UNIT 1
LIFE OF WELL
An oil well is a term for any perforation through the Earth's surface designed to find and release both oil and gas hydrocarbons.
Lead-in
Life of a well can be divided up into five segments. What are they (in Russian)? List the words in English and place the blocks according to the life stages of a well:
Terms and Vocabulary
abandonment ( )
completion
downhole pressure
drilling fluid
drilling rig
drilling site
enhanced recovery
oil rig
production zone
reservoir
produce (v)
workovers
Pay special attention to the pronunciation of the following words.
| secure tubular | reservoir | redundant | permeability | artificial |
| remedial [rimi:djel] | technique | liability | prohibitive | access |
| tertiary |
Pay attention to the underlined stress in the following words.
Ef fect ce ment in te grity re servoir per mea bi lity re me dial tech nique lia bi lity
Define the following terms with their similar meaning in Russian.
| Hydrocarbons | natural | compressor | paraffin | coil |
| tubing | technique | concrete cement |
You are going to learn some vocabulary to help you understand the text. Study the following dictionary entries, paying attention to specific term definition.
Well
1. An open space extending vertically through the floors of a building, as for stairs or ventilation.
2. An abundant source.
3. A mineral spring.
4. A container or reservoir for a liquid, such as ink.
5. A deep hole or shaft sunk into the earth to obtain water, oil, gas, or brine.
Screen
1. The movie industry.
2. A body of troops or ships sent in advance of or surrounding a larger body to protect or warn of attack.
3. A movable device, especially a framed construction such as a room divider or a decorative panel, designed to divide, conceal, or protect.
4. A coarse sieve used for sifting out fine particles, as of sand, gravel, or coal.
Collar
1. A necklace.
2. An arrest, as of a criminal (slang).
3. The part of a garment that encircles the neck.
4. A restraining or identifying band of leather, metal, or plastic put around the neck of an animal.
5. Any of various ring-like devices used to limit, guide, or secure a machine part.
Hole
1. A fault or flaw.
2. An animal's hollowed-out habitation, such as a burrow.
3. An ugly, squalid, or depressing dwelling.
4. A hollowed place in something solid; a cavity or pit.
5. An opening or perforation.
Completion
1. A forward pass that is caught by a receiver.
2. The act of finishing or the state of being finished.
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Washout
1. A total failure or disappointment.
2. One who fails to measure up to a standard, especially one who fails a course of training or study.
3. Erosion of a relatively soft surface, such as a roadbed, by a sudden gush of water, as from a downpour or floods.
Read the following texts and do the exercises.
Drilling
The well is created by drilling a hole 5 to 30 inches (1376 cm) in diameter into the earth with an oil rig which rotates a drill bit. After the hole is drilled, a steel pipe (casing) slightly smaller than the hole is placed in the hole, and secured with cement. The casing provides structural integrity to the newly drilled wellbore in addition to isolating potentially dangerous high pressure zones from each other and from the surface. This process is all facilitated by a drilling rig which contains all necessary equipment to circulate the drilling fluid, hoist and turn the pipe, control downhole pressures, remove cuttings from the drilling fluid, and generate onsite power for these operations.
Terms and Vocabulary
drilling
oil rig
drill bit
Hole , ,
steel pipe (casing)
secure(v)
cement
integrity
drilling rig
drilling site
circulate fluid
hoist
downhole pressure
drilling fluid
cuttings
Completion
After drilling and casing the well, it must be 'completed'. Completion is the process in which the well is enabled to produce oil or gas. In a cased-hole completion, small holes called perforations are made in the portion of the casing which passed through the production zone, to provide a path for the oil to flow from the surrounding rock into the production tubing. In open hole completion, often 'sand screens' or a 'gravel pack' is installed in the last drilled, uncased reservoir section. These maintain structural integrity of the wellbore in the absence of casing, while still allowing flow from the reservoir into the wellbore. Screens also control the migration of formation sands into production tubulars and surface equipment, which can cause washouts and other problems, particularly from unconsolidated sand formations in offshore fields.
After a flow path is made, acids and fracturing fluids are pumped into the well to fracture, clean, or prepare and stimulate the reservoir rock to produce hydrocarbons into the wellbore. Finally, the area above the reservoir section of the well is packed off inside the casing, and connected to the surface via a smaller diameter pipe called tubing. This arrangement provides a redundant barrier to leaks of hydrocarbons as well as allowing damaged sections to be replaced. Also, the smaller diameter of the tubing produces hydrocarbons at an increased velocity in order to overcome the hydrostatic effects of heavy fluids such as water.
In many wells, the natural pressure of the subsurface reservoir is high enough for the oil or gas to flow to the surface. However, this is not always the case, especially in depleted fields where the pressures have been lowered by other producing wells, or in low permeability oil reservoirs. Installing a smaller diameter tubing may be enough to help the production, but artificial lift methods may also be needed. Common solutions include downhole pumps, gas lift, or surface pump jacks. The use of artificial lift technology in a field is often termed as " secondary recovery " in the industry.
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Terms and Vocabulary
completion
produce (v)
cased-hole completion
perforation
production zone
production tubing a -
hole completion
gravel pack
screen
formation sand
production tubular a
washout ,
unconsolidated sand
fracturing fluid
reservoir rock -
reservoir section
leak ,
redundant , ,
depleted field
producing well
permeability
artificial lift methods
secondary recovery
Production
The production stage is the most important stage of a well's life, when the oil and gas are produced. By this time, the oil rigs and workover rigs used to drill and complete the well have moved off the wellbore, and the top is usually outfitted with a collection of valves called a "Christmas Tree". These valves regulate pressures, control flows, and allow access to the wellbore in case further completion work needs to be performed. From the outlet valve of the Christmas Tree, the flow can be connected to a distribution network of pipelines and tanks to supply the product to refineries, natural gas compressor stations, or oil export terminals.
As long as the pressure in the reservoir remains high enough, the Christmas Tree is all that is required to produce the well. If the pressure depletes and it is considered economically viable, an artificial lift method mentioned in the completions section can be employed.
Workovers are often necessary in older wells, which may need smaller diameter tubing, scale or paraffin removal, repeated acid matrix jobs, or even completing new zones of interest in a shallower reservoir. Such remedial work can be performed using workover rigs also known as pulling units to pull and replace tubing, or by the use of a well intervention technique called coiled tubing .
Enhanced recovery methods such as waterflooding, steam flooding, or CO2 flooding may be used to increase reservoir pressure and provide a "sweep" effect to push hydrocarbons out of the reservoir. Such methods require the use of injection wells, and are used when facing problems with reservoir pressure depletion, high oil viscosity, or can even be employed early in a field's life; in certain cases depending on the reservoir's geomechanics reservoir engineers may determine that ultimate recoverable oil may be increased by applying a waterflooding strategy early in the field's development rather than later. The application of such enhanced recovery techniques is often termed as "tertiary recovery" in the industry.
Terms and Vocabulary
production ,
workover rig
refinery
workovers
scale
acid matrix jobs
shallower reservoir
pulling unit
waterflooding ( )
steam flooding
recoverable oil ,
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remedial
injection well
oil viscosity
enhanced recovery
tertiary recovery
Abandonment
Finally, when the well no longer produces or produces so poorly that it is a liability to its owner, it is abandoned. In this simple process, tubing is removed from the well and sections of well-bore are filled with cement as to isolate the flow path between gas and water zones from each other as well as the surface. Completely filling the well-bore with concrete is unnecessary and cost prohibitive.
