CA2228343A1 - Reverse circulation drill assembly - Google Patents
Reverse circulation drill assembly Download PDFInfo
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- CA2228343A1 CA2228343A1 CA 2228343 CA2228343A CA2228343A1 CA 2228343 A1 CA2228343 A1 CA 2228343A1 CA 2228343 CA2228343 CA 2228343 CA 2228343 A CA2228343 A CA 2228343A CA 2228343 A1 CA2228343 A1 CA 2228343A1
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- assembly
- drilling fluid
- drill string
- air
- rotation head
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Abstract
Disclosed is a reverse circulation drill assembly comprising:
a rotation head having portion of a means for supply of drilling fluid to a drill string:
a drill string including an outer wear sleeve and inner tube operationally connected to the rotation head and having a drilling fluid cavity disposed between the outer wear sleeve and inner tube; and a swivel assembly providing at least part of the operational connection of said rotation head and the drill string, the swivel assembly comprising:
a drilling fluid chamber communicating the rotation head portion of the drilling fluid supply means of the rotation head and the drilling fluid cavity;
a sample chamber communicating with the inner tube for recovery of cuttings from the formation, through a sample outlet formed in said sample chamber, during drilling; and means for connection of the swivel assembly to the drill string.
a rotation head having portion of a means for supply of drilling fluid to a drill string:
a drill string including an outer wear sleeve and inner tube operationally connected to the rotation head and having a drilling fluid cavity disposed between the outer wear sleeve and inner tube; and a swivel assembly providing at least part of the operational connection of said rotation head and the drill string, the swivel assembly comprising:
a drilling fluid chamber communicating the rotation head portion of the drilling fluid supply means of the rotation head and the drilling fluid cavity;
a sample chamber communicating with the inner tube for recovery of cuttings from the formation, through a sample outlet formed in said sample chamber, during drilling; and means for connection of the swivel assembly to the drill string.
Description
RFvF~sF CIR~UI,ATION nFll! I ~SSFMRI Y.
The present Invention relates to drill string assemblies for use, for example, in exploration operations and particularly relates to reverse circulation drill string assemblies.
Drilling assemblies are well known in the art of exploration for, and production of, minerals, oil and gas. Two types of drilling assembly are in regular use. In the first, a standard circulation is employed. Air or a suitabledrillinçl fluid is supplied through an inner tube running through the assembly whilst a drill string portion of the assembly is set in rotation. A cutter bit, located 10 at a bottom end of the drill string assembly is likewise set in rotation for cutting of a forrrlation. Cuttings and other drilling products are then flushed by ~he air or suitable drilling fluid through a space between the outer sleeve of the drillingassemlbly and the walls of the hole.
Reverse circulation techniques, as the name suggests, require air or a 15 suitablle drilling fluid to be supplied through a cavily formed belween the inner wall of an outer wear sleeve and outer wall o~ the inner tube. The fluid is typically used to create a percussive motion on a cutter bit to achieve reciprocation thereof and cutting of the formation. Cultings are then flushed bythe fluid through the inner tube and used for sampling. The percussive nature of20 such clrill assemblies lends the name Udown the hole hammer" to this type of drilling apparatus. It will be appreciated that reverse circulation enables sampling to be conducted with greater accuracy as contamination by minerals located at the various zones of the hole is less likely to occur due to isola~ion of the cuttings in the inner tube from the material ot the hole walls during their 25 passal~e to the surface.
It is evident trom the above discussion that reverse circulation drilling equiprnent is of greater complexity than that used in standard circulation.
~ccordingly, rotation heads employed for rotation of a standard circulation drillinsl assembly must be modified before they can be used for reverse 30 circulalion. In particular, modification is required to enable the required air or fluid connection to the air or fluid cavity formed between the outer wear sleeve and tha inner tube while allowing recovery of sample through a sample outlet port whilst allowing the required rotation of th~ overall assen bly.
Two such modifications are common in practice. In the first prior arrang3menl, shown in Figure 2, and known as an "underhead/overhead"
5 arrangement there are provided two assemblies to the rotation head 1. The first "overhead" assembly 2 is a sample recovery assembly which has formed therein a passage 4 for recovery of sample through a sample outlet port (not shown). The second "underhead" swivel assembly 6 is threadably or otherwise engaged with rotation head 1 and has an air inlet passage 8, connected with an 10 air suplply, and communicating, through annular cavity 10 and air inlet ports 12, with the fluid cavit~/ 14 ~ormed between the outer wear sleeve 16 and inner tube18 of the drill string 20 which is threadably connected with a nipple arrangement 24 of the swivel assembly 6. Connection of the drill string assembly 20 to nipple assembly 24 also brings inner tube 1~ into communication with a sample 15 passage 26 ot slightly larger diameter than inner tube 18 allowing a sealed sliding lit. In this case, the air passage 30 of a standard circulation rotation head 1 is gi~len to recovery of sample rather than passage of air and the standard circulation air tapping arrangement 44 as shown in Figure 1 of the prior art mlJst be repklced with a sample recovery assembly 2. Secondly, the simple threaded 20 arrangement 40 to which a typical standard circulation drilling string 42 is threada.bly connected, as shown in Figure 1, must be replaced with a more complex swivel assembly 6. As well as creating difficulties in rnanufacture the costs ol such modification are high.
lherefore, a second possibility is to manufacture a single swivel 25 assembly and have this in an "underhead" arrangement, as shown in Figure 3 ofthe prior art. In this case, rotation head 1 is modified to remove the air passag~
30. Swivel assembly 50 is threadably connected with rotation head 1 and comprises sample passage 52 in communication with inner ~ube 1~ of drill string 20 in the manner described with reference to Figure 2 and an air p~ss~ge 54 in 30 communication with air cavity 14 in the manner described above with referenceto Figule 2. The essential difference between this construction and that of Figure 2 is that the sample outlet and air inlet are formed in a single block and this may reduce manutacturing cost somewhat.
However, in addition to cost problems created by the above descri~ed arranqements, thc arrangements take up space which may be crucial in 5 underground drilling operations where space is restricted. Even above ground, the great space taken ~p by the modified rotation head arrangement may necessitate construction of a larger drilling mast and add to the cost of the drilling apparatus.
It is the object of the present invention to provide a drilling assembly that 10 enables use of rotation heads currently available wi~h ~he rninimum o~ costlymodification and to achieve space savings over arrangements previously used.
With this object in view, the present invention provides a reverse circulation drill assembly comprising:
a r~tation head having portion of a means for supply of drilling fluid to a drill string;
a drill string including an outer wear slee~re and inner tube operationally connected to the rotation head and having a drilling fluid cavity disposed between the outer ~Ivear slee~/e and inner tube; and a swivel assembly pro~iding at least part of the operational connection between lhe rotation head and the drill string, the swivel assembly comprising:
a drilling fluid chamber communicating the rotation head portion of the drilling fluid supply means and the drilling ~luid cavity, a sample chamber communicating with the inner tube for recover,Y of 2~ c;uttings from the formation through a sample outlet formed in said sample chambe- during drilling; and rneans for connection o~ the swivel assembly to the drill string.
[)esirably, the drilling fluid supply means of the rotation head is that standard in standard circulation drilling operations and, accordingly, ~he rotation 30 head and its drilling fluid supply are of convontional type for standard circlllation drilling operations.
The rotation head may be set in rotation by a motor or other driving mean;s known in the art to achieve rotation of the drill string by operational connection therewith.
Similarly, the swivel assembly may be connected to the rotation head in a 5 manner of connection conventional in standard circulation drilling operations at the bottom of the rotation head. Conveniently, the swivel assembly may include threaded connection means to be simply threaded into position "underhead~ in a threaded bore of the ro~ation hsad.
Communication of drilling fluid supply with drilling fluid cavity and drill 10 string; and inner tube with sample outlet may be achieved in any desired operationally effective manner.
The swiv~l assembly is especially contigured for the reverse circulation operation. In a preferred con~iguration, the rotation head portion of the drilling fl~id supply means includes an overhead drilling fluid inlet passage. This 15 passage communicates, via a transfer passage, with a drilling fluid chamber in the swivel assembly.The drilling fluid chamber is blanked off to prevent mixing of sample and drilling fluid in the chamber. Located below the drilling fluid chan~lber and separated by a partition or wall is a sample chamber communicating with the inner tube of the drill string. The sample chamber has 20 an outlet for collection o1 sample in a sample collection means. In a most prelerred embodiment, communication between the drilling fluid chamber and drillincl tluid cavity is established by provision of at least one passage between the drilling fluid chamber and drilling fluid cavity. Plural passages may most pre~erably be provided The swivel assembly is provided with means for connection to the drill string The swivel assembly may have a threaded nipple to which a compl3mentary portion of the upper tub~lar of a drill string may be connected bringing the swivel assembly drilling fluid passage(sj into communication with the dr.illing fluid cavity of lhe drill s1ring. Threading may also connect the upper 30 end ol the drill string inner tube within a sample bore concentric with the swivel assembly drilling fluid p~ss~ge. A neat sealsd sliding, threaded or interference ~it may thus be established preventing leakage of cuttings, dust or the like into the drilling fluid cavity to any substantial degree.
It will be understood that the swivel assembly is desirably a r~placeabl~
part and, accordingly, in a further aspect of the present invention, there is 5 provicled a swivel component connectable to a rotation head for rotating a rever~ie circulalion drill string comprising a drilling fluid chamber communicable with a rotation head drilling fluid supply means and a drilling fluid cavity disposed betw~en an outer wear sleeve and inner tube of a re~rerse circulation drill string; a sample chamber communicable with an inner tube of the drill string 10 havinc1 a sample outlet for recovery in a sample collection means of cuttings from a formation; and means ~or connection ot the component to a drill string.
- ~ny desired drilling fluid may be utilised in accordance with the invention but an especially preterred fluid is air.
The drill ass~mbly and swivel component of the invention enable a rotatic,n head conventionally available for standard circulation drilling operations to be quickly and relatively inexpensively put into use in a re\~ersecirculation drilling application while saving space and reducing the space problem described above.
The present invention will be more completely understood from a detailed description of a preferred embodiment thereof made with reference to the remaining accompanying drawings in which.
Figure 4 is a sectional schematic view of a drill assembly constructed in accordance with a preferred embodiment of the invention; and IFigure 5 is a transverse sectional view taken along axis C-C of Figure 4.
Referring now to Figure 4, there is shown a rotation head 60 of conventional construction for standard circulation drilling operations. Such a rotation head 60 is widely available in the an and may be sourced by a drill operator without difficulty and. accordingly, no detailed description thereof is30 provided here. It suffices that the rotation head 60 incorporates a conventional air supply trom the point ot view of standard circulation drilling operations comprising an air inlet passage 62 and air transfer passage 63 which is brought into communication with a swivel assembly 70 in the manner described below.
The rotation head 60 is driven by any convenient means which will generate the required torque to rotate the drill string assembly 120 and the entir~ assembly may be mounted in a dri11 mast (not shown) in a conventional manner. An 5 electric: motor and suitable control system is preferred enabling rotation head 60 to be driven as required to achieve the desired drilling operation.
At the bottom of rotation head 60 is provided, preferably approximately centrally, a generally cylindrical bore 65 which is threaded around its circumilerence to enable threadable connection of swivel assembly 70, the 10 upper portion 71 of which has a connection means, being a corresponding threaded portion, to allow such connection to rotation head 60. Although a threaded ~orm of connection is most convenient and preferred, other forms of connec~ion could be employed.
l-he swivel assembly 70 will now be described in greater detail. The 1 S swivel assembly 70 cornprises 1wo substantially cylindrical portions 72 and 73.
Cylindrical portion 73 is disposed radially outwardly from the vertical axis 81 of swivel ~ssembly 70 to cylindrical portion 72 and is directly connected to the rotation head 60 to rotate, I~vhen the driving means for the head 60 is operated, within por~ion 72. As a conssquence,the drill string 120, to which it is threadably 20 connected, also rotates. Non-rotating portion 72 forms a b~aring with portion73. Porlion 73 is located in bore 65 to connect the swivel assembly 70 to the rotation head 60. A thre~dablQ connection is preferred.
Portion 72 includes, towards its lo~ r extent, a sample outlet port 76.
Sample outlet port 76 cornmunicates a sample chamber 73 provided at the 25 bottom end o~ cylindrical portion 73 o~ the swivel assembly 70 through ports 79 spaced about th~ periphery of the central portion 73a of cylindrical portion 73 with sample collection means of conventional type (not shown). A n~mber of ports 76 could be provided. Ports 79 open into a sample manifold 83 concentric with axis 81 and having an annular portion 85 provided at least partly within 30 portion 72 of swivel assembly 70.
The swivel assembly 70 ;s also provided, at the top of portion 73, with an air chamber B7 with a tapered expansion section 87a at its upper end and a constant bore cylindrical section 87b at its lower end. Tapered section 87a communicates, when swivel assembly 70 is threaded into position in cavity 65, with rotation head 60 air transter passage 63. Air chamber 37 is not continuous with sample chamber 7~. A wall 88 blanks this chamber off keeping air and 5 samplle separate as is desirable to efficient samp1ing. The only exit from air cham ber ~7 is one, or a number of, second air passage(s) 89 which communicate(s), when upper tlJbular 90 is threaded onto nipple portion 95 of cylindrical portion 73 with air caYity 110 of ths drill string 120. The second air passage 89 is located radially outwardly o~ an axis 81 of swival assembly 70 10 from sample chamber 78. The drill string is o1 conventional construction wellknown in the art and operation of the system also proceeds in conventional manner therefore detailed description thereof is not provided herein.
It will be understood that threading of upper tubular 90 onto correspondingly threaded nipples portion 95 also brings inner tube 118 of drill 15 string 120, which allows trans~er o~ cutting and drilling fluid to the surface for sampling, into sealing engagement with cylindric~l bore 130 ~hich forms an extension, concentric with axis ~1, of sample chamber 78. The fit may be a neat or intel~erence fit, it being important that sample not be allowed to penetrate the air system to any substantial extent. Loss of sample is also minimised.
It will further be understood that while a threaded arrangement for the components of the apparatus is preferred equivalent connsction arrangements exist and may be used instead.
The swivel assembly 70 may be construct~d from the same material as the housing of the rotation head 60 or the drill string 120 as desired by th~se 2~ skilied in the art. Typically, however, the materials of construction would be those conventionally employed in the rotation head/swivel assemblies.
lrhe above design is provided by way of exemplification only and other designs that provide the benef;ts of the apparatus, as the above described, may be developed by those skilled in the art upon reading of this disclosure.
30 Therefore, modifications and variations may be apparent to those skilled in the an thal do not depart from the scope of the present invsntion.
The present Invention relates to drill string assemblies for use, for example, in exploration operations and particularly relates to reverse circulation drill string assemblies.
Drilling assemblies are well known in the art of exploration for, and production of, minerals, oil and gas. Two types of drilling assembly are in regular use. In the first, a standard circulation is employed. Air or a suitabledrillinçl fluid is supplied through an inner tube running through the assembly whilst a drill string portion of the assembly is set in rotation. A cutter bit, located 10 at a bottom end of the drill string assembly is likewise set in rotation for cutting of a forrrlation. Cuttings and other drilling products are then flushed by ~he air or suitable drilling fluid through a space between the outer sleeve of the drillingassemlbly and the walls of the hole.
Reverse circulation techniques, as the name suggests, require air or a 15 suitablle drilling fluid to be supplied through a cavily formed belween the inner wall of an outer wear sleeve and outer wall o~ the inner tube. The fluid is typically used to create a percussive motion on a cutter bit to achieve reciprocation thereof and cutting of the formation. Cultings are then flushed bythe fluid through the inner tube and used for sampling. The percussive nature of20 such clrill assemblies lends the name Udown the hole hammer" to this type of drilling apparatus. It will be appreciated that reverse circulation enables sampling to be conducted with greater accuracy as contamination by minerals located at the various zones of the hole is less likely to occur due to isola~ion of the cuttings in the inner tube from the material ot the hole walls during their 25 passal~e to the surface.
It is evident trom the above discussion that reverse circulation drilling equiprnent is of greater complexity than that used in standard circulation.
~ccordingly, rotation heads employed for rotation of a standard circulation drillinsl assembly must be modified before they can be used for reverse 30 circulalion. In particular, modification is required to enable the required air or fluid connection to the air or fluid cavity formed between the outer wear sleeve and tha inner tube while allowing recovery of sample through a sample outlet port whilst allowing the required rotation of th~ overall assen bly.
Two such modifications are common in practice. In the first prior arrang3menl, shown in Figure 2, and known as an "underhead/overhead"
5 arrangement there are provided two assemblies to the rotation head 1. The first "overhead" assembly 2 is a sample recovery assembly which has formed therein a passage 4 for recovery of sample through a sample outlet port (not shown). The second "underhead" swivel assembly 6 is threadably or otherwise engaged with rotation head 1 and has an air inlet passage 8, connected with an 10 air suplply, and communicating, through annular cavity 10 and air inlet ports 12, with the fluid cavit~/ 14 ~ormed between the outer wear sleeve 16 and inner tube18 of the drill string 20 which is threadably connected with a nipple arrangement 24 of the swivel assembly 6. Connection of the drill string assembly 20 to nipple assembly 24 also brings inner tube 1~ into communication with a sample 15 passage 26 ot slightly larger diameter than inner tube 18 allowing a sealed sliding lit. In this case, the air passage 30 of a standard circulation rotation head 1 is gi~len to recovery of sample rather than passage of air and the standard circulation air tapping arrangement 44 as shown in Figure 1 of the prior art mlJst be repklced with a sample recovery assembly 2. Secondly, the simple threaded 20 arrangement 40 to which a typical standard circulation drilling string 42 is threada.bly connected, as shown in Figure 1, must be replaced with a more complex swivel assembly 6. As well as creating difficulties in rnanufacture the costs ol such modification are high.
lherefore, a second possibility is to manufacture a single swivel 25 assembly and have this in an "underhead" arrangement, as shown in Figure 3 ofthe prior art. In this case, rotation head 1 is modified to remove the air passag~
30. Swivel assembly 50 is threadably connected with rotation head 1 and comprises sample passage 52 in communication with inner ~ube 1~ of drill string 20 in the manner described with reference to Figure 2 and an air p~ss~ge 54 in 30 communication with air cavity 14 in the manner described above with referenceto Figule 2. The essential difference between this construction and that of Figure 2 is that the sample outlet and air inlet are formed in a single block and this may reduce manutacturing cost somewhat.
However, in addition to cost problems created by the above descri~ed arranqements, thc arrangements take up space which may be crucial in 5 underground drilling operations where space is restricted. Even above ground, the great space taken ~p by the modified rotation head arrangement may necessitate construction of a larger drilling mast and add to the cost of the drilling apparatus.
It is the object of the present invention to provide a drilling assembly that 10 enables use of rotation heads currently available wi~h ~he rninimum o~ costlymodification and to achieve space savings over arrangements previously used.
With this object in view, the present invention provides a reverse circulation drill assembly comprising:
a r~tation head having portion of a means for supply of drilling fluid to a drill string;
a drill string including an outer wear slee~re and inner tube operationally connected to the rotation head and having a drilling fluid cavity disposed between the outer ~Ivear slee~/e and inner tube; and a swivel assembly pro~iding at least part of the operational connection between lhe rotation head and the drill string, the swivel assembly comprising:
a drilling fluid chamber communicating the rotation head portion of the drilling fluid supply means and the drilling ~luid cavity, a sample chamber communicating with the inner tube for recover,Y of 2~ c;uttings from the formation through a sample outlet formed in said sample chambe- during drilling; and rneans for connection o~ the swivel assembly to the drill string.
[)esirably, the drilling fluid supply means of the rotation head is that standard in standard circulation drilling operations and, accordingly, ~he rotation 30 head and its drilling fluid supply are of convontional type for standard circlllation drilling operations.
The rotation head may be set in rotation by a motor or other driving mean;s known in the art to achieve rotation of the drill string by operational connection therewith.
Similarly, the swivel assembly may be connected to the rotation head in a 5 manner of connection conventional in standard circulation drilling operations at the bottom of the rotation head. Conveniently, the swivel assembly may include threaded connection means to be simply threaded into position "underhead~ in a threaded bore of the ro~ation hsad.
Communication of drilling fluid supply with drilling fluid cavity and drill 10 string; and inner tube with sample outlet may be achieved in any desired operationally effective manner.
The swiv~l assembly is especially contigured for the reverse circulation operation. In a preferred con~iguration, the rotation head portion of the drilling fl~id supply means includes an overhead drilling fluid inlet passage. This 15 passage communicates, via a transfer passage, with a drilling fluid chamber in the swivel assembly.The drilling fluid chamber is blanked off to prevent mixing of sample and drilling fluid in the chamber. Located below the drilling fluid chan~lber and separated by a partition or wall is a sample chamber communicating with the inner tube of the drill string. The sample chamber has 20 an outlet for collection o1 sample in a sample collection means. In a most prelerred embodiment, communication between the drilling fluid chamber and drillincl tluid cavity is established by provision of at least one passage between the drilling fluid chamber and drilling fluid cavity. Plural passages may most pre~erably be provided The swivel assembly is provided with means for connection to the drill string The swivel assembly may have a threaded nipple to which a compl3mentary portion of the upper tub~lar of a drill string may be connected bringing the swivel assembly drilling fluid passage(sj into communication with the dr.illing fluid cavity of lhe drill s1ring. Threading may also connect the upper 30 end ol the drill string inner tube within a sample bore concentric with the swivel assembly drilling fluid p~ss~ge. A neat sealsd sliding, threaded or interference ~it may thus be established preventing leakage of cuttings, dust or the like into the drilling fluid cavity to any substantial degree.
It will be understood that the swivel assembly is desirably a r~placeabl~
part and, accordingly, in a further aspect of the present invention, there is 5 provicled a swivel component connectable to a rotation head for rotating a rever~ie circulalion drill string comprising a drilling fluid chamber communicable with a rotation head drilling fluid supply means and a drilling fluid cavity disposed betw~en an outer wear sleeve and inner tube of a re~rerse circulation drill string; a sample chamber communicable with an inner tube of the drill string 10 havinc1 a sample outlet for recovery in a sample collection means of cuttings from a formation; and means ~or connection ot the component to a drill string.
- ~ny desired drilling fluid may be utilised in accordance with the invention but an especially preterred fluid is air.
The drill ass~mbly and swivel component of the invention enable a rotatic,n head conventionally available for standard circulation drilling operations to be quickly and relatively inexpensively put into use in a re\~ersecirculation drilling application while saving space and reducing the space problem described above.
The present invention will be more completely understood from a detailed description of a preferred embodiment thereof made with reference to the remaining accompanying drawings in which.
Figure 4 is a sectional schematic view of a drill assembly constructed in accordance with a preferred embodiment of the invention; and IFigure 5 is a transverse sectional view taken along axis C-C of Figure 4.
Referring now to Figure 4, there is shown a rotation head 60 of conventional construction for standard circulation drilling operations. Such a rotation head 60 is widely available in the an and may be sourced by a drill operator without difficulty and. accordingly, no detailed description thereof is30 provided here. It suffices that the rotation head 60 incorporates a conventional air supply trom the point ot view of standard circulation drilling operations comprising an air inlet passage 62 and air transfer passage 63 which is brought into communication with a swivel assembly 70 in the manner described below.
The rotation head 60 is driven by any convenient means which will generate the required torque to rotate the drill string assembly 120 and the entir~ assembly may be mounted in a dri11 mast (not shown) in a conventional manner. An 5 electric: motor and suitable control system is preferred enabling rotation head 60 to be driven as required to achieve the desired drilling operation.
At the bottom of rotation head 60 is provided, preferably approximately centrally, a generally cylindrical bore 65 which is threaded around its circumilerence to enable threadable connection of swivel assembly 70, the 10 upper portion 71 of which has a connection means, being a corresponding threaded portion, to allow such connection to rotation head 60. Although a threaded ~orm of connection is most convenient and preferred, other forms of connec~ion could be employed.
l-he swivel assembly 70 will now be described in greater detail. The 1 S swivel assembly 70 cornprises 1wo substantially cylindrical portions 72 and 73.
Cylindrical portion 73 is disposed radially outwardly from the vertical axis 81 of swivel ~ssembly 70 to cylindrical portion 72 and is directly connected to the rotation head 60 to rotate, I~vhen the driving means for the head 60 is operated, within por~ion 72. As a conssquence,the drill string 120, to which it is threadably 20 connected, also rotates. Non-rotating portion 72 forms a b~aring with portion73. Porlion 73 is located in bore 65 to connect the swivel assembly 70 to the rotation head 60. A thre~dablQ connection is preferred.
Portion 72 includes, towards its lo~ r extent, a sample outlet port 76.
Sample outlet port 76 cornmunicates a sample chamber 73 provided at the 25 bottom end o~ cylindrical portion 73 o~ the swivel assembly 70 through ports 79 spaced about th~ periphery of the central portion 73a of cylindrical portion 73 with sample collection means of conventional type (not shown). A n~mber of ports 76 could be provided. Ports 79 open into a sample manifold 83 concentric with axis 81 and having an annular portion 85 provided at least partly within 30 portion 72 of swivel assembly 70.
The swivel assembly 70 ;s also provided, at the top of portion 73, with an air chamber B7 with a tapered expansion section 87a at its upper end and a constant bore cylindrical section 87b at its lower end. Tapered section 87a communicates, when swivel assembly 70 is threaded into position in cavity 65, with rotation head 60 air transter passage 63. Air chamber 37 is not continuous with sample chamber 7~. A wall 88 blanks this chamber off keeping air and 5 samplle separate as is desirable to efficient samp1ing. The only exit from air cham ber ~7 is one, or a number of, second air passage(s) 89 which communicate(s), when upper tlJbular 90 is threaded onto nipple portion 95 of cylindrical portion 73 with air caYity 110 of ths drill string 120. The second air passage 89 is located radially outwardly o~ an axis 81 of swival assembly 70 10 from sample chamber 78. The drill string is o1 conventional construction wellknown in the art and operation of the system also proceeds in conventional manner therefore detailed description thereof is not provided herein.
It will be understood that threading of upper tubular 90 onto correspondingly threaded nipples portion 95 also brings inner tube 118 of drill 15 string 120, which allows trans~er o~ cutting and drilling fluid to the surface for sampling, into sealing engagement with cylindric~l bore 130 ~hich forms an extension, concentric with axis ~1, of sample chamber 78. The fit may be a neat or intel~erence fit, it being important that sample not be allowed to penetrate the air system to any substantial extent. Loss of sample is also minimised.
It will further be understood that while a threaded arrangement for the components of the apparatus is preferred equivalent connsction arrangements exist and may be used instead.
The swivel assembly 70 may be construct~d from the same material as the housing of the rotation head 60 or the drill string 120 as desired by th~se 2~ skilied in the art. Typically, however, the materials of construction would be those conventionally employed in the rotation head/swivel assemblies.
lrhe above design is provided by way of exemplification only and other designs that provide the benef;ts of the apparatus, as the above described, may be developed by those skilled in the art upon reading of this disclosure.
30 Therefore, modifications and variations may be apparent to those skilled in the an thal do not depart from the scope of the present invsntion.
Claims (10)
1. A reverse circulation drill assembly comprising:
a rotation head having portion of a means for supply of drilling fluid to a drill string;
a drill string including an outer wear sleeve and inner tube operationally connected to the rotation head and having a drilling fluid cavity disposed between the outer wear sleeve and inner tube; and a swivel assembly providing at least part of the operational connection between said rotation head and the drill string, the swivel assembly comprising:
a drilling fluid chamber communicating the rotation head portion of the drilling fluid supply means of the rotation head and the drilling fluid cavity;
a sample chamber communicating with said inner tube for recovery of cuttings from the formation, through a sample outlet formed in said sample chamber, during drilling; and means for connection of the swivel assembly to the drill string.
a rotation head having portion of a means for supply of drilling fluid to a drill string;
a drill string including an outer wear sleeve and inner tube operationally connected to the rotation head and having a drilling fluid cavity disposed between the outer wear sleeve and inner tube; and a swivel assembly providing at least part of the operational connection between said rotation head and the drill string, the swivel assembly comprising:
a drilling fluid chamber communicating the rotation head portion of the drilling fluid supply means of the rotation head and the drilling fluid cavity;
a sample chamber communicating with said inner tube for recovery of cuttings from the formation, through a sample outlet formed in said sample chamber, during drilling; and means for connection of the swivel assembly to the drill string.
2. The assembly of claim 1 wherein said drilling fluid is air.
3. The assembly of claim 2 wherein said air chamber communicates with said air cavity through at least one air passage formed in the swivel assembly.
4. The assembly of claim 3 wherein said air chamber communicates with said air cavity through plural passages.
5. The assembly of any one of claims 2 to 4 wherein said rotation head air supply means includes an overhead air inlet passage.
6. The assembly of claim 5 wherein the swivel assembly further includes a first substantially cylindrical portion directly connected to the rotation head for rotation during drilling; and a second substantially cylindrical portion disposed radially outward from the first cylindrical portion forming a bearing therefor, the first cylindrical portion having formed therein the air chamber; sample chamber;at least one passage for communicating the air supply means with the air cavity of the drill string; and at least one passage for communicating said inner tube with sample collection means.
7. The assembly of claim 6 wherein said first cylindrical portion includes plural passages for communicating said inner tube with sample collection means.
8. The assembly of claim 7 wherein said second cylindrical portion has formed therein a portion of a chamber forming part of the sample collection means.
9. The assembly of claim 5 wherein said sample chamber is disposed below said air chamber and separated therefrom by a wall.
10. A swivel component connectable to a rotation head for rotating a reverse circulation drill string comprising a drilling fluid chamber communicable with arotation head drilling fluid supply means and a drilling fluid cavity of a reverse circulation drill string disposed between an outer wear sleeve and inner tube thereof; a sample chamber communicable with said inner tube having an outlet for recovery in a sample collection means of cuttings from a formation; and means for connection of said component to the drill string.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPO4830 | 1997-01-29 | ||
| AUPO4830A AUPO483097A0 (en) | 1997-01-29 | 1997-01-29 | Reverse circulation drill assembly |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2228343A1 true CA2228343A1 (en) | 1998-07-29 |
Family
ID=3799134
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2228343 Abandoned CA2228343A1 (en) | 1997-01-29 | 1998-01-29 | Reverse circulation drill assembly |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AUPO483097A0 (en) |
| CA (1) | CA2228343A1 (en) |
| ZA (1) | ZA98739B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110530670A (en) * | 2019-09-29 | 2019-12-03 | 王海瑞 | A kind of reacting cycle dust sampling water tail apparatus |
| CN111287743A (en) * | 2020-04-10 | 2020-06-16 | 中国地质科学院探矿工艺研究所 | Air reverse circulation continuous sampling drilling system and process method for water-bearing stratum |
-
1997
- 1997-01-29 AU AUPO4830A patent/AUPO483097A0/en not_active Abandoned
-
1998
- 1998-01-29 ZA ZA98739A patent/ZA98739B/en unknown
- 1998-01-29 CA CA 2228343 patent/CA2228343A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110530670A (en) * | 2019-09-29 | 2019-12-03 | 王海瑞 | A kind of reacting cycle dust sampling water tail apparatus |
| CN111287743A (en) * | 2020-04-10 | 2020-06-16 | 中国地质科学院探矿工艺研究所 | Air reverse circulation continuous sampling drilling system and process method for water-bearing stratum |
| CN111287743B (en) * | 2020-04-10 | 2022-08-23 | 中国地质科学院探矿工艺研究所 | Air reverse circulation continuous sampling drilling system and process method for water-bearing stratum |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA98739B (en) | 1998-07-29 |
| AUPO483097A0 (en) | 1997-02-20 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Dead |