FLUID MECHANICS

Fluid mechanics is the sub-disciplines of continuum mechanics that studies fluids (which may include liquid and gas). Fluid mechanics fluid can be divided into static and dynamic fluid. Fluid static study the fluid at rest while the fluid moving fluid dynamic study (wikipedia).
Substance differentiate into three phases namely:
Solid phase is the substance retains a fixed shape and size, although a large work force on solid objects.
Liquid phase is the substance does not retain permanent shape but the shape of the container.
Gas phase is the substance has no fixed form or volume, but will grow to fill the entire container.
Because the liquid phase and gas does not maintain a fixed shape, both have the ability to flow with the so-called fluid.

 

ρ = m/v

m: mass of the object (kg)

v: volume (m3)

Density is the ratio of the density of the object is the density of water or quantities without dimensions or units.

Pascal's principle states that pressure is done in a fluid will cause the increase in pressure in all directions equally. So, with our small force that can be used to make cross-sectional area greater output from the input section.

The pressure in the fluid (P) is the force per unit area, with the force (F) is considered work perpendicular to the surface area (A)

P = F/A

P: pressure (Pa)
F: force (N)
A: cross-sectional area (m2)
 

Fluid using the pressure in all directions. At a certain point Dalan fluids at rest, pressure is the same for all directions. Pressure on one side must be equal * with pressure on the opposite side. If not the same, the number of forces acting will not move until the working pressure becomes equal.

Other properties of fluids at rest the force caused by fluid pressure is always working secra perpendicular to each surface of the touch.
The pressure in the fluid that has a uniform density will vary with depth.
Pressure caused by fluid in the depth (h), caused by the heavy fluid on top. So the forces acting on an area below the 

 

P = F/A = ρ.A.h.g/A = ρ.g.h

The equation P = ρ.gh can be used to determine the pressure difference, ΔP, at different depths with a density ρ average:

ΔP = ρ.g. Δh

• Fluid Dynamics
Discussing about the diataranya Fluid flow is:
Straight Flow (Streamline) or laminar flow occurs when the flow is smooth, so that adjacent layers of fluid flowing smoothly or Any particles that pass a point moves right along the path followed by other particles that pass through the previous point. Characteristics:
Streamline is the trajectory
o Streamline the different does not intersect
o Streamline at one point stating also the direction
fluid flow at that point

Turbulent flow or turbulent flow that is above a certain speed, which depends on a number of factors, the flow will be turbulent. This flow is characterized by uncertainty, a small, coiled like a whirlpool called Eddy currents or kisaran.Ciri-Characteristics:

1. The flow becomes indeterminate

• Not achieving a certain speed value
• Appears circumstances that led to changes
• speed suddenly
• Flow Eddy (vortex current)
  
  
  HYPOTHESIS KONTINIUM  
  Continuum Hypothesis is only a hypothesis which is basically just the approach. As a result, assuming the continuum hypothesis to provide results with accuracy levels that are not desired. However, if the conditions are right, the continuum hypothesis produces very accurate results. Fluid drawn up by the molecules collide with each other. However, the continuum assumption considers fluids to be continuous. In other words, properties such as density, pressure, temperature, and speed is considered undefined at points which are very small that define REV (''Reference Element Reference Element of Volume'')/(' Volume'') in order geometric distance between opposite molecules in the fluid. a fluid is incompressible the density of the fluid does not change when given the pressure. Sometimes fluid can be modeled as an incompressible fluid while all the gas could not. 

FLUID BY THE EXPERTS  
The Navier-Stokes (Claude-Louis Navier and George Gabriel Stokes) is a set of equations describing the motion of a fluid such as liquid and gas. These equations state that the change in momentum (acceleration) of fluid particles depend on the internal viscous forces and viscous forces of external pressure acting on the fluid. Therefore, the Navier-Stokes equations describe the balance of forces acting on the fluid. Newtonian fluid (named for Isaac Newton) is defined as fluid shear stress is linearly proportional to the gradient of velocity in the direction perpendicular to the shear field. Non-Newtonian Fluid Yang stirred, will remain a "hole". This hole will be filled over time. Such properties can be observed in materials such as pudding. Another event that occurs when non-Newtonian fluid is stirred viscosity reduction which causes the fluid looks "thinner" example: in the paint. 

UNITS AND DIMENSIONS Magnitude is anything that can be measured and expressed with numbers, such as length, area, volume, and speed. Dimension is a measure to declare variables of physics (Physics Variable) quantitatively. Dimensions in International Units (SI) Length: L Mass: M Time: T (S) Temperature: oC Dimensions in the British (BG) Style: F (Newton) Length: L (m3) Massa: T (S) Temperature: F

Unit Quantities Conversion Factor Angle 1 putaran = 3600 = 2 π rad Density 1 gm per cubic centimeter = 103 kg/m3 Berat air = 62,43 lb/ft3 Massa 1 kilogram = 103 gm = 6,85 x 10-2 slug 1 gram = 10-3 kg = 6,85 x 10-5 slug lengt 1 meter = 3,281 ft 1 foot = 0,3048 m 1 mile = 1609 m = 5280 ft 1 angstrom = 10-10 m Style 1 newton = 105 dyne = 0,225 lb 1 dyne = 10-5 N = 2,25 x 10-5 lb 1 pound = 4,448 N = 4,448 x 105 dyne Speed 1 meter/det = 3,281 ft/det = 2,237 ml/jam Pressure atm mmHg N/m2 Lb/ft2 Atm 1 760 1.013 x 105 2116 Mm air raksa 1,316 x 1013 1 133,3 2,785 N/m2 9,869 x 10-6 7,5 x 10-3 1 2,089 x 10-2 Lb/ft2 4,725 x 10-4 0,359 47,88 1 Energy 1 joule = 0,7376 ft-lb = 0,239 cal = 107 ergs 1 ft-lb = 1,356 J = 0,324 cal 1 cal = 4,186 J = 3,087 ft-lb Power 1 watt = 0,737 ft-lb/det = 1,341 x 1013 hp = 1 J/det 1 hp = 550 ft-lb/det = 746 watt 1 ft-lb/det = 1,818 x 10-3 hp = 1,356 W

SUBSEA

 

Subsea is a term used to refer to the equipment, technology, and methods used to explore, drill, development and operation of an oil and gas fields under the water surface. Able for areas that are shallow (shallow) or deep sea (deepwater). Subsea structures built in the sea to explore oil and gas that lies in a shallow sea and deep sea. Installation of subsea (offshore) depending on environmental conditions, as well as surface structure and require updating. Many of the reasons why in doing offshore drilling (offshore):  

1.Menemukan vast reserves of oil and gas fields and can be profitable. 2. Allows for producing from the deeper sea.
As well as things that may need to be noticed are:

1. Need high realibitas  

2. More complex subsea installations  

3. Some technology still in development.  

4. Factors to consider are the depth, tide, waves and currents, wind, earthquake and ice (North Sea).



Well many companies that do offshore drilling: 

1. Petrobras  

2. Statoil  

3. Shell  

4. Exxonmobile  

5. Bp  

6. Norsk Hydro  

7. Chevron  

8. Kerr-McGee  

9. Total  

10. Talisman
 

An estimated 5-10% of world oil reserves under the sea and is currently estimated to be around 30% of the total production comes from offshore oil and gas. So the development of subsea technology into one attractive alternative given the thinning reserves on land. The first offshore drilling done by the chevron is in california. And the deepest wells in the 2008 which was developed by teledo at bay mexico is 3050 m Operational Criteria
Determination of the bridge functions (drilling, production, storage, shelter engineer, etc.), the total number of wells drilled, total deck and equipment needed, and methods of oil and gas transportation is the work of multiple disciplines such as engineering geophysics and geology, oceanography, chemical engineering, mechanical engineering and electrical and instrumentation engineering, marine engineering, and environmental engineering. 

1. Stages of drilling

1.Explorasi Oil and gas exploration is done with the ship that uses the reflection wave to get beneath the surface seismic data. 

2.Drilling
A location has been selected and prepared, several holes dug to make a point of drilling equipment (rigs) and the main hole.
This operation is done to ensure the presence or absence
content of oil and gas. (Using the Jack-Up Rig)

COMPONENTS OFFSHORE PLATFORMS

1. Topsides
The top of the bridge as a place of all equipment (process, mechanical, electrical and instrument) for the drilling / production of oil and gas.
(other terminology: Deck, Upper Structure)
 

2. Supporting STRUCTURE
To support and protect decks / topsides of environmental burdens such as waves, currents, wind, and earthquake) (another term: substructure). 

-TREE
Its function is to control the flow of tree production from the well through several valves and chokes, to a manifold or elsewhere.

-JUMPERS / flowlines
Jumper is a very short spool (also can be rigid or flexible) so that it can be installed in a single generation into the seabed.

-Manifold
Which sends the results to the place of production and storage process which is usually located on top of floating or on land.
Based on the location of manifold:
1.Template manifold that is so one with the wells
2.Cluster manifold that is off-site wells
Based on the structure of the manifold:
`1. Integral manifold of a unified structure
2.Retrievable manifold of structures that can be taken back into the water.

-FTA (Flow Termination Assembly)
To connect the pipeline with other facilities, namely PLET, PLEM and Riser Base.

-Riser
To connect the flow from the seabed into the water. Riser base must be installed separately, so need two connectors for connecting the riser and pipeline.

-FPSO (Floating Production, Storage And Offloading)

 
What is meant by FPSO here is not just a boat-shaped, but also SPAR, TLP and other floating.
1. (TLP = Tension Led Platform) TLP = pavilion is part topsidesnya supported by columns, pontoons (hull) and tethered to the seabed by several fastening (tendons)
2. (SPAR = Spar is Deep draft floater (DDF), which is categorized as a relatively large power muatnya).
Tree mounted above the well and will be on stream by the manifold to be sent to storage (storage) in surface water usually fixed structures on the surface or on land. To connect the manifolds we need a tree with jumper / flowlines. If the storage place is too far in requiring the FTA at the downstream end of the manifold to the riser and forwarded by the riser to raise to the surface or to a FPSO (SPAR / TLP).