Gathering Center.docx 1p306s

Gathering Center There were originally 26 Gathering Centers in KOC operating oilfields prior to invasion of the country. The first center ‘GC-1’ was commissioned on 7th June, 1946 at Burgan Oilfield and the last center ‘GC-26’ on September 1980, at the Ratqa oilfield. Presently twenty-one (21) SEK has 14 Gathering Centres in operation. The overall effective production capacity of the SEK area from these 14 GCs is around 1600 MBOPD. The NK area has three GC's that handle about 650 MBOPD. In the West region, with the recent commissioning of GCs 27 & 28, the output capacity of this area has built up to near 440 MBOPD from the previous output of 160 MBOPD. Most of the crude oil produced from both these areas of North, West & SEK, flow naturally with associated gas and has low viscosity. Very few wells have heavy and viscous crude which require artificial lift systems (ie. Gas Lift, or Electrical Submersible Pumps) to assist the production. Introduction: Kuwait Oil Company manages the production and export of oil and gas with the associated facilities from more than twelve developed oil fields in the state of Kuwait. The oilfields spread over the State and split off into four main parts of North Field, West Field, South and East Field that are locally istered at the site headquarters. Approximate distance from Ahmadi: North Field is 70 miles (112 Km), West Field is 38 miles (60 Km) and South East Field is 12 miles (20 Km). The Company handles and maintain a comprehensive and fully integrated complex of production and export facilities that basically consist of the following: Oil Wellheads Oil Flowlines Gathering Centres Gas Booster Stations Pipeline Transit Systems Water Treatment and Injection Plants The Company also handles Artificial Lift operations and Water Injection Plants which both maintain KOC's oil wells productivity. Oil Wellheads Most of the wellheads in the oilfields are dual completed with parallel strings. There are approximately fifteen (15) different types of wellhead structures (X’mas-Trees)

installed in the oil fields with pressure ratings of 2000# to 15000#. In SEK, most of the hook-ups are rated at 2000# while typical hook-ups in NK have higher pressure rating of 5000# and those of WK oilfields vary from 3000# to 5000#. The Marrat wells in all fields have pressure ratings of 15000#. In the recent past horizontal test wells have also been drilled in SEK and NK areas to increase productivity of lower producing reservoirs. Oil Flowlines & Corridors Flowlines are multi-phase pipelines and transmit the well production (oil, gas and water) to the Gathering Centres where the three phases are separated. The flowlines are 6" in nominal diameter and laid above-ground along organized corridors to minimize cluttering, obstruction and unsafe conditions. The Sketch opposite illustrates a typical arrangement of pipelines corridors at the GC end. Gathering Center Facilities Gathering Centres are operational and receive crude from various wellheads located in the producing oilfields.The GCs stabilize the crude by multi-stage stabilization process and separate gas and water from the crude to meet its quality required for downstream operations. The wet crude is processed through multi-electro desalting facilities. Major mechanical equipment that handle all these processing activities in a Gathering Centre include: Gas Turbines, Pumps, Compressors, Generators, large & small volume Tanks and various types of Oil, Water & Gas Vessels. A Gathering Center (GC) is an Oil Production facility having the following functions: Serves as a central collection (Gathering) location of the Crude Oil Produced by several wells; High Pressure (HP) and Low Pressure (LP) via flow lines. Reduces the Crude Oil Well pressure to zero (atmospheric) to enable the Crude Oil to be transported by ship. Provides facilities for testing oil well production capacity. Provides initial treatment to the crude oil ie. - Separates the Hydrocarbon gas that is associated with crude oil deposits (multistage separators and tanks) - Wash the salts that are dissolved in the crude oil. Provides intermediate storage for the crude oil prior to its pumping to the main storage tanks.

Main Components of a Gathering Center Incomer Headers Separators Desalters Desalter Waste Water Handling System Crude Storage Tanks Crude Transmission Pumps Gas Handling Systems Well Testing Facilities Instruments and Controls

Incomers Headers The unprocessed crude oil from the oil-wells enters the Oil/Gas Separation Plant via the Production Headers. The Production Headers mix crude oil from different oil wells, stabilize flowing pressures and then distribute the oil flow to one or two stages of separation in the Plant. Seperators The Separators are pressure vessels with internals (baffles, demisters, foam/wave breakers, water weir & draw-off boot, etc.) designed to separate the hydrocarbon gases from the Crude Oil. The separation takes place in two stages, High Pressure Separators (1st Stage) which is kept at 300 Psig, and Low Pressure Separators (2nd Stage) which is kept at 60 Psig. Oil from low pressure wells flow directly to the second stage separators. The separation of associated gas and water from the crude oil is affected by gravity due to difference in densities of the streams. The fluid enters the oil/gas separators at a high rate of flow and pressure. The separators drop the pressure and the flow rate of the stream and then retain the fluid for a short period, normally 2 to 3 minutes, to reach its state of equilibrium and flash out the entrained gas. The internal mechanical devices provided in the separators facilitate the separation of

the phases (ie. gas and water from the crude).

Desalters Each GC has a Desalter Plant (DDP) to treat the wet crude to require specifications of 10 PTB Salt and 0.1% BS&W. The Water carried in the crude is normally salty and this salt water is mostly in the form of emulsion (droplets of water dispersed throughout the crude oil). The Desalter plants demulsify and remove this salt water in two stages (dehydration & desalting stages), first by providing settling time in a Wet Tank to allow the separation of the free water, then with the basic principles the process is further enhanced by washing with water, addition of chemicals and heat to break the emulsion and allow the water to settle more rapidly. The use of electric grid (electro-static) to coalesce the droplets is a final polish to the oil. The Wet Tanks are designed to reduce crude water cut from 25% to 10% at the outlet. The desalter plants are designed at maximum of 10% WC at the inlet.

Desalter Waste Water Handling System The separated water from the Desalter Plant is treated to remove residual oil before it is discharged into a Waste Water Disposal System. The treatment consists of removal of oil by means of simple gravity separation in a separator vessel packed with simple separation mechanism, followed by an air flotator which induces air to separate oil and/or other materials. The Air Flotation Unit is equipped with Flotator rotors, skimmers and the necessary transfer pumps. Chemical agent known as ‘Coagulant’ is added in the treatment process at the Flotation Unit to enhance this separation. The floated oil and material are skimmed out and returned to the Wet Crude Tanks and the treated water is discharged to the disposal pit (evaporation pond) located outside the GC. To meet the environmental requirements, the oil concentration in the water is normally reduced to 10 ppm by volume or below. At some areas, the Effluent Water is collected together from a number of GCs and transferred to a Centralized Water Injection Plant where it is further chemically treated and then injected into disposal wells. See Effluent Water Injection Plant for elaboration of this scheme

Crude Storage Tanks The Crude Storage Tank acts as a third stage Oil/Gas Separator and is operating at a pressure slightly above the atmospheric. The gas vapour from the tanks is sent to the Tanks Vapour Compressors (TVC). In the event of TVC shutdown the gas is sent to the LP Flare. The oil from the tank is pumped to Ahmadi Tank Farm. Crude Transmission Pumps Crude oil from the Dry Tanks is exported to Ahmadi Tank Farms via a network of transit pipelines and mixing manifolds. The crude is normally pumped from each GC by two sets of main pumps operating in parallel. The crude flowrate from the main pumps is either controlled by driver speed adjustment or by a Flow Control Valve at the pumps discharge. The pumpsets provided in the GCs are driven by ‘Ruston’ Gas Turbine or Electrical Motors.

The first ‘Ruston’ Gas Turbine was installed at GC-11 in 1957. This turbine got damaged during the invasion and had to be taken out of service. Prior the invasion the turbine had completed a record performance with a credit of 168,042 running hours. This Turbine has been refurbished and now on display at KOC Al-Tameer Building in Ahmadi, to commemorate its accomplishment Gas Handling Systems

Two similar but separate Gas Handling systems are provided in every Gathering Center. These are: High Pressure System: to handle the high pressure gas from the 1st Stage Separator. Low Pressure System: to handle the low pressure gas from the 2nd Stage Separator. The gas in each system is separately pressure regulated, metered (flow, pressure, temperature) scrubbed (to clean and tap hydrocarbon liquid residue) and sent to the Booster Stations, with provision of facilities to divert the flow to Flare, if required. Flaring is allowed only during emergency and process upset conditions at the GCs or when production rates exceed facilities capacities Well Testing Facilities The testing facilities are used for: Production Tests of well zones (ie. casing, tubing)Gas Oil Ratio (GOR) Test of well zones (ie. casing, tubing) Dekilling a zone in case of failure to flow Depressurizing a flow line for maintenance purpose and consist of: Test Headers First and Second Stage Test Separators Test Tank The principle of oil-wells testing is based on flowing and stabilizing the well through the test separators for some time and then let it run through a Test Tank over a certain period of time to measure its oil potential, amount of gases and water separated. Pressures and temperature readings are recorded automatically during this period. Oil, gas and water flow rates are then calculated separately. The oil flow is compensated with pressure and temperature readings. During the well test, no fluids are pumped out of the tank. GC Instrumentation and Controls The instrumentation used in all GCs is ‘electronic’ with the latest state-of-the-art control and monitoring system known as ‘DCS’ (Distributed Control System). There are four types of DCS systems that provide this control and monitoring functions in the GCs. It can be any of the following equipment: Foxboro I/A DCS System Rosemount RS3 DCS System

Honeywell TDC-3000 System ABB System Signals from primary measuring devices and ‘smart-transmitters’ in the field are relayed directly to remote indicating / recording / controlling operator consoles in the control room. The control outputs from this operator station are relayed to the final control element in the field via terminals, marshalling s and junction boxes. Likewise, signals generated in the Field are relayed back to the control room via the same route. All these signals are electronic type in the form of discreet inputs and outputs. Fire and Gas monitoring is also provided from the control room. Any signals generated from devices within the GC Plant are sent to this central facility to generate alarms. In the event of a Fire or Gas detection, automatic shutdown of the equipment or process facility is implemented. The sketches overpage show the key features of the typical DCS Systems installed at some of the GCs. The sketch also illustrates the process variable path route from the Control Room DCS to the Process Plant in the Field and vice versa.

Functions of Booster Stations A Booster Station is part of an oilfield facility installed to fully utilize the separated gas from the Gathering Centers which was previously wasted to flare. Typically, a Booster Station has the following functions: Receives the gas from various Gathering Centers and compresses it. Separates the condensate from the gas stream. Dehydrates (removes water) from both compressed gas and condensate. Receives and dehydrates condensates from the Gathering Centers. The compressed gas and condensate are transmitted separately through pipelines to Mina Al-Ahmadi LPG PLant, where the transmitted gas and liquid is processed to recover Gasoline and Liquefied Petroleum Gases (LPG) and exported. After Processing at the LPG Plant, effluent gas (known as lean gas) is distributed as fuel gas to industrial s in Kuwait (ie. Power Stations and Refineries) and the excess is utilized for fueling the oilfields GCs and/or flared in dedicated excess flares.

Booster Station Process Flow Scheme