ADVANCED STABILIZING SYSTEM FOR DEEP DRILLING

Abstract

The present invention relates to a stabilizing system adapted to be used in a deep drilling system. The stabilizing system comprises a longitudinal housing and a spring, preferably a helical spring, arranged inside the housing. Thereby, the stabilizing system is contracted and the spring is compressed along the longitudinal axis of the stabilizing system when an external load is applied in longitudinal direction onto the stabilizing system. The transversal diameter of the stabilizing system increases when the stabilizing system is contracted. Further, the transversal diameter of the stabilizing system decreases when the stabilizing system expands along the longitudinal axis.

Claims

1. A stabilizing system adapted to be used in a deep drilling system, the stabilizing system comprising a longitudinal housing and a spring arranged inside the housing, wherein the stabilizing system is contracted and the spring is compressed along the longitudinal axis of the stabilizing system when an external load is applied in longitudinal direction onto the stabilizing system, wherein the transversal diameter of the stabilizing system increases when the stabilizing system is contracted, the spring urges the stabilizing system to expand along the longitudinal axis when the external load is released, wherein the transversal diameter of the stabilizing system decreases when the stabilizing system expands along the longitudinal axis.

2. The stabilizing system of claim 1, wherein the spring is a helical spring.

3. The stabilizing system of claim 1, wherein the spring is provided concentrically with the housing.

4. The stabilizing system of claim 1, wherein the spring is provided parallel to the longitudinal axis of the stabilizing system.

5. The stabilizing system of claim 1, further comprising a column arranged inside the housing and being adapted to transfer drilling forces applied onto the stabilizing system, wherein the column extends through the spring.

6. The stabilizing system of claim 1, wherein a spring travel of the spring between its relaxed state and its maximal compressed state is between 1 and 100 cm.

7. The stabilizing system of claim 1, wherein the external load is at least 5 kN.

8. The stabilizing system of claim 1, wherein a spring rate of the spring is between 10 and 5000 kN/m.

9. The stabilizing system of claim 1, further comprising at least one spacer movable relative to the housing between a retracted position and an expanded position, wherein the spring is adapted to act on the spacer along the longitudinal axis of the stabilizing system to urge the spacer to the retracted position.

10. The stabilizing system of claim 9, wherein the spring is in a compressed state when the spacer is in the expanded position.

11. The stabilizing system of claim 9, wherein the spring is adapted to act on the spacer in the expanded position with a force of 5 to 25 kN.

12. The stabilizing system of claim 9, wherein the spacer comprises a tapered section at one end thereof, wherein the tapered section is tapered relative to the longitudinal axis of the stabilizing system by 5 to 70 degrees.

13. The stabilizing system of claim 12, wherein the housing comprises a counter-tapered section adapted to interact with the tapered section of the spacer, wherein the tapered section of the spacer is adapted to slide along the counter-tapered section of the housing to move the spacer along the longitudinal axis of the stabilizing system when the spacer moves between the retracted and the expanded position.

14. The stabilizing system claim 9, wherein the housing comprises one or more passages extending from an interior side of the housing to an exterior side of the housing, wherein the one or more passages connect an inner space occupied by the spring and the spacer to an outside space of the stabilizing system.

15. The stabilizing system of claim 14, wherein a screen filter is provided in each one of the one or more passages.

16. The stabilizing system of claim 9, wherein the stabilizing system comprises at least two spacers, and wherein the spring is adapted to act on each of the spacers along a longitudinal axis of the stabilizing system to urge each one of the spacers to the retracted position.

17. The stabilizing system of claim 16, further comprising a spring force transfer ring provided in the housing between the spring and each one of the spacers.

18. A drilling system comprising a stabilizing system of claim 1, and further comprising a drill bit and drill pipes.

19. A method for drilling a hole utilizing a drilling system of claim 18, the method comprising: applying a positive force onto the stabilizing system in longitudinal direction causing the overall longitudinal length of the stabilizing system to shorten, the spring to compress, and the transversal diameter of the stabilizing system to increase; applying a negative force onto the stabilizing system in longitudinal direction causing the spring to decompress to urge the overall longitudinal length of the stabilizing system to elongate, and the transversal diameter of the stabilizing system to decrease.

Description

DESCRIPTION OF PREFERRED EMBODIMENT

[0044] In the following, the invention as further described exemplarily with references to the enclosed figures. Therein, similar components are provided with same reference signs.

[0045] FIGS. 1-3 illustrate schematically a drilling system in different configurations.

[0046] FIG. 4 illustrates a cross section of a stabilizing system according to a preferred embodiment of the present invention.

[0047] FIG. 5 illustrates the stabilizing system of the embodiment illustrated in FIG. 4 in a different configuration.

[0048] FIG. 6 illustrates particular details of the stabilizing system of FIG. 4.

[0049] FIG. 7 illustrates particular details of the stabilizing system of FIG. 5.

[0050] FIGS. 4 and 5 illustrates a stabilizing system 100 according to an embodiment of the present invention. The stabilizing system 100 is thereby adapted to be connected to drill pipes at each end thereof via respective drill pipe linkages. In the configuration illustrated in FIG. 4, the stabilizing system 100 is in a state with increased transversal diameter, and decreased overall length. In the configuration illustrated in FIG. 5, in turn, the stabilizing system 100 is in an expanded state along the longitudinal axis, and with decreased transversal diameter. FIGS. 4 and 5 thereby illustrates a cross-sectional view of the stabilizing system 100. FIGS. 6 and 7 illustrate particular details of FIGS. 4 and 5, respectively.

[0051] The stabilizing system 100 comprises a hollow housing 110, in which a column 130 is arranged. The column 130 is linearly movable along the main longitudinal direction of the stabilizing system 100, relative to the housing 110. The column is adapted to transfer longitudinal drilling forces, for example to a downstream drive piston, as will be appreciated by the person skilled in the art.

[0052] The stabilizing system 100 further comprises three spacers 120, of which one is clearly visible in the cross section illustrated in FIG. 4. The spacers 120 are equally positioned around the stabilizing system 100. The spacers 120 are thereby positioned in respective openings provided on the housing 110. As the spacers 120 are positioned equally around the housing 110, they provide for an optimal centering of the stabilizer 100 within a bore hole, as will be appreciated by the skilled person. The spacers may have a width of about 5.8 cm, and a length of about 33.5 cm.

[0053] The spacers 120 are not directly connected to the housing 110, as apparent from the detailed views of FIGS. 6 and 7. Each spacer 120 is partially sandwiched between the housing 110 and the column 130, preventing the spacer 120 from accidentally falling out of the stabilizing system 100. As the spacer 120 is not directly fixed to the housing 110 and column 130, the spacer 120 can move relative to the housing 110 and the column 130.

[0054] Furthermore, a helical spring 140 is provided inside the housing 110, through which the column 130 extends. The spring 140 may have a length of 45 cm in its relaxed state. At maximum compression, the spring length may be of about 29 cm. The spring 140 is thereby provided such that spring forces of the spring 140 are parallel to the overall longitudinal axis of the stabilizing system 100. The spring 140 is thereby provided concentrically within the housing 110, and parallel to the longitudinal axis of the stabilizing system 100. One end of the spring 140 is in direct contact with a blocking surface 112 of the housing 110. The other end of the spring 140 engages a spring force transfer ring 141. The spring force transfer ring 141 is in turn in direct contact with the spacers 120, and encompasses the column 130. The spring force transfer ring 141 can be moved by the spring 140 along the longitudinal axis of the stabilizing system 100. Thereby, a movement of the spacers 120 can be evoked.

[0055] Furthermore, the column 130 comprises a thick section 131, which is arranged corresponding to respective recesses 121 of the spacers 120. In the configuration illustrated in FIGS. 4 and 6, the thick section 131 is not provided in the recesses 121 of the spacers 120, i.e. the thick section 131 is at least partially provided apart from the recess 121 of the spacer 120, thereby urging the spacer 120 to the fully expanded position. In the configuration illustrated in FIGS. 5 and 7, the thick section 131 of the column 130 is provided fully inside the recesses 121 of the spacers 120.

[0056] In the configuration illustrated in FIG. 4 (and FIG. 6), the transversal diameter of the stabilizing system 100 is expanded. In the configuration illustrated in FIG. 5 (and FIG. 7), the transversal diameter of the stabilizing system is decreased, contrary to the configuration illustrated in FIG. 4. As can be seen from FIG. 5, the column 130 is in a different longitudinal position with regard to the housing 110, and the thick sections 131 of the column are fully inside the recesses 121 of the spacers 120.

[0057] For changing the configuration of the stabilizing system 100 to increase in transversal diameter (i.e. from the configuration illustrated in FIGS. 5, 7 to the configuration illustrated in FIGS. 4, 6), an external load may be applied to the stabilizing system 100 along the longitudinal axis. Thereby, the housing 110 and the column 130 perform a relative moment to each other, whereby the thick section 131 of the column 130 now urges the spacers 120 into the expanded position, i.e. to protrude to the outside further from the openings provided on the housing 110. For this purpose, the thick section 131 as well as the recesses 121 of the spacers 120 feature respective tapered surfaces, which allow for the thick section 131 to slide along the spacers 120 and thereby push the spacers 120 to the outside.

[0058] At the same time, when applying the external load to the stabilizing system 100, the housing 110 directly interacts with one end of the spacer 120, thereby further promoting a transversal movement of the spacer. For this purpose, the respective end of the spacer 120 features a tapered section 123, and the housing 110 features a respective counter-tapered section which is in sliding contact with the tapered section 123 of the end of the spacer 120.

[0059] Upon movement of the spacers 120 from the retracted position (FIGS. 5, 7) to the expanded position (FIGS. 4, 6), the spacers 120 perform a transferal and longitudinal movement. Due to the longitudinal movement, the spacers 120 act on the spring force transfer ring 141, urging the spring force transfer ring 141 to move and the spring 140 to enter a compressed state. Hence, a spring force of e.g. 15 kN must be overcome in order to bring the spacers 120 into the expanded position.

[0060] When removing the stabilizing system 100 from a bore hole, the external load may be released. As the spring 140 acts on the spring force transfer ring 141, which in turn acts on the spacer 120 to move along the longitudinal direction of the stabilizing system 100, and due to the particular shape of the spacer 120 and the opening of the housing 110, the spacers 120 are urged to perform a movement with a transversal and longitudinal component, whereby the spacers 120 move to the retracted position. Thereby, a tapered section 122 on another end of the spacer 120 may facilitate the transversal movement of the spacer 120, in addition to the longitudinal movement evoked by the spring 140. The tapered section 122 of the spacer 120 may thereby slide along a respective counter-tapered section of the housing 110. All tapering conditions mentioned with regard to this embodiment may be of about 30 degrees, relative to the main axis of the stabilizing system 100.

[0061] Further, as the column 130 moves back the recesses 121 of the spacers 120 receive the thick section 131 of the column 130. In this state of decreased transversal diameter of the stabilizing system 100, only the force from the spring 140 keeps the spacers 120 in the retracted position. Any mud or liquid, present in the space inside the hollow housing 110, may exit the hollow space through the passages 111.

[0062] A spring force transfer ring retainer 142 is further provided, with can be inserted to block a movement of the spring force transfer ring 141, allowing for insertion or removal of spacers 120, for example during assembly or maintenance.

[0063] For removing the spacers 12 from the stabilizing system 100, the spring 140 may be brought into a compressed state, as illustrated in FIGS. 4 and 6. In this state, the spring force transfer ring retainer 142 may be introduced, to block a movement of the spring force transfer ring 141, and hence to block a relaxation of the spring 140. Then, the column 130 can be removed. Thereafter, the spacers 120 can be removed from the housing 110, by tilting the spacers 120 and extracting them. In the reversed order, the stabilizing system 100 may be assembled. Accordingly, if any spacer 120 becomes worn or eroded, the operator can change one or all of the spacers 120 instead of replacing the whole stabilizer. Further, due to the versatility of the stabilizing system 100, different sizes of spacers can be utilized within the same hollow housing 110. Thus, the stabilizing system 100 can be used for different bore hole diameters.

LIST OF REFERENCE SIGNS

[0064] 1 drill string [0065] 2 blade [0066] 3 drill bit [0067] 4 earth [0068] 5 bore hole [0069] 6 cavity [0070] 7 mud cake [0071] 100 stabilizing system [0072] 110 hollow housing [0073] 111 passage [0074] 112 blocking surface of housing [0075] 120 spacer [0076] 121 recess [0077] 122, 123 tapered section [0078] 130 column [0079] 131 thick section [0080] 140 spring [0081] 141 spring force transfer ring [0082] 142 spring force transfer ring retainer