CA2001178C - Rotary drill bit for drilling through sticky formations - Google Patents
Rotary drill bit for drilling through sticky formations Download PDFInfo
- Publication number
- CA2001178C CA2001178C CA002001178A CA2001178A CA2001178C CA 2001178 C CA2001178 C CA 2001178C CA 002001178 A CA002001178 A CA 002001178A CA 2001178 A CA2001178 A CA 2001178A CA 2001178 C CA2001178 C CA 2001178C
- Authority
- CA
- Canada
- Prior art keywords
- bit
- cross
- sectional area
- waterway
- plane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000005553 drilling Methods 0.000 title claims abstract description 12
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 6
- 238000005755 formation reaction Methods 0.000 title claims abstract description 6
- 239000011435 rock Substances 0.000 claims abstract description 31
- 235000013312 flour Nutrition 0.000 claims abstract description 27
- 239000012530 fluid Substances 0.000 claims abstract description 6
- 229910003460 diamond Inorganic materials 0.000 claims description 2
- 239000010432 diamond Substances 0.000 claims description 2
- 230000007423 decrease Effects 0.000 abstract description 6
- 238000005056 compaction Methods 0.000 abstract description 4
- 238000009825 accumulation Methods 0.000 abstract description 2
- 238000004140 cleaning Methods 0.000 description 5
- JILPJDVXYVTZDQ-UHFFFAOYSA-N lithium methoxide Chemical compound [Li+].[O-]C JILPJDVXYVTZDQ-UHFFFAOYSA-N 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- VMXUWOKSQNHOCA-UKTHLTGXSA-N ranitidine Chemical compound [O-][N+](=O)\C=C(/NC)NCCSCC1=CC=C(CN(C)C)O1 VMXUWOKSQNHOCA-UKTHLTGXSA-N 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/60—Drill bits characterised by conduits or nozzles for drilling fluids
- E21B10/602—Drill bits characterised by conduits or nozzles for drilling fluids the bit being a rotary drag type bit with blades
Abstract
A drill bit for drilling through sticky formations, such as chalk or marl, comprises a plurality of waterways (4) for transporting drilling fluid and rock flour to the gauge of the bit. These waterways have in downstream direction gradually increasing cross-sectional areas A, the increase of size of said areas along the length of a waterway being at least substantially proportional to the squared radius r thereof from the central axis (10). In this manner the rock flour velocity remains equal or decreases in downstream direction in the waterways so that the risk of rock flour accumulation and compaction is reduced.
Description
ROTARY DRILL BIT FOIZ DRILLING THROUGH STICK' FORMATTONS
The invention relates to a rotary drill bit for drilling through sticky formations.
It is known that during dulling through sticky formations, such as chalk or marl, the rock flour produced loan; a strong tendency to stick to the bit face. For drilling through such sticky Formations generally fishtail bits are used, which bits have wide waterways between the cutting wings.
Field experience has learned that in spite of the presence of wide waterways it frequently occurs that rock flour accumulates in front of the cutting wings leaving only small channels open to a.llovv drilling fluid to flow from the nozzles to the gauge of the bit. Occasionally it has occurred that the motion of the accumulated rock flour through the waterways was hampered and that the rock flour was compacted in the waterways arid started to carry the majority of the weight on bit, thereby resulting in a completely balled-up bit and a poor drilling performance.
The purpose of the present invention is to provide a rotary drill bit wherein the occurrence of rock flour cornpaction in the waterways is avoided.
The rotary drill bit according to the invention comprises:
-a bit body on which a plurality c>f cutting wings are mounted, said wings extending along the bit body from a central axis of the bit towards the gauge of the bit, and -a plurality of waterways for transporting drilling fluid and rock flour to the gauge of the bit, each waterway being formed between a pair of adjacent wings and having at each point clang its length a cross-sectional area A
25~ measured in a plane perl.-rewdicular to a central chord of the waterway, wherein the size of said crass-sectional areas A increases in a direction from the central axis towards the gauge of the bit in such a manner that the increase in size of said areas in said direction is at least substantially proportional to the squared radius r of said areas from the central axis, said radius r of a particular area A being defined as the average distance between the central axis and the locations where the plane in which said particular area A is measured cr<>sscs the tips of the adjacent: cutting wings.
In particular the bit is characterized in that the size of said cross-sectional area increases in such a manner that the ratio between a cross-sectional area A.l of the waterway in a first plane perpendicular to said chord and a cross-sectional area A2 of the same waterway in a second plane perpendicular to said chord fulfils the equation:
Al /A2<rl2/r22 r1 being the average radius at which the first plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit;
r2 being the average radius at which the second plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit;
and r2 being larger than r1 .
The bit according to tlue invention is designed such that the average velocity of the rock flour in the waterways remains constant or decreases continuously in a 2o direction from the bit centre towards the gauge of the bit thereby providing mechanical cleaning in case the hydraulic cleaning is no longer adequate.
A specific embodiment of the bit .according to the invention will be described by way of example with reference to the accompanying drawings in which:
Figure 1 is a bottom view of a section of a bit according to the invention;
and Figure 2 is a sectional view of the bit of Figure 1, taken along line II-II
and seen in the direction of the arrows.
Figures 1 and 2 show a bit according to the invention. Figure 2 furthermore shows a first plane 1 and a second plane ?. Said planes 1 and 2 are each oriented perpendicular to~ a central chord 3 of a waterway 4 formed between a pair of adjacent cutting wings 5 and ti of the bit.
The bit has eight reguNarly distributed cutting wings, two of which are shown in Figure 1. The cutting wings ~ and 6 extend along the bit body 8 from the central axis 10 of the bit towards the gauge 1 I of the bit. The cutting wings 5 and 6 have a l0 substantially radial orientation relativ°e to said central axis 10 and they are equipped near their tips 12 with a series of disc-shaped polycrystalline diamond compact (PDC) cutters 13.
The waterways 4 are each formed between the hole bottom 15, the bit face 16, the front side of one cutting wing 6 and the back side 17 of another cutting wing 5.
The central chord of each waterway 4 is formed by the centre of the fluid passage provided by the waterway so that each point of said chord 3 is located at equal distances from the Front sidf: of one cutting wing 6 and the back side 17 of another cutting wing 5 and also at equal distances from the hole bottom 15 and the 2o bit face 16.
In view of the rectangular shape of the waterways the cross- sectional area of the waterway 4 can be defined as:
A = w.h. (1) h being the height of the waterway 4 defined as the distance between the bit face 16 and the tips 12 of the wings, said distance being measured in a plane perpendicular to said central chord 3, and v~ being the width of the waterway 4 defined as the distance between the front side of one cutting wing 6 and the back side 17 of another cutting wing, said distance being measured in a plane perpendicular to said central chord 3.
As can be seen in Figt.trcs 1 and 2 the cross-sectional area A, of the waterway 4 in said first plane 1 is defined by A ~ = w 1.1n l , whereas the cross-sectional area A2 of the waterway 4 in said second plane 2 is defined by A2 == w2.h2.
In the bit according to the invention the size of the crc>ss-sectional areas A
of the waterways 4 increases in a direction from the central axis 10 towards tlae gauge 11 of the bit in such a manner that the increase:, in size of said areas A in said direction is at least substantially proportional to the squared radius r of a particular l0 area A from the central axis 10. 'the radius r of a specific area A is defined as the average distance between said central axis 10 and the locations where a plane in which said area A is measured crosses the tips 12 of adjacent cutting wings 5, 6.
The implication of the bit design according to the invention to the cross-sectional areas A 1 and A2 of the first and second plane 1 and 2 shown in Figure 2 is that the ratio between said areas A 1 and A2 fulfils the equation:
A2/A1>_r22/r12 (2) r1 being the average radius at which plane 1 crosses the tips 12 of adjacent cutting wings 5, 6, said radius being measured from the central axis 10, r2 being the average radius at which plane 2 crosses the tips 12 of adjacent cutting wings 5, 6, said radius being measured from the central axis, and r2 being larger than r1.
In the embodiment of the invention shown in the drawing the cutting wings 5 and 6 have a radial orientation relative to the central axis. In this embodiment plane 1 intersects the tips 12 of the adjacent wings S and 6 at about equal distances from the central axis 10, and the same applies to the intersection between plane 2 and 2~~ said tips. Therefore plane 1 intersects said tips 12 at a radius r1 whereas plane 2 also intersects said tips 12 at a r2. In an alternative embodiment of the invention, however, the cutting wings may have a spiraling orientation relative to the central axis. Then a plane cross-axial to a central chord of a waterway will intersect the tips of adjacent wings of different radii, the average of which radii must be taken into account for defining the ratic:~ between the cross-sectional areas A1 and A2.
As in the embodiment shown in the drawing each waterway furthermore has a substantially rectangular cross-sectional area A and the thickness of the cutting wings 5 and 6 is small in comparison to the width w of the waterways 4 the ratio between the width w2 and the width w1 of the waterways in said planes 1 and 2 can be estimated by:
to W1 l W2 =rl sin ai r~ sin a (3) a being the angle between adjacent cutting wings.
Combinations of equations (2 ) and t 3) gives:
hl/h2<_rl/r~ (4) Accordingly in the embodiment shown where the bit has radial cutting wings and rectangular waterways the height h of each waterway will increase in radial direction away from the central axis such that the variation of said height h is at least substantially proportional to the increase oi~ the radius r at which the plane in which said height h is measured intersects the tips 12 of adjacent cutting wings 5 and 6.
2c> The bit design according to the invention is based on the insight that the velocity of the rock flour should not increase along its flow patch through each waterway. An increase of rock dour velocity is an indication of a relative decrease of the cross-sectional area of the waterway in comparison to the rock flour volume V passing therethrough. Accordingly an increased rock flour velocity along said flow path might lead to rock flour compaction and thus to plugging of the waterway. To avoid rock flour compaction under all circumstances it is preferred to design the waterways such that the rock flour velocity gradually decreases in downstream direction throug~t the waterways.
The bit design according to the invention is furthermore based on the insight that the volume V of rock flour that passes through the waterways at the gauge of the bit during one full revolution of the bit equals the volume of a cylinder of rock which is removed liom the earth crust during said revolution. This volume can be expressed as:
V = ~.R2.ROP (5) V is the rock flour volume removed by the bit, R is the outer radius of the cutting tips 12, and ROF' is the rate r>f penetration at which the borehole is deepened during one full revolution of the bit.
In the bit shown in the drawing this rock flour volume V is passed through eight waterways. Accordingly the rock flour volume V' passing through one waterway during one revolution of the bit equals: V' _= 1/8. ~.r2.ROP.
The rock flour volume V', that passes through the cross-sectional area A, during a revolution of the bit of the waterway equals 1/8 of the volume of the cylinder of rock removed liwm the earth crust within a radius r1 during said revolution, or:
V1' = 1/8. n.rl'~.ROP
2o Following the same line of reasoning for the rock dour volume V2' passing through cross-sectional area ,~~ gives:
V2' = 1/8. ~.r2~.ROP
Introduction of the rock flour velocity v in a waterway as the ratio between the rock flour volume V passing at a certain cross-sectional area A through the waterway and the size of said cross-sectional area A gives for the velocities v1 and v2 in said planes 1 and 2:
v1 = ~.rl?.ROP l 8,A p , and v2 = ~.r22.ROP / 8.A ~ (6) Taking now into account that the rock flour velocity should not increase in downstream direction along the flow patch of each waterway, or in other words, said velocity should remain constant or decrease in said downstream direction gores:
v2~vl ( combination of equations (6) and (7) gives:
r22/A2 <_ r1 2/A1, or A~/Al _>_ r22%rl2 (8) l0 Equation (8) equals equation (2) and equations (2) and (8) are based on the principle that the rock flour velocity v should decrease or at least remain equal in downstream direction of each waterway. In this manner accumulation and compaction of rock flour in the waterways is avoided and mechanical cleaning of the waterways is accomplished. T'he mechanical cleaning capability is of 1 ~ importance if the hydraulic cleaning provided by the flow of drilling fluid is no longer adequate.
The bit concept according to the invention can be. used in a fishtail bit or in any other bit in which waterways are formed between cutting wings. The bit body may be dome-shaped and tine cut ing wings of the bit may have a radial or a 2o spiraling orientation relative t.o a central a?cis of the bit body.
Accordingly it is to be clearly understood that the embodiment shown in the drawing is illustrative only.
The invention relates to a rotary drill bit for drilling through sticky formations.
It is known that during dulling through sticky formations, such as chalk or marl, the rock flour produced loan; a strong tendency to stick to the bit face. For drilling through such sticky Formations generally fishtail bits are used, which bits have wide waterways between the cutting wings.
Field experience has learned that in spite of the presence of wide waterways it frequently occurs that rock flour accumulates in front of the cutting wings leaving only small channels open to a.llovv drilling fluid to flow from the nozzles to the gauge of the bit. Occasionally it has occurred that the motion of the accumulated rock flour through the waterways was hampered and that the rock flour was compacted in the waterways arid started to carry the majority of the weight on bit, thereby resulting in a completely balled-up bit and a poor drilling performance.
The purpose of the present invention is to provide a rotary drill bit wherein the occurrence of rock flour cornpaction in the waterways is avoided.
The rotary drill bit according to the invention comprises:
-a bit body on which a plurality c>f cutting wings are mounted, said wings extending along the bit body from a central axis of the bit towards the gauge of the bit, and -a plurality of waterways for transporting drilling fluid and rock flour to the gauge of the bit, each waterway being formed between a pair of adjacent wings and having at each point clang its length a cross-sectional area A
25~ measured in a plane perl.-rewdicular to a central chord of the waterway, wherein the size of said crass-sectional areas A increases in a direction from the central axis towards the gauge of the bit in such a manner that the increase in size of said areas in said direction is at least substantially proportional to the squared radius r of said areas from the central axis, said radius r of a particular area A being defined as the average distance between the central axis and the locations where the plane in which said particular area A is measured cr<>sscs the tips of the adjacent: cutting wings.
In particular the bit is characterized in that the size of said cross-sectional area increases in such a manner that the ratio between a cross-sectional area A.l of the waterway in a first plane perpendicular to said chord and a cross-sectional area A2 of the same waterway in a second plane perpendicular to said chord fulfils the equation:
Al /A2<rl2/r22 r1 being the average radius at which the first plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit;
r2 being the average radius at which the second plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit;
and r2 being larger than r1 .
The bit according to tlue invention is designed such that the average velocity of the rock flour in the waterways remains constant or decreases continuously in a 2o direction from the bit centre towards the gauge of the bit thereby providing mechanical cleaning in case the hydraulic cleaning is no longer adequate.
A specific embodiment of the bit .according to the invention will be described by way of example with reference to the accompanying drawings in which:
Figure 1 is a bottom view of a section of a bit according to the invention;
and Figure 2 is a sectional view of the bit of Figure 1, taken along line II-II
and seen in the direction of the arrows.
Figures 1 and 2 show a bit according to the invention. Figure 2 furthermore shows a first plane 1 and a second plane ?. Said planes 1 and 2 are each oriented perpendicular to~ a central chord 3 of a waterway 4 formed between a pair of adjacent cutting wings 5 and ti of the bit.
The bit has eight reguNarly distributed cutting wings, two of which are shown in Figure 1. The cutting wings ~ and 6 extend along the bit body 8 from the central axis 10 of the bit towards the gauge 1 I of the bit. The cutting wings 5 and 6 have a l0 substantially radial orientation relativ°e to said central axis 10 and they are equipped near their tips 12 with a series of disc-shaped polycrystalline diamond compact (PDC) cutters 13.
The waterways 4 are each formed between the hole bottom 15, the bit face 16, the front side of one cutting wing 6 and the back side 17 of another cutting wing 5.
The central chord of each waterway 4 is formed by the centre of the fluid passage provided by the waterway so that each point of said chord 3 is located at equal distances from the Front sidf: of one cutting wing 6 and the back side 17 of another cutting wing 5 and also at equal distances from the hole bottom 15 and the 2o bit face 16.
In view of the rectangular shape of the waterways the cross- sectional area of the waterway 4 can be defined as:
A = w.h. (1) h being the height of the waterway 4 defined as the distance between the bit face 16 and the tips 12 of the wings, said distance being measured in a plane perpendicular to said central chord 3, and v~ being the width of the waterway 4 defined as the distance between the front side of one cutting wing 6 and the back side 17 of another cutting wing, said distance being measured in a plane perpendicular to said central chord 3.
As can be seen in Figt.trcs 1 and 2 the cross-sectional area A, of the waterway 4 in said first plane 1 is defined by A ~ = w 1.1n l , whereas the cross-sectional area A2 of the waterway 4 in said second plane 2 is defined by A2 == w2.h2.
In the bit according to the invention the size of the crc>ss-sectional areas A
of the waterways 4 increases in a direction from the central axis 10 towards tlae gauge 11 of the bit in such a manner that the increase:, in size of said areas A in said direction is at least substantially proportional to the squared radius r of a particular l0 area A from the central axis 10. 'the radius r of a specific area A is defined as the average distance between said central axis 10 and the locations where a plane in which said area A is measured crosses the tips 12 of adjacent cutting wings 5, 6.
The implication of the bit design according to the invention to the cross-sectional areas A 1 and A2 of the first and second plane 1 and 2 shown in Figure 2 is that the ratio between said areas A 1 and A2 fulfils the equation:
A2/A1>_r22/r12 (2) r1 being the average radius at which plane 1 crosses the tips 12 of adjacent cutting wings 5, 6, said radius being measured from the central axis 10, r2 being the average radius at which plane 2 crosses the tips 12 of adjacent cutting wings 5, 6, said radius being measured from the central axis, and r2 being larger than r1.
In the embodiment of the invention shown in the drawing the cutting wings 5 and 6 have a radial orientation relative to the central axis. In this embodiment plane 1 intersects the tips 12 of the adjacent wings S and 6 at about equal distances from the central axis 10, and the same applies to the intersection between plane 2 and 2~~ said tips. Therefore plane 1 intersects said tips 12 at a radius r1 whereas plane 2 also intersects said tips 12 at a r2. In an alternative embodiment of the invention, however, the cutting wings may have a spiraling orientation relative to the central axis. Then a plane cross-axial to a central chord of a waterway will intersect the tips of adjacent wings of different radii, the average of which radii must be taken into account for defining the ratic:~ between the cross-sectional areas A1 and A2.
As in the embodiment shown in the drawing each waterway furthermore has a substantially rectangular cross-sectional area A and the thickness of the cutting wings 5 and 6 is small in comparison to the width w of the waterways 4 the ratio between the width w2 and the width w1 of the waterways in said planes 1 and 2 can be estimated by:
to W1 l W2 =rl sin ai r~ sin a (3) a being the angle between adjacent cutting wings.
Combinations of equations (2 ) and t 3) gives:
hl/h2<_rl/r~ (4) Accordingly in the embodiment shown where the bit has radial cutting wings and rectangular waterways the height h of each waterway will increase in radial direction away from the central axis such that the variation of said height h is at least substantially proportional to the increase oi~ the radius r at which the plane in which said height h is measured intersects the tips 12 of adjacent cutting wings 5 and 6.
2c> The bit design according to the invention is based on the insight that the velocity of the rock flour should not increase along its flow patch through each waterway. An increase of rock dour velocity is an indication of a relative decrease of the cross-sectional area of the waterway in comparison to the rock flour volume V passing therethrough. Accordingly an increased rock flour velocity along said flow path might lead to rock flour compaction and thus to plugging of the waterway. To avoid rock flour compaction under all circumstances it is preferred to design the waterways such that the rock flour velocity gradually decreases in downstream direction throug~t the waterways.
The bit design according to the invention is furthermore based on the insight that the volume V of rock flour that passes through the waterways at the gauge of the bit during one full revolution of the bit equals the volume of a cylinder of rock which is removed liom the earth crust during said revolution. This volume can be expressed as:
V = ~.R2.ROP (5) V is the rock flour volume removed by the bit, R is the outer radius of the cutting tips 12, and ROF' is the rate r>f penetration at which the borehole is deepened during one full revolution of the bit.
In the bit shown in the drawing this rock flour volume V is passed through eight waterways. Accordingly the rock flour volume V' passing through one waterway during one revolution of the bit equals: V' _= 1/8. ~.r2.ROP.
The rock flour volume V', that passes through the cross-sectional area A, during a revolution of the bit of the waterway equals 1/8 of the volume of the cylinder of rock removed liwm the earth crust within a radius r1 during said revolution, or:
V1' = 1/8. n.rl'~.ROP
2o Following the same line of reasoning for the rock dour volume V2' passing through cross-sectional area ,~~ gives:
V2' = 1/8. ~.r2~.ROP
Introduction of the rock flour velocity v in a waterway as the ratio between the rock flour volume V passing at a certain cross-sectional area A through the waterway and the size of said cross-sectional area A gives for the velocities v1 and v2 in said planes 1 and 2:
v1 = ~.rl?.ROP l 8,A p , and v2 = ~.r22.ROP / 8.A ~ (6) Taking now into account that the rock flour velocity should not increase in downstream direction along the flow patch of each waterway, or in other words, said velocity should remain constant or decrease in said downstream direction gores:
v2~vl ( combination of equations (6) and (7) gives:
r22/A2 <_ r1 2/A1, or A~/Al _>_ r22%rl2 (8) l0 Equation (8) equals equation (2) and equations (2) and (8) are based on the principle that the rock flour velocity v should decrease or at least remain equal in downstream direction of each waterway. In this manner accumulation and compaction of rock flour in the waterways is avoided and mechanical cleaning of the waterways is accomplished. T'he mechanical cleaning capability is of 1 ~ importance if the hydraulic cleaning provided by the flow of drilling fluid is no longer adequate.
The bit concept according to the invention can be. used in a fishtail bit or in any other bit in which waterways are formed between cutting wings. The bit body may be dome-shaped and tine cut ing wings of the bit may have a radial or a 2o spiraling orientation relative t.o a central a?cis of the bit body.
Accordingly it is to be clearly understood that the embodiment shown in the drawing is illustrative only.
Claims (5)
1. A rotary bit for drilling through sticky formations, the bit comprising:
- a bit body on which a plurality of cutting wings are mounted, said wings extending along the bit body from a central axis of the bit towards the gauge of the bit, each wing having a tip, and - a plurality of waterways for transporting drilling fluid and rock flour to the gauge of the bit, each waterway being formed between a pair of adjacent wings and having at each point along its length a cross-sectional area A measured in a plane perpendicular to a central chord of the waterway, the size of said cross-sectional area A
increasing in a direction from the central axis towards the gauge of the bit, characterized in that the size of said cross-sectional area increases in such a manner that the ratio between a cross-sectional area A1 of the waterway in a first plane perpendicular to said chord and a cross-sectional area A2 of the same waterway in a second plane perpendicular to said chord fulfils the equation:
A1 /A2 <=r1 2/r2 2 r1 being the average radius at which the first plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit;
r2 being the average radius at which the second plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit; and r2 being larger than r1 .
- a bit body on which a plurality of cutting wings are mounted, said wings extending along the bit body from a central axis of the bit towards the gauge of the bit, each wing having a tip, and - a plurality of waterways for transporting drilling fluid and rock flour to the gauge of the bit, each waterway being formed between a pair of adjacent wings and having at each point along its length a cross-sectional area A measured in a plane perpendicular to a central chord of the waterway, the size of said cross-sectional area A
increasing in a direction from the central axis towards the gauge of the bit, characterized in that the size of said cross-sectional area increases in such a manner that the ratio between a cross-sectional area A1 of the waterway in a first plane perpendicular to said chord and a cross-sectional area A2 of the same waterway in a second plane perpendicular to said chord fulfils the equation:
A1 /A2 <=r1 2/r2 2 r1 being the average radius at which the first plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit;
r2 being the average radius at which the second plane crosses the tips of adjacent cutting wings, said radius being measured from the central axis of the bit; and r2 being larger than r1 .
2. The bit of claim 1 wherein the cutting wings have a substantially radial orientation relative to the central axis of the bit and each waterway has at each point along its length a substantially rectangular cross-sectional area A, wherein said cross-sectional area A1 has a height h1 and said cross-sectional area A2 has a height h2, and wherein the ratio between the height h1 of the cross-sectional area A1 of the waterway in said first plane 1 and the height h2 of the cross-sectional area A2 of the waterway in said second plane fulfils the equation:
h1/h2<=r1/r2 h1 being the height of area A1 as defined by the distance between the tip of an adjacent cutting wing and the bit body when measured in plane 1, and h2 being the height of area A2 as defined by the distance between the tip of an adjacent cutting wing and the bit body when measured in plane 2.
h1/h2<=r1/r2 h1 being the height of area A1 as defined by the distance between the tip of an adjacent cutting wing and the bit body when measured in plane 1, and h2 being the height of area A2 as defined by the distance between the tip of an adjacent cutting wing and the bit body when measured in plane 2.
3. The bit of claim 1 or 2, wherein the cutting wings are equipped near their tips with a series of disc-shaped polycrystalline diamond compact cutters.
4. The bit of claim 1, 2 or 3, wherein the bit is a fishtail bit.
5. The bit of claim 1, 2, 3 or 4, wherein the bit has a dome-shaped bit body on which a plurality of cutting wings are mounted at equally distributed angular internals.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8824546 | 1988-10-20 | ||
| GB888824546A GB8824546D0 (en) | 1988-10-20 | 1988-10-20 | Rotary drill bit for drilling through sticky formations |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2001178A1 CA2001178A1 (en) | 1990-04-20 |
| CA2001178C true CA2001178C (en) | 2004-03-16 |
Family
ID=10645490
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002001178A Expired - Fee Related CA2001178C (en) | 1988-10-20 | 1989-10-20 | Rotary drill bit for drilling through sticky formations |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5197554A (en) |
| EP (1) | EP0365100B1 (en) |
| CA (1) | CA2001178C (en) |
| DE (1) | DE68912061T2 (en) |
| DK (1) | DK170866B1 (en) |
| ES (1) | ES2048828T3 (en) |
| GB (1) | GB8824546D0 (en) |
| NO (1) | NO180551C (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5803196A (en) * | 1996-05-31 | 1998-09-08 | Diamond Products International | Stabilizing drill bit |
| US6125947A (en) | 1997-09-19 | 2000-10-03 | Baker Hughes Incorporated | Earth-boring drill bits with enhanced formation cuttings removal features and methods of drilling |
| US6302223B1 (en) | 1999-10-06 | 2001-10-16 | Baker Hughes Incorporated | Rotary drag bit with enhanced hydraulic and stabilization characteristics |
| US8020639B2 (en) * | 2008-12-22 | 2011-09-20 | Baker Hughes Incorporated | Cutting removal system for PDC drill bits |
| US8517124B2 (en) * | 2009-12-01 | 2013-08-27 | Northbasin Energy Services Inc. | PDC drill bit with flute design for better bit cleaning |
| CN108945640B (en) * | 2018-07-12 | 2021-11-12 | 江苏恒添源新材料科技有限公司 | Chalk film coating machine |
| CN111520079A (en) * | 2020-06-23 | 2020-08-11 | 西南石油大学 | PDC drill bit blade with crown profile offset |
| CN112324349B (en) * | 2020-11-10 | 2023-10-03 | 河南四方达超硬材料股份有限公司 | Diamond compact and drill bit of multiple plough |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2371489A (en) * | 1943-08-09 | 1945-03-13 | Sam P Daniel | Drill bit |
| US3215215A (en) * | 1962-08-27 | 1965-11-02 | Exxon Production Research Co | Diamond bit |
| US4397363A (en) * | 1980-01-10 | 1983-08-09 | Drilling & Service U.K. Limited | Rotary drill bits and method of use |
| US4554986A (en) * | 1983-07-05 | 1985-11-26 | Reed Rock Bit Company | Rotary drill bit having drag cutting elements |
| US4655303A (en) * | 1985-11-22 | 1987-04-07 | Amoco Corporation | Drill bit |
| GB2185506B (en) * | 1986-01-21 | 1989-03-30 | Shell Int Research | Rotary drill bit |
| US4696354A (en) * | 1986-06-30 | 1987-09-29 | Hughes Tool Company - Usa | Drilling bit with full release void areas |
| GB8628168D0 (en) * | 1986-11-22 | 1986-12-31 | Nl Petroleum Prod | Rotary drill bits |
| US4794994A (en) * | 1987-03-26 | 1989-01-03 | Reed Tool Company | Drag drill bit having improved flow of drilling fluid |
| EP0295045A3 (en) * | 1987-06-09 | 1989-10-25 | Reed Tool Company | Rotary drag bit having scouring nozzles |
-
1988
- 1988-10-20 GB GB888824546A patent/GB8824546D0/en active Pending
-
1989
- 1989-10-18 EP EP89202639A patent/EP0365100B1/en not_active Expired - Lifetime
- 1989-10-18 DE DE89202639T patent/DE68912061T2/en not_active Expired - Fee Related
- 1989-10-18 ES ES89202639T patent/ES2048828T3/en not_active Expired - Lifetime
- 1989-10-19 DK DK519489A patent/DK170866B1/en not_active IP Right Cessation
- 1989-10-19 US US07/422,885 patent/US5197554A/en not_active Expired - Fee Related
- 1989-10-19 NO NO894176A patent/NO180551C/en unknown
- 1989-10-20 CA CA002001178A patent/CA2001178C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| ES2048828T3 (en) | 1994-04-01 |
| EP0365100A3 (en) | 1991-04-03 |
| DE68912061T2 (en) | 1994-04-28 |
| CA2001178A1 (en) | 1990-04-20 |
| US5197554A (en) | 1993-03-30 |
| GB8824546D0 (en) | 1988-11-23 |
| DK170866B1 (en) | 1996-02-19 |
| EP0365100B1 (en) | 1994-01-05 |
| DK519489A (en) | 1990-04-21 |
| EP0365100A2 (en) | 1990-04-25 |
| NO894176D0 (en) | 1989-10-19 |
| NO894176L (en) | 1990-04-23 |
| NO180551B (en) | 1997-01-27 |
| NO180551C (en) | 1997-05-07 |
| DE68912061D1 (en) | 1994-02-17 |
| DK519489D0 (en) | 1989-10-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |