1. Petro Data Mgt III- Facilities Petroleum Professor Collins Nwaneri

2. Introduction History about the origin of Oil: The first oil well discovery was drilled by colonial Edwin Drake in 1859 in northwestern Pennsylvania. The wells were shallow at less than 50 meters deep and produced oil were collected in wooden tanks. After the oil discovery, oil replaced most other fuels for motorized transportation. The automobile industry which was developed at the end of the 19 th century, adopted oil as fuel. Gasoline oil was essential for successful aircraft engine design. Ships driven by oil moved twice as fast as their coal powered counterparts. Gas was burned off or left in the ground. 2

3. Introduction Pipelines were constructed to natural gas and the petrochemical industry increased production. Refineries were built to divide the crude in fractions. Gasoline from crude was about 10 -40 % a century ago and with modern refineries, it can be up to about 70 % due to advanced reforming and cracking processes. Afterwards, came the petrochemical industry at around the 1940’s, and chemicals were derived from petroleum and natural gas. Thereafter, plastics, rubber and several household goods were developed, amongst other products to date. 3

4. Facilities and Processes Oil and gas facilities and systems are defined as per their use in the following oil and gas industry production stream: Exploration: means the prospecting, seismic and drilling activities that occurs prior to a field development. Upstream: Refers to all facilities for production and stabilization of oil and gas. Normally, for upstream this includes: wellhead, well, completion and reservoir only, and downstream of the wellhead as production or processing Midstream: defined as gas treatment, LNG production and regasification plants, and oil and gas pipeline systems. Refining: crude oil and gas, which includes condensate are processed into marketable products such as gasoline, diesel or feedstock for the petrochemical industry. Offsite storage tanks and distribution terminals are included in this segment. Petrochemical: This are chemical products such as plastics, fertilizer from by-products of hydrocarbons. the 4

5. Exploration Currently, this involves using surface geological mapping and advanced sub-surface surveying method such as passive seismic, reflective seismic, magnetic and gravity surveys to help identify potential hydrocarbon rocks. In the past, surface indications such as tar seeps or gas pockmarks gave clues for shallow hydrocarbon locations. Offshore wells typically costs between $10 to $100 million range. Offshore rig leases are typically in the range of $200,000 to $700,000. U.S onshore wells cost about $4 million. ( normally have lower production capacity) A shallow wells at marginal fields can be drilled for as little as $100,000. Therefore oil and gas companies carry out analysis on exploration data from this first drilled wildcat wells for good indication of source rocks and hydrocarbon potential, amongst other things such as probable down-hole pressure for safe drilling of other wells Furthermore, if a find is made, additional requirement production testing, drilling appraisal wells, et.c, to determine the size and production capacity of a well before developmental wells are drilled. 5

6. Production The following diag. is an overview of typical oil and gas production facilities: Fig A: Oil and Gas Production Facilities 6

7. Production The following diag. is an overview of a typical production facility. This varies in size and type. Fig B: Oil and gas production overview Disc… 7

8. Production Many part of the processes in a production facilities are similar despite the oil and gas production rate per day. The diagram in Fig. B shows production and test manifolds (called a gathering system in a distributed production) placed next to the wellheads. A gas oil separation plant (GOSP) that takes a well stream of hydrocarbon from natural gas, condensate and crude oil and unwanted elements such as water, salt, sand e.tc for separation. Utility systems are not part of actual processes in facilities, but they provide the energy, water, air or other types of utility as needed in facilities. 8

9. Onshore Onshore gas and oil production is economically viable with oil production capacity from wells as high as thousands of barrels per day. This is connected to a 1,000,000 barrel or more per day GOSP. The oil product from this facilities are distributed by pipelines or tankers; and can also be stored. Oil from the smallest reservoir can be collected in holding tanks and transported for processing at the refinery via tanker trucks or railcar. Gas gathering network can be large due to production from thousands of wells. 9

10. Onshore The following onshore unconventional plays can be exploited: Heavy crude can be extracted by heating and use of diluents. Tar sands can be strip-mined or extracted with steam. It should be followed processed to separate bitumen from sand. Shale gas and oil have being produced by advances in drilling technology and hydraulic fracturing. 10

11. Offshore A whole range of various type of structures are used offshore, and this depends on size and water depth. More recent structures includes sea bottom installations with multiphase piping to shore and no offshore topside structure at all. The following are examples of common offshore structures: 1. Shallow water complex: has several independent platforms with different parts of processes and utilities linked with a gangway bridge. - Examples of individual platforms are wellhead, riser, processing and power generation platforms. (See Dia. A) - Found in water depths of up to 100 meters 2. Gravity base: fixed concrete structures placed on the bottom with oil storage cells on the sea bed. (See Dia. B) - Has a large deck with all parts of the process and utilities in large modules. - Typically used for large fields I about 100 to 500 meters water depth about 20 -30 years ago. 3. Compliant towers: has flexible narrow towers attached to a seafloor foundation that can operate in deeper water depths unlike the fixed platforms. (See Dia. B) - Typically used in about 500 TO 1000 meters water depth. 11

12. Offshore 3. Floating production: All topside systems are located on a floating structure with dry or subsea wells. Examples are: FPSO (Floating Production, Storage and Offloading) -FPSO main advantage is that they are standalone structures and does not need external infrastructure such as pipelines or storage. -They currently produce about 10,000 to 200,00 barrels per day. -Typically tanker type hull or barge and can be used In water depths of more than 100 meters. -Wellhead or subsea risers used in some FPSO are centrally located for ease of rotation to point into winds, waves or current. -Anchors (positioning mooring-POSMOOR) or Thrusters (dynamic positioning- DYNPOS) can be used to hold FPSO in place on the water. -Most FPSO installations use subsea wells. -Main processes are placed on deck and hulls are used for storage and offloading to a shutter tanker. The hull can also be used for pipeline transportation. -In the future, FPSO with additional processing and systems, required for drilling, production and stranded gas LNF are planned. -One variation of FPSO is Sevan Marine design. (Circular hull has many characteristics of a ship-shaped FPSO, but does not rotate. (See Dia. D and C) 12

13. Offshore 4. Tension Leg Platform (TLP): consists of a structure held in place by vertical tendons connected to the seafloor by pile-secured templates. (See Dia. E2) - Held in a fixed position by tensioned tendons. - can be used in water depths of up to 2000 meters. 5. Semi-submersible platforms: have a similar design but without taut mooring. - Has more lateral and vertical motion and generally used with flexible risers and subsea wells. (See Dia. E1) 6. SPAR: They are single tall floating cylindrical hull, with a fixed deck. - cylinder hull does not extend to the seabed and is anchored to the bottom by cables and lines. (See Dia. F) - Used for water depths from 300 to 3000 meters. - can support dry completion wells and mostly used with subsea wells. 7. Subsea production systems: have wells located on the seafloor or seabed rather than the surface. (See Dia. G) - hydrocarbon is extracted at the seabed and “tied-back” to pre-existing production platform or onshore facility (depends on horizontal distance or offset). - After Wells are drilled, produced hydrocarbons are transported by undersea pipeline and riser to processing facilities. Allows for more production handling from more wells in a large area. - Used in water depths of 500 meters or greater. - cannot be used to drill, bit to extract and transport. 13

14. Common offshore structures Dia. A Dia. BDia. C Dia. E1 & 2Dia. F Dia. D Dia. G 14

15. Upstream Process sections We will introduce the activities and processes after a producing wellhead in an upstream section. 1. Wellheads: Sits on top of the oil or gas well leading to the reservoir. Can be used as an injection well for water or gas injection into the reservoir for pressure maintenance to increase production. Well is normally completed after drilling for flow of oil or natural gas to the surface. Well flow from the wellhead is controlled by a choke. Dry completion (onshore or deck of offshore structure) Subsea completion below the water surface. Wellhead structure (often referred as Christmas tree) should allow for production and work-over activities. 2. Manifolds and gathering: Onshore, individual well streams are brought into the main production facilities over a network of gathering pipelines. Used to select the best producing wells at anytime due to their well flow composition (oil, gas and water). 15

16. Upstream Process sections Gas gathering systems can be metered at the individual gathering lines into the manifold. Multiphase phase flows measurements can use flow-meter or be automated. Offshore, dry completion wells on the main field center, feed directly into production manifolds. Outlying wellhead towers and subsea installations feed via multiphase pipelines back to the production risers 3. Separation: Wells with pure gas can be taken directly for gas treatment and/or compression. Wells with combination of gas, oil and water, with various contaminants must be separated. Production separators come in different forms and design. (Classic variant is the gravity separator). 4. Metering, Storage and Export: Most plants do not allow local gas storage. Oil is often stored before offloading to shuttle tankers for further handling. Offshore production facilities without direct pipeline store crude oil in base or hull then offloads to shuttle tankers for further handling. 16

17. Upstream Process Sections Meters are used to monitor and manage natural gas and oil exported from production installation (i.e. oil and gas flow measurement) The metered volume represents a transfer of ownership from a producer to a customer. (This is referred as custody transfer metering) Custody transfer metering is used for sold product invoicing and also for production taxes and revenue sharing between partners. Metering installations consists of multiple meter runs to accommodate full capacity range. 17

18. Upstream Stream Processes 5. Utility Systems: Are not used in hydrocarbon process flow, but provide service some service to the main process safety and residents i.e. electricity, water e.tc. 18

19. Midstream This is normally made up of gas plants, LNG production and regasification, and oil and gas pipeline transport systems. Fig. C 19

20. Midstream 1.Gas Plants: Handle the separation of various hydrocarbons and fluids from pure natural gas to produce “pipeline quality” dry natural gas. Natural gas is treated before it can be transported and sold. Natural gas that is separated from crude oil, is normally made up of mixtures of ethane, propane, butane and pentanes. Water, H2S, CO2, helium, nitrogen, et.c are examples impurities found in raw natural gas. NGL “Natural gas liquids” (Associated hydrocarbons) are used in oil refineries or petrochemical plants and as sources of energy. 2. Gas Compression: A means to push gas from gas separators outlets because of low gas pressure in order to move the gas through pipelines for transportation. Examples of compressors are: Turbine driven compressors (use natural gas and turbines) and electric driven compressors. Scrubbers (liquid droplets removal), heat exchangers, lube oil treatment e.tc are examples of equipments used in compression stations. 20

21. Midstream 3. Pipelines: Measure anywhere from 6 to 48 inches in diameter. Pipelines are normally inspected for corrosion and defects with “pigs”. Pigs intelligent robotic equipment used to test pipe thickness, roundness, check for corrosion, detect leaks, e.tc. Export facilities normally have depressurization equipments, pig launchers to insert pigs and pig receivers to receive pigs in pipelines. 4. LNG liquefaction and regasification facilities: Involves the cooling of natural gas at (-162 deg. C) into liquid form for transportation to other facilities when a pipeline is not available or it is not economical. A regasificatiion terminal is at the receiving end for the LNG conversion into vapors for pipeline transportation. Compressed natural gas (CNG) is mainly natural gas with methane that is compressed to liquid at normal ambient temperature. 21

22. Refining They use a distillation column to separate crude into fractions of a defined range of products. The quantity and quality of this end products depends on the crude used. Refinery operations often include distribution terminals for product dispensing to bulk customers such as airports, gasoline stations, ports and industries. 22

23. Petrochemical Petrochemical plants produce thousands of chemical products. The main feedstock is natural gas, condensate (NGL) and other refinery by-products such as napthan, gasoil and benzene. Petrochemical plants are divided into three main primary product groups as per their feedstock and primary petrochemical product. 1.Olefins: main source of plastics, industrial chemicals and synthetic rubber. 2.Aromatics: source of plastics, synthetic detergents and dyes. 3.Synthesis gas: used to make ammonia e.g. fertilizer and methanol. Also used in other processes such as Fischer- Tropsch process that produces synthetic diesel. 23

24. Reservoir and wellheads There are 3 main types of convectional wells. -Oil well with associated gas. -Natural gas wells with little or no oil. -Condensate wells with natural gas and liquid condensate. No need for artificial lift installation for most natural gas and condensate well. Oil wells need artificial lift installation with decline in reservoir pressure during years of production. Unconventional wells are created from tight reservoirs with low porosity and varying maturity that creates shale oil and gas, tight gas, heavy oil, etc. 24

25. Crude oil and natural gas Crude Oil: -A complex mixture of various organic compounds. (Mostly alkanes and smaller fraction aromatics). -API gravity is a measure of the specific gravity or density of a particular crude. -Higher the API number (in degrees), the less dense (lighter) the crude and vise-versa. -Crudes from different fields and different formation within a field be similar in composition or largely different. -Crude oil is also characterized for undesired elements like sulfur. -Crude oil API gravities range between 7 to 52 (Most fall between 20 to 45 API gravity range). -Light crude (40 – 45 degrees API) may be the best, but the lighter the crude the Shorter and Less molecules it contains for high octane gasoline and diesel fuel production that are needed for maximum production by refineries. -Heavy crude (less than 35 degree API) has longer and bigger molecules that are not useful as high octane gasoline and diesel fuel without more processing. 25

26. Crude oil and natural gas - API gravity is not used meaningfully for mixed crudes of different type and quality or different petroleum components, except for fluid density measurement. This is unlike, natural crude oil that has not being mixed, blended e.tc. -Heavy crude can be processed by cracking an reforming to reduce the carbon number in order to increase the high value fuel yield. Natural gas: -Natural gas used by consumers contain almost entirely methane. -Wellhead natural gas is not pure. -Natural gas comes form three types of wells (Oil wells, Gas wells, and condensate wells). The following are classification of natural gas per source. 1.Associated gas (Oil well) 2.Free gas ( gas expansion from oil) or dissolved gas ( dissolved in oil) 3.Non-Associated gas (gas wells or condensate wells with little or no oil) -Natural contains mixture of other hydrocarbons such as: ethane, propane, butane, pentane and impurities such as water vapor, hydrogen sulfide (H2S), carbon dioxide, helium, nitrogen and other compounds. 26

27. Crude oil and natural gas Condensate: - Made up of NGL (ethane, propane, butane, iso-butane and natural gasoline). They are sold separately and used as raw materials for oil refineries or petrochemical plants, as a source of energy and for enhance oil recovery. -They are also useful as diluents for heavy crude. 27

28. Reservoir and wellheads The reservoir: See section 3.2 (Discuss in class) Exploration and Drilling: See section 3.3 (Discuss in class) The Well: See section 3.4 (Discuss in class) Wellhead: See section 3.5 (Discuss in class) Artificial lift: See section 3.6 (Discuss in class) Well work-over, intervention and stimulation 28