Lazy Wave Catenary Risers: Scaling Factors and Analytical Approximation of the Static Stress Range in the Touchdown Zone

2013 ◽  
Author(s):  
Lucile M. Quéau ◽  
Mehrdad Kimiaei ◽  
Mark F. Randolph
Keyword(s):  
Oil And Gas ◽  
Structural Response ◽  
High Sensitivity ◽  
Cost Effective ◽  
Analytical Approximation ◽  
Static Stress ◽  
Analytical Determination ◽  
Stress Range ◽  
Dynamic Amplification Factor ◽  
Wide Range

Offshore exploration and production of oil and gas continue to increase and move into ever deeper water. Steel catenary risers (SCRs) are one of the most cost effective type of risers in deep water. However, high sensitivity to vessel motions and hydrodynamic loading in the touchdown zone may limit the feasibility of SCR applications. In recent years, there has been a growing interest in the use of Lazy-wave catenary riser (LWR) due to their better fatigue performance in the touchdown zone through the damping effect of the buoyancy section. The design of LWR involves numerous parameters that lead to a wide range of configurations. Each of these configurations needs to be evaluated against several criteria with respect to geometry, strength and fatigue for instance. This paper presents how tools recently proposed to improve the design of standard SCRs can be extended to benefit LWR applications. The dimensionless groups governing the structural response of LWRs are established in the aim of easing sensitivity analysis to key input parameters for LWR design, assisting experiments and reducing the number of numerical simulations. Moreover, the DAF (dynamic amplification factor) approach for dynamic response which has previously been explored for SCRs could also be used to simplify design of LWRs. As DAF relies on the analytical determination of static response, this framework shows that analytical boundary layer solutions in conjunction with the use of a Winkler type soil model can efficiently and accurately predict the static stress range of LWRs observed in the TDZ.

scholarly journals Near cut-off wavelength operation of resonant waveguide grating biosensors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Balint Kovacs ◽  
Fabio Aldo Kraft ◽  
Zsolt Szabo ◽  
Yousef Nazirizadeh ◽  
Martina Gerken ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Optical Waveguides ◽  
Refractive Index Change ◽  
High Sensitivity ◽  
Cost Effective ◽  
Intensity Change ◽  
Wavelength Shift ◽  
Geometrical Parameters ◽  
Guided Mode ◽  
Wide Range

AbstractNumerical simulations and analytical calculations are performed to support the design of grating-coupled planar optical waveguides for biological sensing. Near cut-off and far from cut-off modes are investigated, and their characteristics and suitability for sensing are compared. The numerical simulations reveal the high sensitivity of the guided mode intensity near the cut-off wavelength for any refractive index change along the waveguide. Consequently, it is sufficient to monitor the intensity change of the near cut-off sensing mode, which leads to a simpler sensor design compared to those setups where the resonant wavelength shift of the guided mode is monitored with high precision. The operating wavelength and the sensitivity of the proposed device can be tuned by varying the geometrical parameters of the corrugated waveguide. These results may lead to the development of highly sensitive integrated sensors, which have a simple design and therefore are cost-effective for a wide range of applications. These numerical findings are supported with experimental results, where the cut-off sensing mode was identified.

scholarly journals 3D-Printable Carbon Nanotubes-Based Composite for Flexible Piezoresistive Sensors

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5482
Author(s):  
Chaima Fekiri ◽  
Ho Chan Kim ◽  
In Hwan Lee
Keyword(s):  
Carbon Nanotubes ◽  
Flexible Electronics ◽  
Applied Pressure ◽  
Structural Complexity ◽  
High Sensitivity ◽  
Cost Effective ◽  
Measurement Range ◽  
Resistance Change ◽  
Piezoresistive Pressure Sensor ◽  
Wide Range

The intersection between nanoscience and additive manufacturing technology has resulted in a new field of printable and flexible electronics. This interesting area of research tackles the challenges in the development of novel materials and fabrication techniques towards a wider range and improved design of flexible electronic devices. This work presents the fabrication of a cost-effective and facile flexible piezoresistive pressure sensor using a 3D-printable carbon nanotube-based nanocomposite. The carbon nanotubes used for the development of the material are multi-walled carbon nanotubes (MWCNT) dispersed in polydimethylsiloxane (PDMS) prepolymer. The sensor was fabricated using the direct ink writing (DIW) technique (also referred to as robocasting). The MWCNT-PDMS composite was directly printed onto the polydimethylsiloxane substrate. The sensor response was then examined based on the resistance change to the applied load. The sensor exhibited high sensitivity (6.3 Ω/kPa) over a wide range of applied pressure (up to 1132 kPa); the highest observed measurement range for MWCNT-PDMS composite in previous work was 40 kPa. The formulated MWCNT-PDMS composite was also printed into high-resolution 3-dimensional shapes which maintained their form even after heat treatment process. The possibility to use 3D printing in the fabrication of flexible sensors allows design freedom and flexibility, and structural complexity with wide applications in wearable or implantable electronics for sport, automotive and biomedical fields.

scholarly journals Sensitivity Enhancement of Curvature Fiber Sensor Based on Polymer-Coated Capillary Hollow-Core Fiber

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3763 ◽  
Author(s):  
Luis A. Herrera-Piad ◽  
Iván Hernández-Romano ◽  
Daniel A. May-Arrioja ◽  
Vladimir P. Minkovich ◽  
Miguel Torres-Cisneros
Keyword(s):  
Fiber Optic ◽  
High Sensitivity ◽  
Single Mode ◽  
Cost Effective ◽  
Fiber Optic Sensor ◽  
Hollow Core ◽  
Sensing Applications ◽  
Optic Sensor ◽  
Wide Range ◽  
Core Fiber

In this paper, we propose and experimentally demonstrate a simple technique to enhance the curvature sensitivity of a bending fiber optic sensor based on anti-resonant reflecting optical waveguide (ARROW) guidance. The sensing structure is assembled by splicing a segment of capillary hollow-core fiber (CHCF) between two single-mode fibers (SMF), and the device is set on a steel sheet for measuring different curvatures. Without any surface treatment, the ARROW sensor exhibits a curvature sensitivity of 1.6 dB/m−1 in a curvature range from 0 to 2.14 m−1. By carefully coating half of the CHCF length with polydimethylsiloxane (PDMS), the curvature sensitivity of the ARROW sensor is enhanced to −5.62 dB/m−1, as well as an increment in the curvature range (from 0 to 2.68 m−1). Moreover, the covered device exhibits a low-temperature sensitivity (0.038 dB/°C), meaning that temperature fluctuations do not compromise the bending fiber optic sensor operation. The ARROW sensor fabricated with this technique has high sensitivity and a wide range for curvature measurements, with the advantage that the technique is cost-effective and easy to implement. All these features make this technique appealing for real sensing applications, such as structural health monitoring.

Parametric Investigation of the Stability of Vessels for Float-Over Deck Transportation

2002 ◽  
Author(s):  
Lee O’Neill ◽  
Shaun O’Brein ◽  
Emmanuel Fakas
Keyword(s):  
Oil And Gas ◽  
Cost Effective ◽  
High Elevation ◽  
Accurate Analysis ◽  
Large Size ◽  
Wide Range ◽  
Transport Vessel ◽  
The Stability ◽  
The Cost ◽  
Vessel Stability

The technical challenge of transporting large size integrated decks, especially float-over decks at high elevation, is well recognised. The cost of such operation usually forms a significant part of the overall development cost, especially in remote parts of the world where the transport routes are longer and the transport vessel choice is limited. In this respect, suitable vessel selection is very critical in terms of the economic viability of oil and gas developments, especially of marginal fields. A cost-effective working method is developed for selecting suitable vessels for a wide range of transport options (deck weights and transport elevations) without the requirement of extensive analyses. This method may be used at the very early stages of any study to assess the feasibility of the transport concept and also provide a wider choice of feasible options to be considered at the next stage of the development, where a more accurate analysis may be justified. Some potential ways for improving vessel stability are also investigated. Findings from the study can also be applied to integrated deck salvage transport.

Benefiting From the Wide Fuel Capability of Gas Turbines: A Review of Application Opportunities

2002 ◽  
Author(s):  
Michel Moliere
Keyword(s):  
Gas Turbines ◽  
Alternative Fuels ◽  
Oil And Gas ◽  
Cost Effective ◽  
Coke Oven ◽  
Operational Reliability ◽  
Coal Bed ◽  
Fuel Gas ◽  
Fuel Flexibility ◽  
Wide Range

Gas Turbines accept a wide range of alternative fuels in connection with the most diverse economy branches, including industry (coal; oil and gas; refining; petrochemistry; steel and mining activities) and, more recently, agriculture (biofuels). This fuel flexibility enhances the other qualities demonstrated by Gas Turbines among which the prominent ones are: energy effectiveness, operational reliability and emission compliance. Therefore, Gas Turbines using local fuel resources and deployed in simple or combined cycles or in cogeneration plants, enable the concept of cost-effective and environmentally-conscious power projects and can make a valuable contribution to the sustainable, regional development. However, in order to benefit from the fuel flexibility of Gas Turbines, some basic technical considerations are necessary. The paper intends to provide the power community with comprehensive information about alternative GT fuels. It offers a review of the main alternative fuel candidates and sets out the primary technical/engineering considerations that underlie their safe and reliable utilization. Special emphasis is placed on: (i) volatile fuels (naphtha, NLG, condensates); (iii) weak gas fuels from the coal/iron industry (coal-bed; coke-oven, blast furnace gas); (iv) paraffin-rich and hydrogen-rich by-products from refineries (‘fuel gas’; LPG) and (iv) ash-forming oils (residuals; heavy crude’s).

DeepStar 11304: Laying the Groundwork for AUV Standards for Deepwater Fields

2013 ◽  
Vol 47 (3) ◽  
pp. 13-18 ◽  
Author(s):  
John Jacobson ◽  
Pierce Cohen ◽  
Amin Nasr ◽  
Art J. Schroeder ◽  
Greg Kusinski
Keyword(s):  
Oil And Gas ◽  
Autonomous Underwater Vehicles ◽  
Cost Effective ◽  
Oil And Gas Industry ◽  
Economic Benefits ◽  
Regulatory Oversight ◽  
Early Adoption ◽  
Regulatory Standards ◽  
Industry Standards ◽  
Wide Range

AbstractEmerging autonomous underwater vehicles (AUVs) developments across the oil and gas industry now include pipeline inspection; structural survey; deepwater inspection, repair and maintenance (IRM); and field resident systems for remote/harsh environments. As these capabilities mature, AUVs will become an increasingly important tool for deepwater field operations. Early adoption of AUV standards will facilitate more rapid deployment of AUV technologies and enable the industry to reap a wide range of safety, environmental, operational, and economic benefits for its deepwater fields. The development of industry standards for AUV interfaces will facilitate more rapid implementation of AUV capabilities and lead to more cost-effective, compatible system designs by AUV vendors and field hardware manufacturers. The development of regulatory standards for the interpretation and acceptance of autonomous inspection results is also an essential step toward the achievement of more cost-effective operations and regulatory oversight of deepwater subsea fields. This paper describes a future vision for the use of AUVs in deepwater field operations, the benefits to be realized, and the future capabilities of AUVs that must be anticipated and facilitated within AUV standards to achieve that vision. Additionally, this paper describes the goals and objectives of DeepStar Project 11304, which is laying the groundwork to achieve accelerated standardization of AUV interfaces and the development of regulatory standards for AUV inspections.

2D Color-Intensity Representation of Ultrasonic Thickness Gauge Measurements

2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong
Keyword(s):  
Cost Effective ◽  
The Other ◽  
Thickness Gauge ◽  
Color Intensity ◽  
Digital Readout ◽  
Flat Surfaces ◽  
Video Cameras ◽  
Wide Range ◽  
Cost Effective Alternative ◽  
Ultrasonic Thickness

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.

Sand Free Production Success Through Proven Technology Enabler from An Untapped Heterogeneous Reservoir Zone Utilizing Gravel Pack Replacement Methodology

2020 ◽  
Author(s):  
Y. Anggoro
Keyword(s):  
Oil And Gas ◽  
Erosion Resistance ◽  
Cost Effective ◽  
High Rate ◽  
Screen Design ◽  
Sand Control ◽  
Rules Of Thumb ◽  
Production Success ◽  
Control Technologies ◽  
Gravel Pack

The Belida field is an offshore field located in Block B of Indonesia’s South Natuna Sea. This field was discovered in 1989. Both oil and gas bearing reservoirs are present in the Belida field in the Miocene Arang, Udang and Intra Barat Formations. Within the middle Arang Formation, there are three gas pay zones informally referred to as Beta, Gamma and Delta. These sand zones are thin pay zones which need to be carefully planned and economically exploited. Due to the nature of the reservoir, sand production is a challenge and requires downhole sand control. A key challenge for sand control equipment in this application is erosion resistance without inhibiting productivity as high gas rates and associated high flow velocity is expected from the zones, which is known to have caused sand control failure. To help achieve a cost-effective and easily planned deployment solution to produce hydrocarbons, a rigless deployment is the preferred method to deploy downhole sand control. PSD analysis from the reservoir zone suggested from ‘Industry Rules of Thumb’ a conventional gravel pack deployment as a means of downhole sand control. However, based on review of newer globally proven sand control technologies since adoption of these ‘Industry Rules of Thumb’, a cost-effective solution could be considered and implemented utilizing Ceramic Sand Screen technology. This paper will discuss the successful application at Block B, Natuna Sea using Ceramic Sand Screens as a rigless intervention solution addressing the erosion / hot spotting challenges in these high rate production zones. The erosion resistance of the Ceramic Sand Screen design allows a deployment methodology directly adjacent to the perforated interval to resist against premature loss of sand control. The robust ceramic screen design gave the flexibility required to develop a cost-effective lower completion deployment methodology both from a challenging make up in the well due to a restrictive lubricator length to the tractor conveyancing in the well to land out at the desired set depth covering the producing zone. The paper will overview the success of multi-service and product supply co-operation adopting technology enablers to challenge ‘Industry Rules of Thumb’ replaced by rigless reasoning as a standard well intervention downhole sand control solution where Medco E&P Natuna Ltd. (Medco E&P) faces sand control challenges in their high deviation, sidetracked well stock. The paper draws final attention to the hydrocarbon performance gain resulting due to the ability for choke free production to allow drawing down the well at higher rates than initially expected from this zone.

The Future of Plasma-Based Surface Engineering Techniques in Tribology (Keynote)

2005 ◽  
Author(s):  
Allan Matthews ◽  
Adrian Leyland
Keyword(s):  
Surface Engineering ◽  
Performance Enhancement ◽  
Bulk Material ◽  
Cost Savings ◽  
Cost Effective ◽  
Ceramic Coatings ◽  
Performance Improvements ◽  
Treatment Techniques ◽  
Wide Range ◽  
Macro Scale

Over the past twenty years or so, there have been major steps forward both in the understanding of tribological mechanisms and in the development of new coating and treatment techniques to better “engineer” surfaces to achieve reductions in wear and friction. Particularly in the coatings tribology field, improved techniques and theories which enable us to study and understand the mechanisms occurring at the “nano”, “micro” and “macro” scale have allowed considerable progress to be made in (for example) understanding contact mechanisms and the influence of “third bodies” [1–5]. Over the same period, we have seen the emergence of the discipline which we now call “Surface Engineering”, by which, ideally, a bulk material (the ‘substrate’) and a coating are combined in a way that provides a cost-effective performance enhancement of which neither would be capable without the presence of the other. It is probably fair to say that the emergence and recognition of Surface Engineering as a field in its own right has been driven largely by the availability of “plasma”-based coating and treatment processes, which can provide surface properties which were previously unachievable. In particular, plasma-assisted (PA) physical vapour deposition (PVD) techniques, allowing wear-resistant ceramic thin films such as titanium nitride (TiN) to be deposited on a wide range of industrial tooling, gave a step-change in industrial productivity and manufactured product quality, and caught the attention of engineers due to the remarkable cost savings and performance improvements obtained. Subsequently, so-called 2nd- and 3rd-generation ceramic coatings (with multilayered or nanocomposite structures) have recently been developed [6–9], to further extend tool performance — the objective typically being to increase coating hardness further, or extend hardness capabilities to higher temperatures.

scholarly journals Gamma models for estimating the odds ratio for a skewed biomarker measured in pools and subject to errors

Biostatistics ◽  
2019 ◽  
Author(s):  
Dane R Van Domelen ◽  
Emily M Mitchell ◽  
Neil J Perkins ◽  
Enrique F Schisterman ◽  
Amita K Manatunga ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Adjusted Odds Ratio ◽  
Lower Cost ◽  
Cost Effective ◽  
Ratio Estimation ◽  
Statistical Efficiency ◽  
Function Model ◽  
Processing Error ◽  
Wide Range ◽  
Pooled Samples

SUMMARYMeasuring a biomarker in pooled samples from multiple cases or controls can lead to cost-effective estimation of a covariate-adjusted odds ratio, particularly for expensive assays. But pooled measurements may be affected by assay-related measurement error (ME) and/or pooling-related processing error (PE), which can induce bias if ignored. Building on recently developed methods for a normal biomarker subject to additive errors, we present two related estimators for a right-skewed biomarker subject to multiplicative errors: one based on logistic regression and the other based on a Gamma discriminant function model. Applied to a reproductive health dataset with a right-skewed cytokine measured in pools of size 1 and 2, both methods suggest no association with spontaneous abortion. The fitted models indicate little ME but fairly severe PE, the latter of which is much too large to ignore. Simulations mimicking these data with a non-unity odds ratio confirm validity of the estimators and illustrate how PE can detract from pooling-related gains in statistical efficiency. These methods address a key issue associated with the homogeneous pools study design and should facilitate valid odds ratio estimation at a lower cost in a wide range of scenarios.

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