What is Subsea Exploration?
Subsea is a term frequently used to refer to equipment, technology, and methods employed to explore, drill, and develop oil and gas fields that exist below the sea bed. This can be in either "shallow" or "deepwater", where deepwater is used for subsea projects located in water depths greater than 300 metres, and may include floating drill vessels, semi-sub rigs or semi-submersible platforms.
"Shallow" or "shelf" is used for shallower depths and can include standing Jackup Rigs or similar.
Subsea production systems can range in complexity from a single satellite well with a pipeline 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.
Simple Subsea Oil or Gas Development
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.
Subsea hydrocarbon (oil and gas) extraction has an exceptionally safe record and has been ongoing for approximately 100 years. Oil and gas fields reside in deep water and shallow water around the world. When they are under water and tapped into for the hydrocarbon production, these are generically called subsea wells, fields, projects, development, or other similar terms.
The development of subsea oil and gas fields requires specialised equipment. The equipment must be reliable enough to safe guard the environment, and make the exploitation of the subsea hydrocarbons economically feasible. The deployment of such equipment requires specialised and expensive vessels, which need to be equipped with diving equipment for relatively shallow equipment work (i.e. 100m 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.
The subsea industry is one of the most exciting and fastest growing technology sectors in the world. Cutting-edge technology combined with world-leading engineering is ensuring that the UK is at the forefront of extracting one of the most precious commodities from under the seabed in a safe and environmentally secure manner.
Increasingly, recovery of the world’s oil and gas reserves is being achieved through subsea wells in some of the deepest waters and most challenging environments on our planet. This presents a real test of engineering ingenuity and expertise.
The UK subsea industry sector leads the world in experience, innovation and technology.
Our subsea services include measurement and control instrumentation solutions for subsea modules, with particular expertise in level, flow and pressure measurement.
We offer RF Admittance interface level detectors which are used for pollution prevention in subsea oil production.
The probes, which detect hydrocarbon / sea water interface, are used as part of pollution control 'Umbrellas" on "Christmas Trees". The "Umbrella" is typically located above the choke and flow cut valve.
Should a hydrocarbon leak occur, the rising hydrocarbon is trapped by the "umbrella" and the RF Admittance probe detects the presence of changing seawater levels. The hydrocarbon is ignored and due to the large dielectric difference between hydrocarbon and seawater, the system is very sensitive to the reduction in seawater levels, thus providing early indication of hydrocarbon contamination.
|McCrometer V-Cone® Subsea Flow Meter
ABLE offer the McCrometer V-Cone Subsea flow meter which delivers high accuracy and repeatability
designed for deepwater Oil & Gas production modules and operations.
Petroleum process engineers looking for a precise, reliable, compact flow measurement solution for deepwater module applications, will find the V-Cone® Subsea flow meter from McCrometer offers superior accuracy and repeatability in a highly compact, no-moving parts instrument that requires virtually no recalibration or maintenance over an exceptionally long life.
McCrometer’s V-Cone Subsea flow meter is ideal for the subsea production environment. It relies on an advanced differential pressure flow sensor designed with built-in flow conditioning to achieve an accuracy of 0.5%, with a repeatability of 0.1%. It operates over a flow range of 10:1, and comes in line sizes from 0.5 to 120 inches.
With its unique ability to self-condition flow, the V-Cone Subsea flow meter is compact, eliminating the need for long up/down stream straight pipe runs required by other DP technologies, such as orifice plates and venturi tubes. It can be installed virtually anywhere in a piping system or be easily retrofit into an existing piping layout, providing installation flexibility and initial cost savings.
Unlike traditional DP instruments such as orifice plates and venturi tubes, the V-Cone Subsea flow meter’s design is inherently more accurate because the flow conditioning function is built-into the basic flow sensor design. The V-Cone conditions fluid flow to provide a stable flow profile that increases accuracy. The flow meter’s design features a centrally-located cone inside a tube. The cone interacts with the fluid flow and reshapes the velocity profile to create a lower pressure region immediately downstream.
The pressure difference, which is exhibited between the static line pressure and the low pressure created downstream of the cone, can be measured via two pressure sensing taps. One tap is placed slightly upstream of the cone and the other is located in the downstream face of the cone itself. The pressure difference can then be incorporated into a derivation of the Bernoulli equation to determine the fluid flow rate.
The cone’s central position in the line optimizes the velocity of the liquid flow at the point of measurement. It forms very short vortices as the flow passes the cone. These short vortices create a low amplitude, high frequency signal for excellent signal stability. The result is a highly stable flow profile that is repeatable for continuously accurate measurement. All of this is possible with a minimal straight pipe run of 0 to 3 diameters upstream and 0 to 1 diameters downstream from the flow meter.
The V-Cone Subsea flow meter’s flow measurement technology has been employed successfully in the oil and gas industry and solves some of the toughest flow measurement problems including wet gas, condensate,and dirty or abrasive flows in off-shore installations. In addition to wet gas applications, other applications include gas lift, gas injection, leak detection, flare emission systems and more.
If you would like further information on our subsea services please contact us Tel: +44 (0)118 9169520