Lecture 5 (Week 7) Production Operations Facilities Sep 2024 PDF

Hisham Ben Mahmud, PhD Department of Petroleum Engineering [email protected] Office: B-12-03-39 Lecturer Profile o Name: Hisham Khaled Ben Mahmud o Position: Associate Professor o Department: Petroleum Eng. o Research interest: Well & Reservoir management, flo...

Hisham Ben Mahmud, PhD Department of Petroleum Engineering [email protected] Office: B-12-03-39 Lecturer Profile o Name: Hisham Khaled Ben Mahmud o Position: Associate Professor o Department: Petroleum Eng. o Research interest: Well & Reservoir management, flow assurance, CCS, and hydrogen storage. 2 Lecture Content o Introduction Subsea Hardware o Describe major surface production facilities o Describe wellhead components o Treatment process of produced water and storage facilities. 3 Learning Outcomes At the end of this lecture, students should be able to: o Identify major surface production facilities o Explain functions of wellhead and X-tree components o Describe Oil and Gas separation processes and equipment o Identify the purpose of artificial lifts in context of well management o Describe produced water treatment process and different types of storage facilities 4 SURFACE FACILITIES SUBSEA DEVELOPMENT CONCEPT The basic equipment common to many surface processing facilities include: o Wellhead and manifold o Separators o Condensate stabilization o Acid gas treater o Well testing equipment o Lease automatic custody transfer (LACT) o Oil treaters o Water treaters o Pumps & Compressors o Gas dehydrator 5 Surface Facilities Subsea Development Concept Introduction Subsea Hardware Compressor station Gas export Oil storage Gas pipeline injection o The fluids produced from Oil export pipeline wells are usually directed through flow lines and Gas injection Wellhead manifold manifolds (gathering system) tubing & casing Water press. disposal well to a central location for processing and treatment. 6 Surface Facilities Subsea Development Concept Subsea Hardware Manifold o When the production of two or more wells is commingled in a central facility. o It is necessary to install a manifold to allow the production of the wells into the common production line or the well test line. 7 Example of Surface Manifold https://www.weldfit.com/products-services/performance-products/headers-manifolds 8 Surface Facilities Subsea Development Concept Subsea Hardware Wet Tree Flowline Umbilical Umbilical. (Courtesy: Technip.) 9  Example Subsea Manifold Fabrication of Subsea Manifold Subsea Manifolds https://www.singatac.com.sg/portfolio/fabrication-of-subsea-manifold-dual-header-6-slot/ https://www.openpr.com/news/3347156/subsea-manifolds-market-seeking-excellent-growth- technipfmc 10 Well Head o Gathering system begins at the wellhead. o Wellhead should include at least one choke used to control well production. o If upstream pressure is too high, it is recommended to use a positive choke in series with an adjustable choke. In case the adjustable choke fails, the positive choke keep the production limited. o Automatic shut-down valve can quickly interrupt production in case of an event. o Block valves are also required to perform regular maintenance on the choke. 11 Different Types of Well to be Found Each flowing wellhead, although differing in detail and exact configuration, is made up of the following components: 1) Casing Head, supports the surface casing. 2) Tubing head, this supports the production tubing and is attached to the top of the casing head with a flanged joint. 3) Christmas Tree, fixed to the top of the tubing head with a flanged joint. 4) Adjustable Choke Valve. This is located downstream of the wing valve and controls the rate of flow of crude from the well. 12 Christmas Tree (Xmas Tree) Christmas Tree, fixed to the top of tubing head and consists of the following: 1) Lower Master Valve. It is kept fully open and is used as the emergency shut-in valve. 2) Upper Master Valve. It is used to open or shut-in the well. It is equipped with a pressure-controlled actuator. 3) Wing Valves. One or two wing valves may be fitted depending on whether the Christmas tree has one flow outlet or two flow outlets. It is used to open and shut off the flow of crude oil to the production line. It is always opened after the upper master valve and closed before it. 13 Christmas Tree (Xmas Tree) 4) Swab Valve. Isolates the tree-top adopter from the well. Only open when carrying out wireline work. 5) Tree-top Adapter. Attached to the top of Christmas tree and is used to locate the wireline equipment when carrying out downhole maintenance work. 6) Tubing Pressure Gauge. Usually fitted to the tree-top adaptor and tubing pressure gauge measures pressure in the production tubing. 7) Casing Pressure Gauge. Measures pressure in the tubing annulus. 14 Wellhead Platform Remotely Wellhead Platform Xmas trees hooked up to flowline. Choke valves drived by hydraulic oil 15 Manifolds and lineed up automated valves Test Separator Wellhead panel SURFACE FACILITIES PROCESS DESIGN 16 Flow Diagram o Process Flow Schemes of flow charts are commonly used to present details of process. It is very important to understand symbol convention used in those charts 17 Process Design o Design of equipment depends on Physical Properties, Phase Behavior and Flow of Hydrocarbon Fluids. o Physical Properties affecting equipment design are vapor pressure, density, molecular weight, viscosity, surface tension, composition and gas/liquid volumes. o Phase Behavior is the change in relationship between phases at various conditions. o Fluid Flow properties affecting transmission system design are: viscosity and type of flow. 18 Physical Properties Physical properties o Density o Viscosity o Formation volume factor o Compressibility o Thermal expansion o Surface tension Need to predict pressure-volume-temperature (PVT) behavior of gas to estimate its properties Techniques used to predict PVT behavior are o Equation of State (EOS) o Corresponding States Principle o Empirical Correlations 19 Fluid Flow Transport properties of oil and gas are significant in the design of equipment and flowlines o Viscosity - indicates fluids resistance to flow o Reynold's number - used to identify flow regime o Laminar Flow exist at Re < 2000 o Turbulent Flow exist at Re > 4000 20 SEPARATION SYSTEM 21 Surface Facilities Oil Processing Basic Separation 22 Oil Processing Basic Separation o Separation is required - gas and liquid require different processing methods. o Separators are classified by physical shape, function or number of phases they separate. o Separator separate a combined liquid-gas flow Two-phase gas and liquid separation Three-phase gas, liquid and water separation Scrubber: Handles stream with unusually high Gas-Liquid Ratios (GLR) Water knockout: Separates free water Filter: Removes solids from gas/liquid stream 23 Oil Processing Separator Gas Liquid Tw o Phase Three Phase 24 Vertical Separator Advantages o Liquid level and fluids control not critical o Easier and cheaper to design for surge capacity o Can handle solids with certain design o Easier to clean Disadvantages o Expensive o Does not adapt to skid mounted assemblies well o Requires larger diameter for same gas capacity. https://kimray.com/training/4-types-three-phase-separator-vessel-design 25 Horizontal Separator Advantages Horizontal Three- phase Separator o More adaptable to skid-mounting With Overflow Weir o More available area for settling o More adaptable to accommodate heating coils or sand jets o Can more effectively handle foamy crude o Less expensive Horizontal Three-Phase Separator with Oil Disadvantages Bucket and Water Weir o Has less liquid surge capacity o Liquid level control is more critical 26  Multistage Separation o Oil and gas separation carried on in several stages at successively lower pressures. o More stages of separation the fluids go through the more perfect overall separation will be. o Separation efficiency increases resulting in higher percentage of recoverable liquids. Figure shows typical stage separation process. https://missrifka.com/equipments/stage-separation-of-gas-condensate.html 27 Gas Separation System o Gas and condensate flow from wellheads to the 3-phase production separator which separate water from the condensate and gas. o Gas is then sent to the glycol dehydration system, condensate to condensate Flash Tank and produced water to skimmer. o Produced gas is dried by contacting it with Triethylene Glycol (TEG) liquid. o Condensate from Flask Tank is passed to Coalescer which allow nearly total removal of remaining produced water 28 WATER TREATMENT 29 Water Treatment Two primary needs for water processing: Disposal o Treatment of produced water separated from oil and gas prior to disposal in an environmentally acceptable manner. Injection o Cleaning of source water from rivers or sea before wellbore injection in EOR projects to minimize zone plugging and maintain high injection rates. 30 Water Treatment o The contents of an oil reservoir may be considered as consisting of three major components gas, crude oil and water. Of these three, gas and oil are saleable products, whereas water unless used for injection purposes, is a WASTE PRODUCT. o The water, separated from the oil and gas in the platform separation trains, is known as PRODUCED WATER. o Before Produced Water can be either disposed of into the sea or used for injection purposes it requires treatment. 31 Surface Facilities Water Treatment 32 Water Treatment Water collected from processing facilities contains: o Suspended oil droplets o Dissolved gases o Entrained solids Selected treatment and disposal method determines: o Water quality target at minimum cost and o Satisfies applicable rules, regulations or laws. 33 Demonstration videos https://www.youtube.com/watch?v=wQ1A8w9Ouy4 https://www.youtube.com/watch?app=desktop&v=WGFPb61qm9I https://www.youtube.com/watch?v=HDBUS_ebFHQ&t=2s 34 PRODUCTION SUPPORT FACILITIES 35 Production Support Facilities Artificial Lift System o Completed producing wells will usually produced fluids from wellbore to the surface by means of natural reservoir energy. o Artificial lift is supplemented into well tubing pressure during their Economic Life in order to obtain maximum recovery of oil for maximum profit before its Economic Limit of producing life is reached. o Notable exceptions are wells completed in a prolific water drive reservoir where wells may continue to flow until as much as 100 % saltwater production is obtained. Usual experience is that a well will require some means of artificial lift. 36 Surface Facilities - Production Support Facilities Artificial Lift System Hydraulic Lift 37 Artificial Lift System Criteria Sucker Rod Pump Progressing Cavity Pump Gas Lift Maximum operating 16,000 6,000 15,000 depth, ft TVD Operating fluid volume, 20 5,000 5 4,500 250 30,000 bbl/day Maximum operating 550 250 400 temperature, oF Corrosion handling Good to excellent Fair to good Good to excellent Gas handling Fair to good Good Excellent Solids handling Fair to good Excellent Good to excellent Fluid gravity, oAPI >8 < 35 > 15 Servicing Workover or pulling rig Workover or pulling rig Wireline or workover rig 0 90o landed pump; 0 90o landed Wellbore deviation 0 70o short to medium radius 15o/100 ft build angle pump;15o/100ft build angle Prime mover Gas or electric Gas or electric Compressor Offshore application Poor Good Excellent 38  Criteria Plunger lift Hydraulic lift Electric submersible pump Maximum operating depth, 17,000 (piston) 14,000 15,000 ft TVD 15,000 (jet) Operating fluid volume, 50 4,000 (piston) 50 200 200 30,000 bbl/day 300 > 15,000 (jet) Maximum operating 500 500 400 temperature, oF Corrosion handling Excellent Good to excellent Good Gas handling Excellent Fair to good Poor to fair Solids handling Poor to fair Poor to good Poor to fair ___ Fluid gravity, oAPI >8 > 10 Servicing Wellhead catcher or wireline Hydraulic or wireline Workover or pulling rig 0 90o pump placement; 0 90o pump placement, Wellbore deviation 80o