Covenant University Petroleum Production Engineering I - PDF

COVENANT UNIVERSITY DEPARTMENT OF PETROLEUM ENGINEERING PETROLEUM PRODUCTION ENGINEERING I PET 318 (ALPHA SEMESTER 2024/25 SESSION) ENGR. S. B. IPINSOKAN Course Contents 1. Surface gathering system - Separation and separators 2. Introduction to sand production, and Detection 3. Oil sample Upgradi...

COVENANT UNIVERSITY DEPARTMENT OF PETROLEUM ENGINEERING PETROLEUM PRODUCTION ENGINEERING I PET 318 (ALPHA SEMESTER 2024/25 SESSION) ENGR. S. B. IPINSOKAN Course Contents 1. Surface gathering system - Separation and separators 2. Introduction to sand production, and Detection 3. Oil sample Upgrading through blended Operations 4. Introduction to Coiled Tubing (CT) 5. Basic Well Completion Design and Practices 6. Well hard wares (Wellheads and Christmas tree, chokes, packers and valves) 7. Production Platforms Corrosion and Erosion 8. Perforation Operations – bullet perforation; jet perforation.  Introduction The oil and gas industry is usually divided into three major sectors: upstream, midstream and downstream. The upstream sector: includes the searching for potential underground crude oil and natural gas fields, drilling of exploratory wells, and subsequently drilling and operating the wells that recover and bring the crude oil and/or raw natural gas to the surface. The midstream sector: involves the transportation (by pipeline, rail, barge, oil tanker or truck), storage, and wholesale marketing of crude or refined petroleum products. Pipelines and other transport systems can be used to move crude oil from production sites to refineries and deliver the various refined products to downstream distributors. The downstream sector: commonly refers to the refining of petroleum crude oil and the processing and purifying of raw natural gas as well as the marketing and distribution of products derived from crude oil and natural gas. The downstream sector touches consumers through products such as gasoline or petrol, kerosene, jet fuel, diesel oil, heating oil, fuel oils, lubricants, waxes, asphalt, natural gas, and liquefied petroleum gas Surface Production (from wellhead todownstrea m) Petroleu Vertical flow Performance (from wellbore to m Wellhead) Productio n Inflow Performance (from reservoir System to wellbor e)  Wellheads - Drilling During drilling process : The well is controlled by a BOP and choke manifold As the well is drilled :Each annulus is sealed off by the wellhead 5  Wellheads - Completed well After the tubing is installed : The BOP's are removed Xmas Tree The Christmas tree is installed to control the flow from the well Wellhead 6  What does a wellhead do ? 1 HANG-OFF WEIGHT 2 CONTAINS PRESSURE 3 MONITOR THE WELL SAFETY PROVIDE A BASE FOR THE 4 XMAS TREE 7  Well  Head The wellhead consists of the pieces of equipment mounted at the opening of the well to manage the extraction of hydrocarbons from the underground formation.  It prevents leaking of oil or natural gas out of the well and also prevents blowouts caused by high pressure.  Formations that are under high pressure typically require wellheads that can withstand a great deal of upward pressure from the escaping gases and liquids.  These wellheads must be able to withstand pressures of up to 20,000 pounds per square inch (psi).  The wellhead consists of three components: A- The casing head (Including casing hangers & Casing head spool) B- The tubing head (Including Tubing hangers & Tubing head spool) C- The 'Christmas tree.’ Surface gathering system Once oil and gas are brought to the surface, our main goal is to transport them from the wellhead to the refinery (for final processing). Starting at the wellhead, the complex mixture of produced fluids makes its way from the production tubing into the flow line. Normally, many wells are drilled to effectively produce the hydrocarbons contained in the field. From each of these wells emerge one or more flow lines depending on how many layers are being produced simultaneously. Depending on the physical terrain of the area and several other environmental factors, each of the flow lines may be allowed to continue from the wellhead to a central processing facility commonly referred as a production platform or a flow station, which then carries the fluids to the production platform.  Surface gathering system The combination of the wellhead, gathering lines, flow lines, bulk headers, valves and fittings, and processing facilities needed to collect and transport the produced fluid to the production platform is referred to as the gathering system. Together, the system moves oil or natural gas from the wells to the main storage site/ facility, or processing plant. There are two types of gathering systems, namely: the radial and the trunk line gathering systems  Hook-up & Flow Line ▶ In using a pipe, the dimensional requirements must be confirmed with the ASME (American Society Of Mechanical Engineers) before it is used for conveying Liquid, Gas or anything that flows. ▶ The selection of a flow line depends on the Flowing and the shut-in pressure-temperature, and the flow rate. ▶ The size of the flow line may vary from 1 inch to 24 inches with various Schedules (ex. 40, 80, 160) including Valves and Flanges with various classes ( ex. 150, 300, 600, 900, 1500, 2500).  Flow line Material ▶ The most common flow line material is carbon steel and Stainless steel. ▶ Stainless steel differs from carbon steel by the amount of chromium present. ▶ Unprotected carbon steel rusts readily when exposed to air and moisture; This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide. ▶ Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion by blocking oxygen diffusion to the steel surface and blocks corrosion from spreading into the metal's internal structure; the most preferable type of stainless steel is the Duplex and specially at gas wells.  Flow line Material ( Carbon Steel ) ▶ Carbon steel is the most common pipe material in hydrocarbon industries. ▶ Carbon steel is steel in which the main interstitial alloying constituent is carbon in the range of 0.12– 2.0%; As the carbon percentage content rises, steel has the ability to become harder and stronger through heat treating. ▶ Steel pipe is generally used for pressure piping. The advantages include long laying lengths, high internal and external strength and the availability of varying pipe thickness to meet almost any design pressure. ▶ The most serious disadvantage is its low resistance to corrosion which makes it a requirement for internal and external protection, with galvanizing the most commonly used method. Flow line Material ( Duplex Stainless Steel) ▶ Duplex steel combines the advantages of ferritic and austenitic steel. ▶ It has excellent resistance to the various corrosive media that are typically found in both onshore and offshore environments. These mainly include CO2, H2S gases, chlorides, low ph conditions, and water. ▶ Its high strength is extremely beneficial in dealing with the high pressures. ferriti Duple c x Flow Line Fittings Flow Line fitting main objectives:- 1. Produce change in geometry 2. Modify flow direction 3. Bring pipes together 4. Alter pipe diameter  Flow Line Fittings ▶ The most common types of Flow line Fitting are as follow: 1. Elbow : It is a pipe fitting installed between two lengths of pipe or tube allowing a change of direction, usually 90° or 45°. 2. Tee-Connection : is used to either combine or split a fluid flow. Most common are tees with the same inlet and outlet sizes.  Flow Line Fittings (Cont.) 3. Reducer : is used to Change the piping diameter. 4. Gasket : is soft material used to be inserted between two flanges. 5. Expansion Joints : are used in piping system to absorb thermal expansion. Others are Flanges, Valves etc.  Venturi Device ▶ The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe. ▶ As fluid flows through a venturi, the expansion and compression of the fluids cause the pressure inside the venturi to change. ▶ An equation for the drop in pressure due to the Venturi effect may be derived from a combination of Bernoulli's principle and the continuity equation. ▶ A venturi can be used to measure the volumetric flow rate (Q) :  Oil and Gas Separation As a well stream flows from the hot, high-pressure petroleum reservoir, it experiences pressure and temperature reductions. Gases evolve from the liquids and the well stream changes in character. The velocity of the gas carries liquid droplets, and the liquid carries gas bubbles. The physical separation of these phases is one of the basic operations in the production, processing, and treatment of oil and gas.  In oil and gas separator design, we mechanically separate from a hydrocarbon stream the liquid and gas components that exist at a specific temperature and pressure. Proper separator design is important because a separation vessel is normally the initial processing vessel in any facility, and improper design of this process component can “bottleneck” and reduce the capacity of the entire facility. Separators are classified as “two-phase” if they separate gas from the total liquid stream and “three-phase” if they also separate the liquid stream into its crude oil and water components  Separators are sometimes called “gas scrubbers” when the ratio of gas rate to liquid rate is very high. Some operators use the term “traps” to designate separators that handle flow directly from wells. In any case, they all have the same configuration and are sized in accordance with the same procedure.  Factors affecting separation Characteristics of the flow stream will greatly affect the design and operation of a separator. The following factors must be determined before separator design; 1- Gas and liquid flow rates (minimum, average, and peak) 2- Operation and design pressures and temperatures. 3- Surging and slugging tendencies of the feed streams. 4- Physical properties of the fluids such as density and compressibility. 5- Designed degree of separation (e.g., removing 100% of particles greater than 10 microns). 6- Presence of impurities (paraffin, sand, scale, etc.). 7- Foaming tendencies of the crude oil. 8- Corrosive tendencies of the liquids or gas.  Production Separators An oil and gas production separator is a pressure vessel that is used for separating the fluid components of an oil and gas well stream into both gaseous and liquid constituents. Separation of the oil and the gas phase enables the handling, metering, and processing of each phase independently, hence producing marketable products. The objective is to achieve a gas phase free of liquid droplets.  an oil phase free of gas carryover water droplets. a water phase free of gas carryover and oil 2 3 2 4 Potential Operating Problems Foaming crude Paraffin build up Sand accumulation Liquid carryover Gas blowby Formation of emulsions 2 5  CLASSIFICATION OF SEPARATORS By orientation: horizontal, vertical, spherical By phase separation: 2-phase, 3-phase By application: production separator, test separator By function: separator, free water- knockout, scrubber By operating pressure: high, medium, low 1- High pressure separators [1500 psi] 2- Medium pressure separators [650 psi] 3- Low pressure separators [60 psi] 2 6  1. Based on Orientation-Vertical Separator Has good solid handling capabilities. They require a smaller footprint, making them suitable for installations where space is limited, such as offshore platforms or compact onshore facilities. The potential for the liquid to re- vaporize into the gas phase is limited due to the significant vertical distance between the liquid level and the gas outlet. For Low GOR Liquid level control is not critical Can handle more sand, paraffin and wax without plugging 27  Disadvanta ges Without ladders or access platforms, several equipment and safety devices may be difficult to reach. In comparison to the horizontal separator, a larger diameter separator is required for a comparable gas capacity. Not recommended when there is a large slug potential 2 8 Horizontal Separators 2 9  Advantages They have a higher liquid/gas interface and hence offer better phase separation. The price of the horizontal separator is lower than that of the vertical separator Can handle large volumes of gas Good for foaming crudes Disadvanta Good for 3-phase separation ges Level control is critical and should be maintained Does not handle solids well Cleaning is challenging 48 3 1  Capacity of a vertical separator In field units: Gas capacity: Qgsc = 67824 * 10-6 d² c [(ρo - ρg) / ρg ] 0.5 sc / zTpsc) (p T Qgsc = gas flow rate at standard condition, MMScf/day d = inside diameter of separator, ft p = separator operating pressure, psia p = standard pressure = 14.7 psia T = separator operating temperature, oR ρg = p Mw / zRT o o o Tsc = standard temperature = 520 R, ( R = F + 460) γg = Mw gas / Mw air = Mw gas / 29 ρgsc = psc Mw / RTsc API = (141.5/γo) – 131.5 Oil Capacity: Qor = 100.7 d² ho / t Qo actual = actual oil capacity bbl/day Qor = rated oil capacity under separator condition bbl/day t = retention time, minute  Introduction to sand production, and Detection  Sand Control A Petroleum Engineer should ask the Question: Do we expect any sand from the well? If so how much and when? What are we going to do to stop it?  Sand production occurs when the overburden stresses round perforations or the wellbore exceed the sand strength.  The overburden stress increases with drawdown as the reservoir pressure helping to support the rock  Sand Production Sand production leads to numerous problems –erosion of downhole tubulars –erosion of valves, fittings and flowlines –clogging of surface process equipment –the well-bore filling-up with sand –collapsed casing as a result of lack of formation support. – disposal problems particularly in offshore So: fields Sand Prediction, and Control is a key requirement in many fields:  Predicting Sand Production “FIST” is the Shell in-house sand prediction tool and uses core strength data, and log strength data (sonic logs, porosity logs) to predict a failure envelope. The envelope indicates at what conditions of a drawdown and reservoir pressure sand failure may occur and under what conditions sand production may become excessive. PT (petroleum engineer or technologist) uses a programme called FIST (Fully Integrated Sand prediction Tool). The input consists of core and log measurements of rock properties.  Sand Control Techniques Passive approaches Maintenance and workover Rate exclusion Selective completion practices Active approaches Chemical consolidation High energy resin placement Consolidated gravel Slotted liners or screens Gravel packing Frac & Pack Completion Types with no Sand Control Perforate Barefo d ot Cased Hole  Sand Control Screens Slotted liner or screen provides a down hole Plugging a problem filter With Poorly Sorted Material Sand “bridges” on holes in the screens while production flows through. Bridging Sand production is often With Well Sorted Material not prevented by screens and failure/erosion can still be a problem  Screens work like filters and are designed in such a way that the slot opening is twice the median grain diameter, so that particles bridge over the opening. In this way, the particles don’t plug the slot, but leave sufficient porosity open between the particles to allow flow into the screen. It may mean that some sand is produced until the bridging is established.  However, if the particles are poorly sorted, then the pore spaces may be plugged off by smaller particles leading to lower productivity. When screens are used in horizontal wells, the annulus is open, which makes it difficult to do any remedial work on the formation like pumping acid to stimulate production or dissolve filter cake. However, running screens in open hole is cheaper than running casing, cementing it  Screen Types Wire Wrapped Screen Prepacked Screen Excluder Screen  Expandable Screen/Slotted Tubular A pipe has overlapping slots cut into it and is expanded by pulling or pushing a cone through the screen. It easily opens up forming a tight fit with the casing or hole. A much finer slotted tubular is sandwiched between 2 normal slotted tubulars in order to have a small slot width for sand control.  Gravel Packing Historically, the most widely applied sand control technique Uses high permeability gravel in conjunction with slotted liner or screen Cased Hole Open Hole Specially sized gravel Gravel Pack Gravel Pack is packed into perforations and  Gravel Packing Gravel packing is basically a downhole filter to stop sand production. It should work better than just a downhole screen, because gravel pack sand (rounded sand particles in range of 200 - 1200 microns in diameter) is pumped into the annulus between the screen and the formation (see next slide for a close-up). The gravel pack sand is squeezed against the formation sand to stop it moving and ensures good sand control, with reduced risk of  Internal Gravel Pack Perforations Gravel Wire Casing Wrapped Screen Cement Formation  Internal Gravel Pack The gravel pack sand is made of rounded sand particles in range of 200 - 1200 microns in diameter). The sand grains should be well rounded and similar in size, with