Unit 11 slim hole drilling. Coiled tubing drilling.

11.1. Remember the meaning of the following words and word-combinations:

slim hole – скважина малого диаметра, малогабаритная скважина

drill string – бурильная колонна

logging tool – каротажный прибор, скважинный зонд (для каротажа)

completion – заканчивание скважины

accrue from – происходить из

consumables – расходные материалы

cuttings – буровой шлам

dispose of – избавляться, убирать, удалять

weigh – весить

installed power – установленная мощность

mud tank capacity – ёмкость (вместимость) резервуара для бурового раствора

bbl = barrel – баррель (мера)

crew size – численность группы (буровой бригады)

reduced volume – уменьшенный объем

influx – приток (нефти или газа в скважину)

continuous coring – непрерывный отбор керна

rather than – а не

exploration venture – разведывательная скважина

coiled tubing drilling – коилд тюбинговое бурение, бурение с использование

гибких насосно-компрессорных труб (ГНКТ)

joint of drill pipe – звено бурильных труб, заканчивающееся замком

seamless tubular – бесшовная труба, цельнотянутая труба

reel (onto) – наматывать (на), сматывать

pipehandling – умение обращаться с трубой

underbalanced drilling – бурение при пониженном гидростатическом давлении

в стволе скважины

result in – приводить к ч-л

day rates = day rate payment – подённая оплата (подрядчику)

production string – эксплуатационная обсадная колонна

reliability – надёжность

11.2. Read and translate the text using a dictionary:

Slim Hole Drilling

Slim hole drilling has been used by the mining industry for a number of years. Recently, the oil industry has been developing rigs, drill string components and logging tools that will allow smaller diameter holes and completions. One definition used for ‘slim holes is “a well in which 90% or more of the length has a diameter of 7 inches or less”. In principle, slim hole drilling has the potential to drill wells at greatly reduced cost (estimates range from 40% to 60%). The cost reductions accrue from several sources:

- less site preparation

- easier equipment mobilisation

- reduction in the amount of consumables (drill bits, cement, muds, fuel)

- less cuttings to dispose of

- smaller equipment

A slim hole rig weighs about one fifth of a conventional rig and its small size can open new frontiers by making exploration economic in environmentally sensitive or inaccessible areas.

The following table highlights the potential of slim hole wells:

Type of Rig Conventional Slim Hole

Hole diameter (inch) 8.5 3 to 6

Drill string weight (tons) 40 5 to7

Rig weight (tons) 80 10

Drillsite area (%) 100 25

Installed power (kW) 350 70 to 100

Mud tank capacity (bbl) 500 30

Hole volume (bbl/1000 feet) 60 6-12

Crew size 25 to 30 12 to 15

The greatly reduced hole volume of slim hole wells can lead to problems if an influx is experienced. The maximum depth drillable with slim hole configurations is another current limitation of this technology.

Some slim hole rigs were adapted from units employed by mining exploration companies and are designed to allow continuous coring rather than breaking the formation into cuttings. These rigs are sometimes employed for data gathering in exploration ventures. They are ideally suited for remote locations since they can be transported in segments by helicopter.

Coiled Tubing Drilling (CTD)

A special version of slim hole drilling currently emerging as a viable alternative is coiled tubing drilling (CTD). Whilst standard drilling operations are carried out using joints of drill pipe, coiled tubing drilling employs a seamless tubular made of high-grade steel. The diameter varies between 1 3/4" and 3 1/2". Rather than being segmented the drill string is reeled onto a large diameter drum.

The advantages of CTD are several:

• Nearly no pipehandling;

• Better well control allows at-balance or even underbalanced drilling, resulting

in higher penetration rates and reduced potential for formation damage;

• Less environmental impact;

• Lower cost for site preparation, lower day rates, lower mobilisation and

demobilisation costs;

• Easier completion by using the CT as a production string.

However, coiled tubing drilling is limited to slim holes, and the reliability of some of the drill string components such as downhole motors is still improving. Presently, the cost of building a new customised CTD rig limits the wider application of this emerging technology.

11.3. Give English equivalents for the following phrases. Use the text:

Горнодобывающая промышленность; позволяют (бурить) скважины меньшего диаметра; семь дюймов или меньше; бурить скважины значительно дешевле; буровые долота, цемент, буровые растворы, топливо; в экологически чувствительных и труднодоступных регионах; выделять \ подчеркивать; площадь проведения буровых операций; предназначены для того, чтобы; разрушение пласта на шлам; сбор данных; отдаленные территории; вертолетом; более высокая скорость проходки; повреждение пласта; подготовка буровой площадки; стоимость монтажа и демонтажа (оборудования); новая переделанная (подогнанная) буровая установка; ограничивает более широкое применение.

11.4. Match the types of drilling in A with their definitions in B:

A B

1) directional drilling a) drilling of a well in which 90% or more of the

length has a diameter of 7 inches or less

2) horizontal drilling b) drilling of a well which has a horizontal

displacement of at least twice the vertical depth

3) ERD c) drilling which requires equipment to deflect the

drill from the vertical

4) slim hole drilling d) drilling that employs a seamless tubular made

of high-grade steel

5) CTD e) drilling which is employed when reservoir

rocks and reservoir fluids have lateral

distribution

11.5. Complete these sentences with a suitable word or phrase from the text:

1) ………….. has been used by the mining industry for a number of years.

2) Slim hole drilling has the potential to drill wells at greatly reduced ……. .

3) Cost reductions come from several sources: less …………., easier equipment mobilization, less cuttings, smaller ………….. .

4) A slim hole rig weighs about one fifth of …………. .

5) The greatly reduced hole volume of slim hole wells can lead to problems if …………… is experienced.

6) Some slim hole rigs are designed to allow ………………. rather than breaking the formation into cuttings.

7) They are suitable for ………….. as they can be …………….. in segments by helicopter.

8) Coiled tubing drilling uses ……………. made of high-grade steel.

9) The advantages of CTD are: nearly no pipehandling, higher penetration ………. , less environmental …………., lower cost for …………. .

10) Coiled tubing drilling is limited to …………….. .

11) The reliability of some drill string components such as …………….. is

still improving.

12) …………… of building a new customized CTD rig limits the wider use of

this technology.

11.6. Answer the following questions on the text:

1) How long has slim hole drilling been used by the mining industry? 2) What is the definition used for ‘slim holes’? 3) What is the main potential of slim hole drilling? 4) Where do cost reductions accrue from? 5) Compare slim hole wells with conventional ones. 6) What are the limitations of this technology? 7) What are slim hole rigs sometimes used for? 8) Why are these rigs ideally suited fro remote locations? 9) What is a special version of slim hole drilling? 10) What are the advantages of CTD? 11) Are downhole motors in CTD reliable? 12) What else limits the wider application of this new technology?

11.7. Make up sentences using the following words:

a. data slim rigs can hole employed for Some gathering be

b. limited slim drilling is Coiled to holes tubing

11.8. Render the text “Slim Hole Drilling. Coiled Tubing Drilling” in English or in Russian.