CA2652563A1 - Core drill assembly with adjustable total flow area and restricted flow between outer and inner barrel assemblies - Google Patents
Core drill assembly with adjustable total flow area and restricted flow between outer and inner barrel assemblies Download PDFInfo
- Publication number
- CA2652563A1 CA2652563A1 CA002652563A CA2652563A CA2652563A1 CA 2652563 A1 CA2652563 A1 CA 2652563A1 CA 002652563 A CA002652563 A CA 002652563A CA 2652563 A CA2652563 A CA 2652563A CA 2652563 A1 CA2652563 A1 CA 2652563A1
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- CA
- Canada
- Prior art keywords
- core
- assembly
- seal
- lower shoe
- core head
- 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.)
- Abandoned
Links
- 230000000712 assembly Effects 0.000 title description 2
- 238000000429 assembly Methods 0.000 title description 2
- 239000012530 fluid Substances 0.000 claims abstract description 58
- 238000005553 drilling Methods 0.000 claims abstract description 42
- 239000000463 material Substances 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 6
- 239000004677 Nylon Substances 0.000 claims description 3
- 239000004698 Polyethylene Substances 0.000 claims description 3
- 229920001778 nylon Polymers 0.000 claims description 3
- 229920006362 Teflon® Polymers 0.000 claims description 2
- 229920001971 elastomer Polymers 0.000 claims description 2
- 229920001084 poly(chloroprene) Polymers 0.000 claims description 2
- -1 polyethylene Polymers 0.000 claims description 2
- 229920000573 polyethylene Polymers 0.000 claims description 2
- 239000011324 bead Substances 0.000 claims 1
- 238000005520 cutting process Methods 0.000 abstract description 12
- 239000002173 cutting fluid Substances 0.000 abstract description 2
- 238000005457 optimization Methods 0.000 abstract description 2
- 230000035515 penetration Effects 0.000 abstract description 2
- 238000013461 design Methods 0.000 description 6
- 230000036961 partial effect Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 235000003625 Acrocomia mexicana Nutrition 0.000 description 1
- 244000202285 Acrocomia mexicana Species 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000007767 bonding agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 230000033001 locomotion Effects 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/02—Core bits
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK 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
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK 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
- E21B10/605—Drill bits characterised by conduits or nozzles for drilling fluids the bit being a core-bit
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B25/00—Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors
Landscapes
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Mechanical Engineering (AREA)
- Earth Drilling (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
- Drilling And Boring (AREA)
Abstract
A core drill assembly with replaceable cutting fluid nozzles permitting effective total flow area adjustment (TFA), substantial optimization of hydraulic force at the cutting face to improve rate of penetration (ROP) and core quality. At least one seal assembly to restrict drilling fluid flow while permitting mutual rotation between the core head ID and the lower shoe is disposed in an annulus defined therebetween.
Description
Printed: 31/03/2008 `rom-BAKER HUGHES LEGAL DESCPAMD 713-625-5657 T-665 P.01.US2007011355 BHI Ref. 564-42972-WO
CORE DRILL ASSEMBLY WITH .4dD,r[TSTABLE TOTAI.FLO'A6V AREA AND
RESTRICTED FLOW BETWEEN OUTER AND IN1VE1(8 BAItREL .
ASSEMBLIES
Y1ITVENTORS: WILSON, Bob T. and ItEGEI\MIt, Thorsten TECHNICAL FIELD
Embodiments of the present invention are related to a core drill assembly with lo adjustable dri.ll fluid total flow area and, more particularly, to a core drill assembly which includes replaceable cutting fluid nozzles and a seal assembly disposed between adjacent portions of the outer barrel assembly and the inner barrel assembly, as well as to methods of coring.
BACKGROUND
Cun;ent core head designs use a fixed total flow area (TFA) to circulate drilling fluid through the core head, also known as a core bit, during down-hole coring operations. The TFA is a calculated discharge area for the drilling fluid which may include an annulus ID gauge fluid course between the core head ID and the exterior of the lower shoe, carried by the.irmer barrel assembly, or core head face discharge ports, or a combination of the two. Drilling fluid is circulated through the ID fluid courses and the face discharge ports to cool and clean cutting structure carried on the face of the core head, and to remove cuttinbs generated when the cutting head penetrates the formation being cored. The hydraulic force, or the ability of the drilling fhdd to removing material cuttings from the cutting head face, is nieasured in hydraulic horsepower/ in"- (HSI) and is an indicator of drilling fluid cleaning efficiency. If the hydraulic force is too low, there will be poor cleaning of the cutting structure and cuttings will interfere with the rate of penetration (ROP) in forming the bore hole. If the hydraulic force is too high, there may be erosion of the bole hole, which can result in a stuck drill string, and the drilling fluid may contaminate the.core sample. By using HSI and ROP measurements, the optimum amount of hydraulic force can be designed into a core drill assembly.
FIG. 1 is a cross-section of a conventional core drill assembly 10, with a non-adjustable TFA or drilling fluid flow area defined by the areas of the annulus 50 and the discharge ports 30. The annulus 50 is the gap between the ID of core head 14 and the outside of the lower shoe 18. With this arrangement, drilling fluid is pumped down the red at the EPO on Feb 05, 2008 21:44:09. P~
1 AMENDED SHEET ::05/02/2008 ' ..
printed: 31/03/2008'rom-BAKER HUGHES LEGAL ;DESCPAMD 713-625-5657 T-685 P.01 BHI Ref. 564-42972-WO 2 drill string, to core drill assembly 10, where a portion of the drilling fluid will travel through the annulus 50 and exit the core drill assembly 10 proximate the leading edge of the lower shoe 18, while the remaining drilling fluid enters ihe fluid course 20 witlxin core head 14, and exits the discharge ports 301ocated on. the face 16 of core head 14, as respectively shown by the arrows in FIG. 1. The drilling fluid is used to cool the cutters 60 and flush cuttings away from the face 16 of core head 14. However, since the TFA is non-adjustable, the operator cannot optin-,ize the amount of drilling fluid at the face 16 of core head 14 and the HSI.
With the non-adjustable TFA of current core head designs, the only variable is the circulation rate of the drilling fluid, and therefore, the HSI cannot be optirnized.
Also, in current core heads there is always some drilling lluid flow through the annular space between the core head ID and the lower shoe. In core heads using ID
fluid courses only, all of the flow travels through the ann.ulus whereas, when core head face discharge ports are used in cotnbination with the annulus, it is difficult to determine t s amount of drilling fluid "split" between the discharge ports and the annulus. The difficulty arises because the actual annulus gap spacing between the core head ID and.
the lower shoe is not known when the core head is down hole.. The annulus gap is nominally 0.95 cm to 1.27 cm ( 3/8" to %"); however, when using an aluminum or fiberglass inner tube, in the inner barrel assembly, gaps up to about 14 cm (5 '/") may 2o be required in order to compensate for the different rates of thermal.
expansion attributed to the materials of the inner tube and the core head. Under bottom-hole temperature, the gap may decrease to the estirnated desirable gap of 0.95 mm to 1.27 cm ('/e" to %z"), but uncertainty about the actual and estimated bottom-hole teniperature, can result in a significant error in spacing adjustment. As the area of the annulus gap is 25 added directly into the TFA calcula.tion, the uncertainty of the gap size xnakes accurately calculating TFA difficult. The split of flow between the annulus between the OD of the inner tube shoe and the ID of the corz head, and the face discharge ports is dependent upon their relative TFA. Depending upon actual spacinb down hole, the annular TFA could be higher than the TFA of the face discharge ports, with the result 30 that most of the flow of drilling fluid will pass through the ID annulus.
This significantly reduces the effective-ness of the face discharge ports, and reduces fiutlier the HSI delivered to the cutting structure of the core head. Adjusting the TFA
of the face discharge ports in this case would not increase HSI, since the bypass flow would :ied at the EPO on Feb 05, 2008 21:44:09. P2 ;2 AMENDED SHEET ;~05/02/2008 , ~'rom-BAKER HUGHES LEGAL ~~~ 713-625-5857 T=685 P.0( ' ~~ ~~ ~ ~
Prmted:' 31 /0372008 ~ :DESGPAMD US2007011355 BHI Ref. 564-~2972-WO 3 simply be increased through the ID annulus. To increase HSI, the bypass flow through the ID annulus must be sealed of~f, or severely restricted, to divert as xnuch of the flow as possible to the face discharge ports, or nozzles.
For a conventional drill bit with replaceable nozzles, the TFA can be optimized by utilizing different diameter nozzles in the discharge po.rts. However, in a' conventional core drill assembly, since at least some of the drilling fluid ilow travels through the annulus, a change of discharge port size will change the resistance at the nozzles and will proportionally ehange the ariiount of drilling fluid bypassing through the annulus. This problem is highlighted when looking at the performance of the drill bit versus a core drill. A drill bit will normally operate in the range of 4-8 HSI, whereas 21.6 czxi x 10.16 cm (8 '/z" x 4") core drill may operate as low as 0.2 I ISI:
U.S. Patent 3,308,896 discloses various configurations of core drill assemblies, two o which are used with reverse, or counterflow, drilling fluid circulation. The remaining embodiment is used with conventional drilli.ng fluid flow with a labyrinth 1S seal located between an end of a core catcher and and the core bit head.
'WO 98/54437 discloses the use of replaceable. nozzles in a convenbtional drill bit.
Clydedale et al, -"Core bit deasign reduces mud invasion, improves ROP, Oil & Gas Journal, Pennweell, I~ouston ~Texas, US, vol. 92, no. 32, 8 Aua~.ust 1994 pages 51-57; discusses core bit ~
technology and specifically design features~ of a low-invasion~ core bit.
In view of the shortcomings in the art, it would be advantageous to provide a core drill with adjustable TFA, by fitting the core hea.d with replaceable nozzles and sealing off the annulus between the core head 1L) and the lower shoe. This will allow i an operator to apply the same drillin~ optimization concepts to coring as used with conventional drilling, and allow the I-1SI to be improved over conventional core hea,d desi~nns, with correspondinD improvements in coring perforzxiance; ROP and core quality.
DISCLOSURE OF INVBNTION
Embodiments of the invention include replaceable nozzles fitted in at least some of the drilling fluid outlet ports, proximate the face of the core head. The nozzle design 'will cornpensate for the smaller surface area of rhe rypical core drill face and new nozzle locations and j et directions are contemplated to take advantage of the improved :3 ied at the EPO on Feb 05, 2008 21:44:09. Ps AMENDED SHEET '05/02/2008 -. , -Printed: 31/03/2008'rom-BAKER HUGHES LEGAL DESCPAMD713-B25-585t T-685 P.01,US2007011355 BHI Ref. 564-42972-WO 4 HSI at the cuttYng face, including directing nozzles towards interior cutters of the core head in order to clear cuttings and provide cooling.
In one embodiment of the present invention, the annulus between the cutting head and the lower shoe is substantially sealed with a seal structure, whicll may be s broadly characterized as a seal asserzably or a seal element, without substantial rotational interference between the core head and the lower shoe, which would cause the lower shoe and inner tube to turn with the outer barrel assembly and core head.
One embodiment includes one or more grooves formed into the ID of the core head to accommodate an annular seal similar to an 0-ring in each of the grooves. The lo design of the 0-ring or other annular seal allows some drilling fluid flow to bypass under reduced pressure, but under normal operating circumstances the 0-ring or other annular seal seals substantially completely.
Iu a second embodiment of the present invention, the annulus between the core head and the lower shoe is substantially sealed using split rings made from a material I s such as nylon or Teflon(t. This embodiment includes one or more grooves formed in the ID of the core head where split rings of the appropriate size are installed to seal the annulus. The seals will fit somewhat loose]y in the grooves and may rotate during coring operations, but will provide a sufficient seal to enable effective TFA
adjustments by installing different sizes of drilling fluid nozzles. The loose fit will reduee friction >o between the core liead ID and the lower shoe, to eliminate any tendency for the lower shoe and inner tube to rotate.
Other embodiments of the present invention employ one or more of a wiper seal, a chevron seal, a packer cup or a restrictor sleeve disposed between the core head and the lower shoe to substantially restrict fluid flow t,herebetween while penniitting 25 rotational movement of the core head about the lower shoe.
Embodiments of the present invention also include methods of using a core drill assembly.
BRIEF DESCRIPTION OF DR.AWINGS
30 The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
;4.ied at the EPO on Feb 05, 200821:44:09. PE
AMENDED SHEET ;,05/0212008 Qrinted:-31/03/2008 `rom-BAKER HUGHES LEGAL DESCPAMD 713-825-5857 T-685 P o~
BHl Ref. 564-42972-WO ~
FIG. 1 is a cross-section of a conventional core drill assembIy vvith a non-adjustable TFA defined by the area of the annulus between the core head and the.
lower shoe, and the area of the drilling fluid ports;
FIG. 2 is a cross-section of a core drill assembly with a seal structure between the core head and rhe lower shoe and replaceable nozzles;
FIG. 3 is a partial cross-section of a core drill assembly including an 0-ring or wiper seal type seal assembly;
FIG. 4 is a partial cross-section of a core drill assembly including a split-ring type seal assembly;
FIG. 5 is a partial cross-section of a core drill assembly including a labyrinth seal assembly; and FIG. 6 is a partial cross-section of a core drill assembly including a restrictor sleeve.
MODES FOR CARRYING OUT THJE INVENTION
FIG. 2 schematicalIy depicts a core drill assembly 10 of the present invention including replaceable nozzles 36 at the discharge ends of fluid courses 20, and at least one seal assembly 40 disposed between the core head 14 and the lower shoe 18.
These features allow the operator to change the TFA of the core drill assembly 10 and optimize the HSI. The operator can select replaceable nozzles 36 having a discharge opening 34 of an appropriate diameter to adjust TFA. Thus, if a volume of drilling fluid is pumped under pressure, at a substantially constant flow rate, down the drill string, seal assembly 40 will divert substantially all of the drilling fluid volume away from the annulus 50 and into the fluid courses 20 where the drilling fluid will exit tlirough discharge opening 34 of replaceable nozzles 36. The diameters of discharge openings 34 will affect both the rate of discharge and the velocity of the escaping drilling fluid. Under opti:mized conditions, as provided by the present invention, the drilling fluid, emanating from the discharge openings 34, will effectively clear cuttings away from the face 16 of core head 14 and properly cool cutters 60. The optimum diameter of dischaige openings 34 for a specific material or formation, and core head or core size, can be determined or predicted by the use of historical data, including ROP
measurements. As shown at the left-hand side of FIG. 2, the seal assembly 40 may be partially received in a groove in ID of the core head 14 or, as shown at the riõht-hand side of FIG. 2, the se3l assembly 40 may be partially received in a groove in the ied at the EPO.on Feb 05, 2008 21:44:09. Pe AMENDED SHEET :05/02/2008.
Printed: 31/03/2008 rom-BAKER HllGHES.LEGAL DESCPAMD 7~3-625-585T T-685 P
0~;US2007011355 _ .:, ..: -: -.,...
i ..: .:..,.. _.,. . , .
BHI Ref. 564-4297?-WO 6 I =
exterior of the lower shoe 1$. As core head 14 rotates about lower shoe 18 during a coring operation, fluid flow therebetween will be substantially restricted by seal assembly 40, as indicated by the smaller size of the arrows below annulus 50 in comparison to those in fluid courses 20.
FIGS. 3 and 4, are partial cross-section views of core drill assembly 10 provided, to show additional detail of several embodiments of the at least one seal assembly 40. The at least one seal assembly 40 is positioned in the annuIus 50, or the gap defuted between the IY) of core head.14 and the outside of the lower shoe 18. The seals 42 and 44 are installed in grooves 46 formed in the ID of core head 14.
The lo seals 44 shown in FIG. 3 may comprise an 0-ring or other continuous ring type that may have a round or oval cross-section, or may include lips which fun.etion as "wipers," as shown. The material of seals 44 may include, but is not limited to, rubber, neoprene, or polyethylene or a combination thereof. The seals 42 shown in FIG.
4 are of a split-ring design which rides loosely in the grooves 46. Examples of suitable materials for the split-ring seals 42 are nylon and Tellon(& polymers. The at least one seal assernbly 40 will substantiaIly restrict the flow of the drilling fluid pumped down the drill string, forcuig the drilling fluid to bypass the annulus 50 and into the fluid courses 20, traveling in, the direction of flow arrows 26.
FIG. 5 is a partial cross-section view of a core drill assembly 10 including a labyrinth seal 48 having a plurality of radially projectinb, axially spaced annular elements separated by labyriuth slots 56. The labyrinth sea148 is formed into the stYUcture of one of the core head 14 ID or the exterior surface of the lower shoe 18.
However, a labyrinth sea148 with mating, interdigitated elements or components as sbown in broken lines at E can be formed with the cooperating parts disposed on both the core head 14 ID atid the lower shoe 18. The total number of labyrinth slots 56 is not specified, and will vary depending on the expected pressure differential between the pumped driIling fluid and drill work face. The labyrinth sea148 must have sufficient length and number of labyrinth slots 56 to effectively seal annulus 50.. With annulus 50 fluid will enter fluid courses 20, flowing in the direction indicated sealed, the drilling 3o by flow aTrows 26.
It is also contemplated,that the seals may be carried on the exterior of the Io-vver shoe 18 instead of on core head 14, or may be carried on both components. It is also contemplated that a seal comprising an upwardly facing packer cup with a frustoconical : 6 ied at the EPO on Feb 05, 2008 21:44:09. P2 AMENDED SHEET 05/02/2008 -' '- 'rom-BAKER HUGHES LEGAL DESCPAMD 713-625-5857 T-685 P:OPrintetl 31/03l2008 US2007011355 ..
BHI Ref. 554-42972-WO 7 elastomenic skirt may be utilized in addition to, or in lieu of, orher seal configurations.
Chevron-type seals, as well as metallic or elastomeric seal baclc-up components, may also be employed.
FIG. 6 depicts yet another embodiment of the present invention, wherein a seal element in.the form of restrictor sleeve 64 is disposed on an annular shoulder machined or otherwise.fonned on the ID of the core head 14, and retained therein through the use of an appropriate bonding agent, such as BAKEI2LOK , compound, available from various operating wuits of Baker Hughes Incorporated, assignee of the present invention. As with the previous embodiments, discharge openings 34 of >. o replaceable noa~zles 36 may be selected for optimum TFA. A conwenuonal lower shoe 18 is run inside of core head 14, and extends longitudinally therethrough. The outer surface (shown in broken lines for clarity) of lower shoe 1$ is in close proximity to the ID of restrictor sleeve 64, so that a very small clearance radial clearance C, for example about 1 mm, is aehieved. This small, annular clearance C betweez> lower shoe IS and ls restriCtor sleeve 64, while permitting rotation of lower shoe 18 and restrictor sleeve 64 about lower shoe 18, will substantially restrict the flow of the drilling fluid pumped down the drill string, forcing the drilling fluid to bypass the annulus 50 and into the fluid courses20 to exit through discharge openings 34 of replaceable nozzles 36.
While the present invention has been depicted and described with reference to 20 certain embodiments, the invention is not so li.mited. Additions and modifications to, and deletions from, the described embodiments will be readily apparent to those of ordinary sldll in the art. The present invention is, thus, limited only by the claims which follow.
~ted at the EPO on Feb 05, 2008 21:44:09. Pc AMENDED SH EET ;05/02/2008
CORE DRILL ASSEMBLY WITH .4dD,r[TSTABLE TOTAI.FLO'A6V AREA AND
RESTRICTED FLOW BETWEEN OUTER AND IN1VE1(8 BAItREL .
ASSEMBLIES
Y1ITVENTORS: WILSON, Bob T. and ItEGEI\MIt, Thorsten TECHNICAL FIELD
Embodiments of the present invention are related to a core drill assembly with lo adjustable dri.ll fluid total flow area and, more particularly, to a core drill assembly which includes replaceable cutting fluid nozzles and a seal assembly disposed between adjacent portions of the outer barrel assembly and the inner barrel assembly, as well as to methods of coring.
BACKGROUND
Cun;ent core head designs use a fixed total flow area (TFA) to circulate drilling fluid through the core head, also known as a core bit, during down-hole coring operations. The TFA is a calculated discharge area for the drilling fluid which may include an annulus ID gauge fluid course between the core head ID and the exterior of the lower shoe, carried by the.irmer barrel assembly, or core head face discharge ports, or a combination of the two. Drilling fluid is circulated through the ID fluid courses and the face discharge ports to cool and clean cutting structure carried on the face of the core head, and to remove cuttinbs generated when the cutting head penetrates the formation being cored. The hydraulic force, or the ability of the drilling fhdd to removing material cuttings from the cutting head face, is nieasured in hydraulic horsepower/ in"- (HSI) and is an indicator of drilling fluid cleaning efficiency. If the hydraulic force is too low, there will be poor cleaning of the cutting structure and cuttings will interfere with the rate of penetration (ROP) in forming the bore hole. If the hydraulic force is too high, there may be erosion of the bole hole, which can result in a stuck drill string, and the drilling fluid may contaminate the.core sample. By using HSI and ROP measurements, the optimum amount of hydraulic force can be designed into a core drill assembly.
FIG. 1 is a cross-section of a conventional core drill assembly 10, with a non-adjustable TFA or drilling fluid flow area defined by the areas of the annulus 50 and the discharge ports 30. The annulus 50 is the gap between the ID of core head 14 and the outside of the lower shoe 18. With this arrangement, drilling fluid is pumped down the red at the EPO on Feb 05, 2008 21:44:09. P~
1 AMENDED SHEET ::05/02/2008 ' ..
printed: 31/03/2008'rom-BAKER HUGHES LEGAL ;DESCPAMD 713-625-5657 T-685 P.01 BHI Ref. 564-42972-WO 2 drill string, to core drill assembly 10, where a portion of the drilling fluid will travel through the annulus 50 and exit the core drill assembly 10 proximate the leading edge of the lower shoe 18, while the remaining drilling fluid enters ihe fluid course 20 witlxin core head 14, and exits the discharge ports 301ocated on. the face 16 of core head 14, as respectively shown by the arrows in FIG. 1. The drilling fluid is used to cool the cutters 60 and flush cuttings away from the face 16 of core head 14. However, since the TFA is non-adjustable, the operator cannot optin-,ize the amount of drilling fluid at the face 16 of core head 14 and the HSI.
With the non-adjustable TFA of current core head designs, the only variable is the circulation rate of the drilling fluid, and therefore, the HSI cannot be optirnized.
Also, in current core heads there is always some drilling lluid flow through the annular space between the core head ID and the lower shoe. In core heads using ID
fluid courses only, all of the flow travels through the ann.ulus whereas, when core head face discharge ports are used in cotnbination with the annulus, it is difficult to determine t s amount of drilling fluid "split" between the discharge ports and the annulus. The difficulty arises because the actual annulus gap spacing between the core head ID and.
the lower shoe is not known when the core head is down hole.. The annulus gap is nominally 0.95 cm to 1.27 cm ( 3/8" to %"); however, when using an aluminum or fiberglass inner tube, in the inner barrel assembly, gaps up to about 14 cm (5 '/") may 2o be required in order to compensate for the different rates of thermal.
expansion attributed to the materials of the inner tube and the core head. Under bottom-hole temperature, the gap may decrease to the estirnated desirable gap of 0.95 mm to 1.27 cm ('/e" to %z"), but uncertainty about the actual and estimated bottom-hole teniperature, can result in a significant error in spacing adjustment. As the area of the annulus gap is 25 added directly into the TFA calcula.tion, the uncertainty of the gap size xnakes accurately calculating TFA difficult. The split of flow between the annulus between the OD of the inner tube shoe and the ID of the corz head, and the face discharge ports is dependent upon their relative TFA. Depending upon actual spacinb down hole, the annular TFA could be higher than the TFA of the face discharge ports, with the result 30 that most of the flow of drilling fluid will pass through the ID annulus.
This significantly reduces the effective-ness of the face discharge ports, and reduces fiutlier the HSI delivered to the cutting structure of the core head. Adjusting the TFA
of the face discharge ports in this case would not increase HSI, since the bypass flow would :ied at the EPO on Feb 05, 2008 21:44:09. P2 ;2 AMENDED SHEET ;~05/02/2008 , ~'rom-BAKER HUGHES LEGAL ~~~ 713-625-5857 T=685 P.0( ' ~~ ~~ ~ ~
Prmted:' 31 /0372008 ~ :DESGPAMD US2007011355 BHI Ref. 564-~2972-WO 3 simply be increased through the ID annulus. To increase HSI, the bypass flow through the ID annulus must be sealed of~f, or severely restricted, to divert as xnuch of the flow as possible to the face discharge ports, or nozzles.
For a conventional drill bit with replaceable nozzles, the TFA can be optimized by utilizing different diameter nozzles in the discharge po.rts. However, in a' conventional core drill assembly, since at least some of the drilling fluid ilow travels through the annulus, a change of discharge port size will change the resistance at the nozzles and will proportionally ehange the ariiount of drilling fluid bypassing through the annulus. This problem is highlighted when looking at the performance of the drill bit versus a core drill. A drill bit will normally operate in the range of 4-8 HSI, whereas 21.6 czxi x 10.16 cm (8 '/z" x 4") core drill may operate as low as 0.2 I ISI:
U.S. Patent 3,308,896 discloses various configurations of core drill assemblies, two o which are used with reverse, or counterflow, drilling fluid circulation. The remaining embodiment is used with conventional drilli.ng fluid flow with a labyrinth 1S seal located between an end of a core catcher and and the core bit head.
'WO 98/54437 discloses the use of replaceable. nozzles in a convenbtional drill bit.
Clydedale et al, -"Core bit deasign reduces mud invasion, improves ROP, Oil & Gas Journal, Pennweell, I~ouston ~Texas, US, vol. 92, no. 32, 8 Aua~.ust 1994 pages 51-57; discusses core bit ~
technology and specifically design features~ of a low-invasion~ core bit.
In view of the shortcomings in the art, it would be advantageous to provide a core drill with adjustable TFA, by fitting the core hea.d with replaceable nozzles and sealing off the annulus between the core head 1L) and the lower shoe. This will allow i an operator to apply the same drillin~ optimization concepts to coring as used with conventional drilling, and allow the I-1SI to be improved over conventional core hea,d desi~nns, with correspondinD improvements in coring perforzxiance; ROP and core quality.
DISCLOSURE OF INVBNTION
Embodiments of the invention include replaceable nozzles fitted in at least some of the drilling fluid outlet ports, proximate the face of the core head. The nozzle design 'will cornpensate for the smaller surface area of rhe rypical core drill face and new nozzle locations and j et directions are contemplated to take advantage of the improved :3 ied at the EPO on Feb 05, 2008 21:44:09. Ps AMENDED SHEET '05/02/2008 -. , -Printed: 31/03/2008'rom-BAKER HUGHES LEGAL DESCPAMD713-B25-585t T-685 P.01,US2007011355 BHI Ref. 564-42972-WO 4 HSI at the cuttYng face, including directing nozzles towards interior cutters of the core head in order to clear cuttings and provide cooling.
In one embodiment of the present invention, the annulus between the cutting head and the lower shoe is substantially sealed with a seal structure, whicll may be s broadly characterized as a seal asserzably or a seal element, without substantial rotational interference between the core head and the lower shoe, which would cause the lower shoe and inner tube to turn with the outer barrel assembly and core head.
One embodiment includes one or more grooves formed into the ID of the core head to accommodate an annular seal similar to an 0-ring in each of the grooves. The lo design of the 0-ring or other annular seal allows some drilling fluid flow to bypass under reduced pressure, but under normal operating circumstances the 0-ring or other annular seal seals substantially completely.
Iu a second embodiment of the present invention, the annulus between the core head and the lower shoe is substantially sealed using split rings made from a material I s such as nylon or Teflon(t. This embodiment includes one or more grooves formed in the ID of the core head where split rings of the appropriate size are installed to seal the annulus. The seals will fit somewhat loose]y in the grooves and may rotate during coring operations, but will provide a sufficient seal to enable effective TFA
adjustments by installing different sizes of drilling fluid nozzles. The loose fit will reduee friction >o between the core liead ID and the lower shoe, to eliminate any tendency for the lower shoe and inner tube to rotate.
Other embodiments of the present invention employ one or more of a wiper seal, a chevron seal, a packer cup or a restrictor sleeve disposed between the core head and the lower shoe to substantially restrict fluid flow t,herebetween while penniitting 25 rotational movement of the core head about the lower shoe.
Embodiments of the present invention also include methods of using a core drill assembly.
BRIEF DESCRIPTION OF DR.AWINGS
30 The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
;4.ied at the EPO on Feb 05, 200821:44:09. PE
AMENDED SHEET ;,05/0212008 Qrinted:-31/03/2008 `rom-BAKER HUGHES LEGAL DESCPAMD 713-825-5857 T-685 P o~
BHl Ref. 564-42972-WO ~
FIG. 1 is a cross-section of a conventional core drill assembIy vvith a non-adjustable TFA defined by the area of the annulus between the core head and the.
lower shoe, and the area of the drilling fluid ports;
FIG. 2 is a cross-section of a core drill assembly with a seal structure between the core head and rhe lower shoe and replaceable nozzles;
FIG. 3 is a partial cross-section of a core drill assembly including an 0-ring or wiper seal type seal assembly;
FIG. 4 is a partial cross-section of a core drill assembly including a split-ring type seal assembly;
FIG. 5 is a partial cross-section of a core drill assembly including a labyrinth seal assembly; and FIG. 6 is a partial cross-section of a core drill assembly including a restrictor sleeve.
MODES FOR CARRYING OUT THJE INVENTION
FIG. 2 schematicalIy depicts a core drill assembly 10 of the present invention including replaceable nozzles 36 at the discharge ends of fluid courses 20, and at least one seal assembly 40 disposed between the core head 14 and the lower shoe 18.
These features allow the operator to change the TFA of the core drill assembly 10 and optimize the HSI. The operator can select replaceable nozzles 36 having a discharge opening 34 of an appropriate diameter to adjust TFA. Thus, if a volume of drilling fluid is pumped under pressure, at a substantially constant flow rate, down the drill string, seal assembly 40 will divert substantially all of the drilling fluid volume away from the annulus 50 and into the fluid courses 20 where the drilling fluid will exit tlirough discharge opening 34 of replaceable nozzles 36. The diameters of discharge openings 34 will affect both the rate of discharge and the velocity of the escaping drilling fluid. Under opti:mized conditions, as provided by the present invention, the drilling fluid, emanating from the discharge openings 34, will effectively clear cuttings away from the face 16 of core head 14 and properly cool cutters 60. The optimum diameter of dischaige openings 34 for a specific material or formation, and core head or core size, can be determined or predicted by the use of historical data, including ROP
measurements. As shown at the left-hand side of FIG. 2, the seal assembly 40 may be partially received in a groove in ID of the core head 14 or, as shown at the riõht-hand side of FIG. 2, the se3l assembly 40 may be partially received in a groove in the ied at the EPO.on Feb 05, 2008 21:44:09. Pe AMENDED SHEET :05/02/2008.
Printed: 31/03/2008 rom-BAKER HllGHES.LEGAL DESCPAMD 7~3-625-585T T-685 P
0~;US2007011355 _ .:, ..: -: -.,...
i ..: .:..,.. _.,. . , .
BHI Ref. 564-4297?-WO 6 I =
exterior of the lower shoe 1$. As core head 14 rotates about lower shoe 18 during a coring operation, fluid flow therebetween will be substantially restricted by seal assembly 40, as indicated by the smaller size of the arrows below annulus 50 in comparison to those in fluid courses 20.
FIGS. 3 and 4, are partial cross-section views of core drill assembly 10 provided, to show additional detail of several embodiments of the at least one seal assembly 40. The at least one seal assembly 40 is positioned in the annuIus 50, or the gap defuted between the IY) of core head.14 and the outside of the lower shoe 18. The seals 42 and 44 are installed in grooves 46 formed in the ID of core head 14.
The lo seals 44 shown in FIG. 3 may comprise an 0-ring or other continuous ring type that may have a round or oval cross-section, or may include lips which fun.etion as "wipers," as shown. The material of seals 44 may include, but is not limited to, rubber, neoprene, or polyethylene or a combination thereof. The seals 42 shown in FIG.
4 are of a split-ring design which rides loosely in the grooves 46. Examples of suitable materials for the split-ring seals 42 are nylon and Tellon(& polymers. The at least one seal assernbly 40 will substantiaIly restrict the flow of the drilling fluid pumped down the drill string, forcuig the drilling fluid to bypass the annulus 50 and into the fluid courses 20, traveling in, the direction of flow arrows 26.
FIG. 5 is a partial cross-section view of a core drill assembly 10 including a labyrinth seal 48 having a plurality of radially projectinb, axially spaced annular elements separated by labyriuth slots 56. The labyrinth sea148 is formed into the stYUcture of one of the core head 14 ID or the exterior surface of the lower shoe 18.
However, a labyrinth sea148 with mating, interdigitated elements or components as sbown in broken lines at E can be formed with the cooperating parts disposed on both the core head 14 ID atid the lower shoe 18. The total number of labyrinth slots 56 is not specified, and will vary depending on the expected pressure differential between the pumped driIling fluid and drill work face. The labyrinth sea148 must have sufficient length and number of labyrinth slots 56 to effectively seal annulus 50.. With annulus 50 fluid will enter fluid courses 20, flowing in the direction indicated sealed, the drilling 3o by flow aTrows 26.
It is also contemplated,that the seals may be carried on the exterior of the Io-vver shoe 18 instead of on core head 14, or may be carried on both components. It is also contemplated that a seal comprising an upwardly facing packer cup with a frustoconical : 6 ied at the EPO on Feb 05, 2008 21:44:09. P2 AMENDED SHEET 05/02/2008 -' '- 'rom-BAKER HUGHES LEGAL DESCPAMD 713-625-5857 T-685 P:OPrintetl 31/03l2008 US2007011355 ..
BHI Ref. 554-42972-WO 7 elastomenic skirt may be utilized in addition to, or in lieu of, orher seal configurations.
Chevron-type seals, as well as metallic or elastomeric seal baclc-up components, may also be employed.
FIG. 6 depicts yet another embodiment of the present invention, wherein a seal element in.the form of restrictor sleeve 64 is disposed on an annular shoulder machined or otherwise.fonned on the ID of the core head 14, and retained therein through the use of an appropriate bonding agent, such as BAKEI2LOK , compound, available from various operating wuits of Baker Hughes Incorporated, assignee of the present invention. As with the previous embodiments, discharge openings 34 of >. o replaceable noa~zles 36 may be selected for optimum TFA. A conwenuonal lower shoe 18 is run inside of core head 14, and extends longitudinally therethrough. The outer surface (shown in broken lines for clarity) of lower shoe 1$ is in close proximity to the ID of restrictor sleeve 64, so that a very small clearance radial clearance C, for example about 1 mm, is aehieved. This small, annular clearance C betweez> lower shoe IS and ls restriCtor sleeve 64, while permitting rotation of lower shoe 18 and restrictor sleeve 64 about lower shoe 18, will substantially restrict the flow of the drilling fluid pumped down the drill string, forcing the drilling fluid to bypass the annulus 50 and into the fluid courses20 to exit through discharge openings 34 of replaceable nozzles 36.
While the present invention has been depicted and described with reference to 20 certain embodiments, the invention is not so li.mited. Additions and modifications to, and deletions from, the described embodiments will be readily apparent to those of ordinary sldll in the art. The present invention is, thus, limited only by the claims which follow.
~ted at the EPO on Feb 05, 2008 21:44:09. Pc AMENDED SH EET ;05/02/2008
Claims (13)
1. A core drill assembly (10) configured for downward flow of drilling fluid within an interior thereof and upward flow about an exterior thereof the core drilling assembly (10) comprising:
a core head (14) including an inside diameter, a face (16), and at least one fluid course having an outlet on the face (16);
a lower shoe (18) disposed within a portion of the inside diameter of the core head (14);
the core drill assembly (10) characterized by:
at least one replaceable nozzle (36) disposed in the at least one fluid course (20) proximate the outlet; and at least one seal structure (40), disposed between the inside diameter of the core head (14) and an exterior side surface of the lower shoe (18), the at least one seal structure (40) configured to prevent substantial downward flow of drilling fluid between an exterior side surface of the lower shoe (18) and the inside diameter of the core head (14) and no permit rotation of the core head (14) about the lower shoe (18).
a core head (14) including an inside diameter, a face (16), and at least one fluid course having an outlet on the face (16);
a lower shoe (18) disposed within a portion of the inside diameter of the core head (14);
the core drill assembly (10) characterized by:
at least one replaceable nozzle (36) disposed in the at least one fluid course (20) proximate the outlet; and at least one seal structure (40), disposed between the inside diameter of the core head (14) and an exterior side surface of the lower shoe (18), the at least one seal structure (40) configured to prevent substantial downward flow of drilling fluid between an exterior side surface of the lower shoe (18) and the inside diameter of the core head (14) and no permit rotation of the core head (14) about the lower shoe (18).
2. The assembly of claim 1, wherein the at least one replaceable nozzle (36) is replaceable with another replaceable nozzle (36) having a different inner diameter (34).
3. The assembly of claim 1, wherein the at least one seal structure (40) comprises a seal assembly (40) and includes at least one groove (46) formed on at least one of the inside diameter of the core head (14) and the exterior side surface of the lower shoe (18).
4. The assembly of claim 3, wherein the seal assembly (40) includes at least one seal element (42, 44) carried in the at least one groove (46).
5. The assembly of claim 4, wherein ft at least one seal element (42, 44) is at least one of an o-ring seal, a wiper seal, a split-ring seal, a chevron seal or a packer cup.
6. The assembly of claim 4, wherein the at least one seal element (42, 44) is made of at least one of a nylon, a Teflon®, a polyethylene, a rubber or a neoprene material.
7. The assembly of claim 1, wherein the at least one seal structure (40) comprises a labyrinth seal (48).
8. The assembly of claim 1, wherein the at least one seal structure comprises a restrictor sleeve (60) disposed within the core head (14) laterally adjacent an exterior side surface of the lower shoe (18).
9. The assembly of claim 8, wherein the restrictor sleeve (60) rests on an annular shoulder (62) on the inside diameter of the core head (14).
10. The assembly of claim 8, wherein an inside diameter of the restrictor sleeve (60) and the laterally adjacent exterior side surface of the lower shoe (18) are mutuaIIy spaced by about 1 mm.
11. A method for substantially controlling the total flow area (TFA) of a core drill assembly (10) comprising:
providing a core drill assembly (10) configured for downward flow of drilling fluid within an interior thereof to a core head (14) at a lower end of the core drill assembly (10) and subsequent upward flow about an exterior of the core drill assembly (10), the core head (14) including at least one fluid course (20) having an outlet on the face (16) thereof;
the method characterized by:
installing a replaceable nozzle (36) having a selected inner diameter (34) in the at least one fluid course (20) proximate the outlet;
disposing a lower shoe (18) at least partially within the core bead (14); and rotating the core head (14) about the lower shoe (19) while flowing drilling fluid downwardly within the core drill assembly (10), substantially preventing a downward flow of the drilling fluid between the core head (14) and the lower shoe (18) using a seal structure (40) disposed between an inside diameter of the core head (14) and an exterior side surface of the lower shoe (18) and directing drilling fluid flow through the at lcast one replaceable nozzle (36) to a face (16) of the core head (14) and upwardly about an exterior of the core drill assembly (10).
providing a core drill assembly (10) configured for downward flow of drilling fluid within an interior thereof to a core head (14) at a lower end of the core drill assembly (10) and subsequent upward flow about an exterior of the core drill assembly (10), the core head (14) including at least one fluid course (20) having an outlet on the face (16) thereof;
the method characterized by:
installing a replaceable nozzle (36) having a selected inner diameter (34) in the at least one fluid course (20) proximate the outlet;
disposing a lower shoe (18) at least partially within the core bead (14); and rotating the core head (14) about the lower shoe (19) while flowing drilling fluid downwardly within the core drill assembly (10), substantially preventing a downward flow of the drilling fluid between the core head (14) and the lower shoe (18) using a seal structure (40) disposed between an inside diameter of the core head (14) and an exterior side surface of the lower shoe (18) and directing drilling fluid flow through the at lcast one replaceable nozzle (36) to a face (16) of the core head (14) and upwardly about an exterior of the core drill assembly (10).
12. The method of claim 11, further including replacing the at least one replaceable nozzle (36) with another replaceable nozzle (36) having a different inner diameter (34).
13. The method of claim 13, further comprising providing an absolute fluid seal between the core head (14) and the lower shoe (18) with the seal structure(40).
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US80062006P | 2006-05-15 | 2006-05-15 | |
| US60/800,620 | 2006-05-15 | ||
| US11/746,931 | 2007-05-10 | ||
| US11/746,931 US20070261886A1 (en) | 2006-05-15 | 2007-05-10 | Core drill assembly with adjustable total flow area and restricted flow between outer and inner barrel assemblies |
| PCT/US2007/011355 WO2007136568A2 (en) | 2006-05-15 | 2007-05-10 | Core drill assembly with adjustable total flow area and restricted flow between outer and inner barrel assemblies |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2652563A1 true CA2652563A1 (en) | 2007-11-29 |
Family
ID=38684052
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002652563A Abandoned CA2652563A1 (en) | 2006-05-15 | 2007-05-10 | Core drill assembly with adjustable total flow area and restricted flow between outer and inner barrel assemblies |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20070261886A1 (en) |
| CA (1) | CA2652563A1 (en) |
| GB (1) | GB2451788B (en) |
| NO (1) | NO20084841L (en) |
| WO (1) | WO2007136568A2 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100051528A1 (en) * | 2008-08-26 | 2010-03-04 | Clark Filter, Inc. | Seal Improvement for Lube Filter |
| US8201642B2 (en) * | 2009-01-21 | 2012-06-19 | Baker Hughes Incorporated | Drilling assemblies including one of a counter rotating drill bit and a counter rotating reamer, methods of drilling, and methods of forming drilling assemblies |
| US20140166366A1 (en) * | 2012-12-13 | 2014-06-19 | Smith International, Inc. | Single-trip lateral coring systems and methods |
| US9752411B2 (en) | 2013-07-26 | 2017-09-05 | National Oilwell DHT, L.P. | Downhole activation assembly with sleeve valve and method of using same |
| US9494004B2 (en) | 2013-12-20 | 2016-11-15 | National Oilwell Varco, L.P. | Adjustable coring assembly and method of using same |
| US9598911B2 (en) * | 2014-05-09 | 2017-03-21 | Baker Hughes Incorporated | Coring tools and related methods |
| US10125553B2 (en) | 2015-03-06 | 2018-11-13 | Baker Hughes Incorporated | Coring tools for managing hydraulic properties of drilling fluid and related methods |
| CN106014314B (en) * | 2016-07-05 | 2018-11-20 | 中交第四航务工程勘察设计院有限公司 | A kind of drill takes device with hydraulic rock core card |
| CN113175307B (en) * | 2021-04-29 | 2022-04-15 | 四川大学 | Rotary seal core lifting mechanism |
| CN115680650B (en) * | 2022-11-28 | 2024-12-10 | 中冶成都勘察研究总院有限公司 | A drilling method for quickly acquiring core information |
| CN116104421B (en) * | 2023-04-04 | 2023-06-20 | 成都迪普金刚石钻头有限责任公司 | PDC mixed-inlaid drill bit suitable for coring of hard broken stratum |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2013838A (en) * | 1932-12-27 | 1935-09-10 | Rowland O Pickin | Roller core drilling bit |
| US2326435A (en) * | 1940-05-24 | 1943-08-10 | Pink T Bynum | Coring apparatus |
| US2760758A (en) * | 1952-03-07 | 1956-08-28 | Us Industries Inc | Core taking apparatus |
| US2870993A (en) * | 1956-09-27 | 1959-01-27 | Koebel Diamond Tool Co | Core bit drilling tool |
| US3308896A (en) * | 1964-08-20 | 1967-03-14 | Homer I Henderson | Drilling bit |
| US3323604A (en) * | 1964-08-28 | 1967-06-06 | Homer I Henderson | Coring drill |
| US3424255A (en) * | 1966-11-16 | 1969-01-28 | Gulf Research Development Co | Continuous coring jet bit |
| US3688853A (en) * | 1971-03-01 | 1972-09-05 | William C Maurer | Method and apparatus for replacing nozzles in erosion bits |
| US4494618A (en) * | 1982-09-30 | 1985-01-22 | Strata Bit Corporation | Drill bit with self cleaning nozzle |
| BE1005201A4 (en) * | 1991-08-28 | 1993-05-25 | Diamant Boart Stratabit S A En | Crown core. |
| BE1010325A3 (en) * | 1996-06-05 | 1998-06-02 | Dresser Ind | Core. |
| US5927410A (en) * | 1997-05-30 | 1999-07-27 | Dresser Industries, Inc. | Drill bit nozzle and method of attachment |
| BE1011502A3 (en) * | 1997-10-17 | 1999-10-05 | Dresser Ind | Core. |
| BE1012557A3 (en) * | 1999-03-15 | 2000-12-05 | Security Dbs | Core. |
| US7055626B2 (en) * | 2002-03-15 | 2006-06-06 | Baker Hughes Incorporated | Core bit having features for controlling flow split |
-
2007
- 2007-05-10 WO PCT/US2007/011355 patent/WO2007136568A2/en not_active Ceased
- 2007-05-10 US US11/746,931 patent/US20070261886A1/en not_active Abandoned
- 2007-05-10 CA CA002652563A patent/CA2652563A1/en not_active Abandoned
- 2007-05-10 GB GB0821569A patent/GB2451788B/en not_active Expired - Fee Related
-
2008
- 2008-11-18 NO NO20084841A patent/NO20084841L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| NO20084841L (en) | 2008-12-12 |
| US20070261886A1 (en) | 2007-11-15 |
| WO2007136568B1 (en) | 2008-04-03 |
| WO2007136568A2 (en) | 2007-11-29 |
| GB2451788A (en) | 2009-02-11 |
| GB2451788B (en) | 2011-02-16 |
| GB0821569D0 (en) | 2008-12-31 |
| WO2007136568A3 (en) | 2008-02-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |