2. SUBSEA EQUIPMENTS MOSTLY USED IN CAMPOSBASIN The list of equipment has been definedunder this title. This list has been created based on most used equipment inCampos Basin at Brazil for fixed offshore oil gas platforms. 2.
1. Subsea Manifold Subsea manifolds are useful to minimize theutilization of subsea pipelines and risers while optimize the flow of fluids inthe 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 theoffshore 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 manifoldsshould provide sufficient piping, valves and flow controls to safely gatherproduced fluids or distribute injected fluids such as gas, water or chemicals.23 (DNV-GL, 2013) Subsea manifolds are installed on the seafloor and located independently from the wells. Jumpers have been used to makeconnection 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 ofmanifold-pipeline and jumpers 24(http://www.
pretechnologies.com/) (Access: 09/29/2017)Apartfrom 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 Xmastrees 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 ofcluster manifold 26(http://www.subseapedia.
org) (Access: 09/30/2017)Subseamanifold consist of various components as shown as below:§ Valves,§ Chokes,§ Hubs,§ Subsea Modules,§ Piping System,§ Control System (Allows toremote control of any hydraulically actuated),§ Framework Structure,§ Foundation (Mud mats, Piles),§ Connection Equipment (Allowssubsea tie-in of multiple pieces of equipment),§ Sensors and Transmitters(Pressure Transmitters, Pig Detector),§ Inspection (Pigging),§ ROV Panel,§ Multiphase Flow Meter,§ Templates.The Pipeline End Termination (PLET) connectsa single pipeline, meantime the Pipeline End Manifolds (PLEM-a simple manifold)is useable to connect two or more pipeline with other subsea structures, suchas manifolds or Xmas Trees through a jumper. The PLET/ PLEM are located at the end of asubsea pipeline, while the inline structure is located in the middle of thepipeline.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)ThePLEMs supply the extra supporting force for the collect connectors and pipingsystems of subsea equipment. (Fig. 13)Figure 13 PLET and PLEM in subseafield layout 28(http://nfatmala.
blogspot.com/) (Access: 09/30/2017) 2.2. Subsea Tree Subsea Trees which are called withdifferent 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 theirequipment which is listed below:§ Subsea Control Module (SCM),§ Subsea Electronic Module,§ CPU,§ Power Supply,§ Communication Boards,§ Solenoid Driver Modules,§ Digital Transmitter Modules,§ Hydraulic Valves,§ Internal Communication via CANbus,§ Subsea Accumulator Module (SAM),§ A set of valves,§ Tubing Hanger,§ Well Head Connectors,§ Connectors,§ Vertical Connector,§ Hydraulic Flying Leads,§ Electronic,§ Flying Leads,§ Sensors/Transmitters,§ Choke,§ ROV Panel.There are two different type of subsea treeas shown as figure 14, 15 and 16.
Figure 14 Horizontal andconventional 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 andRigid) Subsea jumpers (Fig. 17) are a kind ofshort pipe connectors which are located on seabed to transportation ofproduction fluids from one of the subsea component to another one such as likefrom Xmas tree to manifold or between the flow lines to manifolds etc..
.(Fig.18) Additionally, in some systems that are searched during the literaturestudies, some of the jumpers (jumper spools) has been used to connect PLEM/PLETand 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 layout33(http://15511009.blogspot.com/, 2015) (Access: 09/29/2017) 2.4. Umbilical System Umbilical systems (Fig. 19-20) consist offiber optic cables, electrical cables, thermoplastic hoses, and steel tubes.All these components located in a circular cross-sectionUmbilical systems are used by the offshoreindustry.
The main missions of this equipment listed as shown as below:§ Transmit the control ?uid and electriccurrent necessary to control the functions of the subsea production and safetyequipment,§ Control of subsea manifold orisolation valve,§ Subsea production and waterinjection well control,§ Monitor pressures and chemicalInjection,§ Operate subsea electricaldevices.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 umbilicalcomponents has done below. (Fig. 21). Electrical cables have two differenttypes as power cables and signal communication cables.
We assembled power cables in the umbilical forpower transfer to offshore platforms and subsea production equipment. Signalcommunication cables utilizes for the monitoring and remote control of subseaequipment.Fiberoptic cables, umbilical steel tube and thermoplastic hose are capable of uninterruptedoperations 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) putan end to umbilical lines and provide one or more connections for chemical,hydraulic, electrical and fiber optic services.
cFigure 22 Umbilical termination assembly37 (http://www.deepdowninc.com/) (Access: 10/01/2017) 2.5. Subsea Pipelines Subsea pipelinesare one of the most important part of moving hydrocarbons and natural gas fromoffshore production equipment to processing facilities.
Subsea pipelines have avariety of usage aims. There are different kinds of subsea pipelines as shownas Table 1Table 1 Offshore pipelines andrelevant descriptions(Shen, Birkinshaw , & Palmer, 2017)38 Pipelines Typical Dimensions Applications 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 Umbilical 2 to 8 inches Up to 50 km long Chemical hydraulic and communication distribution Thermoplastic polymer or steel tubes; wire armour protected 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 maytransport hydrocarbon resources, lift gas, injection water and chemicals fromwellhead to riser foot.(Fig. 23)The export pipelineslocated from the processing facilities to shore. (Fig.23)Figure 23 Application of subsea pipelines39(http://www.piping-engineering.com)(Access: 10/01/2017)Accordingto figure 23, the subsea pipelines include:§ Export pipelines,§ Flow lines for transfer productsbetween platform, subsea manifolds and wells,§ Flow lines for transfer productsfrom platform to export lines,,§ Pipeline bundles,§ Water injection or chemicalinjection flow lines.
2.6. Risers Riser systems (Fig. 24) are key equipmentfor offshore drilling.
In offshore ?ndustry, risers get in uses for drilling,transportation of hydrocarbons, fluids and gas lifts.There are different types of risers thatare assembled in subsea oil gas offshore platforms in Brazil. A list belowshows 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 fixedplatform 40(ttps://subseaworldnews.com) (Access: 10/05/2017)Attachedand pull tube risers (Fig.
25) are one of the easiest approaches to the riserdesign. “The attached riser utilizes clamps, typically with polymer liners, tofix the riser pipe to the tower. The pulltube differs in that, although it is mounted statically to the tower, it servesas a conduit for a smaller diameter flow line to pass through. The flow line istypically pulled through the riser via a high-capacity winch connected to themessenger wire of the flow line.”41 (https://www.
gateinc.com)Attachedand pull tube riser designs compared on the following table. (Table 2)Table 2 Comparisons of attachedand pull tube risers ATTACHED R?SERS PULL TUBE R?SERS 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 operations Figure 25 Attached risers and pulltube 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 usedfor deep waters, these are more effective.
Figure 26 Steel catenary riser onthe floating oil gas offshore platform 43(https://www.gateinc.com) (Access: 10/05/2017)Flexiblerisers (Fig.
27) have high level of bending capacity. In the general cases, we use these kinds ofrisers for application of flow lines between the vessels.Figure 27 Flexible risers 44(https://www.
gateinc.com)(Access: 10/05/2017)Top tensionedrisers are vertically located and these kinds of risers related with tensionleg platforms and spars. Hybrid risers (Fig. 28) are similar to the toptensioned risers. Also these risers connect points between floating vessel andthe production flow lines.Figure 28 Hybrid riser 45(https://www.
gateinc.com) (Access: 10/05/2017)On this thesis we will discuss just forattached and pull tube risers due to the thesis on the fixed platforms. (Rigidrisers) 2.7. Pressure Booster Pump Subsea pressure pumping(Fig. 29) is one of the most mature solutions for increasing oil recovery fromsubsea tie-backs and these systems give accelerates to production.
One of anotherbenefit 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 pump46(https://mokveld.
com)(Access: 10/06/2017) 2.8. Separation System Subsea separation system’s (Fig. 30) mainpurpose is separate the multiphase fluids on the seabed and then send theseparated oil and gas streams to the surface of the platform. There are twodifferent kinds of separators which are used mainly and they called as gravitybased three-phase subsea separation systems and cyclone based two-phase subseaseparation systems.
Figure 30 Separation system 47(https://www.rigzone.com)(Access: 10/06/2017)Subseaseparation systems have advantages on the production system. They effected toincrease the production and increase the reservoir recovery. These systems alsopositively 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 thatcarries the weight and loads of the structure, and supports the wellhead anddrilling activities, manifold and control system as well as the protectionstructure. The protection structure covers the template, manifold and the treesto 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 seafloortemporarily for jackets and subsea equipment but we will focus on mudmat forsubsea equipment during these studies (Not for jacket).
The function of mudmatis to provide sufficient area for load distribution to the ground. Figure 33 Mudmat for umbilical terminationassembly 50(http://www.deepdowninc.com)(Access: 10/06/2017) Intentionally left blank