Title:
Well drilling system and its method
Kind Code:
A1


Abstract:
A well drilling system includes a platform mounted on the ground, a tubular sleeve mounted movably on the platform, a drilling device inserted into the sleeve, and a circulation device. The drilling device includes a support seat connected detachably to a lower end of the sleeve, a drilling head mounted rotatably on the support seat, and at least one powered actuator connected to the support seat and the drilling head to actuate the drilling head to rotate relative to the support seat. The circulation device includes a pipe, and is mounted inside the sleeve for removing soil out of the sleeve.



Inventors:
Tsai, Te-pin (Taipei City, TW)
Wu, Hsiu-hsuan (Taipei City, TW)
Application Number:
10/405262
Publication Date:
10/07/2004
Filing Date:
04/01/2003
Assignee:
TSAI TE-PIN
WU HSIU-HSUAN
Primary Class:
Other Classes:
175/171
International Classes:
E21B7/20; (IPC1-7): E21B7/20
View Patent Images:
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Primary Examiner:
NEUDER, WILLIAM P
Attorney, Agent or Firm:
OSTROLENK FABER LLP (845 THIRD AVENUE 8TH FLOOR, NEW YORK, NY, 10022, US)
Claims:

We claim:



1. A well drilling system comprising: a platform adapted to be mounted on the ground; a tubular sleeve mounted movably on said platform and having a lower end; a drilling device inserted into said tubular sleeve, and including a support seat connected detachably to said lower end, a drilling head mounted rotatably on said support seat, and at least one powered actuator connected to said support seat and said drilling head to actuate said drilling head to rotate relative to said support seat; and a circulation device including a pipe, said circulation device being mounted inside said tubular sleeve and being adapted to remove soil out of said tubular sleeve.

2. The well drilling system as claimed in claim 1, wherein said drilling device includes a plurality of said powered actuators, said drilling head having a rotary shaft pivotally connected to said support seat, a rotary frame connected fixedly to said rotary shaft, and a plurality of force receiving posts annularly provided at intervals on said rotary frame around said shaft proximate to said support seat, said powered actuators pushing said force receiving posts along tangential directions of said rotary frame so as to actuate said drilling head to rotate relative to said support seat.

3. The well drilling system as claimed in claim 1, further comprising a driving device mounted on said platform, said driving device including a clamping frame detachably connected to said tubular sleeve, and a drive unit for applying a downward driving force to move downwardly said tubular sleeve and having two ends respectively connected to said platform and said clamping frame.

4. The well drilling system as claimed in claim 1, wherein said tubular sleeve includes a sleeve body with an inner wall, and a plurality of rails formed in said inner wall of said sleeve body and extending axially of said tubular sleeve, said support seat of said drilling device being provided with a plurality of guide units, which are slidable respectively along said rails when said drilling device is inserted into said tubular sleeve.

5. The well drilling system as claimed in claim 4, wherein said drilling device further includes a powered positioning unit disposed between said inner wall and said support seat adjacent to said lower end of said tubular sleeve so as to position said support seat when said support seat reaches said lower end.

6. The well drilling system as claimed in claim S, wherein said support seat includes a central base body and a plurality of radial base members extending from said central base body, said radial base members having distal ends, said guide units being respectively mounted on said distal ends and slidingly engaging said rails.

7. The well drilling system as claimed in claim 6, wherein said powered positioning unit includes a plurality of hydraulic members mounted respectively at said distal ends of said radial base members, and a plurality of positioning members connected respectively to said hydraulic members so as to engage releasably said inner wall of said tubular sleeve.

8. The well drilling system as claimed in claim 7, wherein said drilling head is attached rotatably to said central base body of said support seat and is disposed below said support seat.

9. The well drilling system as claimed in claim 8, wherein said drilling head includes a rotary frame which has a central frame body attached rotatably to said central base body, and a plurality of radial frame members extending from said central frame body and disposed below and adjacent to said radial base members.

10. The well drilling system as claimed in claim 9, wherein said radial base members and said radial frame members have opposed surfaces which move toward and away from each other when said rotary frame rotates relative to said support seat, said drilling device further comprising a plurality of grinding jaws and grinding teeth projecting oppositely on said opposed surfaces of said radial base members and said radial frame members.

11. The well drilling device as claimed in claim 1, wherein said powered actuator actuates said drilling head to turn to-and-fro relative to said support seat.

12. The well drilling system as claimed in claim 1, wherein said tubular sleeve is composed of a stack of sleeve bodies.

13. A method for drilling a well, comprising: a) mounting a platform fixedly on the ground; b) placing a tubular sleeve on the ground and mounting said tubular sleeve on said platform; c) positioning a drilling device in said tubular sleeve; d) simultaneously actuating said drilling device and driving downwardly said tubular sleeve into the ground; e) pouring water into said tubular sleeve to fluidize soil within said tubular sleeve; and f) drawing out the fluidized soil from said tubular sleeve.

14. The method for drilling a well as claimed in claim 13, wherein in step (c), said drilling device is positioned within said tubular sleeve by sliding downwardly said drilling device from an upper end of said tubular sleeve to a lower end of said tubular sleeve through a rail disposed on an inner wall of said tubular sleeve, and by preventing said drilling device from sliding movement when said drilling device reaches said lower end.

15. The method for drilling a well as claimed in claim 13, wherein in step (c), a powered actuator is used to turn to-and-fro said drilling device by applying force to said drilling device along a tangential direction.

16. The method for drilling a well as claimed in claim 13, wherein instep (c), a plurality of powered actuators are used to turn to-and-fro said drilling device by applying forces to said drilling device along tangential directions.

17. The method for drilling a well as claimed in claim 13, further comprising: g) separating water from the fluidized soil; and h) sending the separated water into said tubular sleeve for recycling, wherein the steps (d), (e), (f) (g), and (h) are carried out simultaneously.

18. The method for drilling a well as claimed in claim 13, wherein said tubular sleeve is composed of a stack of sleeve bodies, and the method further comprises: i) stopping the operation of said drilling device; j) increasing the length of said tubular sleeve by increasing the number of said sleeve bodies; and k) repeating steps (d) to (f).

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a well drilling system and its method.

[0003] 2. Description of the Related Art

[0004] A conventional method of drilling a well is divided into two stages. The first stage is to embed a tubular sleeve into a desired drilling site by initially preparing a tubular sleeve and a platform that is stably mounted on the ground for supporting the sleeve. The sleeve has a lower periphery formed with a plurality of saw-toothed cutters or provided with a plurality of tungsten steel drilling bits. Afterwards, a driving device that is provided on the platform actuates the sleeve to rotate relative to the platform. Due to rotating and scraping actions of the cutters or the drilling bits, the sleeve is pushed downwardly into the ground.

[0005] The second stage is to remove stones and soil in the sleeve. In this stage, when the drilling site is of soft soil layer, which is made up mostly of slime and sand, a heavy equipment with a hanging dipper bucket is used to continuously dig out the stones and soil in the sleeve. When the drilling site is of hard soil layer, which is made up mostly of pebblestones and cobblestones, the second stage includes two steps. The first step is to hang a rotating drill head or a vibrating crusher on the heavy equipment that extends into the sleeve so as to cut or crush the stones inside the sleeve. The second step is to hang a dipper bucket on the heavy equipment so as to remove the crushed stones and soil out of the sleeve. The first and second steps are repeatedly performed so that the stones and soil can be gradually cleared out of the sleeve. A well is built accordingly.

[0006] When building a well on a drilling site with hard soil layer, since the above-mentioned two steps have to be repeatedly performed, if only one heavy equipment is used, the hanging unit on the heavy equipment has to be alternately and repeatedly changed, thereby increasing the cost, prolonging the working time, and increasing danger. However, if two heavy equipments are used at the same time, not only is the cost largely increased, public safety is affected as well. Moreover, since the above drilling method requires heavy equipment with enormous volume and weight, not only are the drilling steps complicated and slow, use of the method is limited due to its inaccessibility to a drilling site with limited space.

SUMMARY OF THE INVENTION

[0007] Therefore, the object of the present invention is to provide a well drilling system and its method so as to overcome the aforementioned drawbacks of the prior art.

[0008] According to one aspect of this invention, a well drilling system comprises a platform adapted to be mounted on the ground, a tubular sleeve mounted movably on the platform and having a lower end, a drilling device inserted into the tubular sleeve, and a circulation device. The drilling device includes a support seat connected detachably to the lower end, a drilling head mounted rotatably on the support seat, and at least one powered actuator connected to the support seat and the drilling head to actuate the drilling head to rotate relative to the support seat. The circulation device includes a pipe, and is mounted inside the tubular sleeve, and is adapted to remove soil out of the tubular sleeve.

[0009] According to another aspect of this invention, a method for drilling a well comprises the steps of mounting a platform fixedly on the ground, placing a tubular sleeve on the ground and mounting the tubular sleeve on the platform, positioning a drilling device in the tubular sleeve, simultaneously actuating the drilling device and driving downwardly the sleeve onto the ground, pouring water into the sleeve to fluidize soil within the sleeve, and drawing out the fluidized soil from the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

[0011] FIG. 1 is a schematic view of the preferred embodiment of a well drilling system according to the present invention;

[0012] FIG. 2 is schematic top view showing the platform, the tubular sleeve, and the driving units of the preferred embodiment prior to mounting of the drilling device;

[0013] FIG. 3 is a sectional view of the preferred embodiment taken along line III-III of FIG. 1;

[0014] FIG. 4 is a schematic bottom view of the preferred embodiment;

[0015] FIG. 5 illustrates an extension arm of the drilling device of the preferred embodiment in an unfolded state;

[0016] FIG. 6 illustrates the extension arm of the drilling device of the preferred embodiment in a folded state;

[0017] FIG. 7 is a view taken along line VII-VII of FIG. 3, illustrating how a stone can be ground by grinding jaws of the drilling device of the preferred embodiment;

[0018] FIG. 8 is a schematic view illustrating a hydraulic device of the preferred embodiment, which is connected to the platform, the drilling device, and the driving units;

[0019] FIG. 9 illustrates a circulation device of the preferred embodiment; and

[0020] FIG. 10 is a flow chart to illustrate consecutive steps of a method for drilling a well according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] Referring to FIGS. 1 and 2, in the preferred embodiment of a well drilling system 1 and its method according to the present invention, a platform 2 is adapted to be mounted on the ground 9, a tubular sleeve 3 is mounted movably on the platform 2, a drilling device 4 is inserted into the tubular sleeve 3, and a driving device 5 is mounted on the platform 2. A hydraulic device 6 (see FIG. 8) is provided for activating the drilling device 4 and the driving device 5. A circulation device 7 (see FIG. 9) is provided for removing fluidized soil out of the tubular sleeve 3.

[0022] The platform 2 has a base seat 21 mounted fixedly on the ground 9, four counter weights 22 mounted on the base seat 21 for increasing stability of the platform 2, and a plurality of adjustment actuators 23 provided on the base seat 21 and connected to the driving device 5. The adjustment actuators 23 and the hydraulic device 6 are interconnected for adjusting the slope of the driving device 5 and the tubular sleeve 3 with respect to the ground 9.

[0023] The tubular sleeve 3 has an axial line (L) vertical to the ground 9. In this embodiment, the sleeve 3 is composed of a stack of sleeve bodies 31 that extend along the axial line (L). Each sleeve body 31 has a length of 2 meters and an inner diameter of 1.5 meters. The number of the sleeve bodies 31 can be increased so as to extend the length of the sleeve 3. As such, the length of the sleeve 3 along the axial line (L) is unlimited, and can be adjusted as desired. As a whole, the tubular sleeve 3 includes a sleeve body 31 and a plurality of downwardly extending rails 35 provided in an inner wall of the sleeve body 31 and extending axially of the sleeve 3. Specifically, four rails 35 are provided in this embodiment. The sleeve body 31 has a lower end 33 that is distal to the platform 2, and an upper end 34 opposite to the lower end 33. A plurality of retaining units 321 are provided in the inner wall of the sleeve body 31 proximate to the lower end 33 for positioning the drilling device 4. Each retaining unit 321 is formed with a retaining groove 322. The rails 35 extend symmetrically along the axial line (L) from the upper end 34 to the lower end 33. In this embodiment, the rails 35 are protruding posts that protrude inwardly from the inner wall of the sleeve body 31. However, the rails 35 are not limited as such. In an alternative embodiment, the rails 35 are a plurality of grooves formed in the inner wall of the sleeve body 31 and extending along the axial line (L). Since such a modification is obvious to those skilled in the art, a detailed description of the same will be dispensed with herein for the sake of brevity.

[0024] Referring to FIGS. 1, 3 and 4, the drilling device 4 is inserted into the tubular sleeve 3, and includes a support seat 41 connected detachably to the lower end 33 of the sleeve body 31, a drilling head 42 mounted rotatably on the support seat 41, and a plurality of powered actuators 43 disposed between and abutting against the support seat 41 and the drilling head 42.

[0025] The support seat 41 of the drilling device 4 includes a central base body 410, a plurality of radial base members 411 extending from the central base body 410, a plurality of guide units 412 provided on the radial base members 411, and a powered positioning unit. In this embodiment, the guide units 412 are inwardly extending grooves formed respectively in the distal ends of the radial base members 411, and slidingly and respectively engage the rails 35. The support seat 41 slidingly engages the rails 35 through the guide units 412 for sliding movement from the upper end 34 to the lower end 33 of the sleeve body 31 when the drilling device 4 is inserted into the tubular sleeve 3. Since the rails 35 can provide reinforcing effect to the tubular sleeve 3, the rails 35 can also serve as reinforcing ribs of the latter. The powered positioning unit is disposed between the inner wall of the sleeve body 31 and the support seat 41 adjacent to the lower end 33 of the sleeve body 31 so as to position the support seat 41 when the support seat 41 reaches the lower end 33 of the sleeve body 31. The powered positioning unit includes a plurality of hydraulic members 414 mounted respectively at the distal ends of the radial base members 411, and a plurality of positioning members 413 connected respectively to the hydraulic members 414. The positioning members 413 engage releasably and respectively the retaining grooves 322 in the retaining units 321 of the sleeve body 31 so that the support seat 41 and the sleeve body 31 cannot produce relative displacement. The hydraulic members 414 actuate the positioning members 413 to move along a radial direction (N) of the axial line (L) to engage respectively the retaining grooves 322 so that the drilling device 4 is prevented from moving along the rails 35. As such, the drilling device 4 can be positioned relative to the sleeve body 31.

[0026] The drilling head 42 of the drilling device 4 is attached rotatably to the central base body 410 of the support seat 41, is disposed below the latter, and has a rotary shaft 422 pivotally connected to the support seat 41, a rotary frame 421 connected fixedly to the rotary shaft 422, and a plurality of force receiving posts 423 annularly provided at intervals on the rotary frame 421 around the shaft 422 and proximate to the support seat 41. The rotary frame 421 includes a central frame body 421A attached rotatably to the central base body 410, and a plurality of radial frame members 421B extending from the central frame body 421A and disposed below and adjacent to the radial base members 411. The support seat 41 further includes a thrust bearing 416 mounted on the central base body 410. Load capacity of the thrust bearing 416 is 30 tons. The rotary shaft 422 is connected to the thrust bearing 416. The radial base members 411 and the radial frame members 421B have opposed surfaces which move toward and away from each other when the rotary frame 421 rotates relative to the support seat 41. The force receiving posts 423 are symmetrically disposed on the rotary frame 421, are disposed at a uniform distance of 20 cm from an outer periphery of the rotary frame 421, and extend along and parallel to the axial line (L) toward the support seat 41. The total number of the force receiving posts 423 used in this embodiment is 16.

[0027] The powered actuators 43 are provided for actuating the drilling head 42 to rotate relative to the support seat 41. There are four powered actuators 43 used in this embodiment. The powered actuators 43 are symmetrically and respectively mounted on the radial base members 411 of the support seat 41 relative to the axial line (L) of the tubular sleeve 3. Each powered actuator 43 can supply 15 tons of actuating force, and retract and extend within a range of 15 centimeters. Each powered actuator 43 has an actuating force direction parallel to the tangential direction of the rotation of the drilling head 42, and includes a fixed end 431 pivotally connected to a respective one of the radial base members 411, a movable end 432 distal to the fixed end 431, and an intermediate section 433 between the fixed end 431 and the movable end 432. The support seat 41 further includes a plurality of spring units 415, each of which is disposed between and abuts against a respective one of the radial base members 411 and a respective one of the intermediate sections 433 of the powered actuators 43. In this embodiment, each of the spring units 415 is an extension spring. Restoring force of each of the spring units 415 provides dampening and position-limiting effect to the respective one of the powered actuators 43. When each spring unit 415 is in a balanced state, it can maintain the actuating force direction of each powered actuator 43 and a radial rotational direction (R) of the drilling head 42 in a parallel state.

[0028] The powered actuators 43 abut respectively against the force receiving posts 423, and push the latter along a tangential direction of the rotary frame 421 so as to actuate the drilling head 42 to turn to-and-fro relative to the support seat 41.

[0029] Referring to FIGS. 1, 5 and 6, the drilling head 42 further includes a plurality of extension arms 424 connected pivotally and respectively to the radial frame members 421B of the rotary frame 421, and a plurality of spaced-apart cutters 425 that are provided respectively on the extension arms 424 and the radial frame members 421B. Each extension arm 424 is movable from an unfolded state shown in FIG. 5 to a folded state shown in FIG. 6. In the unfolded state, each extension arm 424 projects radially out of the periphery of the rotary frame 421 so that the radius of the drilling head 42 is larger than the inner radius of the tubular sleeve 3. In the folded state, each extension arm 424 does not project radially out of the periphery of the rotary frame 421 so that the radius of the drilling head 42 is smaller than the inner radius of the tubular sleeve 3. Layout method of the cutters 425 is that the cutters 425 are provided around the rotary shaft 422 at intervals, and are arranged on the radial frame members 421B of the rotary frame 421.

[0030] Referring to FIGS. 1 and 7, when applied to the ground 9 with lots of stones 92 (only one is shown in FIG. 7), the drilling device 4 is further designed to include a plurality of grinding jaws 81, 82 and grinding teeth 83 projecting oppositely on the opposed surfaces of the radial base members 411 and the radial frame members 421B. Each of the grinding jaws 81, 82 has a limiting slant surface 811 formed with rough lines. When the drilling head 42 rotates relative to the support seat 41, the grinding jaws 81, 82 are close to each other so that the stone 92 between the limiting slant surfaces 811 can be ground. The teeth 83 can further grind the stone 92 into much smaller pieces due to relative movement between the support seat 41 and the drilling head 42.

[0031] Referring again to FIGS. 1 and 2, the driving device includes a clamping frame 51 detachably connected to the upper end 34 of the tubular sleeve 3, and four drive units 52, each of which has two ends respectively connected to the platform 2 and the clamping frame 51. Each drive unit 52 applies a downward driving force parallel to the axial line (L) of the tubular sleeve 3 so as to move downwardly the tubular sleeve 3 toward the ground 9. In this embodiment, the drive units 52 are connected fixedly to the base seat 21, and, together with the above-mentioned powered actuators 43 and the hydraulic members 414, are controlled by the hydraulic device 6.

[0032] Referring to FIGS. 1 and 8, the hydraulic device 6 includes a hydraulic control unit 61, which has an oil reservoir 610 and a plurality of flow valves 611, and a plurality of hydraulic pipes 62 in fluid communication with the oil reservoir 610. The hydraulic pipes 62 are connected respectively to the adjustment actuators 23, the drive units 52, the powered actuators 43, and the hydraulic members 414. Thus, during operation of the hydraulic control unit 61, the hydraulic members 414 can actuate respectively the positioning members 413 so as to position the support seat 41, the adjustment actuators 23 can adjust the slope of the clamping frame 51 with respect to the ground 9, the drive units 52 can actuate the clamping frame 51 so as to drive downwardly the tubular sleeve 3, and the powered actuators 43 can push the force receiving posts 423 to rotate the drilling head 42 so as to effect drilling.

[0033] Referring to FIGS. 1 and 9, the circulation device 7 includes a discharging pipe 71 disposed inside the tubular sleeve 3, a drawing pump 72 in fluid communication with the discharging pipe 71, a separator unit 73 connected to the drawing pump 72, and a delivery pipe 74 extending from the separator unit 73 to the inside of the tubular sleeve 3. The discharging pipe 71 is formed with a sucking opening 710. The separator unit 73 includes a slanted vibrating screen 731 connected to the drawing pump 72, and a water trough 730 disposed below the screen 731 so as to receive the separated water from the screen 731. The delivery pipe 74 is in communication with the water trough 730, and directs the separated water that passes through the screen 731 into the tubular sleeve 3 for recycling. A blocking plate 417 is disposed on the support seat 41 distal to the drilling head 42 so as to confine the separated water inside the lower end 33 of the tubular sleeve 3, thereby preventing the separated water from staining other portions of the well drilling system 1.

[0034] Below is a description for drilling the well 90 (see FIG. 1) using the well drilling system 1 of the present invention.

[0035] Referring to FIG. 10, in step (a), the platform 2 is mounted fixedly on the ground 9. Drive units 52 are mounted on the base seat 21 of the platform 2. In step (b), one of the sleeve bodies 31 of the tubular sleeve 3 is placed on the ground 9, and the clamping frame 51 is mounted on the sleeve body 31. In this step, the clamping frame 51 is connected to the drive units 52.

[0036] In step (c), the drilling device 4 is positioned in the lower end 33 of the sleeve body 31. In this embodiment, the drilling device 4 is hung by a hanging machine (not shown), and is lowered into the sleeve body 31 by sliding downwardly from the upper end 34 to the lower end 33 of the sleeve body 31 through coordination of the guide units 412 and the rails 35. However, the process is not limited as such. The platform 2 can be provided with a hanging arm (not shown) to undertake similar work. The hydraulic device 6 controls the hydraulic members 414 to actuate the positioning members 413 to extend into the retaining grooves 322 in the retaining units 321 of the sleeve body 31, thereby positioning the support seat 41 of the drilling device 4 in the lower end 33 of the sleeve body 31.

[0037] Note that prior to the installation of the drilling device 4 into the sleeve body 31, the hydraulic device 6 is connected to the adjustment actuators 23, the hydraulic members 414, the drive units 52, and the powered actuators 43, and the circulation device 7 is mounted securely beforehand.

[0038] In step (d), the drilling device 4 is actuated, and the sleeve body 31 is driven downwardly into the ground 9, simultaneously. The powered actuators 43 are used to turn to-and-fro the drilling device 4 by applying forces to the drilling device 4 along tangential directions in a consecutive or simultaneous manner. In this step, the powered actuators 43 apply forces along directions perpendicular to the radial direction (R) of the drilling head 42 so as to activate the drilling head 42 to rotate relative to the support seat 41. The drilling head 42 starts to drill the ground 9 at this time, and the stones 92 (only one is shown in FIG. 7) are ground by the grinding jaws 81, 82 and the grinding teeth 83 into smaller pieces.

[0039] In step (e), water is poured into the sleeve body 31 so as to fluidize soil within the sleeve body 31. In this step, the water trough 730 of the separator unit 73 is filled with a suitable amount of water, and water is guided into the sleeve body 31 through the delivery pipe 74.

[0040] In step (f), fluidized soil is drawn out from the sleeve body 31, and is sucked into the discharging pipe 71 through the sucking opening 710.

[0041] Afterwards, water is separated from the fluidized soil. Through the separator unit 73 and the vibrating screen 731, which communicates with the drawing pump 72, large size solid materials in the fluidized soil are-sifted. The separated water is sent into the sleeve body 31 for recycling. Since the separator unit 73 has a water trough 730 located below the screen 731 for receiving the separated water, and since the delivery pipe 74 extends into the sleeve body 31 and communicates with the water trough 730, the separated water that passes through the screen 731 is automatically sent into the sleeve body 31 for recycling.

[0042] The aforesaid steps (d), (e) and (f) are carried out simultaneously until the sleeve body 31 is entirely lowered into the ground 9. At this stage, the operation of the drilling device 4 is stopped, and another sleeve body 31 is superimposed on the one previously lowered into the ground 9. The length of the tubular sleeve 3 is therefore increased. The above-described steps are repeated, and additional sleeve bodies 31 are consecutively added until the lowermost sleeve body 31 reaches a predetermined depth.

[0043] When the predetermined depth is reached, the operations of the powered actuators 43 and the drive units 52 are stopped. The remaining fluidized soil in the sleeve body 31 are discharged through the discharging pipe 71, and are prevented from flowing back into the sleeve body 31 through the delivery pipe 74.

[0044] Finally, the positioning posts 413 are separated from the positioning grooves 322 by the hydraulic members 414, and the drilling device 4 is pulled out of the tubular sleeve 3 by the heavy equipment (not shown).

[0045] It should be noted that in this embodiment, the hydraulic device 6 controls the powered actuators 43 to apply forces respectively on the force receiving posts 423 in a consecutive manner so as to actuate the drilling head 42 to rotate relative to the support seat 41. Thus, if the ground 9 is soft, the drilling head 42 is first actuated by using some of the powered actuators 43 to move the corresponding force receiving posts 423 to an angular distance. The remaining powered actuators 43 are subsequently operated by the hydraulic device 6 to push the other force receiving posts 423 to successively turn the drilling head 42. As such, the alternating operations of the powered actuators 43 can maintain higher rotational speed of the drilling head 42. If the ground 9 is hard, the drilling head 42 cannot be effectively actuated by merely using some of the powered actuators 43. However, since the remaining powered actuators 43 operate successively, an increased torque can be applied to the drilling head 42, thereby actuating the drilling head 42 at a lower rotational speed but with a larger torque.

[0046] The powered actuators 43 can also be designed to simultaneously apply forces to the force receiving posts 423 so that the drilling head 42 can rotate relative to the support seat 41 with fixed torsion force and at constant rotational speed.

[0047] From the above description of the preferred embodiment of the well drilling system and its method of the present invention, when building the well 90 on hard ground 9, steps (a) to (f) are simultaneously carried out so that it is completely unnecessary to separately perform the crushing and digging operations. As such, the drilling method is simplified so that production cost is lowered, working time is shortened, and public safety is enhanced. Furthermore, the digging work is carried out through the control of the hydraulic device 6 so that the well drilling system 1 and the method according to the present invention can be semi-automated or even fully automated, thereby increasing the drilling efficiency, shortening working hours and lowering manpower cost. Moreover, since the drilling method of the present invention does not require heavy equipment, it can be widely applied to different types of working sites, and is not limited by space.

[0048] While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.





 
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