Introduction to Offshore

Oil and Gas Surface Facilities

By Puput Aryanto Risanto

17 November 2015

Rev.1 4 October 2016

Upstream Oil & Gas Life Cycle

ExplorationExploration• Activities to search for oil & gas deposit on the

certain location beneath the earth surface

AppraisalAppraisal• Activities to define the oil & gas volume and

characteristic more precisely after discovery

• Activities to build the subsurface & surface facilities

DevelopmentDevelopment• Activities to build the subsurface & surface facilities

to produce oil & gas safely and efficiently

ProductionProduction• Activities to extract, process, and export oil & gas

as per contract agreement

AbandonmentAbandonment• Activities to plug wells permanently, remove surface

facilities, and restore the field as per initial state

Exploration� Once the Oil Company is granted a permit to conduct the

business from the government (through host authority), they must start with exploration.

� Exploration is an activities to detect oil & gas presence beneath the earth surface by means of gravity survey, magnetic survey, and seismic reflection survey.

� Seismic surveys work on the principle of the time it takes for reflected sound waves to travel through matter (rock/soil) of varying densities and then translated into a for reflected sound waves to travel through matter (rock/soil) of varying densities and then translated into a profile of the earth soil & rock layers, sometimes called seismic imaging.

� In offshore, seismic survey is done by a seismic vessel.

� Finally, when an indication of oil & gas presence (prospect) exists based on the evaluation, it must be followed by a “drilling” activity to conclusively determine the presence or absence of oil & gas inside the reservoir (a subsurface “pool” where fluids trapped between layer of soils & rocks).

Seismic Vessel

Seismic Imaging

Drilling� Drilling is activities to create a hole from the earth surface to the

reservoir target in the earth subsurface.

� Based on the purposes, drilling can be divided into :

� Exploration : to find the oil & gas reservoir

� Appraisal : to further confirm the reservoir volume and characteristic

� Development : to produce oil & gas from the reservoir

� Injection : to inject fluids (gas,water,chemical,etc) into the reservoir

� A set of machines for drilling is called drilling rig.� A set of machines for drilling is called drilling rig.

� Based on the structure housing the drilling equipment set, offshore drilling rig can be classified into :

1. Bottom supported� Self-contained platform rig

� Tender Assisted Drilling (TAD) rig

� Jack Up (JU) rig

� Inland barge (swamp-barge) rig

2. Floating � Semi-submersible rig

� Drill ship

Drilling Rig (Sketch-1)

Drilling Rig (Sketch-2)

Development� Once significant hydrocarbon volume is confirmed, field

development plan / Plan of Development (FDP/PoD) will be proposed to monetize the oil & gas deposit.

� FDP shall contain :

� Method of oil & gas volume calculation including uncertainties

� Method of hydrocarbon recovery and estimated recovered volume (number of oil & gas that can be lifted through out Method of hydrocarbon recovery and estimated recovered volume (number of oil & gas that can be lifted through out the field life / contract period)

� Surface facilities to extract, process, and export oil & gas

� Operation and Maintenance philosophy

� Cost, Schedule, and Economic calculation

� Abandonment Plan

� FDP is subject to host authority (government appointed body for upstream oil & gas regulation) and shareholders approval

Surface Facilities Definition

� In offshore oil & gas industry, term “Surface” is defined

above the mud-line, or simply seabed / ocean floor /

bottom sea (including several meter below seabed).

� Surface Facilities can be defined as a set of systems

and equipments to extract, process, and export oil &

gas in a safe, controlled, and efficient way which are gas in a safe, controlled, and efficient way which are

located on the surface.

� Generally, surface facilities consists of 2 sections :

� Substructure : a steel structure to support the upper part

(called topside) including the foundations.

� Topside : an integral part of steel deck (can be single or

stacked) and all equipment placed on it, supported by a

substructure.

Topside and Substructure

Topside

Substructure

Pipeline

Substructure Types

In general, substructure can be divided into :

1. Fixed Type (bottom supported the seabed)

� Jacket

� Compliant Tower

� Jack Up� Jack Up

� Gravity Based Structure

2. Floating Type (float on the sea surface)

� Mono/Single Hull

� Semi Submersible (Semi Sub)

� Tension Leg Platform (TLP)

� SPAR

Fixed Substructure - Jacket

Welded tubular space frame with near vertical legs with bracing system between

legs. Piles will be inserted inside legs, hence the tubular frame will act like a “jacket”

covering piles. Jacket can have 3 up to 12 legs, but majority is 4 legs. Jacket is the

most common offshore substructure. The deepest jacket is Shell Bullwinkle at 412

m water depth on US Gulf of Mexico / GoM.

Fixed Substructure - Compliant

Flexible (compliant) tubular space frame with flexible elements to mitigate natural

forces. This tower can be free standing or supported by guy wires. The deepest

installation is Chevron Petronius (US GoM) at 623 m below sea level.

Fixed Substructure – Jack Up

Movable floating hull and three or more legs, which can be moved up and down

relative to hull. For operational mode, legs must be lowered to the seabed, then

raising the hull to the required elevation. Water depth for jack up installation depends

on the legs length, but normally below 100 m. Jack up can be easily moved and is

normally used on a marginal / small field with short production life (below 5 years),

sometimes also called MOPU (Mobile Offshore Production Unit).

Fixed Substructure – Gravity Based

Fixed structures that are held-in-place by its own weight plus any contained ballast,

majority constructed from steel-reinforced concrete, normally called CONDEEP

(concrete deep water structure), majority installed in Norway. The deepest structure

is Statoil Troll-A (Norway North Sea) at 303 m water depth.

Floating Structure – Monohull

Monohull is a type of vessel with only one hull. The hull may be in the form of normal

vessel (ship-shaped) or cylindrical (circular like a bowl) secured by sets of moorings

and anchors. It can have a liquid storage, hydrocarbon processing, and liquid

transfer to tanker capability, hence called FPSO (Floating Production Storage

Offloading). If no processing facility, it is called FSO (Floating Storage Offloading).

The deepest one is FPSO Stones (US GoM) at 2896 m water depth.

Floating Structure – Semi Sub

Semi submersible is floating structures with several columns (vertical hull) and

pontoons (horizontal hull) which can be controlled in such a way that pontoons

become fully submerged and column partially submerged, while the topside remains

above the water line, and secured with spread moorings and anchors. This will

increase the stability and station keeping. Semi sub platform sometimes called sFPS

(semi-sub Floating Production Station), FPS, or FPU (Floating Production Unit). The

deepest FPS is Chevron Jack/St. Malo (US GoM) at 2134 m water depth.

Floating Structure – Tension Leg Platform

TLP is a floating structure, normally in the form of semi-submersible, which is

vertically moored to anchors by a set of tubular steels called tendons. The tendons is

constantly in tension by floating structure buoyancy and tensioner system. The

tension leg keeps the platform very stable, hence surface wellhead can be installed.

The deepest TLP is Chevron Big Foot (US GoM) at 1581 m water depth.

Floating Structure – SPAR

SPAR is floating platform with a deep-draft (most of the section is submerged) large

vertical cylinder hull, completed with heavy ballast on the bottom to ensure center of

gravity is below center of buoyancy, secured with spread moorings and anchors. The

deep-draft design makes it very stable and suitable for surface wellhead. SPAR can

also store liquid. The deepest SPAR is Shell Perdido (US GoM) at 2450 water depth.

Summary of Substructure Types

Surface Facilities Function� Surface facilities function can be described as :

� Extraction : Facilities to extract oil & gas from the reservoir

into surface in a safe and controlled manner.

� Processing : Facilities to process “raw oil & gas / well

stream” into “treated” crude oil and/or natural gas as per

customer requirement.

� Exporting : Facilities to export treated/processed oil and/or � Exporting : Facilities to export treated/processed oil and/or

gas to customer receiving point.

� In offshore platforms, those functions are done by :

� Extraction : Wellhead Platform (WHP)

� Processing : Central Processing Platform (CPP)

� Exporting : Pipeline, F(P)SO, FLNG

� In addition, Living Quarter is provided to accommodate

operation & maintenance crew 24/7.

Wellhead Function� Wellhead : A termination point of a well (a series of tubular

steel running from the surface up to certain target on the reservoir, referred as the bottom hole) on the surface that provides the structural and pressure-containing interface for the drilling and production equipment.

� During drilling, surface pressure control is provided by a Blow Out Preventer (BOP).

� Once drilling completed, surface pressure control is � Once drilling completed, surface pressure control is replaced by a “Christmas Tree” installed on top of the wellhead, with isolation and choke valves to control the flow of well fluids during production.

� Normally, wellhead & Christmas tree is located on the platform and can be easily operated by man, called surface wellhead or dry tree.

� However, for deep water or when platform installation is considered not cost-effective, wellhead & Christmas tree may be located on the seabed, called subsea wellhead or wet tree.

WHP, surface wellhead, & dry tree

Surface

wellhead &

Christmas tree

Subsea wellhead & wet tree

Processing Function� Not like many people think that “oil & gas” reservoir contains

only oil and/or gas, actually it always contain oil, gas, water, and sometimes other contaminants like nitrogen (N2), carbon dioxide (CO2), hydrogen sulfide (H2S), mercury (Hg), and salt.

� Oil & gas molecules are actually constructed from the same elements, Hydrogen (H) and Carbon (C), hence referred as Hydrocarbon. Oil is hydrocarbon mixtures which form liquid at room temperature (25oC), whereas gas is hydrocarbon mixtures which form gas at room temperature.which form gas at room temperature.

� Well fluids coming from the reservoir are actually a mixture of all above fluids in a high pressure and temperature.

� Meanwhile, the customers (downstream industry) require separate treated oil (crude oil) & gas (natural gas) for further processing.

� Processing function is to separate oil, gas, and water, then treat oil and gas to meet customer specification, and treat water for overboard discharge (release to the sea) or re-inject to the reservoir.

Processing Block Diagram

Process System

It is defined as all the system required to process well stream into crude oil and natural gas.

In general, it consists of :

� Separation : to separate well stream into oil, gas, and water

� Gas Dehydration : to further remove water from gas

� Gas Treatment : to remove contaminants from gas

� Gas Conditioning : to regulate gas condition like temperature & dew point

� Gas Compression : to compress (increase pressure & reduce volume) gas so � Gas Compression : to compress (increase pressure & reduce volume) gas so it can travel in a long distance to customer receiving point

� Gas Metering : to measure the volume of gas export as a basis of company revenue

� Oil Dehydration : to further remove water from oil

� Oil Stabilization : to further remove gas from oil

� Oil Desalting : to remove salt content from oil

� Oil Pumping : to pump (increase pressure only without reducing volume) oil so it can travel in a long distance to customer receiving point

� Oil Metering : to measure the volume of oil export

� Produced Water Treatment : to remove oil, gas, and other contaminants from produced water until meeting certain criteria for disposal to the sea

Utility SystemIt is defined as all the system required to support process system. It is as important as

process system itself, since system malfunction may reduce, stop, or even endanger

the production. In general, it consists of :

� Power generation & distribution : to generate & distribute electrical power to the

electrical equipment

� Instrumentation : to measure and monitor process and utility parameters & provide

input to the control system

� Control : to regulate process and non-process system as per requirement

� Heating : to provide heat to hydrocarbon, i.e. crude oil heating for easier flow

� Cooling : to remove heat from hydrocarbon, i.e. gas cooling after compression

� Instrument Air : to compress air and distribute it for instrumentation & control purpose

� Utility Air : to compress air and distribute it for general purpose, i.e. for compressed

air powered hand tool

� Gas Fuel : to condition natural gas for gas powered engine, i.e. Gas Turbine

Generator

� Diesel Fuel : to store and distribute diesel fuel for diesel powered engine, i.e.

Emergency Diesel Generator

Utility System - continued� Drain : to collect and store any excess process and non-process liquid

� Fresh & Potable Water : to treat sea water into fresh (plain but not drinkable) and

potable (drinkable) water

� Fire & Gas : to detect fire & gas leakage and provide warning and input to control

system

� Fire Water System : to provide fire water for fire extinguishing

� Emergency Shutdown : to provide facilities to safely stop the process (shutdown) in

case of any emergencycase of any emergency

� Flare : to provide a safe way to remove and burn excess gas

� Vent : to provide a safe way to remove excess gas without burning it

� HVAC (Heating Ventilation and Air Conditioning) : to provide conditioned air to

enclosed room, i.e. control room

� Telecommunication : to provide telecommunication and remote control/monitoring of

remote facilities

� Crane and Mechanical Handling : to lift and move heavy equipment within platform or

from/to boat

� Marine (only for floating structure) : to control stability and movement of floating

structure

Living Quarter (LQ)In general, accommodation or LQ has facilities :

� Bedroom : number of beds defines maximum number of people can stay

� Galley : also called dining room where people gather for meal and rest

� Kitchen : for safety reason, only electric stoves allowed in offshore platform

� Meeting Room : teleconference capability with onshore office is a must

� Office : normally, only Offshore Installation Manager (OIM) has dedicated room

� Bathroom : normally shared male bathroom, only OIM and VIP guest room have own-bathroom inside the bedroom

� Clinic : sufficient medication and facility to manage emergencies� Clinic : sufficient medication and facility to manage emergencies

� Multi Purpose Room : can be used for sport, recreation, and praying

� Helideck : for helicopter/chopper take off and landing, with/out refueling facility

� Boat Landing : for boat/vessel landing to transfer personnel or light equipment/material

� Emergency Life Boat : for emergency escape if platform damage due to fire or other disaster

� Radio Room : for telecommunication equipment installation

� Material Storage : to store spare equipment, spare parts, and consumables

� Control Room : to remotely control and monitor process parameters

� Maintenance Workshop : to maintain and repair equipment, but normally only minor repair due to limited facility

CPP-only side view illustration

CPP with drilling & LQ illustration

Exporting Function

� Crude oil and natural gas will be evacuated from offshore

platform to onshore receiving facility (ORF) through a

pipeline.

� Pipeline is a long pipe for conveying fluids (oil and/or gas) .

� Offshore pipeline will be placed on the seabed.

� Offshore pipeline may be insulated to keep fluids warm and � Offshore pipeline may be insulated to keep fluids warm and

coated with concrete to add stability and protection.

� If oil pipeline is considered too expensive or no available

ORF, offshore storage may be considered using FSO,

FPSO, or subsea storage, then stored oil exported to oil

shuttle tanker.

� Same case for gas, offshore gas storage may be

considered using Floating Liquefied Natural Gas (FLNG),

then stored liquefied gas exported to LNG shuttle tanker.

Surface Facilities Selection� Selection will be based on several factor, mainly :

� Number and type of wells

� Production capacity and field life

� Water depth and seabed condition

� Nearby and onshore receiving facilities

� Oil & gas evacuation strategy

� Health Safety Environment philosophy

� Operation & Maintenance philosophy

� Contractor capability

� Local regulation

� Cost and schedule

� Technology availability and maturity

� Concept selection will be conducted during

development stage and the result will be part of FDP.

Separate bridge-linked jacket

Integrated WHP-CPP-LQ in single jacket

Separate bridge-linked jacket with FSO

FPSO with wet tree

Semi submersible with wet tree

Tension Leg Platform with dry tree

Have you ever imagine…???

Troll A, the largest and tallest object ever moved by mankind. Overall height is

472 m (20 m taller than Petronas Twin Towers) and the weight is 683,600 tons

Have you ever imagine (again)…???

Katie Melua, a

British female

singer, performed

a concert at the

bottom of Troll A

platform at 303 m

below sea level

as a celebration

of 10 years of 10 years

operation by

Statoil in 2006,

break another

record for the

deepest

underwater

concert on the

earth.

About the AuthorPuput Aryanto Risanto had more than 12 years experience in oil & gas industry. Currently he is working for Premier Oil NatunaSea B.V. in Jakarta, Indonesia. Previously he worked for Petronas Carigali Sdn. Bhd. in KL, Premier Oil Natuna Sea B.V. in Jakarta and Total E&P Indonesie in Balikpapan, Indonesia. Total E&P Indonesie in Balikpapan, Indonesia.

His expertise included project engineering & management,

joint venture management, engineering & construction

management, & electrical engineering-construction-

inspection. This presentation was small contribution to

educate the public during low oil price environment. He can

be contacted at aryantorisanto@yahoo.com