Hole (Borehole) Equipments (1)

7/28/2019 Hole (Borehole) Equipments (1)

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The direction in which education starts a man will determine hisfuture life. Plato, The RepublicAdvicesThe objective of the educational process of this course is to teachthe students to seek and understand themselves any existinginformation in e-books and e-papers, present in e-libraries ofuniversities and companies throughout the World.Regarding the most recent worldwide solutions of the constructionof rotary drilling rigs, I have proposed accessing (via links or keywords)the enormous technical information available on the Internet. Thestudents are invited to search for different links of the specializedtechnical e-literature. Some words, underlined and written in blue, ofthe electronic form of the book, lead directly to specialized links(accessed September 10, 2012).Thus, only by means of this approach, it is possible to reach anoptimal prioritization of the information taught during the specializedcourse, structure compared to the similar achievements from theworldwide e-literature.The advantage of this type of approach is that the students arelearning how to search(on www.google.com, www.books.google.com, www.onepetro.org,www.sciencedirect.com and many others)for information and how to practically solve the technical problems thatthey will meet in their future career.

Overview

Rotary drilling is a method of making holes that relies on continuous

circular motion of the bit, which breaks, crushes or cuts the rock at the

bottom of the hole. Please visit the links:

http://www.youtube.com/watch?v=kvIuRdEZe0U

http://www.youtube.com/watch?v=b8Vf_ZrNNzs&feature=related

http://www.youtube.com/watch?v=U2ms95HX0l4&feature=related

http://www.youtube.com/watch?v=ufYMgHa0d18
http://www.google.com/http://www.books.google.com/http://www.onepetro.org/http://www.sciencedirect.com/http://www.youtube.com/watch?v=kvIuRdEZe0Uhttp://www.youtube.com/watch?v=kvIuRdEZe0Uhttp://www.youtube.com/watch?v=b8Vf_ZrNNzs&feature=relatedhttp://www.youtube.com/watch?v=b8Vf_ZrNNzs&feature=relatedhttp://www.youtube.com/watch?v=U2ms95HX0l4&feature=relatedhttp://www.youtube.com/watch?v=U2ms95HX0l4&feature=relatedhttp://www.youtube.com/watch?v=ufYMgHa0d18http://www.youtube.com/watch?v=ufYMgHa0d18http://www.youtube.com/watch?v=ufYMgHa0d18http://www.youtube.com/watch?v=U2ms95HX0l4&feature=relatedhttp://www.youtube.com/watch?v=b8Vf_ZrNNzs&feature=relatedhttp://www.youtube.com/watch?v=kvIuRdEZe0Uhttp://www.sciencedirect.com/http://www.onepetro.org/http://www.books.google.com/http://www.google.com/


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http://www.youtube.com/watch?v=ku8xvUhFUak&feature=related

From watching the links above, it can see that although the

technology is simple, the equipments required are complicated. To be able

to understand, it is necessary to use a hierarchical presentation from the

simple principles, move gradually to the complex construction. We willbegin with the presentation of comparative drilling methods.

Rotary drilling method is much more efficient than the previous

alternative method, cable tool drilling. Rotary drilling is a continuous

process, because cuttings (fragments of rock), filings (resulting from wear

of drill bit) and gases (from rocks) are continuously removed by drilling

fluid, which is cleaned and is reintroduced in the initial circuit. Thus, the

fluid flow is continuous at all times, from the surface downward through the

inside of drillstring and bit, and back up the wellbore to the surface throughthe annular space, the area between the hole wall and the outside wall of

the tubular.

At the old method, cable tool drilling, the operations were

discontinuous and cuttings and filings removal were inefficient. This

difference in efficiency becomes particularly significant as the depth of the

hole grows. For this reason, the most common drilling rigs in use today are

rotary drilling rigs.

In the present, there are a lot of researches on Advanced Drilling

Technologies for making the holes, as for example: High Pressure Jet,Abrasive Jet, Cavitations Jet, Electric Arc and Plasma, Electron Beam,

Electric Disintegration, Explosive Drills, Flame Jet,Rocket Exhaust, Spark

Drills, Implosion Drills, Laser Drills, Terra-Drill. Since the rig rate (rental

cost of the rig) is one of the most influencing cost factors to the total cost of

a well, careful selection of the future technology type will be vital for a next

successful drilling project.

http://www.nov.com/Engineering_and_Project_Management/New_Technol

ogy_Development.aspx

http://www.nov.com/Downhole/Advanced_Drilling_Solutions.aspx

http://www.bakerhughes.com/products-and-services/drilling

In the following will refer only to the rotary drilling technology.
http://www.youtube.com/watch?v=ku8xvUhFUak&feature=relatedhttp://www.youtube.com/watch?v=ku8xvUhFUak&feature=relatedhttp://www.nov.com/Engineering_and_Project_Management/New_Technology_Development.aspxhttp://www.nov.com/Engineering_and_Project_Management/New_Technology_Development.aspxhttp://www.nov.com/Engineering_and_Project_Management/New_Technology_Development.aspxhttp://www.nov.com/Downhole/Advanced_Drilling_Solutions.aspxhttp://www.nov.com/Downhole/Advanced_Drilling_Solutions.aspxhttp://www.bakerhughes.com/products-and-services/drillinghttp://www.bakerhughes.com/products-and-services/drillinghttp://www.bakerhughes.com/products-and-services/drillinghttp://www.nov.com/Downhole/Advanced_Drilling_Solutions.aspxhttp://www.nov.com/Engineering_and_Project_Management/New_Technology_Development.aspxhttp://www.nov.com/Engineering_and_Project_Management/New_Technology_Development.aspxhttp://www.youtube.com/watch?v=ku8xvUhFUak&feature=related


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1. Process of Rotary Drilling

A method of making holes that relies on continuous circular motion of

the bit, which breaks the rock at the bottom of the hole. This method is

much more efficient than the alternative and previous, in time, cable tooldrilling. Rotary drilling is a nearly continuous process, because cuttings are

removed as drilling fluids circulate through the bit and up the wellbore to

the surface. Cable tool operations are discontinuous and cuttings removal

is inefficient. This difference in efficiency becomes particularly significant as

the depth of the hole grows, such as the rotary method is required to

successfully and economically drill the hole.

In the present, there are a lot of researches on other Advanced

Drilling Technologies for making the holes. They try to use the highpressure jet with abrasive particles, the electric fields, the burning flame or

laser to disintegrate the rocks for the hole construction.

Newest downhole solutions (for drilling, fishing, well intervention, re-

entry and well completion applications) can be found at

http://www.nov.com/Downhole.aspx

To rotary drilling a vertical hole or a directional hole, relating to bit-

rock interaction, several processes are needed, such as:

- a force acting downward on a drill bit;

- rotation torque of the drill bit;

- circulation of fluid, called drilling fluid (liquid, gas, or gasified liquid),

from the surface to the bottom and back to the surface.

As drilling advances, relating to the downwards advancement of thebit, borehole equipments are needed, including:

- drillstring, for downward sending the mechanical power and flowing

(upward or downward) of drilling fluid;

- casing stringis intended to strengthen the walls of the wellbore and to

prevent any transfer of fluids between the borehole and thesurrounding formations.

Depending on the specific formation or reservoir conditions, drillingmay be stopped to insert casing string and cement it to the outercircumference of the borehole.
http://www.nov.com/Downhole.aspxhttp://www.nov.com/Downhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstring.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstring.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstring.aspxhttp://www.nov.com/Downhole.aspx


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In order to continue drilling, the new drill bit must pass through anyinstalled casing. The borehole below of each string of casing is smallerthan the borehole above. In deep wells, the intermediate strings ofprogressively smaller-diameter casing may be used during the drillingprocess.

The casing strings used in the design and construction of a wellborecan be configured in a range of sizes and depths, with the casing settingdepth for each string determined by the formation characteristics and localavailability.

For successive suspension, of these casing strings, is necessary toadd, to the top of the borehole, a component, called

- casing head(Casing Head).

Because the pressure in the borehole must be controlled (managed),several equipments are needed, including:

- blow out preventer for sealing the annular space, the area betweenthe inside wall of the hole and the outside wall of the drillstring;

- inside blowout preventerfor sealing the inside space of the drillstring.

To achieve more objectives, there are more blowout preventers(Blowout Preventer), assembled in aBOP stack.

During drilling operation the casing head is the intermediatecomponent between the firstcasing stringand either theBOP stack.

In order to achieve the borehole, are required many special

operations, performed by means of

- drilling tools and devices (such as casing and cementing devices,

devices for setting and hanging liners, plugs and packers, sand

divider, overshoots, fishing taper taps, die collars for fishing, fishing

spears, cutter for tubular goods, milling tools, safety joints for drill

pipes, fishing magnets, bottom cleaner and casing scraper).

The most recent solutions about drilling tools can be accessed athttp://www.nov.com/Downhole/Drilling_Tools.aspx

In the following, they will be briefly presented some aspects of these

borehole equipments constructions.
http://www.glossary.oilfield.slb.com/en/Terms/b/borehole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/borehole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/wellbore.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/wellbore.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/casing_head.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/casing_head.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/casing_head.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/b/blow_out_preventer.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/blow_out_preventer.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_blowout_preventer.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_blowout_preventer.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/blowout_preventer.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/blowout_preventer.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/blowout_preventer.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=casing%20stringhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=casing%20stringhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=casing%20stringhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=BOP%20stackhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=BOP%20stackhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=BOP%20stackhttp://www.nov.com/Downhole/Drilling_Tools.aspxhttp://www.nov.com/Downhole/Drilling_Tools.aspxhttp://www.nov.com/Downhole/Drilling_Tools.aspxhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=BOP%20stackhttp://www.glossary.oilfield.slb.com/Display.cfm?Term=casing%20stringhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/blowout_preventer.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_blowout_preventer.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/blow_out_preventer.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/casing_head.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/wellbore.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/borehole.aspx


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2. Drillstring

Keywords: drillstring,drill string,bottomhole assembly,bit,drill bit,Drill Bit,

drillpipe, Drill Pipe,kelly, Kelly, crossover, drilling fluid, drilling mud,annulus,Annulus,borehole,openhole,drill collar,Drill Collar,heavyweightdrillpipe, open hole, cased hole, casing string, formation, rock, drill pipe,

connection,mud motors,drillstem,outside diameter,OD,inside diameter,

ID,weight indicator

The drillstring is the assembly of steel pipes and tools that are

extending from the surface down to the bottom hole, in order to transmit the

mechanical energy to the bit in order to drill the wellbore. Steel pipes have

different shapes, diameters and lengths, being all screwed together (with

the exception of coiled tubing). The drill bit is part of the drillstring, being

placed in the bottom of it. Please see the address

http://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspx

The drillstring serves to:

- transmit the rotating power from the surface to thebit(via the kelly drive

or top drive); if the motor is at depth, the drillstring is designed to take

reactive torque;- conduct the mud stream with circulating power from the surface to the

bit (via mud pumps on direct circulation);

- put the weight on the bit to maximize penetration rate, by means of

hoisting power (via bottom hole assembly).

The drillstring is hollow so that the drilling fluid can be pumped down

through it and circulated back up through the annulus (the space between

the drillstring and therockformation or casing string).

The drillstring is an extremely expensive rig component and must bereplaced periodically; consequently, a lot of care should be exercised in

order to insure its long life. Most drillstring failures are due to material

fatigue which has been aggravated by corrosion and improper care and

handling.
http://www.glossary.oilfield.slb.com/en/Terms/d/drillstring.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstring.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_bit.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_bit.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_bit.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_pipe.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_pipe.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/kelly.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/kelly.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/c/crossover.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/crossover.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drilling_fluid.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drilling_fluid.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drilling_mud.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drilling_mud.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/a/annulus.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/a/annulus.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/annulus.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/annulus.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/b/borehole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/borehole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_collar.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_collar.htmlhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_collar.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/open_hole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/open_hole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/cased_hole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/cased_hole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/formation.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/formation.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_pipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_pipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/connection.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/connection.aspxhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Mud_motorhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/outside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/outside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/od.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/od.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/id.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/id.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/weight_indicator.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/weight_indicator.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/weight_indicator.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://en.wikipedia.org/wiki/Drill_bit_(well)http://en.wikipedia.org/wiki/Drill_bit_(well)http://en.wikipedia.org/wiki/Drill_bit_(well)http://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://en.wikipedia.org/wiki/Drill_bit_(well)http://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/w/weight_indicator.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/id.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/inside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/od.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/outside_diameter.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://en.wikipedia.org/wiki/Mud_motorhttp://www.glossary.oilfield.slb.com/en/Terms/c/connection.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_pipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/formation.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/cased_hole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/open_hole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_collar.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/borehole.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/annulus.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/a/annulus.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drilling_mud.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drilling_fluid.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/crossover.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/kelly.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_pipe.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.osha.gov/SLTC/etools/oilandgas/illustrated_glossary/drill_bit.htmlhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstring.aspx


6/19

The drillstring is typically made up of 5 sections:

- bottomhole assembly(BHA);

- transition pipe, which is oftenheavyweight drillpipe(HWDP);

- drillpipe;

- kelly;- drillstemsubs and other tools (such as reamers, shocks, hole openers).

Each section is made up of several components, joined together using

special threaded connections known as tool joints.

Bottom Hole Assembly (BHA)

Thebottomhole assemblymust provide the force (weight on bit) and

torque which are being applied to the bit, in order to crush and cut the rock.

Also the BHA must ensure the directional control of the well, in a hostile

and unpredictable environment.

The bottomhole assembly is the lowest part of the drillstring extended

from the bit to the drillpipe. The BHA is an assembly of different elements

that is much more massive per unit length than the drillpipe is.A simple BHA is made up of adrill bit which is used to break-up the

rock formations, various crossovers and tool joints, drill collar which are

heavy, thick-walled tubular used to apply weight to the drill bit, stabilizers

which keep the drilling assembly centered in the hole. Oftentimes, the BHA

may also contain other components such as a mud motor (mud motor),

rotary steerable system, measurements-while-drilling tools (MWD, MWD),

logging while drillingtools (LWD) and other specialized devices (e.g. shock

absorbers, jammers, instrumented tools). Adjacent and interestingcomments can be found at:

http://en.wikipedia.org/wiki/Rotary_steerable_system

http://en.wikipedia.org/wiki/Mud_motor
http://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/crossover.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/t/tool_joint.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/mud_motor.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/mud_motor.aspxhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Mud_motorhttp://www.glossary.oilfield.slb.com/en/Terms/r/rotary_steerable_system.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rotary_steerable_system.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/measurements-while-drilling.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/measurements-while-drilling.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/mwd.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/mwd.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/mwd.aspxhttp://en.wikipedia.org/wiki/Measurement_while_drillinghttp://en.wikipedia.org/wiki/Measurement_while_drillinghttp://www.glossary.oilfield.slb.com/en/Terms/l/logging_while_drilling.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/l/logging_while_drilling.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/l/lwd.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/l/lwd.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/l/lwd.aspxhttp://en.wikipedia.org/wiki/Rotary_steerable_systemhttp://en.wikipedia.org/wiki/Rotary_steerable_systemhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Mud_motorhttp://en.wikipedia.org/wiki/Rotary_steerable_systemhttp://www.glossary.oilfield.slb.com/en/Terms/l/lwd.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/l/logging_while_drilling.aspxhttp://en.wikipedia.org/wiki/Measurement_while_drillinghttp://www.glossary.oilfield.slb.com/en/Terms/m/mwd.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/m/measurements-while-drilling.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rotary_steerable_system.aspxhttp://en.wikipedia.org/wiki/Mud_motorhttp://www.glossary.oilfield.slb.com/en/Terms/m/mud_motor.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_collar.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/t/tool_joint.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/crossover.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspx


7/19

Rotary Bits

Keywords: bit,fixed-cutter bit,polycrystalline diamond compact bit,PDC bit,

diamond bit, roller-cone bit, rock,soft rock,hard rock, openhole

Thedrill bitis intended for rotary drilling of borehole, and it is located at the

bottom of the drillstring. The rotary bit, under the weight loaded by the

partial drill collars, is turned by the drillstring (or down motor) to scrap,

crush, and chip or cut the rocks to the bottom of the borehole. The rock can

be soft, medium or hard, being also the intermediate variants (sticky,abrasive, extremely). Removing of the rock cuttings and bit filings is

performed using a drilling fluid for continuous washing the bottom of the

hole (if the fluid velocity is very high, it can be used to dislocation the rock).

Please see the Figure 7.1, and the address

http://www.nov.com/Downhole/Drill_Bits.aspx

Figure 7.1. The bit is intended for rotary drilling of borehole.
http://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/pdc_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/pdc_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/pdc_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/diamond_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/diamond_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/roller-cone_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/roller-cone_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/s/soft_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/s/soft_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/s/soft_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hard_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hard_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hard_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.nov.com/Downhole/Drill_Bits.aspxhttp://www.nov.com/Downhole/Drill_Bits.aspxhttp://www.nov.com/Downhole/Drill_Bits.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drill_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/o/openhole.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hard_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/s/soft_rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/rock.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/roller-cone_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/diamond_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/pdc_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bit.aspx


8/19

The drill bits are manufactured in a wide range of dimensions and

types to meet the most varied drilling requirement, depending on different

rocks and mechanical actions. Drill bit operates in an extremely dirty and

hot environment, frequently bounce up and down, and in general are

subjected to high mechanical stresses.Depending on the technical method of the rock cutting, there are several

types of bits: fixed cutter bits, roller cone bits, and hybrid drill bits.

Please see the addresses

http://www.nov.com/Downhole/Drill_Bits.aspx

http://www.lonestarbit.com/media/drillbitclassifier.pdf

http://en.wikipedia.org/wiki/Well_drilling

In Figure 7.2, are presented some of these types of bits.

Figure 7.2. Several types of bits: fixed cutter bits, roller cone bits, and hybrid drill

bits.

A fixed cutter bit is one where there are no moving parts, but drilling

occurs due to rotation of the drill bit, being pressed on the rock.
http://www.nov.com/Downhole/Drill_Bits.aspxhttp://www.nov.com/Downhole/Drill_Bits.aspxhttp://www.lonestarbit.com/media/drillbitclassifier.pdfhttp://www.lonestarbit.com/media/drillbitclassifier.pdfhttp://en.wikipedia.org/wiki/Well_drillinghttp://en.wikipedia.org/wiki/Well_drillinghttp://en.wikipedia.org/wiki/Well_drillinghttp://www.lonestarbit.com/media/drillbitclassifier.pdfhttp://www.nov.com/Downhole/Drill_Bits.aspx


9/19

Fixed cutter bits can be realized in many constructive variants. The

most common fixed cutter bits are either polycrystalline diamond compact

(PDC) or grit hot pressed insert (GHI) as impregnated diamond bits.There

are also other types, such as: fish tail bits, hardened blade bits, tungsten

carbide insert monolith bit, etc.Polycrystalline diamond compact bits (denoted as PDC) are drilling

tools that use attached cutters (fixed-cutter bit) to shear the rock with a

continuous scraping motion (Figure 7.3 and 7.4). These cutters are

synthetic diamond disks with small values of thick and diameter (about 1/8-

in. thick and about 1/2 to 1 in. in diameter). The PDC bit has no moving

parts and a long drilling life, thus, its use allows a reduction of the cost.

Please see the addresses:

http://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/pdc-bits

http://www.torquato.com/index.html

Figure 7.3. Polycrystalline diamond compact bits
http://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspxhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/pdc-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/pdc-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/pdc-bitshttp://www.torquato.com/index.htmlhttp://www.torquato.com/index.htmlhttp://www.torquato.com/index.htmlhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/pdc-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/pdc-bitshttp://www.glossary.oilfield.slb.com/en/Terms/f/fixed-cutter_bit.aspx


10/19

Figure 7.4. Synthetic diamond disks about 1/8 inch.

Natural diamonds bits are constructed with diamonds embedded into

a matrix and are used in rotary with turbine and coring operations.Diamond bits can provide improved drilling rates over roller bits in some

formations, because the bit failure potential is reduced due to the absence

of moving parts, which make them well suited for turbine drilling (big

angular velocity and low torque).

Below are some images of other types of fixed cutter bits, such as:

fish tail bits, hardened blade bits, tungsten carbide insert monolith bit, etc.

Figure 7.5. Fish-tail bit.


11/19

Figure 7.6. Blade bit.

The blades hardening is realized with hard material sintered plates,

placed on parallel rows, on which is placed a granular hard material layer of

various thicknesses.

Figure 7.7. Hard metal insert monolith bit.

Please see the address:


12/19

http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-

Technology_2178

http://www.bit-tech.com/

http://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_c

ompact_bit.aspx

Roller cone bits can be either steel milled-tooth bits (MT) or tungsten

carbideinsertbits (TCI).

Please see the address:

http://www.glossary.oilfield.slb.com/en/Terms/r/roller_cone_bit.aspx

The roller-cone bit is a tool designed to crush rock efficiently, while

incurring a minimal amount of wear on the cutting surfaces.

This type of bit usually has three conical cutters or cones that havespiked teeth around them and is designed to break the rock by indentation

and gouging action.

These bits can be categorized into steel tooth roller cone bits (Figure

7.8.) and roller cone insert bits (Figure 7.9).

Figure 7.8. Steel milled-tooth bit.
http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-Technology_2178http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-Technology_2178http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-Technology_2178http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-Technology_2178http://www.bit-tech.com/http://www.bit-tech.com/http://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/insert.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/insert.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/insert.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/roller_cone_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/roller_cone_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/r/roller_cone_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/i/insert.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/p/polycrystalline_diamond_compact_bit.aspxhttp://www.bit-tech.com/http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-Technology_2178http://www.epmag.com/EP-Magazine/archive/2005-Drill-Bit-Technology_2178


13/19

Figure 7.9. Synterized carbide insert bit.

As the bit is rotated, the bit cones roll along the bottom of the hole in

circles. As they roll, new teeth come in contact with the bottom of the hole

and press against the formation with enough pressure to exceed the failure

strength of the rock, crushing the rock immediately below and around the

bit tooth. As the cone rolls, the tooth then lifts off the bottom of the holeand a high-velocity fluid jet strikes the crushed rock chips to remove them

from the bottom of the hole and up the annulus. As this occurs, another

tooth makes contact with the bottom of the hole and creates new rock

fracture. Thus, the process of chipping the rock and removing the small

rock chips with the fluid jets is continuous.

The lower part of the bits body supports the roller cones, usually

three (Figure 7.10) but also one, two or four can be used. The rows of teeth

can either be milled from the same block of the metal as the bit (non

insert bit) these bits are used in relatively soft formations found at

shallow depths or can be of tungsten carbide inserts that are harder or

more durable than milled teeth. Thus, there are two main types of roller-

cone bits, steel milled-tooth bits and carbide insert bits.

Bit cutting faces, design for bearings sealing and greasing systems,

as well as the application of modern heat treatment technology and


14/19

mechanical processing, give the best performance and operational

durability of the bits.

Figure 7.10. Roller-cone bit construction.

Replacing a bit, when it becomes excessively worn (Figure 7.11.) orstops making progress, is a very expensive operation. The entire drillstring

must be pulled out, the bit must be changed, and then, the drillstring must

be reintroduced. In deep holes, this round tripping can take hours of rig time.

The hole can also be affected by the pieces of hardened steel, left in the

hole from a broken bit. It is, therefore, essential that bits are extremely

competent and long-lasting. The criteria for bit-type selection are related to

factors such as the expected drilling-rate performance, the cost per unit

depth and the bit life.


15/19

Figure 7.11. Worn Roller-cone bit.

Please see the address

http://www.bakerhughes.com/products-and-services/drilling/drill-bit-

systems/tricone-roller-cone-drill-bitsHybrid drill bit technology (Figure 7.12) combines roller cones and

PDC fixed cutters into a single, patented design to reduce drilling time in

the most complex applications. With the rock-crushing strength and

stability of roller cones and the cutting superiority and continuous shearing

action of diamond bits, this technology survives highly interbedded

formations with performance consistency and excellent tool face control.

Figure 7.12. Hybrid drill bit.

Please see the address

http://www.bakerhughes.com/products-and-services/drilling/drill-bit-

systems/kymera-hybrid-drill-bit-technology

Depending on the destination of drilling, there are several types of

bits: drilling bits, coring bits and holeenlarging (ream while drilling) bits.

The drilling bit performs the rock removal on the entire surface of the

borehole cross section.

The mechanical core-barrel is designed to take cores from the drilled

borehole bottom. The core-barrels are provided with core-barrel heads.

The holeenlarging bit is used for simultaneous hole boring and

reaming or only for enlarging a previously drilled borehole.

In Figure 7.13 are presented some of these types of bits, in the roller

constructive solution.
http://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/tricone-roller-cone-drill-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/tricone-roller-cone-drill-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/tricone-roller-cone-drill-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/kymera-hybrid-drill-bit-technologyhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/kymera-hybrid-drill-bit-technologyhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/kymera-hybrid-drill-bit-technologyhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/kymera-hybrid-drill-bit-technologyhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/kymera-hybrid-drill-bit-technologyhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/tricone-roller-cone-drill-bitshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/tricone-roller-cone-drill-bits


16/19

Figure 7.13. Drilling bits, coring bits and hole

enlarging(ream while drilling) bits.

Special types of bits are the core bits, designed to pick up plug-

shaped core samples of rock.

The mechanical core-barrel are designed to take cores from the

drilled hole bottom. The core-barrels are provided with core-barrel heads.

Figure 7.14. Core-barrel heads.


17/19

The core head formation cutting elements have granular material

hard faced blades.

The crown is of monolith construction, the cutting surface being

constituted of sintered carbide inserts and plates.

The roller core-barrel head is used for coring operations in hard andmedium hard rocks. The cutting surface is constituted of six hard material

hardened steel teeth rollers.

For borehole enlargement technology, there are used new bit-types

for improved effectiveness with reduced failures. Can be used either

bicenter PDC bits (with fixed-blade eccentric reamer, Figure 7.15) or

expandable reamers (reams an in-gauge hole, Figure 7.16 and 7.17).

Please see the addresseshttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-

systems/hole-enlargement

http://www.nov.com/Downhole/Borehole_Enlargement.aspx

Figure 7.15. Bicenter PDC bits.
http://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/hole-enlargementhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/hole-enlargementhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/hole-enlargementhttp://www.nov.com/Downhole/Borehole_Enlargement.aspxhttp://www.nov.com/Downhole/Borehole_Enlargement.aspxhttp://www.nov.com/Downhole/Borehole_Enlargement.aspxhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/hole-enlargementhttp://www.bakerhughes.com/products-and-services/drilling/drill-bit-systems/hole-enlargement


18/19

Figure 7.16. Expandable reamers.

Figure 7.17. Roller hole enlarging bit.


19/19

The students are invited to complete the bottomhole assembly (BHA);heavyweight drillpipe(HWDP);drillpipe;kelly;drillstemsubs and other tools(such as reamers, shocks, hole openers).

Also, they are invited to complete about thecasing string,casing head, andBOP stack.To success!
http://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bop_stack.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_head.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/c/casing_string.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillstem.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/k/kelly.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/d/drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/hwdp.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/h/heavyweight_drillpipe.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bha.aspxhttp://www.glossary.oilfield.slb.com/en/Terms/b/bottomhole_assembly.aspx

Documents

Hole (Borehole) Equipments (1)