introduction to drilling well completions 4261888 01[1]

PROVISORY RELEASE

Introduction to Drilling & WellCompletionReference: InTouch content ID#4133663Version: 5.0Release Date: ProvisoryEDMS UID: 275030441Produced: 23-Jul-2008 21:12:29Owner: WS TrainingAuthor: Bernadette Gomez

Private Basic, density, dril ling, well completion, SWBT,WBT, IT Modules, Interface, WCS, WPC, CTS, TBT

PROVISORY RELEASECopyright © 2008 Schlumberger, Unpublished Work. All rights reserved.

To ensure proper duplex reproduction

REMOVE THIS PAGE

AND

for publishing by

● Sophia - remove the previous (Schlumberger) cover

● ALL other channels - remove the following (Sophia) cover

When the document is ready for reproduction,it should have only 1 cover and should NOT have this page.

PROVISORY RELEASE

Introduction to Drilling & WellCompletionReference: InTouch content ID#4133663Version: 5.0Release Date: ProvisoryEDMS UID: 275030441Published: 23-Jul-2008 21:12:29Owner: WS TrainingAuthor: Bernadette Gomez

Private Basic, density, dril ling, well completion, SWBT,WBT, IT Modules, Interface, WCS, WPC, CTS, TBT

PROVISORY RELEASECopyright © 2008 Sophia, Unpublished Work. All rights reserved.

Introduction to Drilling & Well Completion / Legal InformationPROVISORY RELEASE

Legal Information

Copyright © 2008 Schlumberger, Unpublished Work. All rights reserved.

This work contains the confidential and proprietary trade secrets of Schlumbergerand may not be copied or stored in an information retrieval system, transferred,used, distributed, translated or retransmitted in any form or by any means,electronic or mechanical, in whole or in part, without the express writtenpermission of the copyright owner.

Trademarks & Service marks

Schlumberger, the Schlumberger logotype, and other words or symbols usedto identify the products and services described herein are either trademarks,trade names or service marks of Schlumberger and its licensors, or are theproperty of their respective owners. These marks may not be copied, imitatedor used, in whole or in part, without the express prior written permission ofSchlumberger. In addition, covers, page headers, custom graphics, icons, andother design elements may be service marks, trademarks, and/or trade dressof Schlumberger, and may not be copied, imitated, or used, in whole or in part,without the express prior written permission of Schlumberger.

A complete list of Schlumberger marks may be viewed at the SchlumbergerOilfield Services Marks page: http://markslist.slb.com

PROVISORY RELEASEPrivateCopyright © 2008 Schlumberger, Unpublished Work. All rights reserved.W

STraining\BernadetteGomez\InTouchcontentID#4133663\5.0\ReleaseDate:Provisory\EDMSUID:275030441\Produced:23-Jul-200821:12:29

http://markslist.slb.com

Introduction to Drilling & Well Completion / Document ControlPROVISORY RELEASE

Document ControlOwner: WS Training

Author: Bernadette Gomez

Reviewer: Bernadette Gomez

Approver: Torsten Braun, Alice Lee

Contact InformationName: WS TrainingLDAP Alias: IPC-DOC

Revision HistoryRev Effective Date Description Prepared by

5.1 18-Jul-2008 Updated exercises link-url to theperception-resp server.

Beena Hemkar

5.0 25-Oct-2006 Changed instructions for takingmodule test online. Exercisesand test may be launched fromperception-ws server via LMS ortaken online.

Stuart Averett

4.1 12-Apr-2006 Changed label content, and revisiondates

Torsten Braun

4.0 30-Sep-2005 updated graphics and text. .Addedcaptions

Luisa Attaway,Torsten Braun



Introduction to Drilling & Well Completion / Document ControlPROVISORY RELEASE

Intentionally Blank



v Introduction to Drilling & Well Completion / Table of Contents vPROVISORY RELEASE

Table of Contents

1 Objectives

2 Drilling History2.1 Drilling History _______________________________________________ 2-12.2 Drilling History _______________________________________________ 2-22.3 Drilling History _______________________________________________ 2-2

3 Drilling Preparations3.1 Exploration __________________________________________________ 3-13.2 Site Selection ________________________________________________ 3-23.3 Drilling Contracts ____________________________________________ 3-33.4 Preparation of the Rig Site ____________________________________ 3-53.5 Rig Setup ___________________________________________________ 3-63.6 Rigging Up __________________________________________________ 3-73.7 Exercise _____________________________________________________ 3-8

4 Drilling Rig Components4.1 Rig System __________________________________________________ 4-14.2 Drilling Mud _________________________________________________ 4-94.3 Mud Surface Equipment _____________________________________ 4-104.4 Exercise ____________________________________________________ 4-13

5 Well Control5.1 “Kick” animation _____________________________________________ 5-15.2 Primary Well Control _________________________________________ 5-15.3 Secondary Well Control ______________________________________ 5-25.4 Exercise _____________________________________________________ 5-4

6 Rig Operations6.1 Rate of Penetration __________________________________________ 6-16.2 Adding New Pipe Joints ______________________________________ 6-16.3 Trip Equipment In and Out of Hole ____________________________ 6-26.4 Optimum Quality and Cost ____________________________________ 6-26.5 Exercise _____________________________________________________ 6-4

7 Completions7.1 Bottomhole Completions _____________________________________ 7-17.2 Tubing ______________________________________________________ 7-47.3 Wellhead and Chokes ________________________________________ 7-87.4 Artificial Lift __________________________________________________ 7-9

8 Casing



vi Introduction to Drilling & Well Completion / Table of Contents viPROVISORY RELEASE

8.1 Function _____________________________________________________ 8-18.2 Casing Types ________________________________________________ 8-1

9 Special Operations9.1 Offshore Operations __________________________________________ 9-19.2 Directional Drilling ____________________________________________ 9-29.3 Exercise _____________________________________________________ 9-5

10 Summary

11 Take the module test



vii Introduction to Drilling & Well Completion / List of Figures viiPROVISORY RELEASE

List of Figures

2-1 Timeline: 1500 A.D. _______________________________________________ 2-12-2 Timeline: 1859 ____________________________________________________ 2-12-3 Timeline: 1500 A.D. until 1863______________________________________ 2-22-4 Timeline: 1500 A.D. until today _____________________________________ 2-23-1 Seismic exploration ________________________________________________ 3-23-2 Township and range lines __________________________________________ 3-33-3 Cleared and leveled future rig site __________________________________ 3-53-4 Conductor pipe ____________________________________________________ 3-53-5 Land-based rig site setup __________________________________________ 3-63-6 Rigging up ________________________________________________________ 3-73-7 Completed rig-up _________________________________________________ 3-84-1 SCR: Silicon-controlled rectifiers____________________________________ 4-24-2 Hoisting system components _______________________________________ 4-34-3 Derrick ___________________________________________________________ 4-34-4 Rotary system_____________________________________________________ 4-44-5 Downhole motor ___________________________________________________ 4-54-6 Mud circulation system_____________________________________________ 4-54-7 Mud going to mud pit returns _______________________________________ 4-64-8 Mud pit and mixing hopper _________________________________________ 4-74-9 Mud pumped from pit to standpipe __________________________________ 4-74-10 Drillstring__________________________________________________________ 4-84-11 Mud return line ____________________________________________________ 4-84-12 Shale shaker _____________________________________________________ 4-104-13 De-gasser unit____________________________________________________ 4-114-14 De-silter _________________________________________________________ 4-124-15 Decanting centrifuge______________________________________________ 4-125-1 Secondary well control _____________________________________________ 5-25-2 Annular preventer _________________________________________________ 5-35-3 Pipe rams_________________________________________________________ 5-35-4 Blind rams ________________________________________________________ 5-46-1 Weight of string and bit_____________________________________________ 6-37-1 Openhole completion ______________________________________________ 7-17-2 Cased hole completion_____________________________________________ 7-27-3 Perforation phasing ________________________________________________ 7-37-4 Methods of perforating _____________________________________________ 7-37-5 Free or unlimited motion ___________________________________________ 7-47-6 Limited motion_____________________________________________________ 7-57-7 No motion_________________________________________________________ 7-57-8 Buckling effect_____________________________________________________ 7-67-9 Ballooning effect___________________________________________________ 7-67-10 Temperature effect_________________________________________________ 7-77-11 Bubble flow _______________________________________________________ 7-77-12 Slug flow__________________________________________________________ 7-77-13 Annular or mist flow________________________________________________ 7-8



viii Introduction to Drilling & Well Completion / List of Figures viiiPROVISORY RELEASE

7-14 Transition or churn flow ____________________________________________ 7-88-1 Types of casing and lithology _______________________________________ 8-18-2 Conductor casing__________________________________________________ 8-28-3 Surface casing ____________________________________________________ 8-38-4 Intermediate casing________________________________________________ 8-48-5 Liner______________________________________________________________ 8-48-6 Production casing _________________________________________________ 8-59-1 Drilling ship, semi-sub and fixed platforms___________________________ 9-19-2 Kick-off point and deviation_________________________________________ 9-29-3 Drilling motor-bit ___________________________________________________ 9-39-4 Whipstock_________________________________________________________ 9-49-5 Kick-off point (KOP)________________________________________________ 9-4



ix Introduction to Drilling & Well Completion / List of Tables ixPROVISORY RELEASE

List of Tables



x Introduction to Drilling & Well Completion / List of Tables xPROVISORY RELEASE

Intentionally Blank



1-i Introduction to Drilling & Well Completion / Objectives 1-iPROVISORY RELEASE

1 Objectives



1-ii Introduction to Drilling & Well Completion / Objectives 1-iiPROVISORY RELEASE

Intentionally Blank



1-1 Introduction to Drilling & Well Completion / Objectives 1-1PROVISORY RELEASE

1 ObjectivesBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

In this training module, the students will learn to do the following:

• Identify the most common drilling method in use today.

• Identify three of the most important methods used to find oil.

• Put the stages of the exploration process in order.

• Discriminate between the three possible systems used to determineproprietorship of a specific drilling location.

• Discriminate between the three basic types of drilling contracts.

• Put the stages of the drilling preparation process in order.

• Identify the parts of the hoisting system and the mud circulation system.

• Identify the functions of drilling mud.

• Discriminate between de-gassers, de-silters, de-sanders, and centrifuges.

• Identify characteristics of primary and secondary well control.

• Identify the main components of the BOP stack.

• Put the stages of the process of adding new pipe joints in order.

• Identify three of the most important items to control during a drilling operation.

• Discriminate between types of casings and liners.

• Identify characteristics of special drilling operation methods.



1-2 Introduction to Drilling & Well Completion / Objectives 1-2PROVISORY RELEASE

Intentionally Blank



2-i Introduction to Drilling & Well Completion / Drilling History 2-iPROVISORY RELEASE

2 Drilling History

2.1 Drilling History _________________________________________________ 2-12.2 Drilling History _________________________________________________ 2-22.3 Drilling History _________________________________________________ 2-2



2-ii Introduction to Drilling & Well Completion / Drilling History 2-iiPROVISORY RELEASE

Intentionally Blank



2-1 Introduction to Drilling & Well Completion / Drilling History 2-1PROVISORY RELEASE

2 Drilling HistoryBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

Figure 2-1: Timeline: 1500 A.D.

Drilling originated in China with the drilling of brine wells to produce salt withprimitive cable-tool rigs. The Chinese are credited with developing the cable-toolprinciple in drilling. To make a hole, the rigs use a cable to which workers attacha heavy, sharply pointed bit. Rig machinery lifts the cable and bit and drops them.The falling bit strikes the ground with a heavy blow, punching its way into the rock.

Repeated lifting and dropping allow the bit to drill. From time to time, however,workers have to stop drilling, pull the bit from the hole, and remove the pieces ofrock or cuttings that the bit produces. This is done using a bailing tool. By 1500A.D., it is believed that the Chinese were drilling as deep as 2,000 feet using thismethod, which was used as late as the 1940s.

2.1 Drilling History

Figure 2-2: Timeline: 1859

In 1859, Drake’s well became the first known commercial oil well, planned anddrilled solely to search for oil in the United States (Asians and Europeans hadbeen drilling oil wells before). Using the cable-tool method, the well was drilled



2-2 Introduction to Drilling & Well Completion / Drilling History 2-2PROVISORY RELEASEto a depth of 65 feet and produced 2,000 bbl of oil in its first year. This smallproject in Titusville, Pennsylvania marked the beginning of the Petroleum era inthe United States.


Figure 2-3: Timeline: 1500 A.D. until 1863

In 1863, a French civil engineer named Leschot became the first person to userotary drilling to drill a water well. A rotary drilling rig turns, or rotates, a bit on thebottom, which drills and creates the hole. A series of pipes are added to lowerthe bit to the bottom. When the bit is at the bottom, the driller starts rotating itusing a rotating machine called the rotary table. As the bit’s teeth, or cutters,rotate over the formation, they gouge or scrape the rock away.

A rotary rig circulates fluid while the bit drills. A powerful pump can move fluiddown the pipe to the bit and back through the annulus space to the surface. Atthe surface, equipment removes the cuttings, and the clean fluid is recirculatedback down the pipe. Thus, with rotary drilling, drilling does not have to stop inorder to bail cuttings.


Figure 2-4: Timeline: 1500 A.D. until today



2-3 Introduction to Drilling & Well Completion / Drilling History 2-3PROVISORY RELEASEThe advantage of being able to circulate drilling fluid has all but made cable-tooldrilling disappear.

In 1901, this method of drilling was introduced in the oil field in Spindletop, Texas,marking the beginning of the modern petroleum industry. By 1914, 10% of all oilwells were drilled using rotary drilling. Today, except for special applications orthe setting of conductor casing, rotary drilling is used almost exclusively.



2-4 Introduction to Drilling & Well Completion / Drilling History 2-4PROVISORY RELEASE

Intentionally Blank



3-i Introduction to Drilling & Well Completion / Drilling Preparations 3-iPROVISORY RELEASE

3 Drilling Preparations

3.1 Exploration _____________________________________________________ 3-13.1.1 Seismic survey animation ____________________________________ 3-23.2 Site Selection __________________________________________________ 3-23.3 Drilling Contracts ______________________________________________ 3-3

3.3.1 Day-Work Contract ___________________________________________ 3-43.3.2 Footage Contract ____________________________________________ 3-43.3.3 Turnkey Contract ____________________________________________ 3-43.4 Preparation of the Rig Site _____________________________________ 3-53.5 Rig Setup ______________________________________________________ 3-63.6 Rigging Up _____________________________________________________ 3-73.7 Exercise ________________________________________________________ 3-8



3-ii Introduction to Drilling & Well Completion / Drilling Preparations 3-iiPROVISORY RELEASE

Intentionally Blank



3-1 Introduction to Drilling & Well Completion / Drilling Preparations 3-1PROVISORY RELEASE

3 Drilling PreparationsBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

This section will address the preparatory steps prior to drilling the well:

• exploration

• site selection

• drilling contracts

• preparation of the rig site

• rig setup

• rigging up.

3.1 ExplorationAlmost as important as how to drill is where to drill. Exploration for oil is a difficultand risky process. Exploration (or "wildcat") wells are often not successful in theirsearch for oil. In fact, only one out of nine exploratory wells ends in an oil strike.

To define the actual location where the well is to be drilled, a series of trendsmust exist so that hydrocarbons are present. A hydrocarbon reservoir has adistinctive shape, or configuration, that prevents the escape of hydrocarbonsthat migrate into it.

To improve the opportunity to find oil, geologists apply earth science to the searchfor oil. Many techniques have been developed, based on indirect methods toview the subsurface. Among the most important are

• seismology, which is the study of the sound waves that bounce off buriedrock layers. It involves seismic surveys that are analyzed by knowledgeablepersonnel.

• geological mapping, which is used by geologists to define possible reservoirshapes or traps, due to the deformation in the rock layer that containshydrocarbons.

• educated guesses, which use physical geology and seismic information asthe base material to guess where to drill.

A seismic survey is conducted using:

• a shooting truck or special sound generator for offshore exploration



3-2 Introduction to Drilling & Well Completion / Drilling Preparations 3-2PROVISORY RELEASE• geophones or hydrophones

• recording devices in a truck or on a boat.

Figure 3-1: Seismic exploration

Here are the stages of the exploration process:

1. The shooting truck uses compressed air or explosive charges to send aseismic signal into the earth. (Searches often use compressed air becauseexplosions in water can kill marine life.)

2. This signal is reflected back via various formations underground.

3. The returned signals are picked up by the geophones or hydrophones.

4. The information received by the geophones is then recorded usingsophisticated recording devices in a truck or boat.

5. The results are analyzed by geologists to determine the likelihood ofoil-bearing formations beneath the surface of the ground.

3.1.1 Seismic survey animation

Multimedia 3-1: Signals emitted and captured. AnimationNOTE: Multimedia is currently available only in HTML publications.

3.2 Site SelectionIn addition to exploration data, the drill site, selected by the operating company,must also take into account financial, legal, and practical considerations. Theability to establish a lease agreement and drilling rights to a specific location isnecessary before drilling can begin.

The proprietorship of a specific location to be used for drilling is determined byone of three possible systems in the United States:



3-3 Introduction to Drilling & Well Completion / Drilling Preparations 3-3PROVISORY RELEASE• Township and range lines: Township and range lines are used to block offa 36-square-mile block of land called a township. That township is thensubdivided into 36 sections, each one square mile in area.

• Metes and bounds: Metes and bounds means "measurements andboundaries" and describes a tract of land in straight-line segments of lengthand bearing.

• UTM: The UTM system (Universal Transverse Mercator) is used offshore todefine nine-square-mile tracts across open water spaces.

Figure 3-2: Township and range lines

3.3 Drilling ContractsBefore moving equipment onto a site to drill, a drilling contract must be agreedupon by the drilling company and the oil or gas producer. There are three basiccontract types currently being used:

• day-work contract

• footage contract

• turnkey contract.




3.3.1 Day-Work ContractA day-work contract is the most beneficial to the drilling company. Under thistype of contract, the drilling company is paid an agreed-upon fee for each daythat the drilling rig is on site making the hole.

If problems occur, and a job that was thought to take 20 days in fact takes 50days, the added expenses fall entirely on the oil or gas producer. This contractcan be very problematic for the producer, since the total cost for drilling cannotbe determined until the well is complete.

3.3.2 Footage ContractA footage contract is usually used in a developed (or production) field where thedepths to be drilled are already determined. In this type of contract, there is afixed number of feet to be drilled, and a cost-per-foot-drilled is determined.

This system allows the producer to control costs under normal drilling conditions.

It also allows the drilling company to set a price that will be profitable if the drillingteam is efficient in meeting the footage requirements of the contract.

3.3.3 Turnkey ContractA turnkey contract is a type of financing arrangement for the drilling of a wellborethat places considerable risk and potential reward on the drilling contractor.Under such an arrangement, the drilling contractor assumes full responsibilityfor the well to some predetermined milestone such as the successful runningof logs at the end of the well, the successful cementing of casing in the well oreven the completion of the well. Until this milestone is reached, the operatorowes nothing to the contractor. The contractor bears all risk of trouble in the well,and in extreme cases, may have to abandon the well entirely and start over. Inreturn for assuming such risk, the price of the well is usually a little higher thanthe well would cost if relatively trouble free. Therefore, if the contractor succeedsin drilling a trouble-free well, the fee added as contingency becomes profit.Some operators, however, have been required by regulatory agencies to remedyproblem wells, such as blowouts, if the turnkey contractor does not.




3.4 Preparation of the Rig Site

Figure 3-3: Cleared and leveled future rig site

Before drilling begins, the rig site must be prepared. Onshore, access roads andturnarounds for trucks and heavy equipment must be built and the site clearedand leveled. Offshore, buoys are set to mark the site.

One important concern at a wellsite is establishing a sufficient water supply tomeet drilling needs. Often, this means that a water well is dug before drillingfor oil can begin.

Figure 3-4: Conductor pipe



3-6 Introduction to Drilling & Well Completion / Drilling Preparations 3-6PROVISORY RELEASEWhen the water supply is established, a cellar or rectangular pit is dug, typically10 feet on a side and 10 feet deep. Inside the pit, the conductor hole is dug witha special bit. The conductor hole is shallow in depth, but large in diameter; thediameter can be 36 inches or more, depending on the surface condition.

The conductor pipe or casing is then run into the hole and cemented to keep thehole from caving in. It also conducts the drilling fluid back to the surface whenregular drilling begins.

3.5 Rig Setup

Figure 3-5: Land-based rig site setup

Offshore, the type of drilling to be done determines the type of rig to be used.For exploration (or wildcat) wells, mobile offshore rigs (like jack-ups, semis, ordrill ships) are used. For production (or development) wells, a more-permanentplatform is usually used for drilling boats to move the rig from one site to another.

Onshore, trucks are usually used to transport the drilling equipment to thelocation. For remote, inaccessible locations, helicopters and large cargo planescan be used. Current land-based drilling rigs are very portable. A land-basedrig can be moved on location, be set up, and drilling operations can be startedwithin 24 to 48 hours.




3.6 Rigging Up

Figure 3-6: Rigging up

Once the contractor gets the rig to the site, the next step is for the drilling crewto put the rig together, or "rig up." For land rigs, the crew first brings in the rig’ssubstructure. The substructure raises the rig floor anywhere from about 10 to45 feet above ground level. The exact height of a substructure depends on thespace needed to clear the high-pressure valves and other equipment that isconnected to the top of the well’s casing.

Then, many pieces of equipment are set on the substructure, including asteel-and-wood rig floor on which to work, and the drawworks. Inside this largehoist is a drum on which a braided-steel cable is wrapped around. This cable isalso referred to as a drilling line or wire rope.




Figure 3-7: Completed rig-up

Rig-up involves the assembly of lots of additional equipment such as engines,steel tanks, or pits for drilling fluid, pumps, stairways and walkways, electricitygenerators, and water supply pumps.

Rigging-up operations offshore vary with the type of rig.

3.7 ExerciseDrilling Preparations Exercise (online)

Drilling Preparations Exercise (offline)



https://perception-resp.oilfield.slb.com/q4/open.dll?name=TBT&group=SWBT&session=9080177183515789

4-i Introduction to Drilling & Well Completion / Drilling Rig Components 4-iPROVISORY RELEASE

4 Drilling Rig Components

4.1 Rig System _____________________________________________________ 4-14.1.1 Power System _______________________________________________ 4-24.1.2 Hoisting System _____________________________________________ 4-34.1.3 Rotary System _______________________________________________ 4-44.1.4 Mud Circulation System ______________________________________ 4-54.2 Drilling Mud ____________________________________________________ 4-9

4.2.1 Mud circulation animation ____________________________________ 4-94.2.2 Mud removing cuttings animation ____________________________ 4-104.3 Mud Surface Equipment _______________________________________ 4-10

4.3.1 De-Gassers ________________________________________________ 4-114.3.2 De-Silters and De-Sanders __________________________________ 4-124.3.3 Centrifuges _________________________________________________ 4-124.4 Exercise _______________________________________________________ 4-13



4-ii Introduction to Drilling & Well Completion / Drilling Rig Components 4-iiPROVISORY RELEASE

Intentionally Blank



4-1 Introduction to Drilling & Well Completion / Drilling Rig Components 4-1PROVISORY RELEASE

4 Drilling Rig ComponentsBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

Components of a drilling rig include the following:

• rig system

• drilling mud

• mud surface equipment.

4.1 Rig SystemTo make hole, a drilling rig needs a multitude of equipment, which is dividedinto four basic systems:

• the power system

• the hoisting system

• the rotary system

• the mud circulation system.




4.1.1 Power System

Figure 4-1: SCR: Silicon-controlled rectifiers

The power system is the heart of the entire operation: without power, nothingon a rig operates. A normal drilling rig usually requires from 1,000 to 3,000horsepower.

The horsepower is delivered by diesel engines, called prime movers. A rig mayneed from two to four prime movers, depending on its size. The bigger the rig,the deeper it can drill, and the more power it needs.

Electrically powered rigs use turbines or generators to produce electrical power.This powers electrical motors to operate all the rotating equipment (like thedrawworks, rotary table, top drive, mud pumps, hoists, mud mixers, solids controlequipment, etc.).

Shown in the figure above is the SCR (Silicon Controlled Rectifiers) room,where the electric power is distributed among all the rig’s components: Hoists,accommodations, pumps, etc.




4.1.2 Hoisting System

Figure 4-2: Hoisting system components

The hoisting system is used to raise and lower pipe into the hole. In addition,it can be used to maintain weight on the bit. Illustrated here are the principalcomponents of the hoisting system.

Figure 4-3: Derrick



4-4 Introduction to Drilling & Well Completion / Drilling Rig Components 4-4PROVISORY RELEASEThe most striking feature of a drilling rig is the derrick. In some cases, the derrickcan be over 150 feet tall. The taller the derrick, the longer the section of pipe thatcan be handled when going in or pulling out of the hole. his can allow for theadding of two or three joints of pipe at the same time (called doubles and triples),which reduces downtime during the drilling process.

The drawworks consists of a large spool of cable and a brake driven by the rigengines. It provides the cable used by the pulleys hung in the derrick.

The remainder of the hoisting system consists of blocks and lines that do theactual hoisting:

• The crown block is a stationary set of pulleys attached to the top of thederrick that gives mechanical advantage in handling large loads.

• The traveling block is the lower, moving set of pulleys.

• The lines between the crown block and the traveling block are called drillinglines.

• The lines that run from the drawworks are called fast lines.

• The dead line is a portion of line that is tied down after running from thedrawworks and through the pulleys. The dead line allows for the changing ofline in the pulley system when wear or fatigue requires it.

4.1.3 Rotary System

Figure 4-4: Rotary system



4-5 Introduction to Drilling & Well Completion / Drilling Rig Components 4-5PROVISORY RELEASETo make hole, the drillstring turns, which causes the bit to cut into the rock andearth. In a vertical well, this rotary force is applied by the rotating equipment,which includes a swivel, a special length of pipe known as the kelly, the rotarytable, and a kelly bushing.

Some rigs have replaced the conventional swivel, the kelly, and the kelly bushingwith a powered swivel called the top drive.

Figure 4-5: Downhole motor

In highly deviated and horizontal wells, the torque required to turn the drillstringmakes rotary-table drilling impractical or impossible. In these situations, adownhole motor is used to rotate the drill bit. When a downhole motor is used,the drillstring does not rotate. Instead, the mud is used like hydraulic fluid tosupply power to the hydraulic motor, which is placed in the drillstring between thebit and the drill collar.

Also, a bent motor assembly is used to start deviation from vertical. The depth inwhich the deviation is started is commonly referred to as the kick off point (KOP).

4.1.4 Mud Circulation System

Figure 4-6: Mud circulation system



4-6 Introduction to Drilling & Well Completion / Drilling Rig Components 4-6PROVISORY RELEASERotary drilling has two fundamental characteristics:

• rotation

• the circulation of drilling fluid.

Here are the major components of the mud circulation system. As the nameimplies, the mud circulation system moves the drilling fluid (or mud) throughthe system.

Mud is used to do the following:

• remove the cuttings made by the drillbit from the hole

• cool and lubricate the bit

• keep the hole filled with fluid to provide primary well control.

Figure 4-7: Mud going to mud pit returns

The mud is pumped from the surface tank, through the standpipe, down thedrillstring, out of the jet or bit nozzles, up the annulus, and back to the surfacetanks. The annulus is the space between the wellbore and the drillstring.




Figure 4-8: Mud pit and mixing hopper

Mud is circulated, treated, and maintained in the surface tanks or mud pits whiledrilling. While historically these pits were just earthen holes, environmentalconcerns now require that the pits most often be aboveground containers thatprotect the environment from contamination. A mud-mixing hopper is attached tothe pit, so that materials can be added to the mud to meet changing requirementsfor density and other mud properties.

Figure 4-9: Mud pumped from pit to standpipe

A suction line attached to a triplex pump pulls the mud from the pit and pushes itout the discharge line to the standpipe. The standpipe is a section of steel pipemounted vertically to one leg of the derrick that transports the mud up the rig.

A flexible, very strong, reinforced rubber hose called the kelly hose, or rotaryhose, runs from the standpipe to the swivel, or the top drive. The kelly hoseallows the drillstring to move up and down, while the swivel or top drive allowsthe drillstring to rotate.




Figure 4-10: Drillstring

Below the swivel is the kelly, a square- or hexagonal-shaped pipe joint that canbe turned by the rotary table. This specially shaped joint of pipe allows torqueto be applied efficiently to the drilling, without the slippage that might occur witha round joint of pipe.

Below the kelly is the drill pipe, and below the drill pipe are the drill collar andthe drill bit. Drill collars are heavy, thick-walled joints of pipe inserted betweenthe drill pipe and the drill bit. The heavier weight of the drill collars add weightto the drill bit, which improves drilling performance.

Figure 4-11: Mud return line. Mud passing through shale shaker

When mud leaves the drill bit, it moves up the annulus to the mud return line,where it is taken back to the mud pit. Before entering the mud pit, the mudpasses through a shale shaker, which is a vibrating screen that separates out thecuttings from the mud before the mud is returned to the mud pit to be used again.




4.2 Drilling MudDrilling mud has many functions. The first and most important function is toremove cuttings from the hole as it is being drilled. To accomplish this task, themud must have sufficient viscosity to hold the cuttings in suspension as theymove up the annulus.

The mud must also cool and lubricate the drill bit to increase drilling efficiency.

Also, mud is used for primary well control by establishing hydrostatic pressure inthe wellbore that controls underground-formation pressures. The density of themud must often be adjusted to match the changing pressures of the wellbore.The greater the mud density, the greater the hydrostatic pressure created bythe mud.

In addition to these functions, drilling mud is also used to deposit a thinimpermeable filter cake on the wellbore surface. This filter cake blocks the poresof the formation and reduces fluid loss from the mud into the formation. Sincefluid loss changes the density and viscosity of the mud, significant fluid loss canresult in stuck equipment or formation damage. The filter cake protects againstthese problems.

Hydrostatic pressure is maintained via the column of mud balancing theformation or pore pressure.

Also, the drilling fluid is used to transmit hydraulic power to mechanical powerfor downhole motors.

4.2.1 Mud circulation animation

Multimedia 4-1: Mud flow. AnimationNOTE: Multimedia is currently available only in HTML publications.




4.2.2 Mud removing cuttings animation

Multimedia 4-2: Cutting removal. AnimationNOTE: Multimedia is currently available only in HTML publications.

4.3 Mud Surface Equipment

Figure 4-12: Shale shaker

In addition to the shale shaker discussed earlier, de-gassers, de-silters,de-sanders, and centrifuges are also used to clean mud before it is returneddown-hole. The shale shaker uses a vibrating screen to remove large cuttingsfrom the mud.




4.3.1 De-Gassers

Figure 4-13: De-gasser unit

Since gas trapped in the drilling mud can significantly change the density of thefluid and, therefore, its ability to maintain well control, it is important that this gasbe removed from the mud before it goes back downhole.

The two kinds of de-gassers currently in use are

• Gas buster, which is a gravity driven device. The mud is pushed from a smallpipe into a large cylinder, where the liquid mud falls to the bottom. The gasrises to the top where it is vented off or otherwise removed.

• Vacuum device that exposes the gas-filled mud to a vacuum, which draws offthe gas. This is more efficient, but also more costly, than the gravity method.




4.3.2 De-Silters and De-Sanders

Figure 4-14: De-silter

De-silters and De-sanders remove smaller particles or cuttings than does theshale shaker. They do not, however, remove the particulates of the mud thatmust remain to keep mud density correct for a given well application.

4.3.3 Centrifuges

Figure 4-15: Decanting centrifuge



4-13 Introduction to Drilling & Well Completion / Drilling Rig Components 4-13PROVISORY RELEASEA Decanting Centrifuge is a solids control equipment device that uses theprinciple of acceleration and separation of particles.

It is primarily used to eliminate or process fine particles from the drilling fluid (<4microns). The processing capacity is much smaller compared to hydrocyclones(de-sander and de-silter).

4.4 ExerciseDrilling Rig Components Exercise (online)

Drilling Rig Components Exercise (offline)





Intentionally Blank



5-i Introduction to Drilling & Well Completion / Well Control 5-iPROVISORY RELEASE

5 Well Control

5.1 “Kick” animation _______________________________________________ 5-15.2 Primary Well Control ___________________________________________ 5-15.3 Secondary Well Control ________________________________________ 5-2

5.3.1 Annular Preventer ____________________________________________ 5-35.3.2 Pipe Ram ___________________________________________________ 5-35.3.3 Blind Rams and Shear Rams _________________________________ 5-45.4 Exercise ________________________________________________________ 5-4



5-ii Introduction to Drilling & Well Completion / Well Control 5-iiPROVISORY RELEASE

Intentionally Blank



5-1 Introduction to Drilling & Well Completion / Well Control 5-1PROVISORY RELEASE

5 Well ControlBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

When the pressure in a formation is greater than the hydrostatic pressure of themud column, an underbalance condition exists. When formation fluid enters thewellbore, there is an increase in return circulation and return pressure. Thisincrease is called a "kick" and, if it is not controlled, a "blow out" can result. Ablowout is an uncontrolled escape of drilling fluid, gas, oil, or water from a well,caused by the formation pressure being greater than the hydrostatic head of thefluid in the hole.

Well control is divided into

• primary well control

• secondary well control.

5.1 “Kick” animation

Multimedia 5-1: Formation fluid enters the wellbore. AnimationNOTE: Multimedia is currently available only in HTML publications.

5.2 Primary Well ControlThe hydrostatic pressure of the drilling fluid provides primary well control. Aslong as this pressure is greater than the formation pressure, formation fluidscannot enter the wellbore and cause a loss of well control.

As formation pressures change at different depths in the drilling process, thedensity of the mud must be adjusted to maintain well control.




5.3 Secondary Well Control

Figure 5-1: Secondary well control

Secondary well control is provided by a series of valves and cutoffs at thewellhead, called the BOP (or blowout preventer) stack. Here are typicalcomponents of the BOP stack.

• the annular preventer

• pipe rams

• blind rams

• shear rams.




5.3.1 Annular Preventer

Figure 5-2: Annular preventer

The annular preventer is a dynamic seal, which can seal the annulus betweenthe drill pipe and the side of the hole.

The annular preventer works with various sizes of pipes or casing and does nothave to be changed as pipe entering the hole changes diameter. Additionally, thedrillstring can still be rotated with the annular preventer closed.

5.3.2 Pipe Ram

Figure 5-3: Pipe rams

The pipe ram is also an annular seal, but it is static and fits only one specificsize of pipe. As pipe sizes change, the pipe rams must be changed to matchthe diameters of the drill pipe.



5-4 Introduction to Drilling & Well Completion / Well Control 5-4PROVISORY RELEASEThe drillstring cannot be rotated with the pipe rams closed.

5.3.3 Blind Rams and Shear Rams

Figure 5-4: Blind rams

Blind rams seal only on open hole, and blind-shear rams cut or shear the pipeand then seal the hole. The shear rams cut the pipe, and the blind rams sealoff the hole.

Both annular and ram preventers operate with hydraulic fluid, which is storedunder pressure in several steel cylinder units called accumulators. These unitsare controlled from a remote-control unit on the rig floor.

5.4 ExerciseWell Control Exercise (online)

Well Control Exercise (offline)




6-i Introduction to Drilling & Well Completion / Rig Operations 6-iPROVISORY RELEASE

6 Rig Operations

6.1 Rate of Penetration _____________________________________________ 6-16.2 Adding New Pipe Joints ________________________________________ 6-1

6.2.1 Addition of new pipe joints to drillstring animation ______________ 6-26.3 Trip Equipment In and Out of Hole ______________________________ 6-26.4 Optimum Quality and Cost _____________________________________ 6-2

6.4.1 Important Items to Control ____________________________________ 6-26.4.1.1 Weight on the Drill Bit _____________________________________ 6-36.4.1.2 Torque ___________________________________________________ 6-36.4.1.3 Bit Wear _________________________________________________ 6-4

6.5 Exercise ________________________________________________________ 6-4



6-ii Introduction to Drilling & Well Completion / Rig Operations 6-iiPROVISORY RELEASE

Intentionally Blank



6-1 Introduction to Drilling & Well Completion / Rig Operations 6-1PROVISORY RELEASE

6 Rig OperationsBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

This section on rig operations will address

• rate of penetration

• adding new pipe joints

• trip equipment in and out of the hole

• optimum quality and cost.

6.1 Rate of PenetrationThe most important operation in drilling is to make hole. The rate of penetrationis a record of how efficient the drilling team is at making hole. To maintain anoptimum ROP, a sharp bit must be kept rotating at the bottom of the hole.

Variations on the drilling rate can indicate bit wear, formation changes, or whetherweight on bit, rotary speed, and hydraulic are being properly handled.

6.2 Adding New Pipe JointsAs the depth of the hole increases, pipe joints must be added to keep the bit onthe bottom. Here is the process of adding new pipe joints to the drillstring:

1. When the kelly reaches its lowest point, the drillstring is held and suspendedby slips so that it cannot fall into the hole; then the kelly is removed.

2. A joint of pipe is then placed in the mousehole to hold it in a vertical positionso that it can be attached to the kelly.

3. The new joint is then lifted by the hoist and attached to the drillstring.

4. The slips are then released, the drillstring is lowered to the bottom of thehole, and drilling is resumed.




6.2.1 Addition of new pipe joints to drillstring animation

Multimedia 6-1: Drillpipe pick up and addition to drillstring. AnimationNOTE: Multimedia is currently available only in HTML publications.

6.3 Trip Equipment In and Out of HoleThroughout the drilling operation, the drillstring must at times be removedcompletely from the wellbore. Sometimes this must be done to change the drillbit. At other times, this must be done to change the diameter of the drillstring, orto run special tools or equipment down the wellbore. During trips in and out ofthe hole, each joint must be removed or added as described above.

6.4 Optimum Quality and CostThroughout a drilling operation, emphasis must be placed on both optimizing therate of penetration and minimizing costs.

Drilling too quickly can result in damaged or broken drillstrings, which canincrease costs. Every effort should be made to drill efficiently, but also withminimum risk of damaging equipment, which could lead to costly downtime atthe drilling site.

6.4.1 Important Items to ControlImportant items to control are

• weight on the drill bit

• torque

• bit wear.




6.4.1.1 Weight on the Drill Bit

Figure 6-1: Weight of string and bit

One important consideration in maintaining optimum drilling parameters is theweight on the drill bit. While weight is measured by a scale at the crown block,this weight may not be the same as the weight on the drill bit.

Both the friction of the wellbore on the drillstring and the buoyancy of thedrillstring in the mud to reduce the force at the drill bit.

When the drill bit is on bottom and weight is applied on the bit, the section of pipeimmediately above the bit is in compression. The pipe hanging from the hookat surface is still under tension. Somewhere along the drillstring, the load goesfrom compression to tension and the axial force is zero. This point is called theNeutral point. The Neutral point location is affected by frictional and bouyancyforces. Enough heavyweight pipe (Drill Collars) are added above the bit to keepthe drill pipe in tension all the time.

6.4.1.2 Torque

In addition to weight on the drill bit, it is also important to control torque (ortwisting) on the drillstring. Excessive torque can result in broken joints, whichcan fall into the wellbore and be very difficult to remove.




6.4.1.3 Bit Wear

Also, bit wear must be monitored. A worn drill bit will turn easily in the wellbore,but it will not cut rock or earth and allow for continued penetration. A decrease inROP and a change in torque on the bit are some indicators of a worn out bit.

6.5 ExerciseRig Operations Exercise (online)

Rig Operations Exercise (offline)




7-i Introduction to Drilling & Well Completion / Completions 7-iPROVISORY RELEASE

7 Completions

7.1 Bottomhole Completions _______________________________________ 7-17.1.1 Perforating __________________________________________________ 7-27.1.2 Methods of Perforating _______________________________________ 7-37.2 Tubing _________________________________________________________ 7-4

7.2.1 Tubing Design Requirements _________________________________ 7-57.2.2 Multi-Phase Flow Regimes ___________________________________ 7-77.3 Wellhead and Chokes __________________________________________ 7-87.4 Artificial Lift ____________________________________________________ 7-9



7-ii Introduction to Drilling & Well Completion / Completions 7-iiPROVISORY RELEASE

Intentionally Blank



7-1 Introduction to Drilling & Well Completion / Completions 7-1PROVISORY RELEASE

7 CompletionsBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

Topics discussed in this section will be:

• Casing

• Bottomhole Completions

• Tubing

• Wellhead and Chokes

• Artificial Lift.

7.1 Bottomhole CompletionsMany factors affect whether a well is cased or left as an openhole completion. Anopenhole completion is one where there is no casing or liner across the producingformation. A cased hole completion has casing across the producing formation.

Figure 7-1: Openhole completion




Figure 7-2: Cased hole completion

7.1.1 PerforatingIn order for the formation fluid to enter the wellbore in a cased hole completion,there must be a pathway created from the wellbore through the casing andcement sheath to the reservoir. This pathway is called a perforation. Theperforation scheme depends on many factors, including the type of stimulationtreatment needed. There are two important terms that describe the perforationsin a completion. The first is shots per foot (SPF). This is the number ofperforations per vertical foot of casing. The second is perforation phasing. Thisdescribes the angle (in degrees) between the perforations. The diagram belowshows 90 degrees phasing. The length of penetration (also called the perforationtunnel length) can be estimated. All of this information can be gathered from thecompany that does the perforating or the operator.




Figure 7-3: Perforation phasing. The most common perforation phasingconfigurations are 0° , 60°, 90°, 120°, and 180°.

7.1.2 Methods of Perforating

Figure 7-4: Methods of perforating

There are three ways that perforating is done. These methods of perforating aredependent on the bottomhole pressure at the time of perforating.

• Underbalanced perforating – In this method of perforating, the bottom holepressure in the casing is less than the reservoir pressure. This allows for asurge of formation fluid to enter the wellbore cleaning up the debris. Thisrequires special equipment to control the well during perforation operations.



7-4 Introduction to Drilling & Well Completion / Completions 7-4PROVISORY RELEASE• Overbalanced perforating – In this method of perforating the bottomholepressure is greater than the reservoir pressure of the zone being perforated.This allows for the wellbore fluid to surge into the formation compacting thedebris in the perforation tunnels. This method is simple and does not requirespecial equipment.

• Extremely overbalanced perforating – This method of perforating requiresthat the bottomhole pressure be greater than the closure pressure (orfracturing pressure) of the reservoir. The initial surge of wellbore fluid into thereservoir will cause many small fractures.

7.2 TubingTubing is small diameter pipe that is run inside the casing to protect the casingfrom corrosion. It can be pulled and replaced when necessary, unlike casing.Tubing is typically run to a depth right above the producing zone. There is usuallya tubing or production packer set near the end of the tubing string. The packerseals the casing tubing annulus to prevent produced fluids from contacting thecasing and helps to centralize the tubing. Packers can be classified dependingon how freely the tubing can move. There are three classifications:

Figure 7-5: Free or unlimited motion. Tubing can move both up and down.




Figure 7-6: Limited motion. Tubing is limited to movement in one direction, usually up.

Figure 7-7: No motion. Tubing cannot move up or down.

7.2.1 Tubing Design RequirementsWhen selecting a tubing string for a completion, many things must be takeninto consideration. The forces and stress that will be exerted on the tubing byfluids, completion components, temperature changes, pressure changes andfriction must be evaluated. These factors can change throughout the life of thecompletion. Production rate and fluid must also be accounted for in the design.

There are four principle effects that can cause length and force changes in thetubing string. They are the piston effect, buckling effect, ballooning effect andtemperature effect.




Figure 7-8: Buckling effect

Figure 7-9: Ballooning effect




Figure 7-10: Temperature effect

7.2.2 Multi-Phase Flow RegimesThere are four principal multi-phase flow regimes recognized in oil and gas wells.

Figure 7-11: Bubble flow. Small evenly distributed gas bubbles in a continuous liquid phase

Figure 7-12: Slug flow. Series of gas pockets (called Taylor bubbles) unevenlydistributed throughout continuous liquid phase




Figure 7-13: Annular or mist flow. Entrained liquid in continuous gas phase;annular film of liquid along sides of tubing/casing

Figure 7-14: Transition or churn flow. Chaotic flow pattern where neither phase iscontinuous; liquid can appear to move both up and down in the tubing.

7.3 Wellhead and ChokesA wellhead is a permanent, large, forged or cast steel fitting on top of the wellat surface. Wellhead equipment includes the casing head, the tubing head,Christmas tree, stuffing box and pressure gauges.

A well is rarely allowed to produce at an unlimited rate because this can result ina rapid decrease in production and ultimately reduce the total recovery. Also,gas bubbles can form due to the large pressure drop in the near wellborearea blocking reservoir rock pores and thus causing production to decrease.Therefore, production is controlled by surface and subsurface chokes. A chokehas a small hole in it that the fluid flows through called an orifice. The smaller theorifice the lower the production rate. Chokes can either be positive (fixed orificesize) or adjustable (orifice size can be changed).




7.4 Artificial LiftGas wells flow to the surface unassisted, however many oil wells are not ableto flow to the surface due to the hydrostatic pressure of the fluid column. Only4% of oil wells in the United States have sufficient reservoir pressure to produceon their own. In cases where the oil cannot flow by itself, a method of artificiallift is utilized. Common methods include sucker rod pumps, gas lift and electricsubmersible pumps (ESP). These methods help lift the column of oil to thesurface.




Intentionally Blank



8-i Introduction to Drilling & Well Completion / Casing 8-iPROVISORY RELEASE

8 Casing

8.1 Function _______________________________________________________ 8-18.2 Casing Types ___________________________________________________ 8-1

8.2.1 Conductor Casing ____________________________________________ 8-28.2.2 Surface Casing ______________________________________________ 8-38.2.3 Intermediate Casing __________________________________________ 8-48.2.4 Liners _______________________________________________________ 8-48.2.5 Production Casing or Liners __________________________________ 8-5



8-ii Introduction to Drilling & Well Completion / Casing 8-iiPROVISORY RELEASE

Intentionally Blank



8-1 Introduction to Drilling & Well Completion / Casing 8-1PROVISORY RELEASE

8 CasingBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

This section will address the

• functions

• types of well casing.

8.1 Function

Figure 8-1: Types of casing and lithology

A series of casing strings is necessary to complete a well. Casing is large piperun into the wellbore to protect the integrity of the hole and to isolate variousformations from each other and the surface.

8.2 Casing TypesThere are several types of casings, each with its own specific function. Casingdesign is determined by the following:

• well depth

• completion procedures to be used



8-2 Introduction to Drilling & Well Completion / Casing 8-2PROVISORY RELEASE• the existence of lost circulation or high-pressure zones in the formation

• existence of corrosive waters or gases in the formation

• government regulations.

Types of casings include the following:

• conductor casing

• surface casing

• intermediate casing

• liners

• production casing/liners.

8.2.1 Conductor Casing

Figure 8-2: Conductor casing

Conductor casing is run into the hole from the surface to below the topsoil orother unconsolidated earth. Its primary function is to keep the earth under thedrilling rig from caving into the wellbore during later drilling operations. Conductorcasing is driven or drilled to 100 to 300 feet.




8.2.2 Surface Casing

Figure 8-3: Surface casing

Surface casing is run into the hole below any freshwater aquifers found atrelatively shallow depths. It is used to isolate these freshwater zones to preventcontamination of fresh water by formation fluids. Very often, the surface casing isthe first string to which BOPs are connected.




8.2.3 Intermediate Casing

Figure 8-4: Intermediate casing

Intermediate casing is run inside the surface casing to isolate hole problemsand maintain casing integrity. This is normally called the long string and is setbefore the production casing or liner. These zones may be weak, fractured,high-pressure, plastic formations.

8.2.4 Liners

Figure 8-5: Liner



8-5 Introduction to Drilling & Well Completion / Casing 8-5PROVISORY RELEASEA liner is a string of casing that does not extend all the way to the surface. It ishung or seated inside the previous casing string, overlapping and secured withinthe larger pipe. Liners are used in deep wells to reduce iron costs associatedwith running iron all the way to the surface.

8.2.5 Production Casing or Liners

Figure 8-6: Production casing

Production casing and production liners are often called the long string. Whileboth are used to bring formation fluids up the wellbore, the difference betweenproduction casing and production liner is whether the string reaches all the wayto the surface or only as high as an intermediate casing above it.

This string of casing serves to isolate the reservoir from undesirable fluids in theproduction formation and from other zones penetrated by the wellbore.

For production, the liner is perforated, and fluid flows into the wellbore whilethe wellbore is secured and held open.




Intentionally Blank



9-i Introduction to Drilling & Well Completion / Special Operations 9-iPROVISORY RELEASE

9 Special Operations

9.1 Offshore Operations ___________________________________________ 9-19.2 Directional Drilling _____________________________________________ 9-2

9.2.1 Air Drilling ___________________________________________________ 9-59.2.2 Fishing ______________________________________________________ 9-59.3 Exercise ________________________________________________________ 9-5



9-ii Introduction to Drilling & Well Completion / Special Operations 9-iiPROVISORY RELEASE

Intentionally Blank



9-1 Introduction to Drilling & Well Completion / Special Operations 9-1PROVISORY RELEASE

9 Special OperationsBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

While most drilling has been done onshore in vertical or only slightly deviatedwells, more and more drilling is being done offshore and in highly deviated orhorizontal wells. In addition, certain well conditions may require drilling with airrather than mud. Also, lost tools, equipment, or strings can be recovered by"fishing" for these items. All of these are examples of special drilling operations.

9.1 Offshore Operations

Figure 9-1: Drilling ship, semi-sub and fixed platforms

Here is a drilling ship (used more often on exploratory wells or at the greatestwater depths) and a semi-submersible drilling platform (used in deepwater fielddevelopment). Offshore operations require special considerations because ofweather, logistics, environmental or regulatory issues.

Fixed platforms are used when large fields are developed and support facilitiesare required.




9.2 Directional Drilling

Figure 9-2: Kick-off point and deviation

Controlled directional drilling is defined as deviating a wellbore along a plannedcourse to an underground target located a given horizontal distance from thetop of the hole.

To achieve that objective, the well can have a deviation angle from one to ninetydegrees (horizontal). Directional drilling is used to run several wells from one siteinto different pay zones or different parts of the same pay zone.

Directional drilling can also be used to avoid other previously drilled wells froma busy platform.

This is often the case in the following:

• environmentally sensitive areas (e.g., the Arctic)

• offshore operations

• towns and cities.

This method allows a single drilling platform to be used to open a number ofproduction wells. It is also used to correct a well trajectory or sidetrack anobstruction in the well.



9-3 Introduction to Drilling & Well Completion / Special Operations 9-3PROVISORY RELEASEDirectional drilling can also be used to expose more of the wellbore to the payzone, and thereby increase the production from a specific pay zone.

Directional drilling can be accomplished by using either of the following:

• bent sub

• whipstock.

Figure 9-3: Drilling motor-bit

A bent sub is a special piece of equipment that tilts the drilling bit a few degrees(normally between 1 and 3 degrees). The bent sub is run just above the drillingmotor-bit combination. Like a bent needle, a drillstring equipped with a bentsub will deviate from a straight path.




Figure 9-4: Whipstock

A whipstock is a slanted guide that forces the toolstring to follow the desireddirection.

The point where the well deviates from the vertical path is known as the Kick-OffPoint (KOP).

Figure 9-5: Kick-off point (KOP)



9-5 Introduction to Drilling & Well Completion / Special Operations 9-5PROVISORY RELEASEHere are some examples of deviated wells being used to access a pay zoneunder an inhabited area and a blown-out well.

9.2.1 Air DrillingAir drilling is often used in formations where lost-circulation problems makethe use of drilling mud impractical. Drilling rates are faster when air is usedthan when mud is used.

Although air drilling is much less expensive than mud drilling, it can only be donein zones without high pressure or large amounts of water in the formation.

To perform air drilling, compressors are used to pump air down-hole, while aspecial foam or mist is used to lubricate the bit.

9.2.2 FishingOften, through no fault of the driller, equipment, tools, or pipe may be lostdown-hole. This "junk," as it is called, must be removed from the hole beforedrilling can be resumed. This operation is one of the most expensive andpotentially dangerous things that can go wrong in drilling a well.

Removing the material is called "fishing." Fishing requires specialized equipment,such as overshots, spears, magnets, baskets, or hydraulic jars, as well as atrained operator.

9.3 ExerciseSpecial Operations Exercise (online)

Special Operations Exercise (offline)





Intentionally Blank



10-i Introduction to Drilling & Well Completion / Summary 10-iPROVISORY RELEASE

10 Summary



10-ii Introduction to Drilling & Well Completion / Summary 10-iiPROVISORY RELEASE

Intentionally Blank



10-1 Introduction to Drilling & Well Completion / Summary 10-1PROVISORY RELEASE

10 SummaryBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

In this module, you learned about

• the history of drilling

• drilling preparation procedures

• components of a drilling rig

• well control

• rig operations

• casing

• special operations



10-2 Introduction to Drilling & Well Completion / Summary 10-2PROVISORY RELEASE

Intentionally Blank



11-i Introduction to Drilling & Well Completion / Take the module test 11-iPROVISORY RELEASE

11 Take the module test



11-ii Introduction to Drilling & Well Completion / Take the module test 11-iiPROVISORY RELEASE

Intentionally Blank



11-1 Introduction to Drilling & Well Completion / Take the module test 11-1PROVISORY RELEASE

11 Take the module testBasic, density, drilling, well completion, SWBT, WBT,IT Modules, Interface, WCS, WPC, CTS, TBT

To receive credit for completing this module, you must take and pass the moduletest. A score of 90% or higher is required to pass the test. If you are viewing thismodule online, you must take the test for this module from the SchlumbergerLearning Management System (LMS).

To take the test online

If you do not know how to take a test from the LMS, go to:http://intouchsupport.com/intouch/MethodInvokerpage.cfm?caseid=4253433 forinstructions.

If you already know how to use the LMS, click here to go to the LMS and takethe test.

To take the test offline

If you are viewing this module offline, click here to take the module test offline.After you take the test, print the test results and have your manager enter theresults in the LMS.



http://intouchsupport.com/intouch/MethodInvokerpage.cfm?caseid=4253433

https://lms.slb.com/SabaWeb

introduction to drilling well completions 4261888 01[1]

Documents

provisoryedms

completion

completion

completion

mud circulation

mud return

edms uid

drilling uid