Advanced stabilizing system for deep drilling

Abstract

The present invention relates to a stabilizing system (100) adapted to be used in a deep drilling system. The stabilizing system (100) comprises a longitudinal housing (110) and a spring (140) preferably a helical spring, arranged inside the housing (110). Thereby, the stabilizing system (100) is contracted and the spring (140) is compressed along the longitudinal axis of the stabilizing system (100) when an external load is applied in longitudinal direction onto the stabilizing system (100). The transversal diameter of the stabilizing system (100) increases when the stabilizing system (100) is contracted. Further, the transversal diameter of the stabilizing system (100) decreases when the stabilizing system (100) expands along the longitudinal axis.

Description

1. FIELD OF THE INVENTION[0001]The present invention relates to a deep drilling system, and in particular to a stabilizing system to be used in such a deep drilling system, and a method for drilling a hole utilizing such a deep drilling system.2. TECHNICAL BACKGROUND[0002]In a deep drilling system, a drill bit is typically connected via several drill pipes, forming a drill string, to a drilling motor. Such a setup is also generally illustrated in FIG. 1. The drilling motor, provided on the earth's surface, applies drilling forces (the longitudinal and rotational forces as illustrated by arrows in FIG. 1) onto the drill string 1 such that the drill bit 3 advances further into the ground 4, thereby creating a bore hole 5. Since bore holes can reach depths of up to several kilometers, it is desired that the drill string 1 is centered in the bore hole. Particularly, the sections close to the drill bit are centered such that the drill bit 3 advances in a defined direction into the ground...

AI Technical Summary

Benefits of technology

[0015]Thus, by using the external load in combination with the provision of the spring, it is possible to change the transversal diameter of the stabilizing system in a reliable manner, allowing for weakening or even breaking away at least parts of a mud cake formed around the stabilizing system when retracting it from the borehole. This allows for an unhindered and reliable operation of the drilling system, and particularly for easier and faster POOH and / or RIH operation. By means of the external load, the transversal diameter can be easily increased, allowing for a stabilizing function of the stabilizing system, and the external load can easily be applied by means of drilling forces, which are always available during drilling. The spring, in turn, allows for reliably decreasing the transversal diameter of the stabilizing system, so that eventually the drill string can be removed from the borehole in a smooth manner. As the spring may directly act on the stabilizing system to urge it to expand along the longitudinal direction, thereby restoring the extended state of the stabilizing system, the transversal diameter of the stabilizing system can be eventually decreased with reduced risk of jamming. By decreasing the transversal diameter in this manner, a mud cake formed around the stabilizing system can be reliably broken loose. By alternately increasing and decreasing the transversal diameter of the stabilizing system, it is possible to facilitate losing of mud cakes.

[0041]Hence, the present invention allows for providing stabilization of the drill pipes and drill bit during drilling operation and RIH operation. Furthermore, the present invention allows for an efficient handling or losing off mud cakes formed around the stabilizing system during RIH and POOH operations, in a particularly reliable manner.

Problems solved by technology

This balling can create problems, in particular during pulling-out-of-hole (POOH) and / or running-in-hole (RIH) operations.

For example, as illustrated in FIG. 3, when trying to retrieve the drill string out of the hole (POOH), problems arise: The accumulated mud cake 7 can cause a severe drag, and even jam the movement of the drill string.

Accordingly, POOH operations can take much longer due to balling, or in the worst case, the drill string cannot be removed from the hole at all and has to be cut off.

However, these techniques are either expensive in cost, suited for one-time use only, or are ineffective in solving the issue.

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