Offset valve system for downhole drillable equipment

Abstract

Float equipment is constructed to have the check valve in an offset and / or skewed position with respect to the centerline of the tubular housing that is part of a string. The design is applicable to poppet type check valves as well as flapper type valves that are actuated with a flow tube. The off center and / or skewed position of the valve components allows the cutting structure on a drill bit, rather than the nozzle area on the bit bottom to make intimate contact with the valve components to accelerate the milling one of the assembly and the making of additional hole beyond the recently cemented string.

Description

FIELD OF THE INVENTION [0001] The field of this invention is downhole equipment destined to be milled out after use and more particularly the positioning of the movable components within a surrounding tubular to speed up milling and even more specifically in a cementing application to obtain improved cement distribution while minimizing drilling fluid entrainment which can adversely affect the quality of the cement seal in the surrounding annulus. BACKGROUND OF THE INVENTION [0002] Float Equipment or an Auto-fill Collar is normally run at the bottom of a casing or tubing string to halt cement displacement. The short tubular section between the shoe and float collar is called the shoe track and is provided as a buffer within the casing to retain contamination that may build up ahead of the displacement plugs. The length of the shoe track is adjusted accommodating to well conditions. [0003] The float shoe can prevent reverse flow, or U-tubing, of cement slurry from the annulus into th...

AI Technical Summary

Benefits of technology

[0013] Float equipment is constructed to have the check valve in an offset and / or skewed position with respect to the centerline of the tubular housing that is part of a string. The design is applicable to poppet type check valves as well as flapper type valves that are actuated with a flow tube. The off center and / or skewed position of the valve components allows the cutting structure on a drill bit, rather than the nozzle area on the bit bottom to make intimate contact with the valve components to accelerate the milling out of the assembly and the making of additional hole beyond the recently cemented string.

Problems solved by technology

These valve mechanisms are normally placed in the center of the well and can create great problems when they are milled or drilled up at a later stage to deepen the wellbore.

Also, since the valve mechanism is in the center of the borehole, it makes it difficult to prevent the valve mechanisms from spinning.

Either option is not ideal.

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