Apparatus and method for penetrating cement surrounding a tubular

Abstract

Apparatus and method for penetrating cement (300) surrounding a tubular (200) cemented to a formation (400). The apparatus comprises a bore (10) through the tubular wall (200), and an intermediate fluid channel (102) in an insert (100) within the bore. An inner sleeve (120) may be disposed on the interior surface of the tubular wall (200). The inner sleeve (120) is movable between a closed position wherein fluid connection between the interior of the tubular and the bore is prevented, and an open position wherein fluid connection between the interior of the tubular and the bore is allowed. An abrasive and / or etching fluid is supplied through the channel (102) to remove cement and / or the insert (100) or piston assembly.

Description

[0001]The present invention relates to an apparatus and a method for penetrating cement surrounding a tubular.BACKGROUND[0002]A well extending through geological formations may be used for exploration and production of oil and / or gas, water production and / or in geothermal applications. Building a well typically involves drilling a borehole, inserting a steel casing into the wellbore and cementing the casing to the formation. The casing provides structural stability, for example by preventing weak rock or sand from caving into the borehole. When the cement is set, the next section is drilled through the formation in the extension of the existing casing. A liner is then hung off of the casing, and cemented to the formation. This process can be repeated until the well has reached the desired depth. A well may also comprise sections of uncased or open borehole, sections of casing or lining with sand screens, sections surrounded by gravel packs etc, as is well known in the art. However, ...

AI Technical Summary

Benefits of technology

The present invention relates to an apparatus for penetrating cement surrounding a tubular cemented to a formation, and a method of using the apparatus. The apparatus includes a bore through the tubular wall and an intermediate fluid channel disposed within an insert, which can be opened or closed to allow fluid communication between the interior of the tubular and the bore. The insert is a piston assembly movably disposed in the bore, and the method involves providing a fluid from the interior of the tubular through the fluid channel, which can remove cement and / or material from the insert. The method further includes the steps of forcing the hardened tip from the tubular wall into the cement to create a groove and / or cracks in the cement, and then providing the fluid to attack the cement. An inner sleeve may be used to facilitate the movement of the piston and allow fluid communication between the interior of the tubular and the bore. The invention allows for easier and more efficient drilling and wellbore construction.

Problems solved by technology

However, explosives require special handling according to strict safety rules, they may damage the formation and they have other disadvantages.

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