Tantalum Offshore Field Examinations Engineering Essay


This is a study discoursing about Tantalum offshore field analyzing two different strategies to acquire the fluid from offshore to the onshore processing country, strengths and failings and analysing and comparing their constructs in order to take the best possible option for the development of Tantalum field. This study deals with application of complex engineering for earlier production of the field to to the full work the field and explicating major constituents used for processing and transport the fluid.

Basic Facts:

Position: 50 KM from the nearby landfall ;

Depth of H2O: 120 M ;

Climate: Temperate

Estimated recoverable oil: 9.0 MMboe

Expected peak production rate: 1300 three-dimensional meters per twenty-four hours ; Internet Explorer.

62,898 barrels per twenty-four hours

Reservoir Depth: 7,000 pess ;

Initial Pressure: 5,000 psia ;

Bubble-point force per unit area of oil: 3,500 psia ;

Crude quality: Sweet, 25EsAPI gravitation


The H2O ( sea ) is unagitated ; the climatic conditions are favorable. There is no demand for iceberg protection in the design of the subsea installation due to nature of H2O. Heating for the flow of petroleum will non be required.

Gas produced can be used for power and public-service corporations on the installation and any extra will be re-injected into the reservoir to increase oil recovery in future.

Another subsea good caput will be used for H2O injection.

Considered field is fringy in production harmonizing to basic facts.

Grapevines in land line and subsea are non subjected non any harm.


This undertaking tries to happen out different ways to do the oil for the markets, comparing them with each other thereby choosing the best available option with regard to the Tantalum field. The development construct for the Tantalum field located at a H2O deepness of 120m and peak production rate of 1300 three-dimensional metres per twenty-four hours and 502.49 kilometer from the nearby land based oil-processing installation.

Figure 1: Agreement for Tantalum Field

Study of Field Data

Accepted production rate ( in Barrels )

Here 1 three-dimensional metre = 6.289 barrels

Therefore 1300 three-dimensional metre = 8,175.7 barrels per twenty-four hours

Life expectance of reservoir ( 9,000,000 / 8175.7 ) = 1100.8 yearss = three old ages.

The reservoir oil has a 25Es API, about sweet rough oil ; non excessively much sweetener is required. High volatile oil and so high GOR.

Initial force per unit area is above bubble point hence, primary production is done through natural lift ; and for farther phase both gas thrust or H2O injection will be required. Another good caput is already available for H2O injection.



Wellhead gives a good waterproofing protection for oil Wellss. It can be used in onshore every bit good as offshore. Well caput is a set up employed to shut the well and it composed assorted sorts of valves for flow alteration through tube and ring. Wellhead is composed with different parts like tubing caput bobbin, Christmas tree, casing caput bobbin and hanger. It is used for hanging production tube and besides Christmas tree is installed top of it. ( Mathew sand, vinu

From: hypertext transfer protocol: //www.glossary.oilfield.slb.com/DisplayImage.cfm? ID=533


Christmas trees offer a connexion nexus with the completion and installation. It ‘s an agreement of bobbins, valves, force per unit area gages and choking coils.The most of import function of Xmas tree is to pull off the flow in or out of the well. The tree provides assorted extra maps which includes chemical injection, well intercession, tree and good monitoring points, connexion points for devices for illustration down hole force per unit area and temperature transducer. It is available in a broad scope of sizes and constellations, for case individual or multiple completion capacity and low or high force per unit area capacity. ( vinu, sand )

From: hypertext transfer protocol: //www.glossary.oilfield.slb.com/DisplayImage.cfm? ID=476

Umbilical cord:

Umbilical lines are used to supplying control fluids and electrical supply to run valves, instrumentality and manifold. It gives service from host to field. This is dwelling of several packages of nucleus wrapped together. It helps to impede for corrosion, hydrate, graduated table, wax and asphaltenes. ( david, Mathew )

From: hypertext transfer protocol: //www.offshore-technology.com/contractors/cables/parkerhannifin/parkerhannifin5.html


A manifolds map chief is to the reservoir fluid to the centrifuge. Manifold have valves that composed of choking coil valves, corrosion valves, inhibitor valves and production valves. The chief purpose of the manifold faculty are offering an interface between the production grapevine, back uping and protecting all pipe work and valves, flow line and the well, roll uping produced fluids from single subsea Wellss, give out production fluids, inject gas, inject chemicals and control fluid and besides the electrical and hydraulic system and supply raising points for multiplex faculty during installing and retrieval. The H2O from the centrifuge is transmitted to the manifold all the manner through risers. From assorted Wellss fluid is coming with different force per unit area that is stabilised by choking coil and transferred to manifold. ( sand, David )

From: hypertext transfer protocol: //www.petronyx.com/facility_manifolds.htm


Riser is an fond regard between manifold and production platform. Main use of subsea risers are transporting of multiphase fluids from seabed to platform. It ‘s simply we can state it as grapevine used for perpendicular transit in subsea. There are different types of risers available in market, but depending on managing they will be deployed. It is normally insulated for defying seafloor temperature. For fixed platforms by and large attached risers are used. It is clamped to side of platform from seabed to production installation. But in the instance of FPSO, steel catenary risers are used for the ground that it can defy inordinate motion. Another type riser named intercrossed or flexible riser can last both perpendicular and horizontal gesture. A conventional presentation for intercrossed riser shown below: ( sand Mathew rigzone )

From: hypertext transfer protocol: //www.rigzone.com/training/insight.asp? insight_id=308 & A ; c_id=17


A spherical or cylindrical vas used to divide oil, gas and H2O from the entire fluid watercourse produced by a well. Centrifuges can be either perpendicular or horizontal. Horizontal centrifuges are by and large preferred, when liquid is dominant stage such as petroleum oil – natural gas systems, where three stage separation ( oil-water-gas ) is required, or frothing liquids. Vertical centrifuges are typically specified when the vapor liquid ratio is high for scouring service or where limited secret plan infinite is available. Separating method can done by individual or multi phase separation. Most common method used in oil and gas industry is three stage separation. Because by several separation it decrease H2O and gas contents therefore it reduces opportunity of corrosion and remotion of harmful gases like H sulfide will happen.

( sand



Oil Degree











Three-Phase Horizontal Separator



From: Lecture notes of Ted Mason ( Separation System )

Oil Dehydration:

In order to run into market demands, rough oil should hold a H2O specification. This frequently expressed in footings of Basis Sediment and Water content and typical values range from 0.1 % for light petroleum to 3 % for heavy petroleum.

Heat: Application of heat lowers the viscousness of the external stage taking to a higher rate of deposit. It besides lowers the interfacial tenseness of the droplet bettering the chance of coalescency.

Chemicals: Chemical destroys the oil H2O fluid movie and develops deposit.

Electricity: Alternating electrical field forces droplets to stretch and clash, tearing movie.

Retention Time: In this appropriate keeping clip is given which permits the gravitation separation of oil and H2O. ( sand


Gas hydration is normally expressed as H2O vapour remotion from gas. It is method to command development of solid hydrates and cut down the corrosion jobs in installations every bit good as in grapevines. Dehydration can be done through following methods:

Gas watercourse infrigidation



Glycol desiccation ( sand

From: Lecture notes of Ted Mason ( Glycol Dehydration Unit )


The produced H2O that comes out of the centrifuge will be some oil contain. It should be removed before disposal, so that this will non impact any environment instability. The use of the produced H2O, harmonizing to that H2O intervention will be done. The often done with the produced H2O is to reinject into the reservoir for retaining reservoir force per unit area or settles down to sea. There will be several contaminations like hydrocarbon compounds, inorganic compounds, chemicals, sand, waxes etc available from centrifuge H2O in front of intervention. In our undertaking, we have made a determination that reinjection into the reservoir. Assorted types of H2O intervention are available like gravitation separation, enhanced gravitation separation, gas flotation and coalescency. For FPSO, gravitation separation will be more suited with hydrocyclone H2O intervention which uses centrifugal rule. Normally H2O handling equipment consists of oil separation, solid remotion, dissolved gas remotion and chemical intervention. ( sand mathew

From: Lecture notes of Ted Mason ( Enhanced gravitation separation with a hydrocyclone H2O intervention unit )


It ‘s required to travel the fluids from the reservoir to the finish ; either sale or disposal. Rarely the force per unit area of the reservoir can be utilised for that ; nevertheless mechanical systems are the really common in the production installation. They can be divided into

Prime movers- change overing beginning of energy into mechanical power.

Devices- pumps and compressor in the instance of liquids and gas severally.

Assorted premier movers used are


Electric Motors

Reciprocating Engines

Gas turbine is the lone type of turbine set up in offshore sector as premier movers. Gas from the centrifuge is used as fuel in gas turbine. Turbine is connected to DC generator for bring forthing electricity. In land procedure industry, steam turbines are besides employed to supply chief energy for pumping or compaction. The by and large frequent type of a reciprocating engine is the internal burning engine. This is a premier mover in this fuel is burnt in a different chamber or in the on the job rhythm in consecutive communicating with the cylinder.The electric motors are straightforward, holding higher efficiency and necessitate a little fix. ( sand, Mathew )

From: Lecture notes of David Arulananthum


Pumps utilized for increasing the caput of fluids that be transmitted from a lower force per unit area part to higher force per unit area part in the installations every bit good as in subsea. Normally reciprocating pump is employed in procedure installations.

Compressors are employed for increasing the force per unit area of gas and fluids to necessitate value. This pressurized gas and fluid are transferred to another portion of installations for processing. Surplus and jeopardies gas are flame by utilizing Flare. Mainly centrifugal compressors are made usage in procedure installations. ( unni )



This method consists of FPSO and shuttle oiler is the first pick to transport fluid from the field to on shore processing installation. Both FPSO and shuttle oiler are available on the rental from different companies, this will cut down capital disbursal. Other types of platform will be dearly-won for developing a fringy field like Tantalum field.

From: hypertext transfer protocol: //en.wikipedia.org/wiki/Floating_Production_Storage_and_Offloading

In FPSO is an seaward production installation consists of procedure equipments and a sufficient sum of storage capacity for the hydrocarbon and besides by utilizing dual hull to impede taint if any accident occurs. Generally FPSO ‘s processing installation will be located on top side and storage infinite in deck. From FPSO the oil is transferred through a Single Point Mooring System ( SPMS ) to the bird oiler. The oil is metered by mensurating device and pumped into oiler utilizing a flexible gum elastic piping. The major constituent of SPMS is anchored buoy by a rotatable turret that is fixed on large chromium steel steel roller bearings in order to do up gesture of oiler within current way. SPMS are connected to indicate of the oiler with jerk. Normally SPMS are positioned about 400-700 meters to a distance from drifting production storage and offloading. ( vinu Mathew

From: hypertext transfer protocol: //www.fesltd.co.uk/fluid.htm

The FPSO has got several advantages by implementing in this field. It has a bigger storage capacity for the produced oil and gas. It replaces the option of subsea grapevine for 50km and 502.5km in land line. This type of grapevines is really dearly-won. FPSO offers a solution for pull outing short Fieldss with fringy militias. ( Mathew, vinu, sandeep

From: hypertext transfer protocol: //www.fpso.net/index.html


This method consists of steel jacketed platform with subsea every bit good as land grapevine transit system are used for transporting fluid to onshore installation. These constructions are made up of immense cannular steel members. It will take burden from the topside and sea milieus. This type of platform are used were chiefly seabed are with significant more bed of soft, clay and silt. The platform needed four, six or eight hemorrhoids on each corner. It is necessary that drawn-out hemorrhoids needed to travel through the sedimentation of soft clay must be driven exactly and without any divergence. The pile driven templet is called as Jacket. A infinite frame construction will be put pinned together, this will steer goaded hemorrhoids from over the sea surface. Jacket will be placed on ocean floor with equal bearing force per unit area to do certain jacket stay steady and perpendicular. All the hemorrhoids will be able to oppose against tenseness as hydrodynamic force on construction have disposition to happen turn overing. This type of platform normally used in offshore where H2O deepness is shallow. The platform construction is fabricated from thorough design, fiction and review. Normally cathodic protections are used in this platform for corrosion protection. The size of heap is one to two meters diameter made up of steel pipe. This can perforate 100 meter into seabed. Sing pile design, some of information have to taken in history like heap wall thickness, spacing, diameter etc.This platform weights about 18,500 metric tons and will keep up 21,000 metric tons. Steel jacket platform can bear immense perpendicular burden and turn overing minutes. They are designed for resistant against tumbling from big moving ridges. Rigid risers are used in other than flexible risers. It will be attached in the platform construction. These constructions are apt to tire lading like whirl induced quiver and corrosion. It is of import that this construction should be designed right harmonizing to offshore location, H2O deepness, etc. ( david, twi, esru

From: hypertext transfer protocol: //www.esru.strath.ac.uk/EandE/Web_sites/98-9/offshore/steel.htm


Planing of partly processed fluid grapevine has to give certain consideration like:

Pipe line path choice

Flow analysis

Size of pipe

Material specification

Protection for grapevine

Care and operation

Pipeline environing restraint

Design criteria ‘s similar stableness and structural


Pipeline linking from Tantalum field to onshore terminus is done by two phases.

Phase 1: Subsea grapevine for 50 kilometers

In subsea grapevine building, major equipments required for building are trench vas, flatboat Crane for lifting, pipe puting vas, bearer flatboat and supply vas. There are different grade pipes are available in market which is used in both subsea and onshore grapevines. Normally carbon manganese steel is deployed for subsea grapevine. Trench will do by trench vas after that welded and inspected pipes are installed into trench by utilizing pipe puting vas. For protection of grapevine difficult stone is backfilled on it for intent of avoid buckling and prevent from external harm ( like angling cyberspace ) . ( Kraut

Phase 2: Onshore grapevine for 500 kilometers

In inshore grapevine building, there will be tonss of equipments to be used for case pipe bed, Crane, backhoe, boring machine, generator etc. Some of chief activities carried out are transit of pipes to site, study, grapevine trench digging, welding and non destructive trial, corrosion protection equipment installing, readying of trench for grapevine laying, installing, backfilling, mechanical equipment installing and eventually bind in to bing installations. Onshore grapevine working will be straightforward with comparing offshore, nevertheless many combative determination will lift for ecological importance and concern for private belongingss. For future care procedure, block valves and manholes should hold to supply. Automated control constituents are installed for observe from control room. Normally carbon steel stuff pipes are used in inshore grapevines. ( bp pdf



Design of FPSO is simple and modified appropriately for site status. The payback continuance for the FPSO is little respect as to productiveness. FPSO can be used efficaciously and good organized deployed in absence of platform. Capital investing can be reduced by renting FPSO. It have ain production storage and processing installation. So there will be no hold in production procedure. FPSO required a less investing compared to other platform because it does non needed decommissioning. FPSO can be disconnected from subsea manifold at any clip it is needed. This can be used for rather batch Fieldss. Subsea grapevines are eliminated by utilizing shuttle oiler, therefore it reduces entire cost. It can be widely used in deep H2O Fieldss. This can be normally used in fringy Fieldss. FPSO ‘s chief advantage is early production can be started in the field compared to other platforms. FPSO map is wholly trusting on the conditions status. Unfavorably weather can do close down of production due to capacity of FPSO exceed. Shuttle oiler capacity is restricted some volume due to vapour force per unit area bound. This has to be modified harmonizing to different fluid belongingss. FPSO ‘s production can be delayed due to shuttle oiler inaccessibility. Joining and dividing of the manifold can make jobs to vessel and environment. It has merely limited capacity of storage. ( Mathew unni


Steel jacketed platform will keep up monolithic perpendicular burden. It can defy really big moving ridge foreparts. It is chiefly used in oilfield where long life span required. Construction and design of both platform and grapevine is straightforward due to development in engineering. Platform required a less care. Cost for fiction and installing of platform is comparatively low other platform. Fabrication and installing of pipe is simple because of skilled labors and applied scientists. These grapevine can be shared with other parties can derive gross for the company. Capital investing for installations and building of platform are high. Construction and installing takes long continuance and delays the usage of field. Climate status is important for installing of platform. It is exposed to atmosphere will do corrosion, therefore care cost for subsea grapevines and equipments are rather high. This will non suitable for short life oilfields and deep H2O oilfields. Production life of field is about three old ages ; hence use of grapevine around 550km will non be economically executable. Construction and installing of platform every bit good as subsea grapevine will take long clip. If platform used for long clip so it can non be reused. Decommissioning is required for platform every bit good as grapevine. This will increase work and disbursal of undertaking. ( Mathew Kraut


From: hypertext transfer protocol: //www.corrosioncost.com/pdf/oilgas.pdf


Sing all the facts such as proficient, economical, operation safely and environmental analysis, FPSO will be more executable for fringy field like Tantalum. This field can be designed for optimal production and achieve indispensable fiscal result. Company need to put less initial capital and can get down production at the earliest.


ARULANANTHAM, D. , ADAM, A. , 2010. Facilities Lecture Notes. The Robert Gordon University, Aberdeen.

AMIN, A. et al. , 2008. Subsea Development from Pore to Process. [ on-line ] . Available from: hypertext transfer protocol: //www.slb.com [ Accessed 02 January 2011 ] .

University of Strathclyde. , 2009. Steel Jacket Structure. [ on-line ] . Available from: hypertext transfer protocol: //www.esru.strath.ac.uk/EandE/Web_sites/98-9/offshore/steel.htm [ Accessed 03 January 2011 ]

RIGZONE, 2009. How do Risers Work? . [ on-line ] . Available from: hypertext transfer protocol: //www.rigzone.com/training/insight.asp? insight_id=308 & A ; c_id=17 [ Accessed 03 January 2011 ] .

Vinu: FEE, D. , 1986 Technology for developing fringy offshore oilfields. London: New York. Elsevier Applied Science

FMC TECHNOLOGIES, 2008.CDS Separation engineering [ online ] Available from hypertext transfer protocol: //www.fmctechnologies.com/CDSSeparationTechnologies.aspx [ Accessed 10 December,2008 ]

Unni: ROSE, W. , 2001. Development program: Husky Energy. [ on-line ] . 2 Available from: hypertext transfer protocol: //www.huskyenergy.com/downloads/areasofoperations/eastcoast/DevelopmentApplication/Vol2_Operations.pdf

Kraut: www.offshore-technology.com

i‚•iˆ www.omega.com/techref/flowcontrol.html

i‚•iˆ www.petronyx.com