Research on Key Technologies of Precise Measurement of Geographic Coordinates of Subsea Pipelines

2021 ◽  
Author(s):  
Li Jian ◽  
Wang Jialin ◽  
Zhao Jianyuan ◽  
Li Mingze ◽  
Huang Xinjing
Keyword(s):  
Pitch Angle ◽  
Precise Measurement ◽  
Oil And Gas ◽  
Calibration Method ◽  
Angle Measurement ◽  
Continuous Increase ◽  
Ac Servo ◽  
Main Work ◽  
Ac Servo Motor ◽  
Subsea Pipelines

Abstract With the continuous increase of offshore oil and gas exploitation activities, the number of subsea pipelines is becoming larger and larger, which leads to frequent occurrence of subsea pipeline accidents. Long-term safe operation of subsea pipelines can be ensured by regular defect detection. The premise of locating and disposing defects is to accurately measure the geographic coordinates of subsea pipelines. Our research group has put forward a kind of pipeline spherical internal detector (SD), which has the advantages of convenient implementation, low risk to jam. For the SD, this paper has carried out research on the key technology of precise measurement of subsea pipelines’ geographic coordinates using the internal magnetic fields. The main work is as follows: (1) Magnetic tensor invariant calibration method for magnetometer array has been studied and L-M algorithm is taken to solve the parameters, which is efficient and accurate. Field calibration experiment has proved this method is effective and has good robustness. (2) A new method of measuring pipeline’s pitch angle is proposed. Under the experimental condition of using AC servo motor to drive the sensor instead of the SD to rotate, the pitch angle measurement error is less than 0.2°. (3) Magnetic anomaly of spiral weld and buckling pipeline are used as new mark points to calibrate the geographic coordinates of subsea pipelines. Experimental results show that the newly designed SD can successfully identify spiral welds and buckling pipeline.

Sparse Representation Based Dielectric Loss Angle Measurement

2015 ◽  
Vol 9 (1) ◽  
pp. 566-570
Author(s):  
Zhang Ji ◽  
Jianfeng Zheng
Keyword(s):  
Dielectric Loss ◽  
Power Systems ◽  
Sparse Representation ◽  
Precise Measurement ◽  
Angle Measurement ◽  
Measuring Error ◽  
Loss Angle ◽  
Analysis Method ◽  
Electric Capacity ◽  
Dielectric Loss Angle

Precise measurement of dielectric loss angle is very important for electric capacity equipment in recent power systems. When signal-to-noise is low and fundamental frequency is fluctuating, aiming at the measuring error of dielectric loss angle based on some recent Fourier transform and wavelet transform harmonics analysis method, we propose a novel algorithm based on sparse representation, and improved it to be more flexible for signal sampling. Comparison experiments describe the advantages of our method.

Nonlinear Discrete-time feedback error learning with PI Controller for AC servo motor

2008 ◽  
Author(s):  
Noppanan Suwanjatuporn ◽  
Mes Napaamporn ◽  
Waree Kongprawechnon ◽  
Sirisak Wongsura
Keyword(s):  
Discrete Time ◽  
Pi Controller ◽  
Servo Motor ◽  
Ac Servo ◽  
Feedback Error Learning ◽  
Feedback Error ◽  
Error Learning ◽  
Ac Servo Motor

Stability of offshore structures in shallow water depth

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
Structural Response ◽  
Offshore Structures ◽  
Exploration And Production ◽  
Subsea Pipelines ◽  
Wave Induced ◽  
Shallow Water Depth

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.

Integrated technology for conditioning low-mineralized cold ground water

2021 ◽  
pp. 4-9
Author(s):  
А.В. Селюков
Keyword(s):  
Drinking Water ◽  
Hydrogen Sulfide ◽  
Oil And Gas ◽  
Residual Concentration ◽  
Stabilization Treatment ◽  
Integrated Technology ◽  
Main Work ◽  
Treatment Facilities ◽  
Low Efficiency ◽  
Iron Manganese

Сообщается о новой комплексной технологии кондиционирования холодных маломинерализованных подземных вод. Технология разрабатывалась для целей хозяйственно-питьевого водоснабжения нефтегазоносных районов Тюменского Севера. При благополучном соотношении ресурсов пресной воды и фактического объема водопотребления в этом регионе России вопрос питьевого водоснабжения из подземных горизонтов остается острым из-за проблемного качества воды и низкой эффективности очистных сооружений. Технология предназначена для очистки от железа, марганца, сероводорода и обеспечивает стабилизационную обработку воды. Основные работы, включавшие лабораторные исследования и пилотные испытания, выполнены в период 2001–2020 годов. На основе разработанных технологических решений построены и успешно эксплуатируются водопроводные очистные сооружения в городах Ноябрьске (75 тыс. м3/сут, 2006 г.) и Новом Уренгое (65 тыс. м3/сут, 2007 г.). Дополнительные испытания технологии, проведенные в Ханты-Мансийске и Комсомольске-на-Амуре, подтвердили ее эффективность. Технология предусматривает применение в качестве основных реагентов пероксида водорода и перманганата калия для окисления примесей воды, а также щелочного реагента для корректировки рН и стабилизационной обработки. Для обеспечения требований стандарта ВОЗ по содержанию железа и марганца дополнительно может использоваться флокулянт. Обобщены данные по составу подземных вод, использованных для испытаний, и на их основе определена рекомендуемая область применения разработанной технологии. Приведена принципиальная технологическая схема кондиционирования холодных маломинерализованных подземных вод, учитывающая 15-летний опыт эксплуатации построенных станций, а также современные решения по дозированию и смешению реагентов. Указано, что данная технология обеспечивает также частичное снижение содержания кремния в очищенной воде (до 30%). Разработанная технология позволяет получать стабильную питьевую воду при нормативном остаточном содержании железа, марганца и сероводорода. An advanced integrated technology for conditioning low-mineralized cold groundwater is presented. The technology was developed for the purpose of supplying drinking water to the oil and gas-bearing regions of the Tyumen North. With a favorable ratio of fresh water resources and the actual volume of water consumption in this region of Russia, the issue of drinking water supply from underground aquifers remains acute due to the problematic water quality and low efficiency of the treatment facilities. The technology is intended for removing iron, manganese, hydrogen sulfide and providing for the stabilization treatment of water. The main work including laboratory studies and pilot tests was carried out in the period 2001–2020. On the basis of the developed process solutions, water treatment facilities have been built and successfully operated in the cities of Noyabrsk (75 thousand m3/day, 2006) and Novy Urengoy (65 thousand m3/day, 2007). Additional tests of the technology carried out in Khanty-Mansiisk and Komsomolsk-on-Amur confirmed its effectiveness. The technology involves using hydrogen peroxide and potassium permanganate as the basic chemicals for the oxidation of water pollutants, as well as using an alkaline chemical for pH adjustment and stabilization treatment. To meet the requirements of the WHO standard for the concentrations of iron and manganese, an additional flocculant can be used. The data on the composition of groundwater used for testing are summarized, and on their basis the recommended area of ​​application of the developed technology is determined. The basic process flow scheme of conditioning low-mineralized cold groundwater in view of 15 years of experience in operating the existing facilities, and of advanced solutions for dosing and mixing of chemicals, is presented. It is indicated that the technology also provides for a partial reduction in the silicon concentration in purified water (up to 30%). The developed technology ensures stable drinking water with a standard residual concentration of iron, manganese and hydrogen sulfide.

Integrity Assurance of an Oil Transportation Pipeline in a Transformed Design Environment

2015 ◽  
Author(s):  
Amitabh Kumar ◽  
Brian McShane ◽  
Mark McQueen
Keyword(s):  
Field Data ◽  
Oil And Gas ◽  
High Reliability ◽  
Complex Loading ◽  
Calibration Method ◽  
Real Field ◽  
Design Environment ◽  
Data Feedback ◽  
Integrity Management

A large Oil and Gas pipeline gathering system is commonly used to transport processed oil and gas from an offshore platform to an onshore receiving facility. High reliability and integrity for continuous operation of these systems is crucial to ensure constant supply of hydrocarbon to the onshore processing facility and eventually to market. When such a system is exposed to a series of complex environmental loadings, it is often difficult to predict the response path, in-situ condition and therefore the system’s ability to withstand subsequent future loading scenarios. In order to continue to operate the pipeline after a significant environmental event, an overall approach needs to be developed to — (a) Understand the system loading and the associated integrity, (b) Develop a series of criteria staging the sequence of actions following an event that will verify the pipeline integrity and (c) Ensure that the integrity management solution is simple and easy to understand so that it can be implemented consistently. For a complex loading scenario, one of the main challenges is the ability to predict the controlling parameter(s) that drives the global integrity of these systems. In such scenarios, the presence of numerous parameters makes the technical modeling and prediction tasks arduous. To address such scenarios, first and foremost, it is crucial to understand the baseline environment data and other associated critical design input elements. If the “design environmental baseline” has transformed (due to large events e.g. storms etc.) from its original condition; it modifies the dynamics of the system. To address this problem, a thorough modeling and assessment of the in-situ condition is essential. Further, a robust calibration method is required to predict the future response path and therefore expected pipeline condition. The study further compares the planned integrity management solutions to the field data to validate the efficiency of the predicted scenarios. By the inclusion of real field-data feedback to the modeling method, balanced integrity solutions can be achieved and the ability to quantify the risks is made more practical and actionable.

Local Buckling in end Expansion of Subsea Pipelines

2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Jaswar Koto ◽  
Abd. Khair Junaidi ◽  
M. H. Hashim
Keyword(s):  
Crude Oil ◽  
Axial Force ◽  
Oil And Gas ◽  
Local Buckling ◽  
Offshore Platform ◽  
Offshore Pipeline ◽  
Specific Rule ◽  
Subsea Pipelines ◽  
Study Development

Offshore pipeline is mainly to transport crude oil and gas from offshore to onshore. It is also used to transport crude oil and gas from well to offshore platform and from platform to another platform. The crude oil and gas horizontally flows on the seabed, and then vertically flows inside the riser to the offshore platform. One of current issues of the oil and gas transportation system is an end expansion caused by the axial force. If the end expansion occurs over it limit can cause overstress to riser. This paper explores the effect of axial force toward local buckling in end expansion. In the study, development of programming in visual basic 2010 firstly was constructed using empirical equation. The programming code, then, was validated by comparing simulation result with actual data from company. As case study, the end expansion for various thicknesses of pipes was simulated. In this programming, DNV regulation is included for checking either design complied or not with regulation. However, DNV regulation doesn’t have specific rule regarding the end expansion but it is evaluated under load displacement control under strain condition.

Challenges in Hydrate Plug Prevention in Pipelines Seen Over the Lifetime of a Field

2009 ◽  
Author(s):  
Casper Hadsbjerg ◽  
Kristian Krejbjerg
Keyword(s):  
Oil And Gas ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Extended Period ◽  
Oil And Gas Industry ◽  
High Water ◽  
Point Of View ◽  
Field Development ◽  
Hydrate Plug ◽  
Subsea Pipelines

When the oil and gas industry explores subsea resources in remote areas and at high water depths, it is important to have advanced simulation tools available in order to assess the risks associated with these expensive projects. A major issue is whether hydrates will form when the hydrocarbons are transported to shore in subsea pipelines, since the formation of a hydrate plug might shut down a pipeline for an extended period of time, leading to severe losses. The industry practices a conservative approach to hydrate plug prevention, which is the addition of inhibitors to ensure that hydrates cannot form under pipeline pressure and temperature conditions. The addition of inhibitors to subsea pipelines is environmentally unfriendly and also a very costly procedure. Recent efforts has therefore focused on developing models for the hydrate formation rate (hydrate kinetics models), which can help determine how fast hydrates might form a plug in a pipeline, and whether the amount of inhibitor can be reduced without increasing the risk of hydrate plug formation. The main variables determining whether hydrate plugs form in a pipeline are: 1) the ratio of hydrocarbons to water, 2) the composition of the hydrocarbons, 3) the flowrates/flow regimes in the pipeline, 4) the amount of inhibitor in the system. Over the lifetime of a field, all 4 variables will change, and so will the challenge of hydrate plug prevention. This paper will examine the prevention of hydrate plugs in a pipeline, seen from a hydrate kinetics point of view. Different scenarios that can occur over the lifetime of a field will be investigated. Exemplified through a subsea field development, a pipeline simulator that considers hydrate formation in a pipeline is used to carry out a study to shed light on the most important issues to consider as conditions change. The information gained from this study can be used to cut down on inhibitor dosage, or possibly completely remove the need for inhibitor.

Anti load disturbance method for AC servo motor power system

2018 ◽  
Vol 22 (S1) ◽  
pp. 2273-2283
Author(s):  
Haoliang Lv ◽  
Xiaojun Zhou
Keyword(s):  
Power System ◽  
Motor Power ◽  
Servo Motor ◽  
Ac Servo ◽  
Load Disturbance ◽  
Ac Servo Motor
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