Coiled tubing vibration systems and methods

Abstract

Systems and methods for vibrating coiled tubing as it is moved in an earth wellbore.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention is directed to coiled-tubing systems and methods. [0003] 2. Description of Related Art [0004] Coiled tubing (“CT”) systems are used to perform drilling or intervention operations (“coiled tubing operations” or “CTO”) in wells. FIG. 1 illustrates a prior art CT system 100 used for CTO. The CT 102 is stored on the reel 101. The CT 102 is run into the well 106 below the surface 108 by bending around a guide arch 103, passing through an injector 104 and a well control stack 105. A bottom-hole assembly (BHA) 107 is often attached to the end of the CT. The surface 108 may be ground level or a rig floor when on land. Offshore it may be the surface of the water or the floor of a rig or platform, or the sea floor. [0005]FIG. 2 illustrates a similar prior art CTO system 200. The CT 102 is pulled off of the storage reel 101 by a small injector 209. It then loops upwards through the air in what is known as...

AI Technical Summary

Benefits of technology

[0016] By reducing friction with system(s) and / or method(s) according to the present invention more accurate determinations of weight-on-bit (“WOB”) measurements can be accomplished and desired WOB can be achieved. In certain prior art coiled tubing systems, buckling and helical lockup—both caused primarily by friction—limit the amount of WOB that can be applied. A phenomenon known as “stick-slip” can occur when static (or stationary) friction is higher that dynamic (or moving) friction. When the WOB becomes too low, the CT is moved in the well slowly at the surface. Initially the CT and a BHA which are lower in the well stick, and then suddenly surge forward or slip. This surge forward can increase the WOB too much and cause a drilling motor in the BHA to stall. In one aspect, the present invention discloses methods for controlling weight-on-bit on a bit of a wellbore drilling system drilling a wellbore, the wellbore drilling system using a bit on a coiled tubing string for drilling, the wellbore extending from an earth surface down into the earth, the method including reducing friction between the coiled tubing string and the wellbore by vibrating the coiled tubing string with a vibratory system, thereby promoting free movement of the coiled tubing string and of the bit through the wellbore during drilling, the vibratory system comprising a movement apparatus for moving the coiled tubing string in the wellbore, and vibration apparatus at the surface for vibrating the coiled tubing. Any system(s) and method(s) according to the present invention can be used to reduce friction between coiled tubing and a wellbore and, in certain particular aspects, to sufficiently vibrate stuck coiled tubing to free it within a wellbore.

Problems solved by technology

These vibrations may cause axial, lateral and / or rotational movement of the CT.

In certain prior art injector drive systems the hydraulic power often have a positive displacement hydraulic pump driving positive displacement hydraulic motors, and undesirable vibration is often inherent in such systems.

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