CA2137888A1 - Directional drilling method and apparatus - Google Patents
Directional drilling method and apparatusInfo
- Publication number
- CA2137888A1 CA2137888A1 CA002137888A CA2137888A CA2137888A1 CA 2137888 A1 CA2137888 A1 CA 2137888A1 CA 002137888 A CA002137888 A CA 002137888A CA 2137888 A CA2137888 A CA 2137888A CA 2137888 A1 CA2137888 A1 CA 2137888A1
- Authority
- CA
- Canada
- Prior art keywords
- bit
- flow
- nozzle
- drilling fluid
- drilling
- 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
- 238000005553 drilling Methods 0.000 title claims abstract description 68
- 238000000034 method Methods 0.000 title claims abstract description 13
- 239000012530 fluid Substances 0.000 claims abstract description 43
- 230000001360 synchronised effect Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000005755 formation reaction Methods 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- BXMVKQIIJSXIBU-UHFFFAOYSA-N (2,5-dioxopyrrolidin-1-yl) diphenyl phosphate Chemical compound O=C1CCC(=O)N1OP(=O)(OC=1C=CC=CC=1)OC1=CC=CC=C1 BXMVKQIIJSXIBU-UHFFFAOYSA-N 0.000 description 1
- BSFODEXXVBBYOC-UHFFFAOYSA-N 8-[4-(dimethylamino)butan-2-ylamino]quinolin-6-ol Chemical compound C1=CN=C2C(NC(CCN(C)C)C)=CC(O)=CC2=C1 BSFODEXXVBBYOC-UHFFFAOYSA-N 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
- E21B7/06—Deflecting the direction of boreholes
- E21B7/065—Deflecting the direction of boreholes using oriented fluid jets
-
- 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
- E21B7/00—Special methods or apparatus for drilling
- E21B7/18—Drilling by liquid or gas jets, with or without entrained pellets
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
A method (and apparatus) for causing deviation of a borehole being drilled by rotary drilling using a bit (24) having at least one nozzle (38,40,42) through which a drilling fluid is caused to flow such that in use the flow of drilling fluid through the nozzle allows one sector of the bit (24) to cut more effectively than the remainder of the bit, the method comprising modulating the flow of the drilling fluid through the nozzle such that as the bit rotates the cutting action of the one sector is optimised when in the desired direction of deviation and reduced at other locations in the borehole, the apparatus comprising a rotary drill bit (24) with at least one nozzle (38,40,42) and modulator means to modulate the flow of drilling fluid through the nozzle.
Description
213`7888 nirectional l)rillin~ Method snd ADDar~tn~
The present invention relates to a rnethod and a~a~a~us for controlling the direction of progress when drilling a borehole such as that of an oil or gas well.
When drilling a borehole for an oil or gas well it is desirable to be able to control the direction of progress of the hole during drilling, since it is often impossible or undesirable to drill vertically from the surface to reach the target formation. For example, when drilling offshore it is common practice to drill several boreholes from a single location which radiate out in dirr~ t directions; this is because it is economically undesirable to have to relocate the drilling structure (sçmi~ubmersible rig, jack-up rig, drilling platform) to drill several wells which are relatively close together. Also, where the producing formations extend horizontally yet are relatively thin it is desirable that the borehole should remain in the producing formation for as long as possible, rather than passing through it perpendicularly, in order to optimise production th~er~
Currently, the most coll~only used method of controlling the direction of drilling is to use a downhole motor and a bent sub near to the bit. In such a case, the initial, vertical part of the well is drilled using a usual rotary drilling technique in which the entire drill string, with the drill bit on its end, is rotated from the surface. When it becomes desirable to deviate the drilling from the vertical the drill string is pulled and a directional drilling bottom hole assembly (BHA) is used (the BHA comprises a bent sub, typically having a bend of 1/2-3, and a downhole motor which is powered by the flow of drilling mud therethrough and which serves to rotate the bit without the need for drill string rotation). The drill string re-lowered, and is then turned until the bent sub points the bit in the desired direction, and drilling is then recommenced by rotating the bit using the downhole motor. Once the re,quired deviation has been achieved, rotary drilling can reco..,.--f n~e to hold, build or drop from the new direction using a straight BHA.
There are certain problems with this approach. The rate of penetration when drilling with the downhole motor is lower than with rotary ~lrilling, there is a higher likelihood that the drill string will be affected by differential sticking, and the time taken to change the BHA reduces the rate of progress further. Consequently, it is desirable to provide directional control while rotary drilling.
It has been proposed in US4637,479, incorporated herein by reference, to provide directional control by controlling the flow of drilling fluid through jets in the bit, the added force caused ._ by the jet thrust making the bit drill more effectively in one section of the hole than in the rem~incl~r of the hole. This sectional differentiation is achieved by sequentially opening and closing the jets in the bit as the bit rotates, so that the jets only operate in one selected section of the hole and thus cause improved cutting by the bit in that section; in this way the path of the bit is caused to deviate. However, this need for sequential opening and closing of the bit jets requires an associated valving arrangement and fluid supply, with the added eYp&n~e that such a complication entails; the present invention seeks to provide a system for directional control while rotary drilling which utilises the effect of flow of drilling fluid through the bit yet which does not require the sequential opening and closing of the jets in the bit (and so does not require the associated valving arrangement and fluid supply to the jets), and suggests that the fluid flow could simply be mo~ t~,d rather than redirecte~
In accordance with a first aspect of the present invention, therefore, there is provided a method for causing deviation of a borehole being drilled by rotary drilling using a bit having at least one nozzle through which a drilling fluid is caused to flow such that in use the flow of drilling fluid through that nozzle allows one sector of the bit to cut more effectively than the rem~in-lçr of the bit, the method comprising mo(3~ ting the flow of the drilling fluid through that nozzle as the bit rotates such that the cutting action of the chosen sector is optimised when in the desired direction of deviation and is reduced at other loc~*-~n~ in the borehole.
The present invention has the advantage over the Prior Art technique that it does not require each nozzle in the bit to be independently controllable when more than one jet is present; it is the overall flow through the bit which is mod--l~tç~, and by this mod~ tion the flow through the nozzles creates an asy~ Lly in the cutting action which can be used to control the deviation.
A second aspect of the invention provides ~p~aLuS for controlling the direction of drilling of a borehole, the apparatus comprising: a rotary drill bit having at least one nozzle for a drilling fluid to flow the~Llllough in such a manner that the flow of drilling fluid through that nozzle over cutting structures on the bit causes one section of the bit to have a c~m~a~ively illlplvved cutting action with respect to the rem~in-l~r of the bit; and mod--l~tor means to modulate the flow of drilling fluid through that nozzle so as to m~ t~ the cutting action of the section such that the compalaLively i~ r~ved cutting action occurs in a desired direction of deviation of the hole.
The means for modnl~ting the flow preferably forms part of the BHA, and can include further means for synchronising the modulation with the rotation of the drill string. Where more than one nozzle is present, the flow of drilling fluid is modulated through all nozzles at the same time. The means for modulating the flow is conveniently a flow in~.l,lp~
The further means for synchronising the modulation of the drilling fluid can include accele~ and/or m~g-~et~...f ~- ~ to detect the rotary position of the drill string. The further means can also include means for detecting signals from the surface, such as pressure pulses in the ~lrilling fluid supply, to control the modulation and hence the direction of drilling. Also, means for co~ ting the position of the bit to the surface, again such as pressure pulse tel~on~try, can be inf~lud~d The nozzle arrangement in the bit can coml,lise a single nozzle which directs a flow at one part of the bit. ~ltem~tively, a number of nozzles can be used, arranged such that the flow from the nozzles is directed to give the desired effect regarding the cufflng action of the bit - for in~n~e, directing the flow from one nozzle at the workface and the flow from any other nozzles at the cutting structures and the bit to act as mud picks. Additionally or alternatively the internal geometry of the nozzles can be sele~t~l such that there is greater flow in the ay~lu~liate section of the bit colll~aled to the rem~ind~r of the bit.
~137888 The present invention will now be described, by way of example, with reference to the accol~an~ing drawings in which:
Figure 1 shows a test rig for demonstrating the present invention;
Figure 2 shows a plot of results of a drilling test with deviation in one direction;
F;~ure 3 shows a plot collcspollding to Figure 2 with the direction of deviation ch~ng~ during the test;
Figure 4 shows a bit for use in a method on a~l,alalus according to the present invention; and Figure ~ shows a sche~nAtic view of a~lus accol.ling to the present invention.
Referring now to Figure 1, the test rig comprises a chamber 10 into which a drill shaft 12 projects. The drill shaft 12 is connected to a motor 14 and a drilling fluid supply line 16. Inside the chamber a sample of rock 18 is located below the drill shaft 12. A mechAnicm 20 is provided to apply an overburden stress to the sample drill shaft, and a confinen ~nt system 22 is provided so as to control the pore-p~es~ul~; of fluids in the sample. In use, a bit 24 is mounted on the drill shaft 12 and is drilled into the sample under the influen~ of the motor 14.
Drilling fluid is circulated through the drill shaft 12 and bit 24 by means of a pump 26. The drilling fluid exits the bit and hole being drilled in the sample, and the effecdve pl~S~ulG in the hole at the bit (bottom hole pl~,ssurG) is controlled by an intensifier where the drilling fluid leaves the chamber. Any tendency of the bit to deviate from a straight path when drilling is detected by means of shear sensors 28 in the drill shaft a~ove the bit.
The flow rate from the pump is approximately 110 L/mi~L The flow rate to the bit is controlled by a control valve (not shown). This allows all of the flow through to the bit or dumps some of the flow to the well bore annulus through nozzles (see Figure 4). The valve opening and closing is synchronised to the rotation of the bit; thus the flow to the bit is high (approximAtely 90% of flow rate) for 120 degrees of bit rotation and then reduced (to approximately 10%) for ^~40 degrees of rotation. During the low-~.ow-to-the-bit period the flow is diverted to the well bore through the nozzles, thus .nAi~ ing a constAnt pressure drop between pump discharge and bottom hole.
The valve opens and closes on every rotation of the bit. Rotary speed is 30 RPM. The high-to-low-flow period depends on the design of the valve switching element. For these tests ~137888 the valve element is lcsignecl for 120 degree high flow and 240 degrees low flow; however, there is some overlap between the high and low periods, so that the actual high flow period is somewhat greater than 120 degrees.
Test Details Samples~ h~ml~nt limestone.
Bit: 3/18" tri-cone, moflifil~A with two 'mud pick type' nozzles and one 'jetting nozzle', jetting into the corner of the wellbore.
Mud. Water based CMC polymer with a PV of 12.5 and a YP of 2.5.
WOB: approximately 4.5 kN.
(weight on bit) SDPP: 7.6 MPa.
(surface drill pipe ples~u~ = pump discharge pressure) SBHP: 3.0 MPa.
(surface bottom hole pressure = ~nn~ s~ule) Rock conrl~ lg ~lcssulc: 4 MPa Rock overburden plessuuG: 1.5. MPa.
Mud t~n~ Lul~; 18 to 24C
The test rig is used to provide the results plotted in Figures 2 and 3.
Figure 2 shows a plot of the bending mom~nt co~ al~d to the rotary position of the drill bit. In this case, the high flow period occurs when the 'jetting' nozzle is in the 120 segment centred on 0 (east). The bending moment is shown as a '+' on the plot, and coincides with the plere~;ntial jetting mud, thus cutting action due to the flow pulsing.
The test plotted in Figure 3 compr ~es initially a repeat of the test plotted in Figure 2 (and shown as 'o' on the plot), but halfway through the test the flow pulsing was shifted by 180 such that the high flow occurred when the 'jetting' nozzle was in the segment centred on 180 (west) and is represented as '+' on the plot.
The bit used in these tests is shown in Figure 4 (viewed from below), and comprises a rollercone bit having three cones 30, 32, 34 moullted on a bit body 36. Drilling fluid nozzles 38, 40, 42 are located in the bit body 36 bet~. ~n the cones 30, 32, 34, and are arranged such that two of the nozzles (38, 40) direct flow F, F' of the drilling fluid directly at adjacent cones 30, 32 to act as mud picks, and do not direct any flow at the workf~ce The rem~ining nozzle (42) directs flow F" into the corner of the workface. Thus, the flow of drilling fluid is ~137888 asymmetric relative to the bit, and because of the direction of flow from the nozzles the portion of the bit near nozzle 42 will have a relatively improved cutting action relative to the rem~in~er of the bit when drilling fluid is flowing from the nozzles. This difference beco...cs greater as the flow of drilling fluid through the bit increases. Thus, if the flow of drilling fluid is pulsed such that the flow is high whenever nozzle 42 passes point A on the workface and low for the rem~in~er of the rotation, the bit will drill p~felGntially in the direction of point A. While the bit still cuts better near nozzle 42 when the flow is low, the difference co~ d to the rest of the bit is small, and is ~ignifirantly less that the cutting effect when the flow is high. Clearly, the flow of drilling fluid has to be modulated according to the position of the bit (nozzles) relative to the workface, and this is best done once per revolution (although lower frequencies can be used).
It will be appreciated that the exact number and type of nozzles used can be varied while still maintaining this effect. In its simplest case, only one nozzle is required (for example, nozzle 42), but this can lead to problems with bit balling in certain ci~;u.-.~l~nces, and hence the other two nozzles 38, 40.
The complete BHA for pelrclming the method according to the present invention is shown schem~tirally in Figure S. The BHA is connected to a drill string 50 through which a drilling fluid is pumped from the surface, and comprises a Measurelllent While Drilling (MWD) and mud pulse telemetry pa~ ge 52 which, in~er alia, allows co-~ -ir~tion belwæl~ the BHA and surface equipment by means of positive pressure pulses in the drilling fluid. The MWD
package 52 includes a generator driven by mud flow to provide power for the various parts of the BHA. Below the MWD p~ck~ge 52 is a direction-mea~llring tool 54 which measures the direction and inclination of the BHA in the borehole and hence provides an inrliration of the direction of drilling at a given time. IIlÇcl~ ion from the direction---.~... ;n~ tool 54 is passed to the surface via the MWD package 52. A flow modulator 56 is located adjacent to the direction-mPacuring tool 54, and serves to modulate the flow of drilling fluid through the bit 58 so as to cause the deviation in the direction of drilling. The bit 58 has the asymmetric flow pattern through the nozzles as described previously. The flow m~nl~t ~r 56 inclu-1-os a sensor to in~lic~t~ the position of the bit in the borehole during rotation, and causes the flow of drilling fluid through the bit 58 to be modulated according to the position of the bit 58 relative to the workface as des-~ri~l in relation to Figure 4. Instructions are provided from the surface via the MWD package 52 to the modulator 56 to control the direction of drilling. The direction ~e~ulil~g tool 54 provides an indication of the current path of the borehole, and the mo~ tor 56 is controlled to cause the bit 58 to deviate in the desired direction.
The present invention relates to a rnethod and a~a~a~us for controlling the direction of progress when drilling a borehole such as that of an oil or gas well.
When drilling a borehole for an oil or gas well it is desirable to be able to control the direction of progress of the hole during drilling, since it is often impossible or undesirable to drill vertically from the surface to reach the target formation. For example, when drilling offshore it is common practice to drill several boreholes from a single location which radiate out in dirr~ t directions; this is because it is economically undesirable to have to relocate the drilling structure (sçmi~ubmersible rig, jack-up rig, drilling platform) to drill several wells which are relatively close together. Also, where the producing formations extend horizontally yet are relatively thin it is desirable that the borehole should remain in the producing formation for as long as possible, rather than passing through it perpendicularly, in order to optimise production th~er~
Currently, the most coll~only used method of controlling the direction of drilling is to use a downhole motor and a bent sub near to the bit. In such a case, the initial, vertical part of the well is drilled using a usual rotary drilling technique in which the entire drill string, with the drill bit on its end, is rotated from the surface. When it becomes desirable to deviate the drilling from the vertical the drill string is pulled and a directional drilling bottom hole assembly (BHA) is used (the BHA comprises a bent sub, typically having a bend of 1/2-3, and a downhole motor which is powered by the flow of drilling mud therethrough and which serves to rotate the bit without the need for drill string rotation). The drill string re-lowered, and is then turned until the bent sub points the bit in the desired direction, and drilling is then recommenced by rotating the bit using the downhole motor. Once the re,quired deviation has been achieved, rotary drilling can reco..,.--f n~e to hold, build or drop from the new direction using a straight BHA.
There are certain problems with this approach. The rate of penetration when drilling with the downhole motor is lower than with rotary ~lrilling, there is a higher likelihood that the drill string will be affected by differential sticking, and the time taken to change the BHA reduces the rate of progress further. Consequently, it is desirable to provide directional control while rotary drilling.
It has been proposed in US4637,479, incorporated herein by reference, to provide directional control by controlling the flow of drilling fluid through jets in the bit, the added force caused ._ by the jet thrust making the bit drill more effectively in one section of the hole than in the rem~incl~r of the hole. This sectional differentiation is achieved by sequentially opening and closing the jets in the bit as the bit rotates, so that the jets only operate in one selected section of the hole and thus cause improved cutting by the bit in that section; in this way the path of the bit is caused to deviate. However, this need for sequential opening and closing of the bit jets requires an associated valving arrangement and fluid supply, with the added eYp&n~e that such a complication entails; the present invention seeks to provide a system for directional control while rotary drilling which utilises the effect of flow of drilling fluid through the bit yet which does not require the sequential opening and closing of the jets in the bit (and so does not require the associated valving arrangement and fluid supply to the jets), and suggests that the fluid flow could simply be mo~ t~,d rather than redirecte~
In accordance with a first aspect of the present invention, therefore, there is provided a method for causing deviation of a borehole being drilled by rotary drilling using a bit having at least one nozzle through which a drilling fluid is caused to flow such that in use the flow of drilling fluid through that nozzle allows one sector of the bit to cut more effectively than the rem~in-lçr of the bit, the method comprising mo(3~ ting the flow of the drilling fluid through that nozzle as the bit rotates such that the cutting action of the chosen sector is optimised when in the desired direction of deviation and is reduced at other loc~*-~n~ in the borehole.
The present invention has the advantage over the Prior Art technique that it does not require each nozzle in the bit to be independently controllable when more than one jet is present; it is the overall flow through the bit which is mod--l~tç~, and by this mod~ tion the flow through the nozzles creates an asy~ Lly in the cutting action which can be used to control the deviation.
A second aspect of the invention provides ~p~aLuS for controlling the direction of drilling of a borehole, the apparatus comprising: a rotary drill bit having at least one nozzle for a drilling fluid to flow the~Llllough in such a manner that the flow of drilling fluid through that nozzle over cutting structures on the bit causes one section of the bit to have a c~m~a~ively illlplvved cutting action with respect to the rem~in-l~r of the bit; and mod--l~tor means to modulate the flow of drilling fluid through that nozzle so as to m~ t~ the cutting action of the section such that the compalaLively i~ r~ved cutting action occurs in a desired direction of deviation of the hole.
The means for modnl~ting the flow preferably forms part of the BHA, and can include further means for synchronising the modulation with the rotation of the drill string. Where more than one nozzle is present, the flow of drilling fluid is modulated through all nozzles at the same time. The means for modulating the flow is conveniently a flow in~.l,lp~
The further means for synchronising the modulation of the drilling fluid can include accele~ and/or m~g-~et~...f ~- ~ to detect the rotary position of the drill string. The further means can also include means for detecting signals from the surface, such as pressure pulses in the ~lrilling fluid supply, to control the modulation and hence the direction of drilling. Also, means for co~ ting the position of the bit to the surface, again such as pressure pulse tel~on~try, can be inf~lud~d The nozzle arrangement in the bit can coml,lise a single nozzle which directs a flow at one part of the bit. ~ltem~tively, a number of nozzles can be used, arranged such that the flow from the nozzles is directed to give the desired effect regarding the cufflng action of the bit - for in~n~e, directing the flow from one nozzle at the workface and the flow from any other nozzles at the cutting structures and the bit to act as mud picks. Additionally or alternatively the internal geometry of the nozzles can be sele~t~l such that there is greater flow in the ay~lu~liate section of the bit colll~aled to the rem~ind~r of the bit.
~137888 The present invention will now be described, by way of example, with reference to the accol~an~ing drawings in which:
Figure 1 shows a test rig for demonstrating the present invention;
Figure 2 shows a plot of results of a drilling test with deviation in one direction;
F;~ure 3 shows a plot collcspollding to Figure 2 with the direction of deviation ch~ng~ during the test;
Figure 4 shows a bit for use in a method on a~l,alalus according to the present invention; and Figure ~ shows a sche~nAtic view of a~lus accol.ling to the present invention.
Referring now to Figure 1, the test rig comprises a chamber 10 into which a drill shaft 12 projects. The drill shaft 12 is connected to a motor 14 and a drilling fluid supply line 16. Inside the chamber a sample of rock 18 is located below the drill shaft 12. A mechAnicm 20 is provided to apply an overburden stress to the sample drill shaft, and a confinen ~nt system 22 is provided so as to control the pore-p~es~ul~; of fluids in the sample. In use, a bit 24 is mounted on the drill shaft 12 and is drilled into the sample under the influen~ of the motor 14.
Drilling fluid is circulated through the drill shaft 12 and bit 24 by means of a pump 26. The drilling fluid exits the bit and hole being drilled in the sample, and the effecdve pl~S~ulG in the hole at the bit (bottom hole pl~,ssurG) is controlled by an intensifier where the drilling fluid leaves the chamber. Any tendency of the bit to deviate from a straight path when drilling is detected by means of shear sensors 28 in the drill shaft a~ove the bit.
The flow rate from the pump is approximately 110 L/mi~L The flow rate to the bit is controlled by a control valve (not shown). This allows all of the flow through to the bit or dumps some of the flow to the well bore annulus through nozzles (see Figure 4). The valve opening and closing is synchronised to the rotation of the bit; thus the flow to the bit is high (approximAtely 90% of flow rate) for 120 degrees of bit rotation and then reduced (to approximately 10%) for ^~40 degrees of rotation. During the low-~.ow-to-the-bit period the flow is diverted to the well bore through the nozzles, thus .nAi~ ing a constAnt pressure drop between pump discharge and bottom hole.
The valve opens and closes on every rotation of the bit. Rotary speed is 30 RPM. The high-to-low-flow period depends on the design of the valve switching element. For these tests ~137888 the valve element is lcsignecl for 120 degree high flow and 240 degrees low flow; however, there is some overlap between the high and low periods, so that the actual high flow period is somewhat greater than 120 degrees.
Test Details Samples~ h~ml~nt limestone.
Bit: 3/18" tri-cone, moflifil~A with two 'mud pick type' nozzles and one 'jetting nozzle', jetting into the corner of the wellbore.
Mud. Water based CMC polymer with a PV of 12.5 and a YP of 2.5.
WOB: approximately 4.5 kN.
(weight on bit) SDPP: 7.6 MPa.
(surface drill pipe ples~u~ = pump discharge pressure) SBHP: 3.0 MPa.
(surface bottom hole pressure = ~nn~ s~ule) Rock conrl~ lg ~lcssulc: 4 MPa Rock overburden plessuuG: 1.5. MPa.
Mud t~n~ Lul~; 18 to 24C
The test rig is used to provide the results plotted in Figures 2 and 3.
Figure 2 shows a plot of the bending mom~nt co~ al~d to the rotary position of the drill bit. In this case, the high flow period occurs when the 'jetting' nozzle is in the 120 segment centred on 0 (east). The bending moment is shown as a '+' on the plot, and coincides with the plere~;ntial jetting mud, thus cutting action due to the flow pulsing.
The test plotted in Figure 3 compr ~es initially a repeat of the test plotted in Figure 2 (and shown as 'o' on the plot), but halfway through the test the flow pulsing was shifted by 180 such that the high flow occurred when the 'jetting' nozzle was in the segment centred on 180 (west) and is represented as '+' on the plot.
The bit used in these tests is shown in Figure 4 (viewed from below), and comprises a rollercone bit having three cones 30, 32, 34 moullted on a bit body 36. Drilling fluid nozzles 38, 40, 42 are located in the bit body 36 bet~. ~n the cones 30, 32, 34, and are arranged such that two of the nozzles (38, 40) direct flow F, F' of the drilling fluid directly at adjacent cones 30, 32 to act as mud picks, and do not direct any flow at the workf~ce The rem~ining nozzle (42) directs flow F" into the corner of the workface. Thus, the flow of drilling fluid is ~137888 asymmetric relative to the bit, and because of the direction of flow from the nozzles the portion of the bit near nozzle 42 will have a relatively improved cutting action relative to the rem~in~er of the bit when drilling fluid is flowing from the nozzles. This difference beco...cs greater as the flow of drilling fluid through the bit increases. Thus, if the flow of drilling fluid is pulsed such that the flow is high whenever nozzle 42 passes point A on the workface and low for the rem~in~er of the rotation, the bit will drill p~felGntially in the direction of point A. While the bit still cuts better near nozzle 42 when the flow is low, the difference co~ d to the rest of the bit is small, and is ~ignifirantly less that the cutting effect when the flow is high. Clearly, the flow of drilling fluid has to be modulated according to the position of the bit (nozzles) relative to the workface, and this is best done once per revolution (although lower frequencies can be used).
It will be appreciated that the exact number and type of nozzles used can be varied while still maintaining this effect. In its simplest case, only one nozzle is required (for example, nozzle 42), but this can lead to problems with bit balling in certain ci~;u.-.~l~nces, and hence the other two nozzles 38, 40.
The complete BHA for pelrclming the method according to the present invention is shown schem~tirally in Figure S. The BHA is connected to a drill string 50 through which a drilling fluid is pumped from the surface, and comprises a Measurelllent While Drilling (MWD) and mud pulse telemetry pa~ ge 52 which, in~er alia, allows co-~ -ir~tion belwæl~ the BHA and surface equipment by means of positive pressure pulses in the drilling fluid. The MWD
package 52 includes a generator driven by mud flow to provide power for the various parts of the BHA. Below the MWD p~ck~ge 52 is a direction-mea~llring tool 54 which measures the direction and inclination of the BHA in the borehole and hence provides an inrliration of the direction of drilling at a given time. IIlÇcl~ ion from the direction---.~... ;n~ tool 54 is passed to the surface via the MWD package 52. A flow modulator 56 is located adjacent to the direction-mPacuring tool 54, and serves to modulate the flow of drilling fluid through the bit 58 so as to cause the deviation in the direction of drilling. The bit 58 has the asymmetric flow pattern through the nozzles as described previously. The flow m~nl~t ~r 56 inclu-1-os a sensor to in~lic~t~ the position of the bit in the borehole during rotation, and causes the flow of drilling fluid through the bit 58 to be modulated according to the position of the bit 58 relative to the workface as des-~ri~l in relation to Figure 4. Instructions are provided from the surface via the MWD package 52 to the modulator 56 to control the direction of drilling. The direction ~e~ulil~g tool 54 provides an indication of the current path of the borehole, and the mo~ tor 56 is controlled to cause the bit 58 to deviate in the desired direction.
Claims (14)
1. Apparatus for controlling the direction of drilling of a borehole, the apparatus comprising: a rotary drill bit having at least one nozzle for a drilling fluid to flow therethrough in such a manner that the flow of drilling fluid through that nozzle over cutting structures on the bit causes one section of the bit to have a comparatively improved cutting action with respect to the remainder of the bit; and modulator means to modulate the flow of drilling fluid through that nozzle so as to modulate the cutting action of the section such that the comparatively improved cutting action occurs in a desired direction of deviation of the hole.
2. Apparatus as claimed in Claim 1, wherein the modulator means forms part of the bottom hole assembly.
3. Apparatus as claimed in either of the preceding Claims, wherein the modulator means is a flow interrupter.
4. Apparatus as claimed in any of the preceding Claims, including synchronising means which synchronises the modulation of the flow of drilling fluid with the rotation of the drill string.
5. Apparatus as claimed in Claim 4, wherein the synchronising means includes accelerometers and/or magnetometers to detect the rotary position of the drill string.
6. Apparatus as claimed in Claim 4 or 5, wherein the synchronising means also includes a detector for detecting signals from the surface.
7. Apparatus as claimed in any of the preceding Claims, further including a transmitting device for communicating to the surface signals indicative of the position of the bit.
8. Apparatus as claimed in Claim 6 or 7, wherein the signals comprise pressure pulses in the drilling fluid.
9. Apparatus as claimed in any of the preceding Claims, wherein the nozzle arrangement in the bit comprises a single nozzle which directs a flow at one part of the bit.
10. Apparatus as claimed in any of Claims 1 to 8, wherein the nozzle arrangement comprises a number of nozzles, and the flow from one nozzle is directed at the workface and the flow from the other nozzles is directed at the cutting structures on the bit to act as mud picks.
11. Apparatus as claimed in Claim 10, wherein the internal geometry of the nozzles is such that there is greater flow in the one section of the bit compared to the remainder of the bit.
12. Apparatus as claimed in any of the preceding Claims, and substantially as described hereinbefore.
13. A method for causing deviation of a borehole being drilled by rotary drilling using a bit having at least one nozzle through which a drilling fluid is caused to flow such that in use the flow of drilling fluid through that nozzle allows one sector of the bit to cut more effectively than the remainder of the bit, the method comprising modulating the flow of the drilling fluid through that nozzle as the bit rotates such that the cutting action of the chosen sector is optimised when in the desired direction of deviation and is reduced at other locations in the borehole.
14. A method as claimed in Claim 13, wherein the modulation of the flow of drilling fluid is synchronised with the rotation of the bit in the borehole during drilling.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9325876.2 | 1993-12-17 | ||
| GB9325876A GB2284837B (en) | 1993-12-17 | 1993-12-17 | Directional drilling method and apparatus |
| FR9415101A FR2714108B1 (en) | 1993-12-17 | 1994-12-13 | Directional drilling method and apparatus. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2137888A1 true CA2137888A1 (en) | 1995-06-18 |
Family
ID=26231616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002137888A Abandoned CA2137888A1 (en) | 1993-12-17 | 1994-12-12 | Directional drilling method and apparatus |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA2137888A1 (en) |
| FR (1) | FR2714108B1 (en) |
| GB (1) | GB2284837B (en) |
| NO (1) | NO309905B1 (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9517378D0 (en) * | 1995-08-24 | 1995-10-25 | Sofitech Nv | Hydraulic jetting system |
| AUPO062296A0 (en) * | 1996-06-25 | 1996-07-18 | Gray, Ian | A system for directional control of drilling |
| JP3406214B2 (en) * | 1998-01-30 | 2003-05-12 | ユニ・チャーム株式会社 | Disposable diapers |
| US6308790B1 (en) * | 1999-12-22 | 2001-10-30 | Smith International, Inc. | Drag bits with predictable inclination tendencies and behavior |
| FR2819850B1 (en) * | 2001-01-22 | 2003-12-19 | Cie Du Sol | PRESSURE LIQUID JET DRILLING TOOL |
| US6585061B2 (en) | 2001-10-15 | 2003-07-01 | Precision Drilling Technology Services Group, Inc. | Calculating directional drilling tool face offsets |
| WO2005005768A1 (en) | 2003-07-09 | 2005-01-20 | Shell Internationale Research Maatschappij B.V. | Tool for excavating an object |
| ATE511595T1 (en) | 2003-07-09 | 2011-06-15 | Shell Int Research | TOOL FOR LIFTING AN OBJECT |
| AR045022A1 (en) * | 2003-07-09 | 2005-10-12 | Shell Int Research | SYSTEM AND METHOD FOR PERFORATING AN OBJECT |
| ATE374304T1 (en) | 2003-10-29 | 2007-10-15 | Shell Int Research | FLUID JET DRILLING TOOL |
| US7357182B2 (en) | 2004-05-06 | 2008-04-15 | Horizontal Expansion Tech, Llc | Method and apparatus for completing lateral channels from an existing oil or gas well |
| US8186459B1 (en) | 2008-06-23 | 2012-05-29 | Horizontal Expansion Tech, Llc | Flexible hose with thrusters and shut-off valve for horizontal well drilling |
| AU2011347447B2 (en) | 2010-12-22 | 2015-07-09 | Shell Internationale Research Maatschappij B.V. | Directional drilling |
| WO2014177502A1 (en) | 2013-04-29 | 2014-11-06 | Shell Internationale Research Maatschappij B.V. | Method and system for directional drilling |
| US10151150B2 (en) | 2013-04-29 | 2018-12-11 | Shell Oil Company | Insert and method for directional drilling |
| US10100627B2 (en) | 2013-04-29 | 2018-10-16 | Shell Oil Company | Method and system for directional drilling |
| CN110107227A (en) * | 2019-04-28 | 2019-08-09 | 中国石油集团长城钻探工程有限公司 | A kind of diamond bit with efficient outlet hole structure |
| NL2024001B1 (en) | 2019-10-11 | 2021-06-17 | Stichting Canopus Intellectueel Eigendom | Method and system for directional drilling |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3746108A (en) * | 1971-02-25 | 1973-07-17 | G Hall | Focus nozzle directional bit |
| US4518048A (en) * | 1983-04-18 | 1985-05-21 | Robert F. Varley Co., Inc. | Method for improved hydraulic jetting of drill bore holes using high pressure pulses of fluid |
| CA1217759A (en) * | 1983-07-08 | 1987-02-10 | Intech Oil Tools Ltd. | Drilling equipment |
| US4637479A (en) * | 1985-05-31 | 1987-01-20 | Schlumberger Technology Corporation | Methods and apparatus for controlled directional drilling of boreholes |
| GB8806506D0 (en) * | 1988-03-18 | 1988-04-20 | Pilot Drilling Control Ltd | Drilling apparatus |
| US4991667A (en) * | 1989-11-17 | 1991-02-12 | Ben Wade Oakes Dickinson, III | Hydraulic drilling apparatus and method |
| AU8044091A (en) * | 1990-07-17 | 1992-01-23 | Camco Drilling Group Limited | A drilling system and method for controlling the directions of holes being drilled or cored in subsurface formations |
| DE4122350C2 (en) * | 1991-07-05 | 1996-11-21 | Terra Ag Tiefbautechnik | Method for controlling the direction of a rough drilling device and device for producing earth bores |
| US5314030A (en) * | 1992-08-12 | 1994-05-24 | Massachusetts Institute Of Technology | System for continuously guided drilling |
| GB2282614A (en) * | 1993-10-05 | 1995-04-12 | Anadrill Int Sa | Bottom hole assembly for directional drilling |
-
1993
- 1993-12-17 GB GB9325876A patent/GB2284837B/en not_active Expired - Lifetime
-
1994
- 1994-12-12 CA CA002137888A patent/CA2137888A1/en not_active Abandoned
- 1994-12-13 FR FR9415101A patent/FR2714108B1/en not_active Expired - Fee Related
- 1994-12-16 NO NO944891A patent/NO309905B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| NO944891L (en) | 1995-06-19 |
| FR2714108A1 (en) | 1995-06-23 |
| GB2284837A (en) | 1995-06-21 |
| GB2284837B (en) | 1997-11-12 |
| GB9325876D0 (en) | 1994-02-23 |
| NO309905B1 (en) | 2001-04-17 |
| FR2714108B1 (en) | 1998-01-30 |
| NO944891D0 (en) | 1994-12-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |