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Файл:Нефтегазовое дело. Бурение скважин (на английском языке) = Oil and gas drilling engineering through English. Учебное пособие.pdf
– Dispersants, including iron lignosulfonates, break up solid clus-
ters into small particl es so they can be carried by the fluid.
cles to group together so they can be removed from the fluid at the
formations.
Student 10
Professor, where may air and foam fluids be used in drilling wells?
Professor
On land, air and foam fluids may be used in drilling wells. These
rilling muds and can enter smaller
pores more easily. They are used when a higher rate of penetration
uid, however, these fluids cannot exert the same pressure in the
ters liquid in the formation. For this reason, air and foam fluids are
ferred in these situations because these fluids are
much less expensive than other fluids.
Student 11
Professor, why must a casing be desig ned properly?
Professor
Casing is cemented to pre vent migrati on of fluids behind the casing
features and equipment will be installed during the completion
process for production: perforations will allow reservoir fluid to
Casing is important for both the drilling and production phases of
operating, and must therefore be designed properly. It prevents
wellbore and facilitates the movement of equipment up and down
the hole.
Student 12
Professor, what considerations are involved in planning the casing?
Professor
First, the bottom of the wellbore must be large enough to accommodate any pumping equipment that will be needed either upon
– Flocculants, primarily acrylic polymers, cause suspended parti-
surface.
– Surfactants, like fatty acids and soaps, defoam and emulsify the
mud.
– Biocides, typically organic amines, chlorophenols or formaldehydes, kill bacteria th at may produce toxic hydrogen sulfide ga s.
– Fluid loss reducers include starch and organic polymers and limit
the loss of drilling m ud to unde r-pr e s sur iz ed or hig hly -permeability
fluids are less viscous than d
into the formation is desired. Because air is less dense than a liq-
hole as liquid, and their viscosity can be altered if drilling encoun-
used only in relatively low-pressure and water-free drilling locations, but are pre
and to prevent communication of higher pressure productive formations with lower pressure non-productive formatio ns . Addi ti onal
enter the wellbo re; tub ing strin gs wil l c arry th e flu id to the su rfac e;
packers (removable plugs) may be installed to isolate productive
zones.
natural gas, oil and associated brine from leaking out into the surrounding fresh -water aquifer(s), limits sediment from entering the
61
commencement of pumping, or in the later years of production. Also, unusually pressurized zones will require thicker casing in that
immediate are
a. Any casing strings that fit within this string must
ment. Finally, the driller is encouraged to keep the hole size to a
minimum; as size increases, so does cost and waste.
Student 13
Professor, we’d like to know about th e casing functions, what are
they? Tell us, plea se .
Professor
As the hole is drilled, casing is placed in the well to stabilize the
hole and prevent caving. The casing also isolates water bearing and
s. In locations where surface soils may
cave in during drilling, a “conductor” casing may be placed at the
face. This string is often placed prior to the commencement of
water aquifer(s) from the incursion of oil or brine from greater
ntermediate” string begins at the surface and ends
ment of equipment used in the hole, for example drill strings and
tools. The final “production” string extends the full length
of the wellbore and encases the downhole production equipment.
Shallow well may have only two casing strings, and deeper wells
may have multiple intermediate casings. After each casing string
been installed, cement is forced out through the bottom of the
mented to the surface.
Students
Thank you, Professor!
Drilling fluid
Буровой раствор
To counterbalance
Уравновешивать
Bentonite clay
Бентонитовая глина
To alter
Изменяться, изменять
Substitutes
Заместители, заменители
Reactivity with shales
Реактивность со сланцами
To discharge onsite
Сбрасывать на месте эксплуатации
High-angle directional drilling
Направленное бурение под большим углом
Burden
Трудность
Pore-clogging
Закупорка пор
Vegetable ester
Растительный сложный эфир
then be smaller, but must still accommodate the downhole equip-
hydrocarbon bearing zone
surface, extending only twenty to one hundred feet from the sur-
drilling with a pile driver. The next string, or “surface” casing, begins at the surface and may penetrate two thousand to three thousand feet. Its primary purpose is to protect the surrounding fresh-
depths. The “i
within a coupl e thousand feet of the bottom of the wellbore. This
section prevents the hole from caving in and facilitates the move-
logging
has
casing up the annulus to hold it in place and surface casing is ce-
(abridged from https://en.wikipedia.org/wiki/Drilling_fluid)
62
Poly alpha olefins
Полиальфаолефины
Internal olefins
Внутренние олефины
Linear alpha olefins
Линейные альфаолефины
Ethers
Простые эфиры
Linear alkybenzenes
Линейные алкибензены
Oleaginous
Маслянистый
Biodegradability
Биоразлагаемость
Barite
Барит
Hematite
Гематит
Dispersants
Диспергирующее вещество
Lignosulfonates
Лигносульфонаты
Flocculant
Флоккулятор, коагулянт
Surfactants
Сурфактанты
Biocides
Биоциды
Organic amines
Органические амины
Starch
Крахмал
Communication
Соприкосновение, контакт
Removable plug
Сменный штепсель
Packer
Пакер, сальник
Immediate area
Непосредственная близость
Conductor casing
Направляющая обсадная колонна
Surface casing
Первая колонна обсадных труб
Pile driver
Свайный копер
Intermediate string
Промежуточная обсадная колонна
Production string
Эксплуатационная обсадная труба
Annulus
Затрубное пространство
1 conditional
(real action, now or in future)
2 conditional
(possible action, now or in future)
arn
a lot (you are a future petroleum engineer)
If you were a petroleum engineer, you would
earn a lot (you are not a petroleum engineer)
Subordinate
Principal
Subordinate
Principal
If you are a petroleum engineer
You will earn a lot
If you were a p etroleum engineer
You would earn a lot
4. Grammar review: C onditional
Subordinate: If+V in the first form;
Principal: will+V in the first form
If you are petroleum engineer, you will e
Exercise 1. Put the verbs into correct form using Conditional 1.
1. If there (be) no bentonite clay in the drilling fluid, the fluid viscosity
not (increase).
2. If the drilling mud (contain) additional additives they (alter) the
properties of the f l uid .
Subordinate: If+V in the second form;
Principal: would+V in the I form
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3. If there (be) no drill ing fl uid in th e drillin g process , it (be ) impossible
to cool and l ubricate the drill bit.
4. If there (be) high-temperature working conditions, one (need) a high-
density drilling fluid.
5. If the crew (need) an advantageous replacement for water-based
muds in some situations, they (use) synthetic-based muds.
6. If you (use) water-based drilling muds, the drilling process (be) the
least expen sive.
7. If the drilling mud (be) water-based, this factor (limit) lubricity and
make reactivity with some shales possible.
8. If the company (buy) oil-base muds that are composed primarily of
diesel fuel it (be) more expensive that to buy water -based muds.
9. If there (be) drilling through reactive or high pressure shales, high-
angle directional dril ling and drilling in deep wa ter, oil-based muds (be) u sed.
10. If the industry trend (be) toward deeper wells, oil-based muds (be-
come) mor e prominent.
11. If the additives (be) either liquid or solid, they not (mix) with air and
foam drilli ng fluids.
12. If the drilling (take) place on land, air and foam fluids (be) used in
drilling proce ss.
Exercise 2. Put the verbs into correct form using Conditional 2.
1. If these fluids (be) less viscous than ordinary drilling muds they (en-
ter) smalle r pores more easily.
2. If casing (be) not cemented it not (prevent) migration of fluids behind
the casing and not (prevent) communication of higher pressure productive formations with lower pressure non-productive formations.
3. If casing (be) important for the drilling, it (be) good for production
phase of operati ng.
4. If the hole (be) drilled, casing (be) placed in the well to stabilize the
hole and (prevent) caving in.
5. If surface soils (cave in) during drilling, a “conductor” casing (be)
placed at the surface, extending only twenty to one hundred feet from the surface.
6. If the surface casing (begin) at the surface, it (extend) to hundreds of
feet undergrou n d.
7. If the section (prevent) the hole from caving in, it (facilitate) the
movement of equipment used in the hole, for example drill strings and logging
tools.
8. If the final “production” string (extend) the full length of the wellbore, it (enc ase) the downhole production equi pment.
64
9. If the bottom of the wellbore (be) not large enough , i t not (accommodate) the necessary pumping equipment that will (be) needed either upon commenceme nt of pumping, or in the later years of production.
10. If pressurized zones (be) unusual, they (require) thicker casing in
that immediate area.
11. If the driller (be) not encouraged to keep the hole size to a minimum
the size (increase), so ( do) cost and waste.
12. If the well drilling practice (use) cable tool drilling instead of rotary
drilling, the petroleum industry (have) a terrible time and money loss and a serious psyc hological cris is.
5. Readin g without dictionary. Supplementar y texts
Text 1
Read the article about oil production, don’t consult a dictionary.
Choose the correc t w ord in the ital ic te xt.
Read again. Is there any unknown information for you? Say what is
new for you (see examples in Unit 1).
Answer the following questions using fragments from the article.
1. What should one consider when discussing oil industry production?
2. What happens when no trapping mechanism exists?
3. How do oil companie s pr oduce oil in general ?
4. What happens to subsurface pressures with the drilling of a well?
5. What two task s does the petroleum business have?
6. In what case does oil stored deep in reservoir flow to t he surface?
7. What governs the rate of the flow of the fluids in the reservoir?
8. How long does it take the well’s production to slow and finally
cease?
9. What are steam injection and in situ combustion techniques used to?
10. What are service companies hired to?
How is oil produced
When discussing oil industry production, consider this: geologists have
estimated that the migration of petroleum from their place of origin deep inside
the earth into surrounding reservoir rocks takes a long time. Time is measured
in millions of years, not centuries.
They argue that this fact is based on th e physics of fluid flow through
semi-permeable material (rock) under a pressure gradient. The fluid must
65
travel from pore to pore, micrometer by micrometer until settling in its host
reservoir – a nd th at si mply takes time.
If no trapping mechanism exists, then the hydrocarbon rises to the top of
the fluid column and/or surface where it seeps out. Although seeps are plentiful, their natural flow r ates are not en ough to meet demand.
Society, today, needs lots of oil – and right now. Oil industry production
must continually be produced in the millions of barrels per day to quench our
thirst. So, how do oil companies prod uce o il to sat i sfy this need?
They explore, drill wells, and produced oil at the field’s maximum efficient rate.
In places where an oil tr ap exists, pr ior to well penetration, little if any
fluid movement occurs, as the trapping mechanism prevents any escape of hydrocarbon within the structure. An equilibrium condition is established, balancing fluid pha ses and reser voir pressures – that is, until the we ll i s dril le d.
Imagine for a moment that the oil reservoir, located a mile or so
beneath/above the earth’s surface, is like a giant sponge sitting on a kitchen
counter. Oil/gas saturates the reservoir like water saturates the sponge, filling
the most of the available pore spaces. Just like a sponge sitting on a counter,
the oil sits in suspension within the r eservoir with no drople ts escaping. Only
when pressure is applied to the sponge by squeezing it or placing something on
it, will the sponge give up some of its water. Similarly, petroleum/oil will not
move until its equilibr ium condition is upset. Once a well/borehole penetrates
this isolated environment, releasing sored pressure, the well balance suddenly
shifts and its characteri stics will never again be the same.
So, how is oil produced?
Oil is produced through the creation of a significant pressure drop between the outer reaches of the reservoir and the wellbore at de pth.
With pressure drops sufficient to overcome pore pressures, oil stored
deep in reservoirs will flow to the low-pressure sink.
Getting oil to move out of the ground and to the market is what oil industry production and the petroleum business is all about. The challenge for the
production engineer then is to first get the oil of the wellbore. The next challenge is to get it to the sur face.
With the drilling of a well, surface/subsurface pressures can be re-
leased. These pressures can and do exceed thousands of pounds per square
centimeter/inch/millimeter (psi). When producing without artificial support,
the reservoir pressure automatically begins to decline. It is estimated in most
producing wells, half of the total reservoir pressure drop occurs within the fi rst
10–20 feet/miles from th e wellbore. Now, having a means of escape, the enormous weight of the rock sitting atop of the reservoir squeezing the once resistant pores, now forces the pores to compress, expelling oil, gas and water
66
through the well. The c haracteristics of the oil itself contain entrained lighter
carbohydrates/hydrocarbons (gases), which in the presence of a drop in pressure, begin to separate from heavier liquids and cause hydrocarbon to exit the
reservoir. Water inflow, fed from external sources, constantly pushes against
the hydrocarbons, which now can escape through the well.
These characteristics of a reservoir are known as natural/artificial drive
mechanisms and are individually called compaction drive, solution gas/gas cap
drive and water drive. Reservoirs typically have components of several, if not
all of the drive mechanis ms at work, but usually have one of th em b ehav in g in a
more dominant fa s hi on the n the othe rs.
Understanding the particular drive mechanisms at work within a specific
reservoir is essential to efficient and effective petroleum extraction. A company
can easily drill and produce wells in locations that hamper natural drive mechanisms, leaving oil behind that will never be recovered.
The rate of flow of the fluids in the reservoir is governed by the fluid
densities and the drop in pressure from the reservoir to the wellbore. Henry
Darci, a nineteenth century engineer, was first to document the proportional relationship of flow rate and pressure drop in porous media.
As fluid is produced from the well under natural drive mechanisms, the
pressure drop from the well, which was highest when the well was first produced, begins to diminish. As a consequence, the flow rate of the well, normally measured in terms of barrels per day, also diminishes. Without any assistance from the engineer, the well’s production will eventually slow to a trickle,
and finally cease, this c ould take days, years or decades to occur.
In some cases, the natural drive mechanisms currently aren’t or never
were sufficient to prod uce oil at the su rface. Bu t, just because the oil can’t flow
to the surface doesn’t mean it is not sufficient in size or quality for commercial
production.
It is estimated that primary drive mechanisms can typically produce
about 30 % of the oil in place within a reservoir. That means 70 % of the original oil rem ains in place.
Once the oil is in the wellbo re, pumps are used as necess ary to lift oil to
the surface. Oil, gas and water enter the well through perforations placed in the
cemented pipe at the re ser v oir de pt h.
Typically, a ball and seat pump is attached to a series of slender metal rods
called “sucker rod” that is ultimately connected to a pumping unit sitting on the
surface, adjacent to the wellhead. As the pumping unit head bobs up and down
each time, the pump completes a stroke, lifting a column of fluid closer to the surface. Once at the surface, the rese rvoir fluids are piped to pr oduction fa cilities.
Supplementary production techniques (also called secondary and tertiary
recovery) like wa terf loodi ng and gas in jecti on se rve to replenish reservoir pres-
67
sures, driving oil towards the wellbore. Steam injection and in situ combustion
techniques are generally designed to improve the viscosity of the oil (enhance
in ability to flow).
Miscible floodin g, carbon diox ide flooding and sur factant flooding focus
on improving oil’s relative permeability to water and increase recovery.
Supplementary production techniques can add approximately 30% recovery of the original oi l in place.
Current production rates are often compared with historical records and
reservoir data to protect future production trends and to assist in characterizing
well performance. Production forecasts are vital to estimating the producible
life of a well and its potential economic profitability.
Engineers have derived functions that describe and match a given well’s
declining production history. This function can be extended to predict future
well performance.
If a well deviates slightly/considerably from the history matched projec-
tion, it could suggest a change in the condition of the reservoir, well, well
equipment or op erations and measurement devices (sur face or subsurface deviations). Various staff and /or resources can then be employed to investi-
gate/correct the situation. Remedial work can be scheduled to fix the identified
problem (such as tubing leaks, water breakthrough, rod spacing, pumping unit
imbalance, pump malfunctions, scale development, broken flowmeter impeller,
test station malfunction, etc.) Service companies are hired to conduct a variety
of tasks like oil well stimulation/simulation by injecting acid into wells to dissolve downhole obs tr uct i ons, an d rod, pumps and tubing ret rie v al s.
The regular and disciplined surveillance of production operations and
subsequent repair and maintenance cannot be stressed enough to ensure optimal
well perform a nce an d m aximize oil producti on.
(abridged from http://www.oilprimer.com/oil-industry-production.html)
Text 2
R ead the text about well design, don’ t consult a dictionary. I s there
any unknown information for you? S ay what is new for y ou ( see example
in Unit 1).
Read again, then correct the mistakes in the following statements.
1. Pressure gauges are never installed on Christmas tree to measure
pressure in annu l us and tu bin g.
2. Christmas tre e is one the main components of wellhead equipment.
3. The first casing string called production casing is installed from the
surface, passes inside conductor, surface casing and intermediate casing to the
formation p ay zone or below it.
68
4. The first and the smallest in diameter casing string is called con ductor.
5. Christmas tree required for field operations includes: wellhead,
valves and chokes, emergency shut down systems, blowout preventers, fluid
tanks, separators, line heaters, dehydration equipment, gas sweetening equipment, compressors.
6. On wells where high formation pressure or presence of aggressive
gases are expected, special control equipment should be installed above casing
string or tubing spool after well completion.
7. Casing strings run in the hole have specific purposes and include:
conductor, surface casing, intermediate casing and production casing always
with a liner.
8. Intermediate casing strings should be run in the hole when it is feasible to drill the well to the design depth without preliminary isolation of problematic zones (blowouts, collapses).
9. Surface casing is the firs t str in g run in t he ho le a nd cemented.
10. Well design can be d escribed as tunnel from the ground surface to the
oil bearing formation.
Read once again and make summary (see examples in Unit 2).
Well design
Well design can be described as pipeline from the ground surface to the
oil bearing formation. Oil comes to the surface through this pipeline. Such
pipeline includes a number of special pipes connected between each other
called a casing str i ng.
Casing strings run in the hole have specific purposes and include: conductor, surface casing, intermediate casing and production casing often with a
liner.
The first and the largest in diameter casing string is called conductor.
This string c an be installed in the well or driv en in so i l.
Surface casing is the second string run in the hole and cemented. It is installed to the depth, which is sufficient in order to protect the well from underground waters and collapse of surfac e soil.
Another smaller in diameter casing string can be applied. It is called intermediate casing. If the well is shallow, intermediate casing, as a rule, is not
used. Intermediate casing strings should be run in the hole when it is not feasible to drill the well to the design depth without preliminary isolation of problematic zones (blowouts, collapses) .
The last casing string called production casing is installed from the surface, passes inside conductor, surface casing and intermediate casing to the
69
formation pay zone or below it. This is the string, in which the well is completed and contr olled.
Well equipment required for field operations includes: wellhead, valves
and chokes, emergency shut down systems, blowout preventers, fluid tanks,
separators, line heaters, dehydration equipment, gas sweetening equipment,
compressors.
On wells where high formation pressure or presence of aggressive gases
are expected, special control equipment should be installed above casing string
or tubing spool before well completion. A set of such control equipm ent including valves and pressure gauges controls oil and gas flow from the well and is
called Christmas tree, which is associated with its shape and high number of
branches w ith valves on the tree trunk.
Christmas tree is the main component of wellhead equipment. Christmas
tree is attached to casing. It is designed to hold casing and tubing strings, isolate or seal annulus between these strings, provide fluid access to all strings,
control proce ss es of f luid a nd ga s inje c ti on and production by means of valves.
Standard Christmas tree assembly includes adaptor flange, master valve,
flanged cross, top adaptor, secondary master valve, wing valve, wing valve and
a choke.
Pressure gauges are installed on Christmas tree to measure pressure in
annulus and tubing. When pressure values under different working conditions
are known the well can be controlled much easier.
(abridged from
http://www.adventuresinenergy.org/Exploration-and-Production/Extracting-Oil-and-Natural-Gas.html)
Text 3
Read the text about a drilling rig, don’t consult a dictionary. Is there
any unknown information for you? Say what is new for you (see example in
Unit 1).
Read again, then answer in short the questions after the text, don’t
quote phrases from the te xt.
1. What is referred to as a drilling rig?
2. What types of drilling rig exist?
3. What is the term “rig” referr ed to?
4. How powerful a r e hoists in a rig?
5. Can a marine r ig be operated a t a certain distance?
6. What two functions do oil and gas drilli ng rigs have?
7. What is a servi ce rig used for?
8. How does drilling process go?
9. What risk can be posed to the environment by the process of drilling?
70