Apparatus and method

Abstract

The invention relates to tubing handling apparatus for injecting tubing into and recovering the tubing from a wellbore. In an embodiment, the apparatus includes a storage reel of coiled tubing, a first injector head and a second injector head for injecting the tubing from the reel into the wellbore. The second injector head may be located between the storage reel and the wellbore, and the first injector head may be disposed between the storage reel and the second injector head. The first and second injector heads can control bending of a length of the coiled tubing from the reel which is passed between the first and second injector heads.

Description

FIELD OF THE INVENTION[0001]The present invention relates to tubing handling apparatus and associated methods. In addition, the invention relates to a gooseneck device for a tubing injector head.BACKGROUND TO THE INVENTION[0002]Tubing is commonly used in oil, gas and water wells, to convey fluids between the well and the surface. Coiled tubing is normally supplied in continuous lengths wound onto a reel, and is unwound from the reel as it is injected into the wellbore. Normally the injection of the coiled tubing into the wellbore is controlled by an injector head. In offshore wells, the tubing is injected into the well through a riser, which is secured to the wellhead on the seabed, and which forms a rigid and stationary conduit between the platform or drill ship at the surface, and the wellhead on the seabed. When the platform is subject to heave, the platform and derrick therefore move relative to the injector head attached to the stationary riser. In order to accommodate this rel...

AI Technical Summary

Benefits of technology

[0013]Said length of tubing passed between the first and second injector heads may, at least in part, form a lazy loop of tubing therebetween. Thus, the length of tubing passed between the first and second injector heads may have a degree of slack or sag between the injector heads due to gravity. This may help to provide stability.

[0015]The second injector head may be provided with a gooseneck device for facilitating introduction of the tubing into a central injection point of the injector head. The gooseneck device provides typically a curved or arched track bed for receiving a section of tubing and / or for guiding the tubing toward the injection point. Thus, the gooseneck device may be adapted to help control bending of the length of tubing. The gooseneck device and / or track bed may have a first portion and a second portion having different radii of curvature. In particular, a first portion of the track bed closer to the injection point than the second portion may have a smaller radius than the second portion of the track bed. The track bed curvature may be selected so that when tubing is being guided by the second portion of the track bed, the tubing is kept within the elastic bend radius limits of the tubing by the second portion of the track bed. This may help to restrict plastic deformation of the tubing. The track bed may be adapted to provide contact with the length of tubing passed over the track bed / gooseneck along its length so as to support the tubing and control its bend radius from the point at which the tubing is brought onto the gooseneck to the injection point. The gooseneck may include clamps to maintain contact between the track bed and the tubing.

[0017]Controlling the rate of injection of tubing through the second injector head on the derrick to be the same as the rate of tubing drawn off the reel means that the length of the tubing between the main derrick injector head and the reel is maintained substantially constant, and the bend radius can thus be maintained within acceptable limits, within the elastic bend radius of the tubing, so that plastic deformation of the tubing is avoided or mitigated. Also, the reel does not need to cycle to maintain the bend radius of the tubing within the limits of elastic deformation, which reduces the fatigue on the tubing.

Problems solved by technology

This has drawbacks in relation to the deck space required.

However, this arrangement can be problematic since the lazy loop of tubing may tend to bend repeatedly due to the cyclical relative motion between the platform and the injector head.

In those areas, the tubing may tend to bend or sag about its fixed support points.

In addition, the tubing may deform plastically when it is bent and repeated plastic bending can lead to fatigue and damage to the tubing and significantly shorten its lifespan.

Images