Marine Riser Systems And Subsea Blowout Preventers Pdf

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A blowout preventer BOP pronounced B-O-P, not "bop" [1] is a specialized valve or similar mechanical device, used to seal, control and monitor oil and gas wells to prevent blowouts , the uncontrolled release of crude oil or natural gas from a well.

Year of fee payment : 4. Methods for deploying a subsea blowout preventer stack system comprising a lower marine riser package, a blowout preventer stack with a first ram blowout preventer, and an additional blowout preventer package releasably coupled to the blowout preventer stack and comprising a second ram blowout preventer.

Blowout preventer

A multibody system including a drilling riser system, tensioners and a floating platform is key equipment for offshore oil and gas drilling.

Most of the previous studies only focus on the drilling riser system rather than the multibody system. Mechanical characteristics of the deepwater drilling riser system cannot be analyzed accurately in a simplified model. Therefore, a three-dimensional multibody analysis program is developed.

The static and dynamic characteristics of the deepwater drilling riser system under different platform motions are analyzed based on the developed program. The results show that the static displacement of the riser system with tensioners is smaller than that without tensioners, which means the tensioners can suppress the deformation of the riser system.

Under surge and sway motions of the platform, the dynamic displacement of the riser system with tensioners is also smaller than that without tensioners due to the tensioner suppression effect.

Besides, the heave motion induces a uniform axial vibration of the riser system, while roll and pitch motions excite the riser system to vibrate laterally. Compared with the stress amplitude due to surge and sway motions, the stress amplitude of the riser system due to heave, roll and pitch motions is relatively small but cannot be neglected.

A drilling riser system is a key component connecting the drilling platform with subsea wellhead in offshore drilling engineering.

The top end of the riser system is hung on the drilling platform via tensioners, and the bottom end of the riser system is connected to the subsea wellhead via lower marine riser package LMRP and blowout preventer BOP Chen et al. The drilling riser system, platform and tensioners form a multibody system. The drilling riser system suffers marine environment loads and interaction loads between the multibody system such as tension force and platform motions.

The combined loads cause the drilling riser system deformation and vibration. An excessive deformation and vibration may lead to failure of the riser system. It is necessary to conduct multibody mechanical analysis to reveal the mechanical characteristics of the deepwater drilling riser system accurately, which is of great significance to the safety of the drilling riser system.

Mechanical characteristics of the multibody system are difficult to be analyzed due to its complex structure. Therefore, the drilling riser system is often taken as an individual research object. Tensioners are simplified as a constant tension force, and the drilling platform is taken as a displacement boundary applied on the top of the riser system.

Then, a simplified mechanical model for the riser analysis can be derived. A series of static and dynamic analysis was conducted to study the mechanical behavior of the riser system based on the simplified model Patel and Seyed ; Chen et al. Actually, the tension force applied on the top of the riser system varies with the heave motion of the drilling platform. A coupling model including the riser system and tensioners is then introduced to simulate the axial dynamic behavior of the riser system.

Sullivan et al. Lang et al. Wang et al. The tensioner is simplified as a linear model, and the predicted axial responses are compared with that of the nonlinear model. Zhang et al. Wang and Liu developed a mathematical model of a direct-acting tensioner system to analyze the effect of internal friction of tensioner cylinder on the tensioner performance and axial dynamics of a riser system. A more accurate analysis method needs to be proposed to analyze the complex multibody system.

Multibody dynamics may be a good choice since it can handle linearly and nonlinearly elastic multibody systems with arbitrary topologies Amirouche ; Bauchau In recent years, multibody dynamics has been applied gradually to ocean engineering Lee and Roh Cha et al.

Ku and Ha introduced multibody dynamics to study the dynamic characteristics of different suspension cables and the motion of a crane. Ham et al. Lee et al. Besides the riser recoil analysis based on multibody dynamics, an extensional multibody analysis model including a drilling riser system, tensioners and a floating platform needs to be established to study the static and dynamic mechanical behavior of the drilling riser system.

Problems that involve mechanical analysis of a deepwater drilling riser system based on multibody system dynamics are addressed in this study. The remainder of this paper is organized as follows. The top end of the riser system is hung on the drilling platform via tensioners and upper flex joint, and the bottom end of the riser system is connected to BOP, subsea wellhead and conductor via LMRP.

Tensioners provide the riser system with a tension force in the axial direction opposite to gravity. The upper part of the tensioners is directly connected to the drilling platform, and the lower part of the tensioners links to tension rings on the outside of the telescopic joint. The multibody system deforms and vibrates under marine environment loads.

In addition, each body of the multibody system also interacts with each other complicatedly. Therefore, the mechanical analysis model for each body should be established, respectively, and then assembled into a multibody analysis model. Theoretical models of each body will be presented in the following subsections.

The riser system vibrates laterally under environment loads and horizontal platform motion, as shown in Fig. Besides, the riser system may also vibrate axially under the excitation of platform heave motion. The lateral and axial dynamic equations of the riser system can be given, respectively Park and Jung ; Liu et al.

The lateral marine environment load per unit length on the riser system above the mudline are written as follows Liu et al. Tensioners are equipped between a drilling platform and the riser system to compensate the heave motion of the platform and prevent buckling of the riser system due to its own weight Haziri The DAT is becoming predominant in recent deepwater field development due to its simple structure and high payload Wang and Liu Therefore, the DAT system is selected for the multibody analysis, as shown in Fig.

The pressure difference between high-pressure gas vessels and low-pressure gas vessels ensures that a tension force is applied to the riser system. The high pressure P h and low pressure P L can be written as follows:. The gas volume in the high- and low-pressure gas vessels changes with poison stroke.

Assuming the hydraulic fluid is incompressible, the gas volume in the gas vessels can be written as follows:. Substituting Eqs. Finally, substituting Eqs. A semi-submersible platform is selected for the multibody analysis due to its good performance of stability, great mobility and a wide range of applicable water depth Zhu and Ou The motion of a drilling platform is the upper boundary of the multibody system and very important for the multibody mechanical analysis.

The motion of a drilling platform is often characterized by six degree-of-freedom motions with surge, sway, heave, pitch, roll and yaw motions Mao et al. The six degree-of-freedom motions of the platform are often determined based on the response amplitude operator RAO. RAO defines the amplitude and phase relationship between the platform motion and wave frequency.

Each degree-of-freedom motion of platform in the regular wave can be calculated as follows Sexton and Agbezuge ; Chang et al. A simulation model needs to be developed to conduct the multibody mechanical analysis based on established theoretical models of the riser system, tensioners and the platform.

Users can model a multibody system using basic blocks representing bodies, joints and other blocks and integrate hydraulic, pneumatic and other physical systems into the established simulation model Wang et al. Besides, users can also develop specific modules to meet simulation requirements, such as the marine environment load module. The multibody system is often split into several bodies during modeling.

Each body of the multibody system will be built separately and then assembled together according to their topological relation, as shown in Fig.

Body 2 represents the riser system, which is a nonlinear structure. Body 3 shows the outer and inner pipe of the telescopic joint, which can slide relative to each other. The outer pipe of the telescopic joint connects to the riser system, while the inner pipe of the telescopic joint connects to the platform Body 4 through a flex joint.

Body 5 represents the DAT system, which is directly connected to the tensioner ring and provides a tension force for the riser system. Simulation models of Body 2 and Body 5 will be individually introduced in the following parts due to their complexity. The theoretical model of the riser system shown in Eqs. The lumped mass method is chosen for the riser analysis since there is a provided lumped mass method package of general use for flexible body modeling in Simscape.

In the lumped mass method, the riser system is modeled using lumped masses connected by extensional and rotational springs including structural damping Raman-Nair and Baddour , as shown in Fig. Each riser unit is formed by an elastic damping element and a rigid body element. The elastic damping element is used to define the translation spring coefficient k T , translation damping coefficient b T , rotational spring coefficient k R and rotational damping coefficient b R.

The simulation model of a riser unit is established based on the lumped mass model in Simscape, as shown in Fig. A solid block is used to define the structure parameters of a riser unit. The coordinate transformation module is set to transfer the local coordinate system to a global coordinate system.

The telescoping joint is used to define the spring stiffness and damping coefficient shown in Eqs. The water particle velocity induced by a wave, water particle acceleration induced by a wave and steady current velocity are calculated in the marine environment load module.

Riser velocity and acceleration defined in Eq. A delay module, which can make time difference in data transmission, is set to avoid algebraic loop and improve calculation speed. The buoyancy module is set to apply the buoyancy force of the riser unit in sea water since the dry weight of the riser has been defined in the solid block. A tensioner is composed of a hydro-pneumatic tensioner cylinder, an oil—gas accumulator and several high-pressure and low-pressure gas vessels, as shown in Fig.

Each part of a tensioner can be simulated in Simscape fluids-hydraulics and multibody module, as shown in Fig. A double-acting hydraulic cylinder is used to define the piston area, piston stroke and piston initial position.

Gas-charged hydraulic fluid accumulator 1 is set to simulate oil—gas accumulator and high-pressure gas vessels, while gas-charged hydraulic fluid accumulator 2 is used to model low-pressure gas vessels.

The ideal force sensor, ideal translational velocity sensor and tension force scope are set to monitor and display the key parameters of the tensioner during the simulation.

Flex joints 1 and 2 are placed at the end of the piston and piston rod to connect the tensioner with the platform and riser tension ring, respectively. Simulation models for complex riser Body 2 and tensioner Body 5 have been established. Then, a 3D multibody simulation model can be assembled through coordinates based on established simulation models of each body, as shown in Fig. Each body in the multibody system is physically connected to one another by joints.

The telescopic joint and tensioner assemblies are connected to the platform by flex joints. The lower part of the tensioners links to the riser tension ring with flex joints.

Sec6 Subsea Blowout Preventers[1].pdf

The present application is a continuation-in-part of U. The present invention relates to systems for diverting the flow of hydrocarbons from a blowout preventer. More particularly, the present invention the relates to diverters that are applied to the outlet of a blowout preventer so as to provide a safety mechanism in the event of a failure of the blowout preventer. Additionally, the present invention relates to capping stack that are utilized for the purpose of diverting the flow of high pressure fluids to a surface location. As the worldwide demand for hydrocarbon fuel has increased, and known onshore reserves have not kept up with the demand, there has been increasing activity in offshore oil exploration and production.

The risers are pipes through which the drill string carries out the drilling function. A marine drilling riser system provides a tubular conduit from the drilling unit to the subsea blow out preventer BOP and the wellbore below it. The riser assembly guides down whole tools and equipment from the surface to the wellbore, permits drilling fluids circulate back to the drilling unit, and carries the BOP stack as it is run or retrieved. The drilling riser is composed of a series of joints which are connected by couplings. Choke and kill lines for the BOP are run integrally down the outside of the riser tub along with other auxiliary lines.


L esson 9: Life Offshore. L esson Marine Riser Systems and Subsea Blowout Preventers. Petroleum Extension-The University of Texas at Austin.


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Provisional Patent Appln. Patent Appln. In particular, embodiments disclosed herein are related to subsea oil and gas drilling systems in high pressure environments.

Circulating heavier and more viscous drilling mud down through the drill pipe and back up through the choke and kill lines controls the pressure in the well bore. Once the well is brought back into pressure balance, the preventers are reopened and the drilling operation continued. The subsea wellhead system, and BOP stack generally have the same nominal inside diameter and pressure rating. The BOP stack components are integrated within a structural steel framework.

WO2016061444A1 - High pressure subsea blowout preventer system - Google Patents

Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. If hydrocarbons unexpectedly flow into the well during drilling or other operations despite the use of primary barriers in the well, the blowout preventer BOP system serves as a secondary means of well control i.

A multibody system including a drilling riser system, tensioners and a floating platform is key equipment for offshore oil and gas drilling. Most of the previous studies only focus on the drilling riser system rather than the multibody system. Mechanical characteristics of the deepwater drilling riser system cannot be analyzed accurately in a simplified model. Therefore, a three-dimensional multibody analysis program is developed. The static and dynamic characteristics of the deepwater drilling riser system under different platform motions are analyzed based on the developed program. The results show that the static displacement of the riser system with tensioners is smaller than that without tensioners, which means the tensioners can suppress the deformation of the riser system.

 Отпусти ее, - спокойно сказал Стратмор.  - Она тебе все равно не поверит. - Да уж конечно, - огрызнулся Хейл.  - Лживый негодяй. Вы промыли ей мозги. Вы рассказываете ей только то, что считаете нужным.


BOPs for land rigs and jack ups are a fairly simple system, as shown. Because they The BOP has two sections, the Lower Marine Riser Package. (LMRP)and​.


Mechanical analysis of deepwater drilling riser system based on multibody system dynamics

Introduction

 - Если оба элемента - уран, то как мы найдем различие между. - А вдруг Танкадо ошибся? - вмешался Фонтейн.  - Быть может, он не знал, что бомбы были одинаковые. - Нет! - отрезала Сьюзан.  - Он стал калекой из-за этих бомб.

Как всегда, одна кабинка и один писсуар. Пользуются ли писсуаром в дамском туалете -неважно, главное, что сэкономили на лишней кабинке. Беккер с отвращением оглядел комнату. Грязь, в раковине мутная коричневатая вода. Повсюду разбросаны грязные бумажные полотенца, лужи воды на полу. Старая электрическая сушилка для рук захватана грязными пальцами. Беккер остановился перед зеркалом и тяжело вздохнул.

Не знаю, как оно правильно произносится… Густа… Густафсон. Ролдан слышал имя впервые, но у него были клиенты из самых разных уголков мира, и они никогда не пользовались настоящими именами. - Как он выглядит - на фото. Быть может, я смогу его узнать. - Ну… - произнес голос.

Не было видно даже кнопочных электронных панелей на дверях кабинетов. Когда ее глаза привыкли к темноте, Сьюзан разглядела, что единственным источником слабого света в шифровалке был открытый люк, из которого исходило заметное красноватое сияние ламп, находившихся в подсобном помещении далеко внизу. Она начала двигаться в направлении люка.

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