Wellhead Fatigue Damage Based on Indirect Measurements

2015 ◽  
Author(s):  
Guttorm Grytøyr ◽  
Fredy Coral ◽  
Halvor Borgen Lindstad ◽  
Massimilliano Russo
Keyword(s):  
Fatigue Damage ◽  
Oil And Gas ◽  
Time History ◽  
Bending Moment ◽  
Oil And Gas Industry ◽  
Fatigue Properties ◽  
Marine Riser ◽  
Gas Industry ◽  
Blowout Preventer ◽  
The Moment

Enabling safe and reliable operations of subsea wellheads has a high priority in the global oil and gas industry. The objective of the current paper is to provide a novel method for bending moment estimates at the wellhead based on indirect moment measurements; this moment, together with fatigue properties are then used for fatigue damage estimation. Indirect bending moments are based on inclinations and accelerations measured by motion reference units (MRU) attached to blowout preventer (BOP), lower marine riser package (LMRP) and lower riser joint (LRJ) immediately above the lower flexible joint (LFJ). Also, required is the tension time history in the same period at the LRJ. The proposed methodology here can be implemented and integrated into a portal for data acquisition and visualisation. In order to validate the proposed method for indirect bending moment estimation, strain gages have been attached to a BOP and marine riser during drilling operations offshore Norway. Strain gage readings are transformed to bending moment which is used as reference (the so-called direct moment). The proposed method is used to calculate the moment indirectly, the so-called indirect moment. The resulting indirect moments agree very well with the direct moments.

Towards Implementing Condition-Based Maintenance (CBM) Policy for Offshore Blowout Preventer (BOP) System

2019 ◽  
Author(s):  
Tobiloba Elusakin ◽  
Mahmood Shafiee ◽  
Tosin Adedipe
Keyword(s):  
Oil And Gas ◽  
Cost Savings ◽  
Oil And Gas Industry ◽  
Condition Based Maintenance ◽  
Gas Industry ◽  
Training Requirements ◽  
Blowout Preventer ◽  
Integrity Management ◽  
Maintenance Personnel ◽  
Oil And Gas Companies

Abstract With the steadily growing demand for energy in the world, oil and gas companies are finding themselves facing increasing capital and operating costs. To ensure the economic viability of investments and improve the safety of operations, oil and gas companies are promoting their asset integrity management (AIM) systems. In the past, the oil and gas industry adopted reactive maintenance regimes, which involved recertification, testing and repair of faulty equipment while trying to achieve minimum downtime. As technology becomes more affordable, operators have been able to carry out improved fault diagnosis, prognosis and maintenance optimisation. As a result of this, condition-based maintenance (CBM) is being adopted more and more as the preeminent maintenance regime for oil and gas equipment. The blowout preventer (BOP) is one of the most expensive and safety critical drilling equipment in the oil and gas industry. However, there have been very few studies and best practices about how to develop a CBM policy and what specific monitoring techniques and devices will be required to implement it for the BOP system. This paper proposes a V-model based architecture for designing a CBM policy in BOP systems. As a result of the model proposed, gaps in implementation are identified and all the hardware, software and training requirements for implementing the CBM solution in BOP systems will be outlined in detail. Our proposed CBM framework will help BOP operators and maintenance personnel make cost savings through less repairs and replacements and minimal downtime.

Prediction of Riser VIV With Staggered Buoyancy Elements

2016 ◽  
Author(s):  
Jie Wu ◽  
Malakonda Reddy Lekkala ◽  
Muk Chen Ong
Keyword(s):  
Fatigue Damage ◽  
Oil And Gas ◽  
Systems Design ◽  
Oil And Gas Industry ◽  
Flexible Cylinder ◽  
Natural Period ◽  
Gas Industry ◽  
Vibration Period ◽  
Offshore Industry ◽  
Different Diameters

Steel lazy-wave riser (SLWR) are attractive deepwater applications for offshore oil and gas industry. When subjected to current, both the buoyancy elements and the riser may experience Vortex Induced Vibrations (VIV). Such vibrations are the result of the periodic hydrodynamic forces that are induced by the interaction of slender bodies and external fluid flow. If the vibration period is close to the natural period of the system, it can lead to fast accumulation of fatigue damage to the risers and amplified drag loads. There is a competition between the vortex induced forces acting on the buoyancy element and the riser segment due to its different diameters. The interaction of the vortex shedding from the riser and the buoyancy element depends on many parameters, such as the arrangement of the buoyancy element, aspect ratio of the buoyancy element, etc. Shell Oil Company conducted VIV model tests with a straight flexible cylinder and staggered buoyancy elements corresponding to a buoyant section of a SLWR in MARINTEK in 2011. Five different buoyancy element configurations were tested. The test data has been extensively studied (Rao, et al 2015 and Jhingran, et al 2012). The interaction of the buoyancy elements and bare riser and its influence on the riser response (frequency, displacement and fatigue damage) have been investigated. Semi-empirical VIV prediction software, such as VIVANA [4], SHEAR7 [13] and VIVA [11] are most commonly used by the offshore industry in the riser systems design against VIV loads. However, these software are not purposely designed to account for the interaction of the bare riser section and the buoyancy elements. It is of great interest to evaluate the prediction accuracy. The purpose of this study is to benchmark the VIV prediction of riser with buoyancy elements using VIVANA. The prediction is compared with Shell model test results with focus on CF responses. Uncertainty and improvement of the prediction are also discussed.

Methodology to Obtain the Life Cycle Mooring Loads on a Semisubmersible Wind Platform

2014 ◽  
Author(s):  
Raúl Guanche ◽  
Lucía Meneses ◽  
Javier Sarmiento ◽  
César Vidal ◽  
Íñigo Losada
Keyword(s):  
Life Cycle ◽  
Numerical Model ◽  
Data Base ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Mooring System ◽  
Gas Industry ◽  
Wave Basin ◽  
The Moment

Nowadays there are few methodologies related with the design of mooring systems for floating offshore wind platforms. The ones used until the moment are inherited from the oil and gas industry. Because of that, mooring loads may be incorrectly estimated. This study presents a validated methodology in order to estimate the loads of the moorings of offshore floating platforms along the life cycle of the structure. The methodology is based on an extensive laboratory test data base carried out in a wave basin of the University of Cantabria. The proposed methodology has been applied to a floating semisubmersible platform (similar to the one in Agucadoira by Principle Power). The methodology is composed by a few steps. The first step consist on the selection of the most representative sea states of a long term met-ocean data base through a selection technique named MDA (Maximum dissimilitude algorithm). Afterwards, mooring system loads and platform motion are numerically simulated. SESAM (DNV) numerical model has been used in this particular application. SESAM numerical model was previously calibrated based on the laboratory tests. Finally, based on a multidimensional interpolation technique named Radial Basis Function life cycle mooring system loads were reconstructed. A sensitivity analysis of the methodology were carried out. Based on it, it can be concluded that selecting 1000 sea states with the MaxDiss technique, life cycle mooring loads can be accurately predicted.

Incorporating the Higher Harmonics in VIV Fatigue Predictions

2007 ◽  
Author(s):  
Vikas Jhingran ◽  
J. Kim Vandiver
Keyword(s):  
Fatigue Damage ◽  
Strain Energy ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Dynamic Strain ◽  
Higher Harmonics ◽  
Gas Industry ◽  
Ongoing Research ◽  
Fatigue Design ◽  
Vortex Induced Vibrations

Vortex-Induced Vibrations (VIV) are an important source of fatigue damage for risers in the Oil and Gas industry. Results from resent VIV experiments by Vandiver et al. [1] indicate significant dynamic strain energy at not only the Strouhal frequency, but also its harmonics. In certain regions of the pipe, these higher harmonics accounted for more that half of the measured RMS strain and increased fatigue damage by a factor exceeding twenty. However, the state-of-the-art in VIV prediction only accounts for the vibrations at the Strouhal frequency. Preliminary results from a second set of experiments, described in this paper, confirm the importance of the higher harmonics in fatigue life estimates of pipes. Further, the authors formulate an approach to incorporate the higher harmonics in VIV related fatigue design. Finally, the authors identify the estimation of the higher harmonics, in both location and magnitude, as an important area of ongoing research, the results of which will be required to implement this proposed method.

scholarly journals Effect of hydrosorption polymers on the properties of water-swellable rubber

2020 ◽  
Vol 64 (10) ◽  
pp. 90-93
Author(s):  
Konstantin V. Efimov ◽  
◽  
Evgeny N. Egorov ◽  
Nikolay F. Ushmarin ◽  
Nikolay I. Koltsov ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Oil And Gas ◽  
Guar Gum ◽  
Oil And Gas Industry ◽  
Rheological Parameters ◽  
Rubber Compound ◽  
Rubber Mixture ◽  
Gas Industry ◽  
The Moment ◽  
Sealing Elements

Currently, in the oil and gas industry there is a growing demand for sealing elements capable of limited swelling upon contact with water and sealing the annular space of certain sections of the well. The swelling capacity of the sealing elements is predetermined by a well-chosen combination of polymer base and targeted functional ingredients. At the moment, a big drawback of water-swellable sealing elements is the loss of their sealing ability due to the washing out of hydrosorption additives from the sealing element. In this regard, in this work, the effect of hydrosorption polymers (polyacrylamide, sodium carboxymethylcellulose, polyvinyl alcohol and guar gum) on the properties of water-swellable rubber based on a combination of nitrile-butadiene SKN 1855, acrylate nipol AR22 and chloroprene CR 232 rubbers and epoxy 20 with sulfur curing system. The rubber mixture was prepared by mixing rubbers with ingredients on a laboratory roll LB 320 160/160. The rheological characteristics of the rubber compound were studied on an MDR 3000 Basic rheometer at 150 °C. Standard rubber samples were vulcanized at 150 °C for 30 min in a P-V-100-3RT-2-PCD vulcanization press. The main properties of vulcanizates were determined according to the standards in force in the rubber industry. It is shown that the introduction of polyacrylamide together with sodium carboxymethyl cellulose, polyvinyl alcohol and guar gum into a rubber compound leads to a change in its rheological parameters. Vulcanizates containing a combination of polymers are characterized by lower values of the conventional tensile strength and rebound elasticity, but higher elongation at break and the degree of swelling in distilled and formation water as compared to the vulcanizate of the base version of the rubber mixture.

Automation CAE Toolkit Method for Ram BOP Design

2020 ◽  
Author(s):  
Yaou Wang ◽  
Chris Nault ◽  
Matthew Givens ◽  
Micah Threadgill ◽  
Seth Berry ◽  
...  
Keyword(s):  
Design Optimization ◽  
Computer Aided Design ◽  
Oil And Gas ◽  
Safety Valve ◽  
Oil And Gas Industry ◽  
Drilling Process ◽  
Gas Industry ◽  
Computer Aided ◽  
Blowout Preventer ◽  
Aided Design

Abstract A Blowout Preventer (BOP) serves as a safety valve in the drilling process in the oil and gas industry. It will be closed if an influx of formation fluids occurs and threatens the rig. A Ram BOP is one type of widely used BOP. It is composed of two ram blades, which will move towards each other to shear the drilling pipe and to close the valve. To ensure the shearing process be completed on the rig, lab tests are often run to evaluate the BOP’s capability and the required shearing pressure. The paper presents a new automation CAE (Computer-Aided Engineering) toolkit method recently developed to simulate the Ram BOP pipe shearing process. The toolkit method automates and integrates the process from computer aided design (CAD) to computer aided simulation for the Ram shearing process. It significantly simplifies the modeling effort and facilitates the design optimization process.

Subsea Intervention System Connector Capacities per the Elastic-Plastic Analysis Methodology

2019 ◽  
Author(s):  
Ali Sepehri ◽  
Gaurav Bansal ◽  
Mangesh Edke
Keyword(s):  
Oil And Gas ◽  
New Technology ◽  
Bending Moment ◽  
Oil And Gas Industry ◽  
Plastic Collapse ◽  
Element Analysis ◽  
Gas Industry ◽  
Elastic Plastic ◽  
Standard Design ◽  
Plastic Analysis

Abstract The offshore oil and gas industry is drilling into and producing from wells in high-pressure, high-temperature (HPHT) environments. This has created a greater demand to develop more advanced tools and new technology to safely overcome the challenges in these operations. Due to the sensitivity and potential impact on the environment, the industry is striving to homogenize the design and acceptance criteria. The API 17G is the industry standard for offshore intervention operations. According to the standard, design verification is performed using finite element analysis (FEA). The standard provides three sets of criteria for determining capacities that adopt the methodologies from ASME Boiler Pressure Vessel Code (BPVC) Section VIII, Div. 3. The objective of this study is to evaluate tension, pressure, and bending moment capacities per the elastic-plastic analysis methodologies outlined in API 17G for a subsea intervention system connector. The global and local failure capacities are presented for yielding load, plastic collapse, and 2% strain methods. Results indicate that the plastic collapse method is the most conservative approach for evaluating the global capacity of the connector.

Deployment of Digital NDT Solutions in the Oil and Gas Industry

2020 ◽  
Vol 78 (7) ◽  
pp. 861-868
Author(s):  
Casper Wassink ◽  
Marc Grenier ◽  
Oliver Roy ◽  
Neil Pearson
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry
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