Flowing well operation

Method of well operation in which oil and gas mixture raises from the bottomhole to the surface by means of natural energy is called the flowing. Flowing well operation may be used only if the pressure on bottomhole exceeds the hydrostatic pressure of liquid-gas mixture that fills the entire wellbore from the mouth up to the face.

In all methods of operation lifting the liquid and gas to the surface occurs in small diameter pipes which are lowered into the well before using the flow pipes (tubing, stalk or lifting pipes). The flow pipes are seamless. At one end the pipe has a thread, at the other end there is a sleeve screwed at the factory.

Application of the flow pipes is caused by the following considerations:

1) Simplification of well development, since the two individual channels (lifting pipes and annular space) can substitute the mud in the barrel for lighter fluid –water or oil. Besides, there is the possibility of using a compressor.

2) Rational use of energy of the dissolved gas, since when lifting the mixture over a channel with a small cross-sectional area loss of oil when it runs off the pipe walls is greatly reduced. As a result, the friction during gas slip decreases. Use of lifting pipes with small diameter extends flowing of a marginal well.

3) Preventing the formation of sand plugs in the bottom hole, since high rates of gas-oil stream in pipes of smaller sections provide a complete removal of sand from the well to the surface.

4) Facilitation of paraffin control, in case when paraffin is deposited during the extraction of paraffin oil.

The top of flowing well is equipped with steel reinforcement (tubing head and Christmas tree).

Tubing heads are designed for suspension of flowing pipes and isolation of the annulus. Christmas tree is used to direct gas-liquid jets into the flow lines, as well as for controlling and monitoring the wells.

At the top of the wells a pressure gauge is usually installed. Pressure that it shows is called wellhead pressure. In flow lines after the valves there are installed chokes with small round bores to control the well operation.

In oil extracting paraffin is deposited mainly in the upper part of the lifting pipe. The main methods of paraffin control are:

1) melting paraffin by heating;

2) dissolution of paraffin by various solvents;

3) mechanical removal of paraffin from the walls of pipes using scrapers.

The main way to prevent paraffin accumulation is to coat inside surface of the pipe with varnish, enamel, glass. Coating is resistant to acids, alkalis, and strata water. It protects the pipes from corrosion.

In the oil fields in Russia there are widely used gas separators in the form of vertical cylindrical tanks. Gas-liquid mixture is fed from the well to the middle of the ladder. Gas has time to separate from liquid and is discharged into the gas collector. Oil is deposited, and then it is sent from the bottom of gas separator to the oil reservoir.

Ex.3 Find Russian equivalents in part B to words and word combinations from part A.

1. Well operation, oil and gas mixture, flowing well, seamless flow pipes, a screwed sleeve, to be caused by, rational use of energy, high rates of gas-oil stream, a small cross-sectional area, bottom hole, extraction of paraffin oil, the top of flowing well, to be equipped with, wellhead pressure, suspension of flowing pipes, a pressure gauge, gas-liquid jet, to protect from corrosion, coating;

2. Подвеска фонтанных труб, покрытие, устье фонтанирующей скважины, бесшовные фонтанные трубы, малое поперечное сечение, защищать от коррозии, манометр, быть вызванным чем-либо, большие скорости газонефтяной струи, газожидкостная струя, навинченная муфта, забой скважины, добыча парафиновых нефтей, рациональное использование энергии, быть оснащенным чем-либо, устьевое давление, фонтанирующая скважина, смесь нефти и газа, эксплуатация скважины.

Ex.4 Answer the question about flowing well operation.

1.What is flowing? 2. Under what condition is it possible to use flowing well operation? 3. What pipes are needed for lifting the liquid and gas to the surface? 4.What considerations are pursued when applying the flow pipes? 5. What steel reinforcement is mounted at the top of flowing well? 6. What are the methods of paraffin control? 7 . What is the inside surface of the pipe coated with to prevent paraffin accumulation on its walls? 8.For what purpose are gas separators used?

Ex.5 Put the following verbs in the correct columns according to the prepositions they are usually followed by. Use these verbs in the sentences of your own.

Cause, substitute, run, equip, resist, protect, separate, extend, depend, apply, fill, be subject, be exposed, pass, carry, act, be characterized, be rich, transport, rely, be superior, search, result, compare.

to

by

for

off

with

from

upon

in/into

through

over

like

out

Ex.6 Connect a word or a word combination from the left with a word combination from the right.

Method	of	well development
by means		well operation
Application		sand plugs
simplification		natural energy
rational use		paraffin control
formation		energy
rate		a marginal well
removal		the flow pipes
facilitation		paraffin oil
extraction		stream
flowing of		sand

Ex.7 Translate the following sentences using a dictionary.

1.Managed pressure drilling is a general term for controlling the mud circulation to optimize the bottomhole pressure. 2.Hydrostatic pressure is the pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. 3.A marginal gas well is one that produces 60,000 cubic feet (1,700 m³) or less of gas per day at its maximum flow rate. 4.The deepest installed subsea Christmas tree is in the Gulf of Mexico at approximately 9000 feet below water. 5.This paper presents an experimental verification of numerical solutions of the differential equation describing the transient flow of an ideal gas through a porous material including gas slip effects. 6. A wellbore is any hole drilled for the purpose of exploration for or extraction of natural resources such as water, gas or oil where a well may be produced and a resource is extracted for a protracted period of time. 7. Paraffin oil is most commonly used to power jet engines for aircraft, but can also be used for heating, lighting, and cooking. 8. The annulus of an oil well refers to a void between piping and casing immediately surrounding it.

Ex.8 Complete the idea using the text “Flowing well operation”.

1.Flowing well operation can’t be used if the pressure… . 2. At one end the flow pipe has … . 3. In all methods of operation, before using the flow pipes … . 4. Simplification of well development, rational use of energy, preventing the formation of sand plugs and facilitation of paraffin control are main reasons… . 5. Tubing head and Christmas tree are examples of steel reinforcement which… . 6. Chokes with small round bores are installed in … . 7. Melting, dissolution and mechanical removal of paraffin … . 8. Coating with varnish, enamel, glass… . 9. Gas separators in the form of vertical cylindrical tanks... . 10. In method of well operation oil and gas mixture… .

Ex.9 Translate sentences from Russian into English.

1.Фонтанные трубы имеют внутренний диаметр 40 -103 мм, наружный диаметр 48 - 114 мм, толщину стенок 3,5 - 7 мм, длина одной трубы составляет 6 - 9 м. 2.При подъеме смеси по каналу с незначительной площадью поперечного сечения резко сокращается потеря нефти при стекании ее по стенкам труб. 3.Фонтанная арматура различается по конструктивным и прочностным признакам: рабочему давлению, размеру проходного сечения ствола, конструкции фонтанной елки, по числу спускаемых в трубу рядов труб. 4.Правильная эксплуатация заключается в обеспечении оптимальной добычи при возможно меньшем газовом факторе.

5.Если манометр снять, то через вентиль можно выпускать скопившийся в затрубном пространстве газ или нефть. 6.Этот отвод (branch pipe) от затрубного пространства используется также при промывках скважины и других ремонтных работах. 7. Для очистки стенок труб используется скребок в форме цилиндра, опускаемый на длинной проволоке через лубрикатор (lubricator). 8.При установке башмачной воронки (shoe funnel) скважина работает более устойчиво, но полностью пульсация не исключается.

Ex.10 Retell the text “Flowing well operation”.