2. used to make connection between the wells and




The list of equipment has been defined
under this title. This list has been created based on most used equipment in
Campos Basin at Brazil for fixed offshore oil gas platforms.

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2.1.     Subsea Manifold


Subsea manifolds are useful to minimize the
utilization of subsea pipelines and risers while optimize the flow of fluids in
the system. Main objectives of the system clarified as shown as below:

§  Minimize the flow lines,

§  Optimization of subsea layout,

§  Diminish the quantity and size of risers that are connected to the
offshore platforms,

§  Full production in advance,

§  Distribute electrical and hydraulic systems,

§  Distribute production fluids, chemicals, and gas and control fluids.

According to ISO 13628-1, the manifolds
should provide sufficient piping, valves and flow controls to safely gather
produced fluids or distribute injected fluids such as gas, water or chemicals.
23 (DNV-GL, 2013)

Subsea manifolds are installed on the sea
floor and located independently from the wells. Jumpers have been used to make
connection between the wells and pipelines to the manifolds. (Fig. 9)

There are different kinds of manifolds.  One of the most used manifolds is PLEM/PLET.
These kinds of manifolds have direct connections to the pipelines.

Figure 9 Example of layout plan of
manifold-pipeline and jumpers 24

(http://www.pretechnologies.com/) (Access: 09/29/2017)

from PLEM, There are some kinds of manifolds as template and cluster manifolds.
Template manifold (Fig. 10) has the necessity to be used while Xmas tree
(Christmas tree) is grouped side by side. On the other perspective, if the Xmas
trees have been located near to central location, cluster manifolds (Fig. 11)
can get the priority to be used on the system instead of template manifolds.

Figure 10 Template manifold 25

(http://www.fishsafe.eu/en/home.aspx) (Access: 09/30/2017)

Figure 11 Schematic drawing of
cluster manifold 26

(http://www.subseapedia.org) (Access: 09/30/2017)

manifold consist of various components as shown as below:




Subsea Modules,

Piping System,

Control System (Allows to
remote control of any hydraulically actuated),

Framework Structure,

Foundation (Mud mats, Piles),

Connection Equipment (Allows
subsea tie-in of multiple pieces of equipment),

Sensors and Transmitters
(Pressure Transmitters, Pig Detector),

Inspection (Pigging),

ROV Panel,

Multiphase Flow Meter,


The Pipeline End Termination (PLET) connects
a single pipeline, meantime the Pipeline End Manifolds (PLEM-a simple manifold)
is useable to connect two or more pipeline with other subsea structures, such
as manifolds or Xmas Trees through a jumper.

The PLET/ PLEM are located at the end of a
subsea pipeline, while the inline structure is located in the middle of the

The PLEM consists of following assemblies
(Fig. 12):

§  Piping system,

§  Foundation,

§  Structural Frame,

§  Installation yoke.

Figure 12 Typical PLEM 27

(Bai & Bai, 2010) (Access: 09/30/2017)

PLEMs supply the extra supporting force for the collect connectors and piping
systems of subsea equipment. (Fig. 13)

Figure 13 PLET and PLEM in subsea
field layout 28

(http://nfatmala.blogspot.com/) (Access: 09/30/2017)


2.2.     Subsea Tree


Subsea Trees which are called with
different names as Xmas Trees, Christmas trees, subsea Xmas trees or tree,
monitors and controls production flow and manages gas or fluids injection.

Basically subsea trees are group of valves,
pipes, fittings and it is located on a subsea wellhead.

Subsea Trees are consisting as their
equipment which is listed below:

Subsea Control Module (SCM),

Subsea Electronic Module,


Power Supply,

Communication Boards,

Solenoid Driver Modules,

Digital Transmitter Modules,

Hydraulic Valves,

Internal Communication via CAN

Subsea Accumulator Module (SAM),

A set of valves,

Tubing Hanger,

Well Head Connectors,


Vertical Connector,

Hydraulic Flying Leads,


Flying Leads,



ROV Panel.

There are two different type of subsea tree
as shown as figure 14, 15 and 16.

Figure 14 Horizontal and
conventional subsea trees 29

(http://nfatmala.blogspot.com/)(Access: 09/30/2017)

Figure 15 Horizontal subsea tree 30

(http://www.drillingformulas.com)(Access: 09/30/2017)

Figure 16 Vertical subsea tree 31

(http://www.drillingcontractor.org)(Access: 09/30/2017)

2.3.     Jumper (Flexible and


Subsea jumpers (Fig. 17) are a kind of
short pipe connectors which are located on seabed to transportation of
production fluids from one of the subsea component to another one such as like
from Xmas tree to manifold or between the flow lines to manifolds etc…(Fig.
18) Additionally, in some systems that are searched during the literature
studies, some of the jumpers (jumper spools) has been used to connect PLEM/PLET
and riser bases and it can be utilized to inject water into the wells.

Figure 17 Sample of jumper 32

(http://www.fogt.com/index.php)(Access: 09/30/2017)

Figure 18 Typical subsea template layout

2015)  (Access: 09/29/2017)

2.4.     Umbilical System


Umbilical systems (Fig. 19-20) consist of
fiber optic cables, electrical cables, thermoplastic hoses, and steel tubes.
All these components located in a circular cross-section

Umbilical systems are used by the offshore
industry. The main missions of this equipment listed as shown as below:

Transmit the control ?uid and electric
current necessary to control the functions of the subsea production and safety

Control of subsea manifold or
isolation valve,

Subsea production and water
injection well control,

Monitor pressures and chemical

Operate subsea electrical

Figure 19 Umbilical cross-section 34

(http://www.subseapedia.org) (Access: 09/31/2017)

Figure 20 Subsea control umbilical 35

(http://gcaptain.com/)(Access: 09/31/2017)

The clarification of subsea umbilical
components has done below. (Fig. 21). Electrical cables have two different
types as power cables and signal communication cables.

We assembled power cables in the umbilical for
power transfer to offshore platforms and subsea production equipment. Signal
communication cables utilizes for the monitoring and remote control of subsea

optic cables, umbilical steel tube and thermoplastic hose are capable of uninterrupted
operations when immersed in seawater.

Figure 21 Components of umbilical 36

(http://www.offshore-mag.com/index.html)(Access: 09/31/2017)

Umbilical termination assemblies (Fig. 22) put
an end to umbilical lines and provide one or more connections for chemical,
hydraulic, electrical and fiber optic services.


Figure 22 Umbilical termination assembly

 (http://www.deepdowninc.com/) (Access: 10/01/2017)

















2.5.     Subsea Pipelines


Subsea pipelines
are one of the most important part of moving hydrocarbons and natural gas from
offshore production equipment to processing facilities. Subsea pipelines have a
variety of usage aims. There are different kinds of subsea pipelines as shown
as Table 1

Table 1 Offshore pipelines and
relevant descriptions

(Shen, Birkinshaw , &
Palmer, 2017)38


Typical Dimensions


Primary Materials

Trunk lines/Export Lines

Up to 44 inches,
Up to 840 km long

Major Export infrastructure for oil and gas

Carbon Steel

Rigid Flow lines

Up to 16 inches
Less than 50 km long

Infield flow lines and tie in spools

Carbon steel

Flexible Flow lines

Up to16 inches
Up to 10 km long

Infield flow lines and tie in spools

Carcass and polymer layers; alloy end fittings


2 to 8 inches
Up to 50 km long

Chemical hydraulic and communication distribution

Thermoplastic polymer or steel tubes; wire armour

Power Cables

2 to 4 inches diameter
Up to 300 km long

Power distribution between and within fields

Copper cores with wire armour protected

The flow lines may
transport hydrocarbon resources, lift gas, injection water and chemicals from
wellhead to riser foot.(Fig. 23)

The export pipelines
located from the processing facilities to shore. (Fig.23)

Figure 23 Application of subsea pipelines

(http://www.piping-engineering.com)(Access: 10/01/2017)

to figure 23, the subsea pipelines include:

§  Export pipelines,

§  Flow lines for transfer products
between platform, subsea manifolds and wells,

§  Flow lines for transfer products
from platform to export lines,,

§  Pipeline bundles,

§  Water injection or chemical
injection flow lines.




2.6.     Risers


Riser systems (Fig. 24) are key equipment
for offshore drilling. In offshore ?ndustry, risers get in uses for drilling,
transportation of hydrocarbons, fluids and gas lifts.

There are different types of risers that
are assembled in subsea oil gas offshore platforms in Brazil. A list below
shows these types of risers:

Attached Risers,

Pull Tube Risers,

Catenary Steel Riser,

Flexible Risers,

Top Tensioned,

Hybrid Tower Risers.

Figure 24 A riser installed on fixed
platform 40

(ttps://subseaworldnews.com) (Access: 10/05/2017)

and pull tube risers (Fig. 25) are one of the easiest approaches to the riser
design. “The attached riser utilizes clamps, typically with polymer liners, to
fix the riser pipe to the tower.

The pull
tube differs in that, although it is mounted statically to the tower, it serves
as a conduit for a smaller diameter flow line to pass through. The flow line is
typically pulled through the riser via a high-capacity winch connected to the
messenger wire of the flow line.”41 (https://www.gateinc.com)

and pull tube riser designs compared on the following table. (Table 2)

Table 2 Comparisons of attached
and pull tube risers



Limited to the fixed platforms

Limited to the fixed platforms

Applicable in depths up to 3000 feet

Applicable in depths up to 3000 feet

High ROV installation expense

Dry connection at deck level can be
monitored more reliably

Exposed to platform movements that may
induce stress on riser

High stresses on components during pulling


Figure 25 Attached risers and pull
tube risers 42

(https://www.gateinc.com) (Access: 10/05/2017)

Steel catenary risers (Fig. 26)
assembled with semi-submersible floating platforms and when these risers used
for deep waters, these are more effective.

Figure 26 Steel catenary riser on
the floating oil gas offshore platform 43

(https://www.gateinc.com) (Access: 10/05/2017)

risers (Fig. 27) have high level of bending capacity.  In the general cases, we use these kinds of
risers for application of flow lines between the vessels.

Figure 27 Flexible risers 44

(https://www.gateinc.com)(Access: 10/05/2017)

Top tensioned
risers are vertically located and these kinds of risers related with tension
leg platforms and spars. Hybrid risers (Fig. 28) are similar to the top
tensioned risers. Also these risers connect points between floating vessel and
the production flow lines.

Figure 28 Hybrid riser 45

(https://www.gateinc.com) (Access: 10/05/2017)

On this thesis we will discuss just for
attached and pull tube risers due to the thesis on the fixed platforms. (Rigid


2.7.     Pressure Booster Pump


Subsea pressure pumping
(Fig. 29) is one of the most mature solutions for increasing oil recovery from
subsea tie-backs and these systems give accelerates to production. One of another
benefit of these systems is increase the recovery and extensions of field life.
They reduce OPEX and they improve flow assurance performance.

Figure 29 Subsea pressure booster pump

(https://mokveld.com)(Access: 10/06/2017)


2.8.     Separation System


Subsea separation system’s (Fig. 30) main
purpose is separate the multiphase fluids on the seabed and then send the
separated oil and gas streams to the surface of the platform. There are two
different kinds of separators which are used mainly and they called as gravity
based three-phase subsea separation systems and cyclone based two-phase subsea
separation systems.

Figure 30 Separation system 47

(https://www.rigzone.com)(Access: 10/06/2017)

separation systems have advantages on the production system. They effected to
increase the production and increase the reservoir recovery. These systems also
positively influence the flow insurance. (Fig. 46)

Figure 31 Subsea separator system 48

(https://publicintelligence.net)(Access: 10/06/2017)


2.9.     Protection Structure /
Template Structure


The template (Fig. 32) is the basis that
carries the weight and loads of the structure, and supports the wellhead and
drilling activities, manifold and control system as well as the protection
structure. The protection structure covers the template, manifold and the trees
to protect the equipment from third-party damages as e.g. dropped objects,
anchors or trawl equipment.

Figure 32 Subsea protection structure
/ Template structure 49

(https://subseaworldnews.com)(Access: 10/06/2017)

2.10.    Mudmat


Mudmat (Fig. 33) give support to seafloor
temporarily for jackets and subsea equipment but we will focus on mudmat for
subsea equipment during these studies (Not for jacket).The function of mudmat
is to provide sufficient area for load distribution to the ground.

Figure 33 Mudmat for umbilical termination
assembly 50

(http://www.deepdowninc.com)(Access: 10/06/2017)




























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