
Offshore geotechnical engineering is a sub-field of
geotechnical engineering
Geotechnical engineering, also known as geotechnics, is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics to solve its engineering problems. I ...
. It is concerned with foundation design, construction, maintenance and decommissioning for human-made structures in the
sea
A sea is a large body of salt water. There are particular seas and the sea. The sea commonly refers to the ocean, the interconnected body of seawaters that spans most of Earth. Particular seas are either marginal seas, second-order section ...
.
[Dean, p. 1] Oil platform
An oil platform (also called an oil rig, offshore platform, oil production platform, etc.) is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms w ...
s,
artificial island
An artificial island or man-made island is an island that has been Construction, constructed by humans rather than formed through natural processes. Other definitions may suggest that artificial islands are lands with the characteristics of hum ...
s and
submarine pipeline
A submarine pipeline (also known as marine, subsea or offshore pipeline) is a pipeline that is laid on the seabed or below it inside a trench.Dean, p. 338-340Gerwick, p. 583-585 In some cases, the pipeline is mostly on-land but in places it cross ...
s are examples of such structures. The seabed has to be able to withstand the weight of these structures and the applied loads.
Geohazard
A geologic hazard or geohazard is an adverse geology, geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological ...
s must also be taken into account. The need for offshore developments stems from a gradual depletion of hydrocarbon reserves onshore or near the coastlines, as new fields are being developed at greater distances offshore and in deeper water,
[Randolph & Gourvenec, p. 1] with a corresponding adaptation of the offshore site investigations.
[Kolk & Wegerif, 2005] Today, there are more than 7,000 offshore platforms operating at a water depth up to and exceeding 2000 m.
A typical field development extends over tens of square kilometers, and may comprise several fixed structures, infield flowlines with an export pipeline either to the shoreline or connected to a regional trunkline.
[Randolph & Gourvenec, p. 3]
Differences between onshore and offshore geotechnical engineering
An ''offshore'' environment has several implications for geotechnical engineering. These include the following:
*Ground improvement (on the seabed) and site investigation are expensive.
*Soil conditions are unusual (''e.g.'' presence of carbonates, shallow gas).
*Offshore structures are tall, often extending over above their foundation.
*Offshore structures typically have to contend with significant lateral loads (''i.e.'' large moment loading relative to the weight of the structure).
*Cyclic loading can be a major design issue.
*Offshore structures are exposed to a wider range of
geohazard
A geologic hazard or geohazard is an adverse geology, geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological ...
s.
[Cardenas et al. 2022]
*The codes and technical standards are different from those used for onshore developments.
*Design focuses on ultimate limit state as opposed to deformation.
*Design modifications during construction are either unfeasible or very expensive.
*The design life of these structures often ranges between 25–50 years.
*The environmental and financial costs in case of failure can be higher.
The offshore environment
Offshore structures are exposed to various environmental loads:
wind
Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...
,
wave
In physics, mathematics, engineering, and related fields, a wave is a propagating dynamic disturbance (change from List of types of equilibrium, equilibrium) of one or more quantities. ''Periodic waves'' oscillate repeatedly about an equilibrium ...
s,
currents
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (hy ...
and, in cold oceans,
sea ice
Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world' ...
and
iceberg
An iceberg is a piece of fresh water ice more than long that has broken off a glacier or an ice shelf and is floating freely in open water. Smaller chunks of floating glacially derived ice are called "growlers" or "bergy bits". Much of an i ...
s.
[Randolph & Gourvenec, Section 2.4][Gerwick, 2000] Environmental loads act primarily in the horizontal direction, but also have a vertical component. Some of these loads get transmitted to the foundation (the seabed). Wind, wave and current regimes can be estimated from meteorological and oceanographic data, which are collectively referred to as
metocean data.
Earthquake
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...
-induced loading can also occur – they proceed in the opposite direction: from the foundation to the structure. Depending on location, other
geohazard
A geologic hazard or geohazard is an adverse geology, geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological ...
s may also be an issue. All of these phenomena may affect the integrity or the serviceability of the structure and its foundation during its operational lifespan – they need to be taken into account in offshore design.
The nature of the soil
Following are some to the features characterizing the soil in an offshore environment:
[Randolph & Gourvenec, Section 2.3]
*The soil is made up of
sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
s, which are generally assumed to be in a
saturated state – saline water fills in the pore space.
*Marine sediments are composed of detrital material as well as remains of marine organisms, the latter making up calcareous soils.
*Total sediment thickness varies on a regional scale – it is normally higher near the coastline than it is away from it, where it is also finer grained.
*In places, the seabed can be devoid of sediment, due to strong bottom currents.
*The
consolidation state of the soil is either normally consolidated (due to slow sediment deposition), overconsolidated (in places, a relic of glaciation) or underconsolidated (due to high sediment input).
Metocean aspects
Wave
In physics, mathematics, engineering, and related fields, a wave is a propagating dynamic disturbance (change from List of types of equilibrium, equilibrium) of one or more quantities. ''Periodic waves'' oscillate repeatedly about an equilibrium ...
forces induce motion of floating structures in all six degrees of freedom – they are a major design criterion for offshore structures.
[Randolph & Gourvenec, p. 24][For instance, a given structure may undergo 2x108 wave cycles during its design service life.] When a wave's orbital motion reaches the seabed, it induces sediment transport. This only occurs to a water depth of about , which is the commonly adopted boundary between ''shallow water'' and ''deep water''. The reason is that the orbital motion only extends to a water depth that is half the wavelength, and the maximum possible wavelength is generally considered to be .
In shallow water, waves may generate pore pressure build-up in the soil, which may lead to flow slide, and repeated impact on a platform may cause
liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics.
It occurs both naturally and artificially. As an example of t ...
, and loss of support.
Currents
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (hy ...
are a source of horizontal loading for offshore structures. Because of the
Bernoulli effect, they may also exert upward or downward forces on structural surfaces and can induce the vibration of wire lines and pipelines.
Currents are responsible for eddies around a structure, which cause
scouring and erosion of the soil.
There are various types of currents:
oceanic circulation,
geostrophic,
tidal, wind-driven, and
density currents.
Geohazards
Geohazard
A geologic hazard or geohazard is an adverse geology, geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological ...
s are associated with geological activity, geotechnical features and environmental conditions. Shallow geohazards are those occurring at less than below the seafloor.
[Peuchen and Raap, 2007.] Information on the potential risks associated with these phenomena is acquired through studies of the geomorphology, geological setting and tectonic framework in the area of interest, as well as with geophysical and geotechnical surveys of the seafloor.
Examples of potential threats include
tsunami
A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
s,
landslides
Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslide ...
, active
faults, mud diapirs and the nature of the soil layering (presence of
karst
Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...
,
gas hydrates, carbonates).
[Randolph & Gourvenec, Fig. 3.14][Kolk & Wegerif, p. 151] In cold regions,
gouging ice features are a threat to subsea installations, such as pipelines.
[Palmer and Been, 2011][Barrette 2011] The risks associated with a particular type of geohazard is a function of how exposed the structure is to the event, how severe this event is and how often it occurs (for episodic events). Any threat has to be monitored, and mitigated for or removed.
[Hogan et al., 2008][Younes et al., 2005]
Site investigation
Offshore site investigations are not unlike those conducted onshore (see
Geotechnical investigation
Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks ...
). They may be divided into three phases:
[Randolph & Gourvenec, Chap. 3]
*A ''desk study'', which includes data compilation.
*''
Geophysical survey
Geophysical survey is the systematic collection of geophysical data for spatial studies. Detection and analysis of the geophysical signals forms the core of Geophysical signal processing. The magnetic and gravitational fields emanating from the ...
s'', either shallow and deep seabed penetration.
*''Geotechnical surveys'', which includes sampling/drilling and in situ testing.
Desk study
In this phase, which may take place over a period of several months (depending on project size), information is gathered from various sources, including reports, scientific literature (journal articles, conference proceedings) and databases, with the purpose of evaluating risks, assessing design options and planning the subsequent phases.
Bathymetry
Bathymetry (; ) is the study of underwater depth of ocean floors ('' seabed topography''), river floors, or lake floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of wate ...
, regional geology, potential geohazards, seabed obstacles and
metocean data
[Dean, section 1.4] are some of the information that are sought after during that phase.
Geophysical surveys
Geophysical survey
Geophysical survey is the systematic collection of geophysical data for spatial studies. Detection and analysis of the geophysical signals forms the core of Geophysical signal processing. The magnetic and gravitational fields emanating from the ...
s can be used for various purposes. One is to study the bathymetry in the location of interest and to produce an image of the seafloor (irregularities, objects on the seabed, lateral variability,
ice gouges, ...).
Seismic refraction
Seismic refraction is a geophysical principle governed by Snell's Law of refraction. The seismic refraction method utilizes the refraction of seismic waves by rock or soil layers to characterize the subsurface geologic conditions and Structural ge ...
surveys can be done to obtain information on shallow seabed
stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks.
Stratigraphy has three related subfields: lithost ...
– it can also be used to locate material such as sand, sand deposit and gravel for use in the construction of
artificial island
An artificial island or man-made island is an island that has been Construction, constructed by humans rather than formed through natural processes. Other definitions may suggest that artificial islands are lands with the characteristics of hum ...
s.
[Dean, p. 33] Geophysical survey
Geophysical survey is the systematic collection of geophysical data for spatial studies. Detection and analysis of the geophysical signals forms the core of Geophysical signal processing. The magnetic and gravitational fields emanating from the ...
s are conducted from a
research vessel
A research vessel (RV or R/V) is a ship or boat designed, modified, or equipped to carry out research at sea. Research vessels carry out a number of roles. Some of these roles can be combined into a single vessel but others require a dedicated ...
equipped with
sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...
devices and related equipment, such as single-beam and
multibeam echosounder
A multibeam echosounder (MBES) is a type of sonar that is used to seafloor mapping, map the seabed. It emits acoustic waves in a fan shape beneath its transceiver. The time of flight, time it takes for the sound waves to reflect off the seabed an ...
s,
side-scan sonar
Side-scan sonar (also sometimes called side scan sonar, sidescan sonar, side imaging sonar, side-imaging sonar and bottom classification sonar) is a category of sonar system that is used to efficiently create an image of large areas of the sea ...
s, ‘towfish’ and
remotely operated vehicles (ROVs).
[Dean, section 2.2][Randolph & Gourvenec, p. 34] For the sub-bottom stratigraphy, the tools used include boomers, sparkers, pingers and chirp.
[Randolph & Gourvenec, p. 32] Geophysical surveys are normally required before conducting the geotechnical surveys; in larger projects, these phases may be interwoven.
Geotechnical surveys
Geotechnical surveys involve a combination of sampling, drilling, in situ testing as well as laboratory soil testing that is conducted offshore and, with samples, onshore. They serve to ground truth the results of the geophysical investigations; they also provide a detailed account of the seabed stratigraphy and soil engineering properties.
[Randolph & Gourvenec, p. 31] Depending on water depth and metocean conditions, geotechnical surveys may be conducted from a dedicated
geotechnical drillship, a
semi-submersible
Semi-submersible may refer to a self-propelled vessel, such as:
*Heavy-lift ship, which partially submerge to allow their cargo (another ship) to float into place for transport
*Narco-submarine, some of which remained partially on the surface
*S ...
, a
jackup rig
A jackup rig or a self-elevating unit is a type of mobile platform that consists of a buoyant hull fitted with a number of movable legs, capable of raising its hull over the surface of the sea. The buoyant hull enables transportation of the unit ...
, a large
hovercraft
A hovercraft (: hovercraft), also known as an air-cushion vehicle or ACV, is an amphibious craft capable of travelling over land, water, mud, ice, and various other surfaces.
Hovercraft use blowers to produce a large volume of air below the ...
or other means.
[Dean, p. 47] They are done at a series of specific locations, while the vessel maintains a constant position.
Dynamic positioning
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompas ...
and
mooring
A mooring is any permanent structure to which a seaborne vessel (such as a boat, ship, or amphibious aircraft) may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to ...
with four-point anchoring systems are used for that purpose.
Shallow penetration geotechnical surveys may include soil sampling of the seabed surface or in situ mechanical testing. They are used to generate information on the physical and mechanical properties of the seabed.
[Dean, section 2.3] They extend to the first few meters below the mudline. Surveys done to these depths, which may be conducted at the same time as the shallow geophysical survey, may suffice if the structure to be deployed at that location is relatively light. These surveys are also useful for planning subsea pipeline routes.
The purpose of deep penetration geotechnical surveys is to collect information on the seabed
stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks.
Stratigraphy has three related subfields: lithost ...
to depths extending up to a few 100 meters below the mudline.
[Dean, section 2.4] These surveys are done when larger structures are planned at these locations. Deep drill holes require a few days during which the drilling unit has to remain exactly in the same position (see
dynamic positioning
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompas ...
).
Sampling and drilling
upBox corer for extracting soil samples from the seabed.
Seabed surface sampling can be done with a grab sampler and with a
box corer.
[Dean, Fig. 2.5] The latter provides undisturbed specimens, on which testing can be conducted, for instance, to determine the soil's
relative density
Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...
,
water content
Water content or moisture content is the quantity of water contained in a material, such as soil (called ''soil moisture''), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed ...
and
mechanical properties
A material property is an intensive property of a material, i.e., a physical property or chemical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one mate ...
. Sampling can also be achieved with a tube corer, either gravity-driven, or that can be pushed into the seabed by a piston or by means of a vibration system (a device called a vibrocorer).
[Dean, p. 43]
Drilling
Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross section (geometry), cross-section in solid materials. The drill bit is usually a rotary Cutting tool (machining), cutting tool, often multi-point. The bit i ...
is another means of sampling the seabed. It is used to obtain a record of the seabed stratigraphy or the rock formations below it. The set-up used to sample an offshore structure's foundation is similar to that used by the oil industry to reach and delineate hydrocarbon reservoirs, with some differences in the types of testing.
[Randolph & Gourvenec, p. 44] The
drill string
A drill string on a drilling rig is a column, or string, of drill pipe that transmits drilling fluid (via the mud pumps) and torque (via the kelly drive or top drive) to the Well drilling#Drill bits in mechanical drilling, drill bit. The term ...
consists of a series of pipe segments in diameter screwed end to end, with a drillbit assembly at the bottom.
[Dean, p. 43] As the dragbit (teeth extending downward from the drillbit) cut into the soil, soil cuttings are produced. Viscous drilling mud flowing down the drillpipe collects these cuttings and carry them up outside the drillpipe. As is the case for
onshore geotechnical surveys, different tools can be used for sampling the soil from a drill hole, notably "Shelby tubes", "piston samplers" and "split spoon samplers".
In situ soil testing
Information on the mechanical strength of the soil can be obtained in situ (from the seabed itself as opposed to in a laboratory from a soil sample). The advantage of this approach is that the data are obtained from soil that has not suffered any disturbance as a result of its relocation. Two of the most commonly used instruments used for that purpose are the
cone penetrometer (CPT) and the
shear vane.
[Dean, section 2.3.4][Newson et al., 2004]
The
CPT is a rod-shaped tool whose end has the shape of a cone with a known apex angle (''e.g.'' 60 degrees).
[Dean, p. 45] As it is pushed into the soil, the resistance to penetration is measured, thereby providing an indication of soil strength.
[Das, p. 646] A sleeve behind the cone allows the independent determination of the frictional resistance. Some cones are also able to measure
pore water pressure
Pore water pressure (sometimes abbreviated to pwp) refers to the pressure of groundwater held within a soil or Rock (geology), rock, in gaps between particles (soil pore, pores). Pore water pressures below the phreatic level of the groundwater are ...
. The shear vane test is used to determine the
undrained shear strength of soft to medium
cohesive soils.
[Dean, p. 60] This instrument usually consists of four plates welded at 90 degrees from each other at the end of a rod. The rod is then inserted into the soil and a torque is applied to it so as to achieve a constant rotation rate. The torque resistance is measured and an equation is then used to determine the undrained shear strength (and the residual strength), which takes into account the vane's size and geometry.
[Das, p. 406]
Offshore structures and geotechnical considerations
''Offshore structures'' are mainly represented by
platforms, notably
jackup rig
A jackup rig or a self-elevating unit is a type of mobile platform that consists of a buoyant hull fitted with a number of movable legs, capable of raising its hull over the surface of the sea. The buoyant hull enables transportation of the unit ...
s, steel jacket structures and
gravity-based structures.
[Dean, 2010] The nature of the seabed has to be taken into account when planning these developments. For instance, a gravity-based structure typically has a very large footprint and is relatively buoyant (because it encloses a large open volume).
[Ramakrishnan, p. 9] Under these circumstances, vertical loading of the foundation may not be as significant as the horizontal loads exerted by wave actions and transferred to the seabed. In that scenario, sliding could be the dominant mode of failure. A more specific example is that of the Woodside "North Rankin A" steel jacket structure offshore Australia.
[Randolph and Gourvenec, p. 146] The shaft capacity for the
piles making up each of the structure's legs was estimated on the basis of conventional design methods, notably when driven into siliceous sands. But the soil at that site was a lower capacity calcareous sand. Costly remediation measures were required to correct this oversight.
Proper seabed characterization is also required for
mooring systems. For instance, the design and installation of
suction piles has to take into account the soil properties, notably its undrained shear strength.
[Bai and Bai, pp. 121, 129] The same is true for the installation and capacity assessment of ''plate anchors''.
[Bai and Bai, p. 131]
Submarine pipelines
Submarine pipeline
A submarine pipeline (also known as marine, subsea or offshore pipeline) is a pipeline that is laid on the seabed or below it inside a trench.Dean, p. 338-340Gerwick, p. 583-585 In some cases, the pipeline is mostly on-land but in places it cross ...
s are another common type of man-made structure in the offshore environment.
[Palmer and King 2008] These structures either rest on the seabed, or are placed inside a trench to protect them from
fishing trawler
A fishing trawler is a commercial fishing vessel designed to operate fishing trawls. Trawling is a method of fishing that involves actively dragging or pulling a trawl through the water behind one or more trawlers. Trawls are fishing nets tha ...
s, dragging anchors or
fatigue
Fatigue is a state of tiredness (which is not sleepiness), exhaustion or loss of energy. It is a signs and symptoms, symptom of any of various diseases; it is not a disease in itself.
Fatigue (in the medical sense) is sometimes associated wit ...
due current-induced oscillations.
[Ramakrishnan, p. 186] Trenching is also used to protect pipelines from
gouging by ice keels.
[Palmer and Been, 2011][Barrette 2011] In both cases, planning of the pipeline involves geotechnical considerations. Pipelines resting on the seabed require geotechnical data along the proposed pipeline route to evaluate potential stability issues, such as passive failure of the soil below it (the pipeline drops) due to insufficient
bearing capacity, or sliding failure (the pipeline shift sideways), due to low sliding resistance.
[Zhang and Erbrich, 2005][Catie et al., 2005] The process of trenching, when required, needs to take into account soil properties and how they would affect ploughing duration.
[Bransby et al., 2005] Buckling potential induced by the axial and transverse response of the buried pipeline during its operational lifespan need to be assessed at the planning phase, and this will depend on the resistance of the enclosing soil.
[Catie et al., 2005]
Offshore embedded anchors
Offshore embedded anchors are
anchor
An anchor is a device, normally made of metal, used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ', which itself comes from the Greek ().
Anch ...
s that derive their capacity from the frictional and/or bearing resistance of the soil surrounding them. This is converse to gravity anchors that derive their capacity from their weight. As offshore developments move into deeper waters,
gravity based structures become less economical due to the large required size and cost of transportation. This proves opportune for the employment of embedded anchors.
See also
*
Civil engineering
Civil engineering is a regulation and licensure in engineering, professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads ...
*
Earth materials
*
Floating wind turbine
*
Geohazard
A geologic hazard or geohazard is an adverse geology, geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological ...
*
Geotechnical engineering
Geotechnical engineering, also known as geotechnics, is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics to solve its engineering problems. I ...
*
Geotechnical investigation
Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks ...
*
Geotechnics
Geotechnical engineering, also known as geotechnics, is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics to solve its engineering problems. I ...
*
Ocean
The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...
*
Offshore construction
Offshore construction is the installation of structures and facilities in a marine environment, usually for the production and transmission of electricity, oil, gas and other resources. It is also called maritime engineering.
Construction a ...
*
Offshore drilling
Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum that lies in rock formations beneath the seabed. Most commonly, the ter ...
*
Offshore (hydrocarbons)
"Offshore", when used in relation to hydrocarbons, refers to operations undertaken at, or under the, sea in association with an Petroleum, oil, natural gas or Natural gas condensate, condensate field that is under the seabed, or to activities carr ...
*
Oil platform
An oil platform (also called an oil rig, offshore platform, oil production platform, etc.) is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms w ...
*
Seabed
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
*
Seabed gouging by ice
Seabed gouging by ice is a process that occurs when floating ice features (typically icebergs and sea ice ridges) drift into shallower areas and their keel comes into contact with the seabed.King 2011Palmer & Been 2011Barrette 2011 As they keep ...
*
Sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
*
Soil
Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
*
Soil mechanics
Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids (usually air and ...
*
Submarine pipeline
A submarine pipeline (also known as marine, subsea or offshore pipeline) is a pipeline that is laid on the seabed or below it inside a trench.Dean, p. 338-340Gerwick, p. 583-585 In some cases, the pipeline is mostly on-land but in places it cross ...
*
Subsea
Subsea technology involves fully submerged ocean equipment, operations, or applications, especially when some distance offshore, in deep ocean waters, or on the seabed. The term ''subsea'' is frequently used in connection with oceanography, marin ...
Notes
References
Bibliography
*Bai Y. and Bai Q. (2010) ''Subsea Engineering Handbook''. Gulf Professional Publishing, New York, 919 pp.
*
*Bransby M.F., Yun G.J. Morrow D.R. and Brunning P. (2005) The performance of pipeline ploughs in layered soils. In: S.C.M. Gourvenec (Editor), ''Frontiers in Offshore Geotechnics'', Taylor & Francis, Perth, Australia, pp. 597–605.
*
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{{Engineering fields
Geotechnical engineering
Oceanography
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Engineering education