An interesting observation from this case study is that each of the phases have significant challenges, although these challenges do vary in nature and complexity through the phases. As the project progresses, choices made early on often gain increasing significance in later design processes. As an example, in this project the choice of the primary sensing technology later dictated requirements for installation height and verticality relative to seabed, which in turn affected design of the foundation solution for each installation. A second important observation is that a detailed strategy for developing and managing system documentation should be established at the concept phase, as the industry requires stringent and detailed documentation.
The case presented represents the complete design cycle, from initial concept development through final deployment. The experience from this process provides insight in the design process, as well as the technical and administrative challenges associated with developing an underwater monitoring network near offshore installations. This insight is useful for potential system designers, as well as for organizations considering implementing a dedicated scientific monitoring network on or near their infrastructure.
Endogenously Expressed IL-13Rα2 Attenuates IL-13–Mediated Responses but Does Not Activate Signaling in Human Lung Fibroblasts
Authors: Chandriani Sanjay , DePianto Daryle J. , N’Diaye Elsa N. , Abbas Alexander R. , Jackman Janet , Bevers Jack , Ramirez-Carrozzi Vladimir , Pappu Rajita , Kauder Steven E. , Toy Karen , Ha Connie , Modrusan Zora , Wu Lawren C. , Collard Harold R. , Wolters Paul J. , Egen Jackson G. , Arron Joseph R. 
Published: May 2014

Abstract
IL-13 can bind to two distinct receptors: a heterodimer of IL-13Rα1/IL-4Rα and IL-13Rα2. Whereas IL-13Rα1/IL-4Rα engagement by IL-13 leads to the activation of STAT6, the molecular events triggered by IL-13 binding to IL-13Rα2 remain incompletely understood. IL-4 can bind to and signal through the IL-13Rα1/IL-4Rα complex but does not interact with IL-13Rα2. Idiopathic pulmonary fibrosis is a progressive and generally fatal parenchymal lung disease of unknown etiology with no current pharmacologic treatment options that substantially prolong survival. Preclinical models of fibrotic diseases have implicated IL-13 activity on multiple cell types, including macrophages and fibroblasts, in initiating and perpetuating pathological fibrosis. In this study, we show that IL-13, IL-4, IL-13Rα2, and IL-13–inducible target genes are expressed at significantly elevated levels in lung tissue from patients with idiopathic pulmonary fibrosis compared with control lung tissue. IL-4 and IL-13 induce virtually identical transcriptional responses in human monocytes, macrophages, and lung fibroblasts. IL-13Rα2 expression can be induced in lung fibroblasts by IL-4 or IL-13 via a STAT6-dependent mechanism, or by TNF-α via a STAT6-independent mechanism. Endogenously expressed IL-13Rα2 decreases, but does not abolish, sensitivity of lung fibroblasts to IL-13 and does not affect sensitivity to IL-4. Genome-wide transcriptional analyses of lung fibroblasts stimulated with IL-13 in the presence of Abs that selectively block interactions of IL-13 with IL-13Rα1/IL-4Rα or IL-13Rα2 show that endogenously expressed IL-13Rα2 does not activate any unique IL-13–mediated gene expression patterns, confirming its role as a decoy receptor for IL-13 signaling.
BCL6 Controls Th9 Cell Development by Repressing Il9 Transcription
Authors: Bassil Ribal , Orent William , Olah Marta , Kurdi Ahmed T. , Frangieh Michael , Buttrick Thomas , Khoury Samia J. , Elyaman Wassim 
Published: May 2014

Abstract
The transcriptional repressor B cell lymphoma 6 (BCL6) is required for the development of Th follicular cells, and it has been shown to suppress Th2 cell differentiation. We demonstrate that BCL6 is a key regulator of Th9 cell development. BCL6 expression is transiently downregulated in polarized Th9 cells, and forced expression of BCL6 in Th9 cells impairs Th9 cell differentiation. In contrast, BCL6 knockdown upregulated IL-9 production in Th9 cells. The function of BCL6 in Th9 cells is under the control of IL-2/JAK3/STAT5 signaling pathway. Using chromatin immunoprecipitation, we show that, in Th9 cells, BCL6 and STAT5 bind to adjacent motifs in the Il9 promoter. Furthermore, we found that STAT5 binding was associated with the abundance of a permissive histone mark at the Il9 promoter, whereas under conditions in which BCL6 binding was predominant, a repressive histone mark was prevalent. The effects of STAT5 and BCL6 on IL-9 transcription were further demonstrated using an IL-9 luciferase reporter assay in which BCL6 repressed STAT5-mediated Il9 transactivation. In experimental autoimmune encephalomyelitis, forced expression of BCL6 in myelin oligodendrocyte glycoprotein35–55-specific Th9 cells resulted in decreased IL-9 production and induction of IFN-γ, causing an exacerbation of the clinical disease. Our findings demonstrate a novel role of BCL6 in the regulation of Th9 cell development and their encephalitogenicity.