Subsea is a general term frequently used to refer to
equipment, technology, and methods employed in marine biology, undersea
geology, offshore oil and gas developments, underwater mining, and offshore
wind power industries.
Oil and gas
Oil and gas fields reside beneath many inland waters and
offshore areas around the world, and in the oil and gas industry the term
subsea relates to the exploration, drilling and development of oil and gas
fields in underwater locations.
Under water oil field facilities are generically referred to
using a subsea prefix, such as subsea well, subsea field, subsea project, and
subsea development.
Subsea oil field developments are usually split into Shallow
water and Deepwater categories to distinguish between the different facilities
and approaches that are needed.
The term shallow water or shelf is used for very shallow
water depths where bottom-founded facilities like jackup drilling rigs and
fixed offshore structures can be used, and where saturation diving is feasible.
Deepwater is a term often used to refer to offshore projects
located in water depths greater than around 600 feet, where floating drilling
vessels and floating oil platforms are used, and remotely operated underwater
vehicles are required as manned diving is not practical.
Subsea completions can be traced back to 1943 with the Lake
Erie completion at a 35-ft water depth. The well had a land-type Christmas tree
that required diver intervention for installation, maintenance, and flow line
connections.
Shell completed its first subsea well in the Gulf of Mexico
in 1961
The first known subsea ultra-high pressure waterjet system
capable of operating below 5,000 ft was developed in 2010 by Jet Edge and
Chukar Waterjet. It was used to blast away hydrates that were clogging a
containment system at the Gulf oil spill site.
Chukar Waterjet has since developed a deepwater subsea
waterjet system capable of operating at depths of up to 3000 meters (10,000
feet).Effective at cutting steel up to 250 mm thick or waterjet blasting at
pressures up to 3800 bar, the system can be used to blast away coatings and
marine growth to inspect welds, or as a cutting tool in emergency response and
salvage operations. It also can be used for hydrate remediation.
Systems
Subsea production systems can range in complexity from a
single satellite well with a flowline linked to a fixed platform, FPSO or an
onshore installation, to several wells on a template or clustered around a
manifold, and transferring to a fixed or floating facility, or directly to an
onshore installation.
Subsea production systems can be used to develop reservoirs,
or parts of reservoirs, which require drilling of the wells from more than one
location. Deep water conditions, or even ultradeep water conditions, can also
inherently dictate development of a field by means of a subsea production
system, since traditional surface facilities such as on a steel-piled jacket,
might be either technically unfeasible or uneconomical due to the water depth.
The development of subsea oil and gas fields requires
specialized equipment. The equipment must be reliable enough to safeguard the
environment and make the exploitation of the subsea hydrocarbons economically
feasible. The deployment of such equipment requires specialized and expensive
vessels, which need to be equipped with diving equipment for relatively shallow
equipment work (i.e. a few hundred feet water depth maximum) and robotic
equipment for deeper water depths. Any requirement to repair or intervene with
installed subsea equipment is thus normally very expensive. This type of
expense can result in economic failure of the subsea development.
Subsea technology in offshore oil and gas production is a
highly specialized field of application with particular demands on engineering
and simulation. Most of the new oil fields are located in deep water and are
generally referred to as deepwater systems. Development of these fields sets
strict requirements for verification of the various systems’ functions and
their compliance with current requirements and specifications. This is because
of the high costs and time involved in changing a pre-existing system due to
the specialized vessels with advanced onboard equipment. A full-scale test (System
Integration Test – SIT) does not provide satisfactory verification of deepwater
systems because the test, for practical reasons, cannot be performed under
conditions identical to those under which the system will later operate. The
oil industry has therefore adopted modern data technology as a tool for virtual
testing of deepwater systems that enables detection of costly faults at an
early phase of the project. By using modern simulation tools, models of
deepwater systems can be set up and used to verify the system's functions, and
dynamic properties, against various requirements specifications. This includes
the model-based development of innovative high-tech plants and system solutions
for the exploitation and production of energy resources in an environmentally
friendly way as well as the analysis and evaluation of the dynamic behavior of
components and systems used for the production and distribution of oil and gas.
Another part is the real-time virtual test of systems for subsea production,
subsea drilling, supply above sea level, seismography, subsea construction
equipment, and subsea process measurement and control equipment.[citation
needed]
Offshore wind power
The power transmission infrastructure for offshore wind
power utilizes a variety of subsea technologies for the installation and
maintenance of submarine power transmission cables and other electrical energy
equipment. In addition, the monopile foundations of fixed-bottom wind turbines
and the anchoring and cable structures of floating wind turbines are regularly
inspected with a variety of shipborne subsea technology.
Underwater mining
Recent technological advancements have given rise to the use
of remotely operated vehicles (ROVs) to collect mineral samples from
prospective mine sites. Using drills and other cutting tools, the ROVs obtain
samples to be analyzed for desired minerals. Once a site has been located, a
mining ship or station is set up to mine the area.
Remotely operated vehicles
Main article: Remotely operated underwater vehicle
Remotely Operated Vehicles (ROVs) are robotic pieces of
equipment operated from afar to perform tasks on the sea floor. ROVs are
available in a wide variety of function capabilities and complexities from
simple "eyeball" camera devices, to multi-appendage machines that
require multiple operators to operate or "fly" the equipment.
Organizations
A number of professional societies and trade bodies are
involved with the subsea industry around the world. Such groups include
Subsea Engineering
Society
Society for
Underwater Technology
Subsea Project
Awards
Subsea UK
Subsea Valley The
largest subsea technology business cluster.
Society of
Petroleum Engineers
American Petroleum
Institute (API)
American Society
of Mechanical Engineers (ASME)
National
Association of Corrosion Engineers (NACE).
Government agencies administer regulations in their
territorial waters around the world. Examples of such government agencies are
the Minerals Management Service (MMS, US), Norwegian Petroleum Directorate
(NPD, Norway), and Health & Safety Executive (HSE, UK). The MMS administers
the mineral resources in the US (using Code of Federal Regulations (CFR)) and
provides management of all the US subsea mineral and renewable energy resources.
SUBSCRIBERS - ( LINKS) :FOLLOW / REF / 2 /
findleverage.blogspot.com
Krkz77@yahoo.com
+234-81-83195664
No comments:
Post a Comment