Rotary Drilling System:Introduction

Drilling Engineering 1 Course3rd Ed. , 3rd Experience

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http://about.me/Alaminia

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1. Introduction2. Types of rigs3. Personnel at Rig Site4. How to drill a well

2 drilling goalsto build the well according to its purpose and in a

safe manner (i.e, avoiding personal injuries and avoiding technical problems)

to complete it with minimum costThereto the overall costs of the well during its lifetime in

conjunction with the field development aspects shall be minimized.

Fall 14 H. AlamiNia Drilling Engineering 1 Course (3rd Ed.) 4

ParametersThe overall cost minimization, or optimization, may

influence the location from where the well is drilled,

(e.g., an extended reach onshore or above reservoir offshore), the drilling technology applied,

(e.g., conventional or slim–hole drilling, overbalanced or underbalanced, vertical or horizontal, etc),

and which evaluation procedures are run to gather subsurface information to optimize future wells.


drilling technologiesTo build a hole,

different drilling technologies have been invented:Percussion drilling

Cable drilling “Pennsylvanian drilling”

Drillstring• With mud Quick

percussion drilling• Without mud

“Canadian drilling”

Rotating drilling (Will be discussed exclusively)Full cross-section drilling

• Surface driveno Rotary bito Rotary nozzle

• Subsurface driveno Turbine drillingo Positive

displacement motor drilling

o Electro motor drilling

Annular drilling• Diamond coring• Shot drilling


drilling technologies (Cont.)Special techniques

Abrasive jet drillingCavitating jet drillingElectric arc and plasma

drillingElectric beam drillingElectric disintegration

drillingExplosive drillingFlame jet drillingImplosion drilling

Laser drillingREAM drillingReplaceable cutterhead

drillingRocket exhaust drillingSpark drillingSubterrene drillingTerra drillingThermal-mechanical

drillingThermocorer drilling


drilling rig

A drilling rig is a device used to drill, case and cement oil and gas wells.The correct procedure for selecting and sizing a

drilling rig is as follows:Design the wellEstablish the various loads to be expected during drilling

and testing operations and use the highest loads. This point establishes the DEPTH RATING OF THE RIG. Compare the rating of existing rigs with the design loadsSelect the appropriate rig and its components.


Rig Classification

Rotary Drilling Rigs

Land

Mobile

Jackknife Portable Mast

Conventional

Marine

Bottom Supported

Platform

Self Contained Tendered

Barge

Jack-Up Submersible

Floating

Drill Ship Semi Submersible

Caisson Vessel Tension Leg


Land: Mobile Rigs

Jackknife rig Portable mast


Marine: Bottom Supported Platform rigs

Self Contained Tendered


Marine: Other Bottom Supported rigs


A Jack–Up rig A submersible platformA cantilever rig on a barge

Marine: Floating rigs


Caisson vessel (also called sparbuoy) and Diagram of a spar–buoy

A tension–leg platform

A drill–ship Semi–submersible vessel

comparison of drilling rigs


Well ClassificationsAccording to a wells final depth, it can be classified

into:Shallow well: < 2000mConventional well: 2 000m – 3500mDeep well: 3500m – 5000mUltra deep well: > 5 000m

With the help of advanced technologies in MWD/LWD and extended reach drilling techniques, horizontal departures of more than10000m are possible today.


PersonnelPeople directly involved in drilling a well are

employed either by the operating company, the drilling contractor, or one of the service and supply companies

The operating company is the owner of the lease/block and principal user of the services provided by the drilling contractor and the different service companies.


TasksSince drilling contractors are companies that

perform the actual drilling of the well, their main job is to drill a hole to the depth/location and specifications set by the operator. Along with hiring a drilling contractor, the operator

usually employs various service and supply companies to perform logging, cementing, or any other special operations, including maintaining

the drilling fluid in its planed condition.


drilling crewsMost drilling crews consist of a tool pusher, a driller, a derrickman, a mud logger, and two or three rotary helpers

(also called floormen or roughnecks).

Along with this basic crew configuration the operator sends usually a representative, calledcompany man to the rig.

For offshore operations the crews usually consist of many more employees.


crew requirementsTool Pusher: supervises all drilling operations and is the leading man

of the drilling contractor on location.

Company Man: The company man is in direct charge of all company’s

activities on the rig site. He is responsible for the drilling strategy as well as the

supplies and services in need. His decisions directly effect the progress of the well.


crew requirements (Cont.)Driller: The driller operates the drilling

machinery on the rig floor and is the overall supervisor of all floormen. He reports directly to the tool

pusher and is the person who is most closely involved in the drilling process. He operates, from his position at the

control console, the rig floor brakes, switches, levers, and all other related controls that influence the drilling parameters. In case of a kick he is the first person

to take action by moving the bit off bottom and closing the BOP.


Inside a control console


crew requirements (Cont.)Derrick Man: The derrickman works on the so–

called monkeyboard, a small platform up in the derrick, usually about 90 ft above the rotary table. When a connection is made or

during tripping operations he is handling and guiding the upper end of the pipe.

During drilling operations the derrickman is responsible for maintaining and repairing the pumps and other equipment as well as keeping tabs on the drilling fluid.


crew requirements (Cont.)Floormen:

During tripping, the rotary helpers are responsible for handling the lower end of the drill pipe as well as operating tongs and wrenches to make or break up a connection.

During other times, they also maintain equipment, keep it clean, do painting and in general help where ever help is needed.

Mud Engineer, Mud Logger: The service company who provides the

mud almost always sends a mud engineer and a mud logger to the rig site. They are constantly responsible for logging what is happening in the hole as well as maintaining the proper mud conditions.


drilling processIn rotary drilling, the rock is destroyed by the action

of rotation and axial force applied to a drilling bit. The drilling bit is located at the end of a drill string

which is composed of drill pipes (also called joints or singles), drill collars, and other specialized drilling tools.Drill collars are thick walled tubes responsible for

applying the axial force at the bit. Rotation at the bit is usually obtained by rotating the

whole drill string from the surface.


A simplified drillstringThe components of the

drillstring are:DrillpipeDrillcollarsOther Accessories called bottom

hole assembly (BHA) including:Heavy-walled drillpipe (HWDP)StabilisersReamersDirectional control equipmentEtc.


Functions of the drillstring

The drill string is the mechanical linkage connecting the drillbit at the bottom of the hole to the rotary drive system on the surface. The drillstring serves the following functions:transmits rotation to the drillbit exerts weight on the bit;

the compressive force necessary to break the rockguides and controls the trajectory of the bit; andallows fluid circulation

which is required for cooling the bit and for cleaning the hole.


drilling process (Cont.)A large variety of bit models and designs are available in

industry. The choice of the right bit,

based on the characteristics of the formations to be drilled, and the right parameters (weight on bit and rotary speed) are the two most basic problems the drilling engineer faces

during drilling planning and drilling operation.

The cuttings are lifted to the surface by the drilling fluid. At the surface, the cuttings are separated from the drilling

fluid by several solid removal equipment. Drilling mud is picked up by the system of pumps and

pumped again down the hole.


connectionAs drilling

progresses, new joints are added to the top of the drill string increasing its length, in an operation called connection. A pipe slips is

used to transfer the weight of the drillstring from the hook to the master bushing.


round tripAs the bit gets dull, a round trip is performed to

bring the dull bit to the surface and replace it by a new one. A round trip is performed also to change the BHA. The drillstring is also removed to run a casing

string. The operation is done by removing stands of two (“doubles”), three (“thribbles”) or even four (“fourbles”) joints connected, and stacking them upright in the rig.


Removing one stand of drillstring


wiper tripSometimes the drillstring is not completely run out

of the hole. It is just lifted up to the top of the open-hole

section and then lowered back again while continuously circulating with drilling mud. Such a trip, called wiper trip, is carried out to clean the hole from remaining cuttings

that may have settled along the open–hole section.


1. (CDF) Jorge H.B. Sampaio Jr. “Drilling Engineering Fundamentals.” Master of Petroleum Engineering. Curtin University of Technology, 2007. Chapter 1 and 2

2. (WEC) Rabia, Hussain. Well Engineering & Construction. Entrac Consulting Limited, 2002.Chapter 16

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