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Объясните разницу между Буровой установкой и установкой КРС.

Преимущество и недостатке заканчивания с «необсаженным» стволом

Какие ваши действия, что бы провести циркуляцию скважины перед тем как вытянуть колонну НКТ.

Кері айналым: Ұңғыны тұншықтарғаннан кейін пакер астында мұнай не газ жыньығы қалып қояды. Пакер алғаннан кейін жанагы газдан құтылу керек. Ол үшін өте үлкен сақтық қажет:_ a кері айналым кетіреді;_ followed by a direct circulation to complete the well conditioning.Note: The reverse circulation (annulus - tubing/pipes) is always included in a workover after a well killing with the bullheading technique and also when it is necessary to expel the bottom cushion rapidly. The latter situation usually occurs after the packer release.

Procedure:Starting reverse circulation• Gradually start the pump increasing its flowrate and monitoring the circulation pressure as well as the return flow from the tubing that indicates that the communication/circulation process has started.

• Increase the number of pump strokes per minute until the programmed flowrate is reached and at the same time operate the choke of the tubing.

• The value reached at the casing is the circulation pressure (ICP) and it will ensure an overbalance on the formation.

Reverse circulation• During the circulation, the following values must be monitored and kept constant until expulsion of the gas cushion:_ circulation pressure, by operating on the tubing choke_ pump flowrate

Procedure:Gas expulsion• When the gas cushion reaches the surface and starts to be released, the pressure at the tubing/pipes starts to decrease; to keep the established value of the circulation pressure it will be necessary to adjust on the choke.

• Once the gas has been totally expelled, the arrival of the completion fluid at the choke causes a rapid increase of the tubing pressure; the choke must be adjusted accordingly.

End of reverse circulation• Once the cushion has been totally expelled reduce the pump flowrate until it stops.• Make sure that there is no pressure in the tubing and in the casing.

Direct circulation• At the conclusion of the reverse circulation, after a complete direct circulation at the well bottom with the BOPs opened, the well can be considered to be under control and the following operations can be carried out safely.

4. Какая основная цель управления за «целостностью скважиной» («well integrity management»)технкалық, оператвті, ұжымдыұқ жұмыстапдың ұңғы өміпшендігін ұзартудағы атқарылатын жұмыстар.

.As a minimum, the following elements shall be addressed:


• well integrity policy and strategy

• resources, roles, responsibilities and authority levels

• risk assessment aspects of well integrity management

• well barriers

• well component performance standards

• well operating limits

• well monitoring and surveillance

• annular pressure management

• well handover

• well maintenance

• well integrity failure management

• management of change

• well records and well integrity reporting

• performance monitoring of well integrity management systems

• compliance audit.


Какая цель бурового раствора для ремонта скважины?

WO fluids:


Completion Fluid

• It controls the formation pressure

• It cleans the hole from drilling cuttings

• It is used for carrying gravel pack fluids

• It prevents the formation from being damaged during perforations

Packer Fluid

• It controls the hydrostatic pressure

• It equalizes the casing pressure behind the tubing

• It protects the casing from contacting the fluids produced

• It guarantees hydrostatic pressure on the packer

• It is chemically and physically stable

Killing Fluid

• It impedes the reservoir pressure

• It is compatible with the formation

• It preserves the stability of the well

Characteristics

To the extent possible, the killing fluid shall be:

• Undamaging

• Solids free

• Compatible with any required additives

• Chemically and physically stable

• Noncorrosive

• Not dangerous to handle

• Environment-friendly

• Compatible with the formation and fluids present therein

• Have wide density and viscosity range

• Thermally stable


 

 

Функции и типы раствора для глушения скважины при ремонтных работах


Clay base mud

Profits

• Low costs

• Readily available

• High suspension capability and solids

carrying capacity

Constraints

• Clay swelling

• Formation plugging

• Water block and emulsion block

• Degradability over time

Polymer base mud

Profits

• Poor solids content

• Low filtrate

• High suspension capability and solids

carrying capacity

Constraints

• Potentially damaging

• Unstable with the temperature

• Water block

• Degradability over time

Oil base mud

Profits

• Thermal stability

• Low filtrate

• High suspension capability and solids

carrying capacity

• Noncorrosive

• Low-damaging filtrate in oil reservoirs

Constraints

• Clogging of formation

• Wettability alteration

• Emulsion block

• Degradability over time

• Polluting

Brines

Profits

• Solids free

• Low costs

• Stable over time within saturation limits

• Does not damage the formation

Constraints

• Limited density

• Low suspension capability and solids carrying capacity

• May cause well control problems in highpermeability formations

Made up brines

Profits

• Solids free

• Wide density range

• Controlled chemical composition

• Does not damage the formation

• Free from bacterial actions

Constraints

• High costs

• May require safety measures


 

Brines

Profits

• Solids free

• Low costs

• Stable over time within saturation limits

• Does not damage the formation

Constraints

• Limited density

• Low suspension capability and solids carrying capacity

• May cause well control problems in highpermeability formations

Made up brines

Profits

• Solids free

• Wide density range

• Controlled chemical composition

• Does not damage the formation

• Free from bacterial actions

Constraints

• High costs

• May require safety measures


Функции и применение пакера


Production Packers

Purposes

• Protect the casing from reservoir

fluids and pressures

• Separation of zones to avoid

crossflow

• Subsurface pressure and fluid

control

• Artificial lift efficiency – gas lift

Components

• Seal assembly

• Slips

• Cone assembly

• Friction element

_Not on permanent or

hydraulic set units

• Setting and releasing

mechanism

_Not on permanent units

• Mandrel assembly

• Control head or bypass

 

Retrievable Packers

• Can act as a bridge plug prior to production

• Connect to tubing via On/Off tool with blanking plug

• Tubing can be landed in tension, compression or neutral

• Slips above and below the elements

• Triple element pack off system

• Pressure up to 10,000 psi

• Fluid bypass needed for pressure equalization

• Retrieved on tubing

• Secondary shear release needed


 

Oil base mud

Profits

• Thermal stability

• Low filtrate

• High suspension capability and solids

carrying capacity

• Noncorrosive

• Low-damaging filtrate in oil reservoirs

Constraints

• Clogging of formation

• Wettability alteration

• Emulsion block

• Degradability over time

• Polluting


 

Polymer base mud


Profits

• Poor solids content

• Low filtrate

• High suspension capability and solids

carrying capacity

Constraints

• Potentially damaging

• Unstable with the temperature

• Water block

• Degradability over time


With


Retrievable Packer

Begin procedure:

Killing the well

_ Depressurise the string

_- Kill the well with Bullheading method

Reverse circulation and Direct circulation

_ Open the circulation valve (or puncher)

_ Execute Reverse circulation

_ followed by a direct circulation

With Retrievable Packer

Check the well

_ if the well flows: check the mud density and repeat the circulation

_ if the well does not flow: continue

Remove Xmas tree

_ Close SCSSV (if present)

_ Insert BPV

_ Remove Xmas tree


 

Clay base mud

Profits

• Low costs

• Readily available

• High suspension capability and solids

carrying capacity

Constraints

• Clay swelling

• Formation plugging

• Water block and emulsion block

• Degradability over time


 

Use

• It is mainly used in operations that require a circulation inside the well, such as well killing, washing, acid jobs, lifting, cement plugs and others.

• Recently, due to the large diameters available, the coiled tubing is also used to carry out

final completions or to rectify completions that have become inadequate. This solution is

much more cost-effective than the operations with a rig.

Advantages

• Possibility of completing the well and carrying out workover operations without the use of the drilling/workover rig.

• High mob/demob speed towards workover rigs.

• Reduction of size of the required area towards workover rigs.

• High run in hole /pull out speed towards workover rigs.

• Possibility of carrying out underbalanced workover operations without killing the well.

 

Permanent packers

Permanent packers can be removed from the wellbore only by milling. The retrievable packer may or may not be resettable, but removal from the wellbore normally does not require milling. Retrieval is usually accomplished by some form of tubing manipulation. This may necessitate rotation or require pulling tension on the tubing string.

The permanent packer is fairly simple and generally offers higher performance in both temperature and pressure ratings than does the retrievable packer. In most instances, it has a smaller outside diameter (OD), offering greater running clearance inside the casing string than do retrievable packers. The smaller OD and the compact design of the permanent packer help the tool negotiate through tight spots and deviations in the wellbore. The permanent packer also offers the largest inside diameter (ID) to make it compatible with larger-diameter tubing strings and monobore completions.

Retrievable packers

The retrievable packer can be very basic for low pressure/low temperature (LP/LT) applications or very complex in high pressure/high temperature (HP/HT) applications. Because of this design complexity in high-end tools, a retrievable packer offering performance levels similar to those of a permanent packer will invariably cost more. However, the ease of removing the packer from the wellbore as well as features, such as resettability and being able to reuse the packer often, may outweigh the added cost.

Components

• The Baker Roto-Vert mod. 'C' Scraper consists of a body with a top male connection and a bottom female connection.

• The body is equipped with 2 sets of three-blade scrapers (each set covers a 360-degree range).

• Each blade has grooves with a left-hand helical screw development which is pushed outwards by four springs.

Scraping action

The scraping action of the scraper can be achieved both

• with reciprocation of drillstring (vertical reciprocating motion)

• and with a rotating motion.

The maximum scraping action is achieved with reciprocation of drillstring.

Security type Scraper

Components

• The Security type scraper consists of a quadrangular cross section body with a top male

connection and a bottom female connection.

• There are 4 cutters on the body which are pushed outwards by special springs and set so as to cover a 360-degree range.

• Each cutter has a helical development blade profile that virtually has a cutting action on the existing obstructions.

Scraping action

• Cleaning is achieved with reciprocation action: it is not recommended for situations that entail rotating operations.

• In case of an open hole, do not let the tool come out of the shoe: the retraction may be quite difficult.

• When the blades are worn out, the cutter can be rotated by 180°in order to extend its life

Packer Fluid

• It controls the hydrostatic pressure

• It equalizes the casing pressure behind the tubing

• It protects the casing from contacting the fluids produced

• It guarantees hydrostatic pressure on the packer

• It is chemically and physically stable

 

 

Принцип гидроразрыва пласта

Hydraulic Fracturing allows you to increase productivity, thereby creating a high conductivity fracture within the formation. This operation is particularly difficult and very expensive, thus it must be planned in every detail.

Pumping for fracturing

The fracture can be achieved by:

• pumping fracturing fluid within the formation at a higher rate than the absorption rate

• and by reaching a pressure higher than the consolidation pressure of the rock.

The fracture forms along a perpendicular plane at minimum compressive stress of the matrix. The fracture tends to move upward, downward and within the formation. The formation must be between two argillaceous intervals in order to contain the propagation of the fracture downwards and upwards. Soft formations cannot be fractured.

Pumping of proppants

• When pumping, the fracture continues to expand and to extend. Proppants (sand or ceramic micro-beads / sintered metal oxides) shall be pumped inside the fracture to prevent the two parts from closing again when the pumping pressure force has failed

• As the fracture spreads, the absorbing surface will increase and when this absorbs the entire pumping rate, the fracture propagation ceases inside the formation.

• When an adequate amount of proppants has been pumped, the pumps stop and the operation ends.

• The more proppant is pumped in the fracture, the better the result of the operation.

 

 

Uses of packers

In addition to providing a seal between the tubing and casing, other benefits of a packer are as follows:

§ Prevent downhole movement of the tubing string

§ Support some of the weight of the tubing

§ Often improve well flow and production rate

§ Protect the annular casing from corrosion from produced fluids and high pressures

§ Provide a means of separation of multiple producing zones

§ Limit well control to the tubing at the surface for safety purposes

§ Hold well-servicing fluid (kill fluids, packer fluids) in the casing annulus.

Packer components

Packers have four key features:

§ Slip

§ Cone

§ Packing-element system

§ Body or mandrel.

The slip is a wedge-shaped device with wickers (or teeth) on its face, which penetrate and grip the casing wall when the packer is set. The cone is beveled to match the back of the slip and forms a ramp that drives the slip outward and into the casing wall when setting force is applied to the packer. Once the slips have anchored into the casing wall, additional applied setting force energizes the packing-element system and creates a seal between the packer body and the inside diameter of the casing.

Milling

Milling operations are carried out to clean the well from obstacles that cannot be removed with the bit:

• bridge plug

• cement retainer

• packers

• metal objects that have fallen to the bottom

• stuck strings

Milling cutters

Milling cutters are used for milling operations. A milling cutter is a rugged tool but it is very fragile; it is basically used as a lathe machining tool: high number of revolutions and scarcely loaded. The operating performances of a milling cutter are based on the preparation method (coating and tempering application) and on the usage procedures.

Milling

Never start milling with a mill set against the obstacle:

• Approach the obstacle with the string rotating and without circulation, then determine its exact depth

• Lift the string

• Start circulating at a low rate: high rates may damage the mill

• Set the required number of revolutions (60 - 100 RPM) and check the weight of the string

• Gently approach the object to be milled

• Unload 2 – 8 tons and then continue without producing vibrations

• Always check the torsion indicator (if any)

Variation of parameters

To change any parameter:

• Stop rotation

• Lift the string

• Reset the system under operating conditions and restart as above

The mill can be modified during operations so as to monitor the situation as it evolves. By

examining the mill that has been pulled out, it is possible to obtain useful indications on how to

use the next one.

Milling string

A junk sub, located just above the mill, shall be inserted in the milling string. It is used for

collecting the biggest parts of the milled material, thereby preventing blockage at the bottom ofthe well. During milling operations, the string shall be stabilized in order to minimize damage tothe casing. A jar must always be inserted into the string but never insert a bumper.

Milling fluid

Milling fluid is very important because its viscosity must be able to keep the milled material insuspension. Insert a magnet in the mud circuit upstream of the shaker in order to recover junkfrom the mud coming out of the well. Use viscous fluid cushions to clean the bottom. Using oil base mud could make milling operations more difficult.

 

Борьба с солеотложением

Ловильные работы в скважине

Fishing Operations

Fishing is a heavy workover operation that is carried out to rectify incidents occurred in the well during:

_ Completion

_ Production

_ Workover

Conditions requiring fishing operations

Fishing operations shall be carried out when the following occurs:

_ failure of the string (pipes and tubing)

_ unfeasibility to release the packer(s) when pulling out the completion equipment

_ recovery of objects that have fallen in the well

_ string getting stuck:

_ during plugging or cement squeezing

_ when running-in a packer that gets stuck

_ when pulling out a packer that gets stuck due to deformation of the column or to a slip

coming out or objects falling in the well

Fishing recommendations

When approaching the fish:

_ run in slowly with very slow circulation

_ Once the fish is caught, stop the pump

_ release according to the type of fisher

It is recommended to insert a safety joint in the string, right above the fisher Insert the jar into the string

 

Объясните разницу между Буровой установкой и установкой КРС.

Капитальный ремонт скважин проводится в соответствии с планом-заказом и в указанной последовательности. Капитальный ремонт скважин предполагает обследование и исследование скважин.

Обследование скважины - это работы по определению глубины забоя, состояния эксплуатационной колонны, местонахождения и состояния аварийного подземного оборудования и др. Исследование скважин - комплекс работ по: установлению интенсивности притока жидкости из пласта в скважину; определению места поступления воды, притока жидкостей и газов через нарушения в эксплуатационной колонне; отбору глубинных проб нефти; измерению давлений и температур по стволу скважины, глубины и колебаний уровней; контролю за техническим состоянием обсадной колонны и цементного кольца и др. Обследование скважины с помощью печатей (плоских, конусных и универсальных) начинают с проверки состояния эксплуатационной колонны, оставшейся в скважине НКТ, насосов, штанг и других предметов.

Печать представляет собой металлический корпус, покрытый свинцовой оболочкой толщиной 8-10 мм, меньше диаметра колонны на 10-12 мм. Вместо свинцовой оболочки иногда используют сплав АС, состоящий из 98 % алюминия и 2 % сурьмы - для универсальной печати. Печать спускают на трубах, НКТ или бурильных трубах и по отпечатку на печати судят о состоянии верхнего конца аварийного оборудования, а также о состоянии стенки эксплуатационной колонны на участке нарушений, смятий, трещин и т.п.

Однако наличие дефектов в резьбе, продольных трещин в колонне печатью обнаружить невозможно. Для этого необходимо провести опрессовку колонны, которая проводится после установки пакера.

К числу работ капитального ремонта относятся работы по созданию каналов связи ствола скважины с пластом. Для этого применяют перфорацию (кумулятивную, пулевую, торпедную) обсадных колонн, а также гидропескоструйную.

Кумулятивный перфоратор. Кумулятивный заряд представляет собой шашку взрывчатого вещества, имеющую выемку, расположенную со стороны, противоположной месту детонации взрыва. Газы, образующиеся при взрыве такого заряда, движутся от поверхности выемки и встречаются на оси заряда, образуя мощную струю. Встречая на своем пути какую-либо преграду, эта струя выбивает в ней лунку глубиной, приблизительно равной диаметру заряда (рис. 9.28, а). Если выемку в кумулятивном заряде облицевать тонким слоем металла и поместить заряд на некотором расстоянии от преграды, то пробивное действие кумулятивного заряда резко усилится. Образующаяся при взрыве кумулятивного заряда металлическая струя движется по оси заряда с большой скоростью, достигающей 8000 м/с. При встрече с преградой она создает давление до 30 000 МН/м2, чем и достигается ее большая пробивная сила.Кумулятивные перфораторы применяются корпусные и бескорпусные. Корпусные перфораторы имеют герметически закрытый корпус, в котором помещаются группы зарядов. Такие перфораторы, так же как пулевые и снарядные, могут быть использованы многократно. В бескорпусных перфораторах каждый заряд закупоривается отдельно в индивидуальную герметическую оболочку, разрушающуюся при взрыве.

В кумулятивных перфораторах обеих конструкций заряды взрываются при помощи детонирующего шнура, а шнур в свою очередь взрывается от электродетонатора, присоединенного к кабелю, на котором перфоратор опускают в скважину.

Кумулятивный перфоратор собирается в гирлянду общей длиной до 10 м с числом зарядов до ста и более.

Пулевой перфоратор бывает селективный (выстрелы пулей проводятся поочередно) и залповый (одновременные выстрелы из группы стволов) Применяют пули диаметром 11-12,7 мм. Диаметр перфоратора 65, 80, 98 мм.

Торпедный перфоратор отличается от пулевого тем, что заряжается не пулями, а снарядами замедленного действия. Снаряд торпедного перфоратора, пробив колонну и цементное кольцо, проникает на некоторую глубину в пласт и здесь разрывается, в результате чего в призабойной зоне скважины создаются каверны и трещины. На промыслах применяются торпедные перфораторы Колодяжного ТПК-22 и ТПК-32 (с диаметром снарядов 22 и 32 мм).

При выборе способа перфорации руководствуются следующими положениями. Пули и снаряды, пробивая обсадную колонну, сильно деформируют ее и вызывают образование трещин в колонне и цементном камне.

Кумулятивная перфорация характеризуется большой пробивной способностью в твердых и плотных преградах и не вызывает повреждений обсадных колонн и цементного кольца. Поэтому кумулятивную перфорацию целесообразно применять при твердых породах, снарядную - при относительно плотных и малопроницаемых породах, а пулевую перфорацию при неплотных породах и слабосцементированных песчаниках.

Торпедирование - взрывание зарядов взрывчатого вещества в скважинах для очистки призабойной зоны от посторонних предметов и улучшения притока нефти или газа на забое скважины.

Дефекты в эксплуатационной колонне обычно ликвидируют путем спуска дополнительной колонны в случае:

· невозможности ликвидации дефекта путем цементирования;

· наличия нескольких дефектов на разных глубинах;

· возможности спуска дополнительной обсадной колонны ниже места слома основной эксплуатационной колонны.

Дополнительные колонны спускают внутрь основной обсадной колонны с установок ее башмака ниже дефекта (выше эксплуатационного объекта или на забое). Иногда спускаемая колонна является промежуточной, т.е. перекрывает только интервал ствола с дефектом. Дополнительная колонна спускается в скважину с пакером или с последующим ее цементированием.

Отклонитель - инструмент в виде плоского или желобообразного клина, спускаемый в скважину на бурильных трубах или кабеле. Предназначен для обеспечения необходимого отклонения райберов при вскрытии окна в колонне и бурового инструмента при бурении второго ствола.

Райбер-фрезер скоростного резания типа РПМ предназначен для вскрытия окна в колоннах диаметром 146-273 мм. Вскрытие окна производят роторным способом последовательно набором трех райберов. После вскрытия окна бурение второго ствола проводят обычным порядком.

 

Последнее изменение этой страницы: 2016-08-11

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