overview of diamond bits

8/9/2019 Overview of Diamond Bits

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Beijing Petroleum University


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Type number indication

Introduction of diamond bit

series

Special diamond bits

Development of designing

technology

Development of PDC cutter

Diamond bit selection guide

Diamond bit application


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Bit diameter

Bit series

Cutter density

Cutter size

Crown profile

Additional features

The model number consists six parts:

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Type number indication of Kingdream diamond

H

W

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Classification series Cutter Cutter size Crown profile Additional structure

code type code description

density code inch code length

shape code description

none convention

1(low) 1 2 1 short + Tipped&roundcutter

2 1 1/2 4 medium

round

B PDC — PolyscrystallineDiamondCompact

3 1 M Milling bit headshape

(BC) （PDC core H Force balance

4 3/4 7 long

bit） 6 1/2 B Bi-center/off-center

8 3/8 2 short

parabolic

ST Side-trackingW Anti-whir l

5 medium

1 1 8 long HZ Horizontal/directional

P TSP — Ther mally StablePolycrystalli

ne

2 2

(PC) （TSP core

bit）

none convention

3 33

short

G×

Gage protection

tappered

6 medium

H Mixed cutter

1 1

ND — Natural Diamond

2 2 9 long C Cylindricalcutter

D （ ND core none convention

3 3

(DC) bit） 4 4-5Special shape

Y Impregnatedcutter

7 6-8 0

9（高） 9 >10-12 R Randomly setcutter

BC

B

P

PC

D


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Examples of Designation of Diamond Bit ：

“8 1/2BH461ST-1”

It indicates the bit diameter is 8 1/ 2", a force

balanced PDC bit with class 4 cutter density,

nominal cutter size is 1/ 2" , and the bit profile isshort round. It is a side tracking bit that was

redesigned on the basis of the basic model.




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Standard PDC bit (B)

TSP diamond bit (P)

Natural diamond bit (D)

Diamond core bit (BC PC

DC)


I ntroduction of diamond bit ser ies


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Standard PDC Bit B series PDC bit

•B series PDC bit uses synthetic

polycrystalline diamond compacts as cutters.

The compacts are made by thin layers of

synthetic diamond pressed to WC substrateunder high temperature and high pressure,

which are then firmly brazed onto the

erosion and wear resistant WC matrix. The

cutter sizes include 3/8", 1/2", 3/4",

1"and 1-1/4". This kind of compacts can

engage the formation under relatively lowWOB, breaking rocks with shear actions and

obtaining high ROP.

•There are three types of crown profile-

parabolic, round and tapered.

•B series PDC bit uses integral threadedexchangeable nozzle,it’s easy for field

hydraulic design, can meet differentdrilling hydraulic requirements, and is



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B series PDC bitB461

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•Short round crown, medium cutter

density, long service life, and candrill through hard transition sections

smoothly

•Blade type cutter layout which can

effectively remove cuttings and

prevent bit balling, cutters can have

better cooling effect in harder andhigher abrasive

•formations.Applicable formations:

mudstone, fine sandstone, marl,

sandstone with low to medium

compressive strength, and medium

abrasive formation



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B series PDC bitB461R •Short round crown, even

WOB distribution.•Spiral cutter layout and

medium cutter density,

good cleaning effect, high

ROP and long service life.

•Applicable formations:

mudstone, fine sandstone,

soft to medium non-

hydratable shale, sandstone

with low to medium

compressive strength, and

medium abrasive

formation..

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B series PDC bit

B669

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•Deep cone crown, ridge type cutterlayout and high cutter density.

•With tipped and cylindrical cutters set

in combination, cutting efficiency is

increased, and can achieve higher ROP in

hard formations.

•TSP and natural diamond cutters are

used for gage protection, making the

gage more wear resistant.

•Applicable formations: hard shale,

dolomite, sandstone and medium to high

abrasive formations.



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Anti-whirl PDC Bit

(BW series PDC bit)

Anti-whirl PDC bit is a new product that was developedwith patented designing technology. During drilling,

the side forces generated on cutters under the action

of WOB and torque are directed to the smooth and low

frictional gage pads which always keep sliding contact

with the bore-hole wall, so that the side forces of the

bit being counteracted, making the bit rotates around

its centerline without any off-center rotation. And the

bit can drill steadily by overcoming the whirl action.

Both the service life and the ability of the bit to

drill through formation with stringers are improved,

and the application range of the bit extended.

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BW series PDC bit

BW461/M232

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Short round crown, blade type cuttingstructure.

Anti-whirl design broadened the

formation range the bit can be applied,

and has a better bit stability and longer

service life.

1/2" claw type cutters and mediumcutter density increased cutting

efficiency, providing enhanced cutter

retention and further improved the impact

strength of the bit.

Applicable formations:Soft to medium

hard formations such as mart, salt,limestone and low abrasive sand, etc.



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Force Balanced PDC Bit

(BH series PDC bit)

Force balanced PDC bit is designed according to the

force balance principle. Load of the cutters is analyzed

with the special program during designing process so

that the resultant forces of the bit when drilling tend

to be balanced. Unequal space blades and higher blade

designs are utilized to reduce the tendency of whirling

of the bit and make it drilling more smoothly. Force

balanced PDC bit can chieve higher rate of penetration

when drilling in upper soft formation, and can have the

cutters get good cooling and cleaning in lower formation.Consequently, service life of the bit improved.

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TSP Diamond Bit

P series TSP bit

P series TSP bit uses self-sharpening synthetic

thermal stable polycrystalline diamond as cutting

elements which directly sintered into the erosionand wear resistant WC matrix..

Apart from some main features of PDC bit, the P

series diamond bit also has good thermal

stability, TSP cutters can sustain the high

temperature up to 1200℃, thus suitable for using

on high speed down-hole power drilling tools.

In order to meet application requirements in

different formations, the P series diamond bits

can also be designed into different cutter

density, cutter layout and different crown shapes

(parabolic, round or cone). Specific flow areacan be designed based on customers’ request.

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Natural Diamond Bit

D series ND bit

D series natural diamond bit utilizesselected premium natural diamond as

its cutting elements, which are

cemented in erosion and wear

resistant WC matrix by sintering. The

diamond breaks rocks with shearing or

grinding action in different

formations. The natural diamond bitsare designed with different crown

profiles as parabolic, round or cone,

utilize different diamond sizes,

density, placement and different

hydraulic designs, for using in

medium to hard formations with high

abrasiveness.

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D series ND bit

D756/M713

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Medium long cone and

deep inner cone crown

for better stability.

Radius flow course forgood cooling and

cleaning.

Applicable formations:

medium hard to hardformations.



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BC Series Diamond Core Bit

The main products of diamond core

bits include BC, PC and DC series

bits, which made of erosion

resistant WC matrix and the inner

and outer gages are protected by

natural diamond. The bit profiles

include round, parabolic and cone

shapes, with the advantages of

high ROP and high rate of corerecovery as well as long bit life,

etc.

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Diamond bits for horizontal or

directional drilling (HZ)

Diamond bits for sidetracking (ST)

BI-center/off-center diamond bit (B)


Special diamond bits


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Diamond bits for horizontal/directional drilling

--HZ series

Diamond bits for

horizontal/directional drilling feature

impact pad along with special gage

protection, increased the steer ability

and directional ability of the bit inhigh angle and horizontal wells.

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--HZ series

Short round crown, overall length of the

bit is shorter for easy directional control.

Cutters placed in the gage bevel can take

up-drilling function, thus the bit can deal

with special down-hole conditions.

The impact pad on bit face can

effectively control cutting depth of the

cutters, reducing impact damages tocutters due to changes in formation and

WOB, Keeping the bit working smoothly.

Suitable for sidetracking and horizontal

drilling in soft to medium hard

formations.

B461HZ/M232

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Diamond Bit For Sidetracking --ST series

Diamond bits for sidetracking

feature the flat crown profile,short gage, premium

hydraulic design, and high-

density cutter placement in

shoulder area, therefore the

load capacity in directional

drilling can be ensured andhole diameter is maintained.

The bit can be used for

sidetracking and angle

building effectively in well

bores of different azimuth. next

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Near flat crown and short gage,advantageous to fast angle building.

Combined diamond cutter placement

can maximize performance while

reducing the torque; gage cutters on the

ridge can reduce breakage of the

diamond and improve service life.

Alternatively arranged slot ports and

cross pad water way allow the drilling

fluid across the bit with large flow rate

and low pressure drop.

Suitable for formation: shale, limestone,

dolomite, anhydrite and high abrasive

formations.

D651ST

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Diamond Bit For Sidetracking

--ST series



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Bi-center/off-center Diamond Bit

--B series

Bi-center and off-center diamond bits can meet special drilling

requirements. They can be used

to flowing salt, and can also be

used second time completion,

increase casing annular, and

improve cementing quality.

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(1)Compensating cutting structure: The cutting structure includes the major

and the subsidiary structure, the major structure can rapidly cut rocks,

while subsidiary structure provide progressive compensation and also hold

the impact load.

(2)Mechanical balance : The force balance of the cutting structure is

analyzed by the computer, the crux of the bit is given the balance cutting

structure design to retain the stable drilling operation.

(3)Low — friction gage: Adopt ND,TSP,TCI flat pad complex gage, and themechanical dynamic pressure lubricating theory is used in the design of bit

gage, ensures the full cooling and lubricating of the mud to the gage

bore-hole wall.


Development of designing technology


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(4)Full release fluid course/exchangeable nozzle hydraulic structure: Improve

the fluid condition of the bit , increase the ability of lifting detritus.(5)Computer aided design and manufacture: Applying CAD\CAM technology,

insures the manufacturing precision and quality of products, and greatly

increases the design and manufacture speed of new products.

(6)New material and new technology: The new gradient of tungsten carbide

is used, further increase the structure strength and wear-resistant capability,

the complex die NC technology plays a very important role in increasing thequality of the bit.


Development of designing technology


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1) Bevel PDC cutters: The bevel of diamond layer is also rounded except the

improvement is made in the interior of the cutters, thus increase PDC structure

strength and anti-erosion ability.

2) Super small particles PDC cutters: Compare with the conventional PDC

cutters, the impact resistance, wear resistance and self-sharpening ability are

greatly improved.

3) Multi-layers PDC cutters: The newest diamond compacting technology is

employed, the cutting capability are greatly improved except the good impactresistance. The infinitely gradient blade sharpening maintains the sharp blade

and rapid drilling.




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4) Large size PDC cutters: Large size PDC cutters can greatly

increase the cutting efficiency of the bit.

5) PDC cutters with trenches: The cutter has high impact

resistance, because its diamond layer meshes with the tungsten

carbide interface.

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ReturnDiamond bit selection Guide

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Diamond bit selection guide

Factors in selecting bit

The procedures of selecting bits


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Diamond bit selection Guide

The Procedures of Selecting Bits

：

1.Collect and analysis offset formation information2.Collect and analysis offset bit application

information .(including dull bit analysis)

3.Bit product samples

4.Bit technology instruction information

5.Composite consideration, correct selection6.If there are other requirements, please contact with

the manufactures for special design and manufacture.

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Diamond bit application Return

When do you use diamond bit

1bit is needed to run long time.2.Oil based mud is used (preferable)

3.Water based mud is used in non-hydrated formations.

4.Penetrate at high rotary speed (turbine or down-hole

power)

5.High bottom hole temperature.6.Slope section should be controlled under low bit weight.

7.Penetrating at over balance pressure.



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What formations need diamond bit

1.very soft, brittle and shallow sedimentary formations. (such as

sand, siltstone and clay)

2.low strength, brittle, non-consolidated and non-abrasive

fragmental formations.(such as halite, anhydrite and marl)3.medium strength, moderate abrasive and brittle, hardened

fragmental and sedimentary rocks in medium deep formations

(such as siliceous shale, silt clay, and anhydrite)

Polycrystalline Diamond Compact Bit (PDC bit)

Diamond bit application



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What formations need diamond bit

Natural Diamond/Thermally Stable Polycrystalline(TSP) Bit

1.medium strength, moderate abrasive and brittle, hardened

fragmental and sedimentary rocks(such as carbonatite, anhydrite

and silt clay)

2.comparatively high strength and abrasive and hard rocks (such as

sandy shale, calcite sand limestone).

3.High strength and high abrasive, hard and ductile formations

(such as hard sand and bromide).




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Which formations do not need Diamond Bit

Polycrystalline Diamond Compact

（PDC）Bit:Natural Diamond/Thermally StablePolycrystalline Bit:

.hard and cemented abrasive

sand (such as quartz)

.hard dolomite

.ferruginous rock

.flint

granite and basalt.

.hard and very brittle abrasive

cemented quartz sand stone.




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What information are needed to decide which diamond bit to be used?

1． Bit record in drilling adjacent well:

• what type of bit is used in different section?

•.Bit grade information for each section.

•.Economic analysis

2．Associated data:

• Well Log

• Geologic information




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Application of diamond bit

Bit running(bottom hole motor turbine drilling):

1.turn on pump when bit reaches hole bottom and gradually increase to thedesired displacement.

2.After cleaning the bottom in a short time, reach bottom with low

pressure then increase bit weight slowly.

3.When bit weight increased, pump pressure should be increased

accordingly. The changes of pressure and bit weight should be controlled

within the associated specifications.4.Pipe should be running slowly to prevent from sticking.

5.Normal operation procedures should be followed.

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Application of diamond bit

When pull out bit:

1.when there is no penetration.2.It is no worthy drilling by calculating of cost per foot.

3.Torque is increased when bit weight is low, and penetrate slowly.

4.Penetration rate is decreased and no way to correct

5.Pressure changed in vertical tube

(1)increased pressure indicates that the cutting structure is failure

(2)decreased pressure indicates that the nozzle loss of wash off.

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Diamond bit dull grading& analysis

Broken Teeth/Cutters

BT

:

Reason SolutionsInner cutting structure breakage indicatesexcessive bit weight was used.

Outer cutting structure breakage indicatesexcessive rotary speed was used.Fish.

Too rapid running in, percussion drill or drilling

string not well braked.Too hard formation or fractured formation

Not full or no bottom hole pattern making.

Reasonably adjust drilling parameters.

Keep well bore cleaning, fishing or press to thewall.

Slowly and smoothly run in; prevent percussion

drill or drilling string not well braked.Correctly make bottom hole pattern, do not use

diamond bit in fractured formation or adjustdrilling parameters.

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Diamond bit dull grading & Analysis

Balled Up

BU

:

Reason Solutions

Improper making bottom hole pattern.

Over low mud displacement and hydraulic

horsepower.

Inappropriate mud property.

Excessive WOB.

Run a softer formation bit.

Increase pump’s flow rate and hydraulic

horsepower.

Improve mud property.

Decrease WOB.Adopt measures to clean bit.

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Diamond bit dull grading &Analysis

Cored

CR

:

Reason Solutions

Excessive WOB.

Improper making bottom pattern, too

hard formation.

Fish or large detritus.

Too rapid running in, percussion drill

or drilling string not well braked.

Not full or no bottom hole patternmaking.

Lost teeth due to bit body erosion.

Adjust drilling parameters.

Use a core ejector bit or a harder formation bit.

Keep well bore cleaning.

Slowly and smoothly run in; prevent percussion

drill or drilling string not well braked.

Correctly make bottom hole pattern.

Adjust hydraulic parameters, and treat mud.

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Diamond bit dull grading & analysis

Erosion

ER

:

Reason Solutions

Excessive displacement.

Nozzle or fluid course area too

small.

Bad mud property.

Drill abrasive formations.

Reduce displacement.

Increase fluid course area.

Treat mud, improve property,

and reduce sand contents.

Use wear resistant bit.

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Heat Checking

HC

:

Reason Solutions

Excessive WOB.

Excessive rotary speed.

Low displacement.

Overmuch ream.


Increase displacement.

Reduce reaming.

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Junk Damage(JD

:

Reason Solutions

Fish.

Broken or lost teeth.

Cleaning, fishing, treating.

Use shock absorber, and adjust

operating parameters.

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Diamond bit dull grading & analysis

Lost Nozzle

LN

:

Reason Solutions

Loose nozzle installation.

Damage to nozzle or nozzle

socket.

Proper nozzle installation.

Check for nozzle, nozzle

socket, and seal in good

condition.

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Lost Teeth

LT

:

Reason Solutions

Fluid erosion.

Impact, shock.

Decrease displacement, increase

flow area.

Operate correctly, adjust

parameters.

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Off-Center Wear

OC

：

Reason Solutions

Bad stabilization.

Bent BHA.

Increase gage length, use

stabilizer.

Check and calibrate drilling tool.

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Plug Nozzles

PN

：

Reason SolutionsSmall nozzle.

Low displacement and hydraulic

horsepower.

High mud solid contents or other

substance.

Larger nozzles.

Increase displacement and HHP.

Treat mud, and use a drill pipe

strainer.Continue circulation when coming

off bottom.

Pull-to-release.

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Rounded Gage(RG

：

Reason Solutions

High rotary speed in abrasive

formation.

Bad stabilization.

Too much reaming.

Reduce rotary speed.

Increase stabilization.

Reduce reaming.

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Ring Out

RO

：

Reason Solutions

Improper bit selection.

Fish

Broken or lost teeth

Use a flatter profile of bit.

Keep well bore clean.

Prevent from breaking or losing

teeth.

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Worn Teeth

WT

：

Reason SolutionsImproper bit selection.

Detritus are not discharged

promptly, there are tracing break

of rock.

Cutters are not cooled well.

Use proper bit.


Improve hydraulics.


overview of diamond bits

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