Control Valve Design Impact on Piping Vibration

2004 ◽  
Author(s):  
James McGhee ◽  
Doug Newlands ◽  
Stuart Farquhar ◽  
Herbert L. Miller
Keyword(s):  
Energy Levels ◽  
Control Valve ◽  
Piping System ◽  
Detection Systems ◽  
The North ◽  
Air Supply ◽  
The North Sea ◽  
Pipe Breakage ◽  
And Control ◽  
Fatigue Failures

Vibration of the recycle piping system on the Main Oil Line (MOL) Export Pumps from a platform in the North Sea raised concern about pipe breakage due to fatigue. Failures had already occurred in associated small bore piping and the instrument air supply lines and control accessories on the recycle flow control valves. Concern also existed due to the vibration of non-flowing pipe work and systems such as the deck structure, cable trays and other instrumentation, which included fire and gas detection systems. Many changes involving bracing of small bore attachments, stiffening of supports, adding supports and stiffing the deck structure were implemented without resolving the problem. The vibration was finally solved by adding enough pressure stages to assure the valve trim exit velcoities and energy levels were reduced to levels demonstrated historically as needed in severe service applications. This vibration energy reduction was more than 16 times. This was achieved by reducing the valve trim exit velocity from peaks of 74 m/s to 12 m/s (240 ft/s to 40 ft/s).

Clay mineral distribution and provenance in Mesozoic and Tertiary mudrocks of the Moray Firth and northern North Sea

Clay Minerals ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 519-541 ◽  
Author(s):  
M. J. Pearson
Keyword(s):  
Clay Mineral ◽  
North Sea ◽  
Volcanic Activity ◽  
Volcanic Material ◽  
The North ◽  
Moray Firth ◽  
History Of ◽  
The North Sea ◽  
Northern North Sea ◽  
And Control

AbstractClay mineral abundances in Mesozoic and Tertiary argillaceous strata from 15 exploration wells in the Inner and Outer Moray Firth, Viking Graben and East Shetland Basins of the northern North Sea have been determined in <0·2 µm fractions of cuttings samples. The clay assemblages of more deeply-buried samples cannot be unambiguously related to sedimentary input because of the diagenetic overprint which may account for much of the chlorite and related interstratified minerals. Other sediments, discussed on a regional basis and related to the geological history of the basins, are interpreted in terms of clay mineral provenance and control by climate, tectonic and volcanic activity. The distribution of illite-smectite can often be related to volcanic activity both in the Forties area during the M. Jurassic, and on the NE Atlantic continental margin during the U. Cretaceous-Early Tertiary which affected the North Sea more widely and left a prominent record in the Viking Graben and East Shetland Basin. Kaolinite associated with lignite-bearing sediments in the Outer Moray Firth Basin was probably derived by alteration of volcanic material in lagoonal or deltaic environments. Some U. Jurassic and L. Cretaceous sediments of the Inner Moray Basin are rich in illite-smectite, the origin of which is not clear.

Transport and Water Quality Modelling in the Southern North Sea in Relation to Coastal Pollution Research and Control

1986 ◽  
Vol 18 (4-5) ◽  
pp. 245-256 ◽  
Author(s):  
J. A. van Pagee ◽  
H. Gerritsen ◽  
W P. M. de Ruijter
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Coastal Zone ◽  
North Sea ◽  
Water Levels ◽  
Coastal Pollution ◽  
The North ◽  
Pollution Research ◽  
The North Sea ◽  
And Control

Mathematical modelling techniques are used to quantify the transport in the southern part of the North Sea of pollutants originating from various inputs. Special attention was given to the anthropogenic increase in local concentrations of nutrients (N, P) and heavy metals (Cd, Hg, Cu, Pb, Zn, Cr) and their potential impact on marine organisms. A depth-averaged hydrodynamic model is used to calculate tidal and wind driven velocities and water levels. By averaging, residual flows are calculated, forming the basis for advective transports in a water quality model. Dispersive transports are derived from a comparison of simulated and observed salinity distributions. Water mass distributions and age functions for various inflowing water types are determined with the model. Transports of nutrients and heavy metals in the southern part of the North Sea are calculated using annual pollution inputs for 1980. Although interactions with bottom sediments are not considered, the calculated and measured concentrations show good similarities. The water quality in the Dutch coastal zone and German Bight area is shown to be highly determined by local pollution loads from the rivers Rhine, Weser and Elbe respectively. Comparison of simulated concentrations for 1980 with those resulting from simulations with estimated natural river inputs, shows that more than 50% of nutrients and heavy metal concentrations originate from human activities in large coastal zone areas. From toxicological information and standards, it is concluded that Cd, Hg and Cu are substances that need special attention in pollution research and control for the Dutch coastal waters.

scholarly journals Sealand, HavenCo, and the Rule of Law

2018 ◽  
Author(s):  
James Grimmelmann
Keyword(s):  
World War Ii ◽  
Rule Of Law ◽  
The Rule Of Law ◽  
The North ◽  
The North Sea ◽  
Internet History ◽  
The 1960S ◽  
And Control ◽  
Start Ups ◽  
Pirate Radio

2012 University of Illinois Law Review 405 (2012)In 2000, a group of American entrepreneurs moved to a former World War II anti-aircraft platform in the North Sea, seven miles off the British coast, and launched HavenCo, one of the strangest start-ups in Internet history. A former pirate radio broadcaster, Roy Bates, had occupied the platform in the 1960s, moved his family aboard, and declared it to be the sovereign Principality of Sealand. HavenCo's founders were opposed to governmental censorship and control of the Internet; by putting computer servers on Sealand, they planned to create a "data haven" for unpopular speech, safely beyond the reach of any other country. This article tells the full story of Sealand and HavenCo - and examines what they have to tell us about the nature of the rule of law in the age of the Internet.The story itself is fascinating enough: it includes pirate radio, shotguns and .50-caliber machine guns, rampant copyright infringement, a Red Bull skateboarding special, perpetual motion machines, and the Montevideo Convention on the Rights and Duties of State. But its implications for the rule of law are even more remarkable. Previous scholars have seen HavenCo as a straightforward challenge to the rule of law: by threatening to undermine national authority, HavenCo was implacably opposed to all law. As the fuller history shows, however, this story is too simplistic. HavenCo also depended on international law to recognize and protect Sealand, and on Sealand law to protect it from Sealand itself. Where others have seen HavenCo's failure as the triumph of traditional regulatory authorities over HavenCo, the article argues that in a very real sense, HavenCo failed not from too much law but from too little. The "law' that was supposed to keep HavenCo safe was law only in a thin, formalistic sense, disconnected from the human institutions that make and enforce law. But without those institutions, law does not work, as HavenCo discovered.

Umbilical-Less Tubing Hanger Installation Controls System

2021 ◽  
Author(s):  
Thor Lovland ◽  
Trond Lokka
Keyword(s):  
Drill Pipe ◽  
Control Valve ◽  
Human Interface ◽  
The North ◽  
Control Functions ◽  
Directional Control ◽  
The North Sea ◽  
Tubing Hanger ◽  
User Friendly ◽  
Production Tubing

Abstract The umbilical-less tubing hanger running installation tool, ROCS ("Remote Operated Control System") was first introduced as an R&D project to the market in early 2020. By February 2021, it is in operation for Aker BP in the North Sea on Deepsea Nordkapp. ROCS is specifically designed to increase the robustness and efficiency of running the production tubing in the well. In a traditional operation, the Tubing Hanger Running Tool ("THRT") normally communicates topside through an umbilical. The ROCS eliminate the controls umbilical by having two methods of communication to the THRT, either acoustic or through wired pipe, preference is acoustic. This also eliminates the topside WorkOver Completion System ("WOCS"). The approximately 16meter long ROCS is also designed with a Ready To Run ("R2R") principle, where the ROCS, THRT and Tubing Hanger ("TH") is made ready on land for offshore operations, already connected and tested. The system is redundant and based on a closed loop hydraulics, powered by a subsea HPU, electrically supplied from subsea batteries. The SHPU is small in size and power consumption, capable of providing the required flow at 690bar. The control functions occur through electrically held DCV's ("Directional Control Valve") for controlling all of the required TH functions. The ROCS is capable of performing 3 operations of each TH function within the allocated deployed period. The energy required is provided between the hydraulic accumulators and batteries. Pressure balanced accumulators are included to optimize all deepwater operations. A properly sized clean reservoir is installed, interfacing the pre charged accumulators. ROCS is controlled through a modular and user-friendly topside HMI ("Human Interface Machine"), communicating acoustically or through wired pipe over any type communication protocol. The benefits include removing personnel from red zone, as well as eliminating time to clamp umbilical to the drillpipe. This significantly reduces mobilization of the system to a few hours, which also eliminates the topside deck space considerably. The running time is reduced and allows to increase speed of the drill pipe. This also reduces the risk of damaging production tubing or downhole equipment. There is no risk of downtime due to damaged conduit and the operating weather window is increased.

scholarly journals Acute otitis externa in divers working in the North Sea: a microbiological survey of seven saturation dives

1977 ◽  
Vol 78 (3) ◽  
pp. 395-409 ◽  
Author(s):  
S. R. Alcock
Keyword(s):  
North Sea ◽  
Otitis Externa ◽  
Control Measures ◽  
Monitoring And Control ◽  
Ear Canal ◽  
The North ◽  
The North Sea ◽  
Offshore Oil Industry ◽  
And Control ◽  
Offshore Oil

SUMMARYSaturation diving is an important and widely used technique in the Offshore Oil Industry. During 1974–5 two saturation dives in the North Sea were terminated because of outbreaks of incapacitating otitis externa, and others were disrupted. Pseudomonas aeruginosa was consistently isolated from the ears of affected divers. Because complex work schedules were threatened seven subsequent dives were subjected to microbiological monitoring and control. Colonization of the ear canal with P. aeruginosa or with other gram-negative bacilli occurred in 39 (67%) of the 58 divers studied, usually within 7 days of starting the dive. Data obtained by serotyping the isolations of P. aeruginosa suggested that a single infected diver may be the source of organisms which rapidly spread to his colleagues and throughout the living chambers, that the living chambers may constitute a reservoir of infection during and between dives, and that certain serotypes of P. aeruginosa are more likely than others to colonize the ear canal in the conditions of a saturation dive. The control measures used during the dives were only partially effective, but none of the divers suffered severe pain and all the dives were an operational success.

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