Method of sealing wells by squeezing sealant

Abstract

A method for sealing a well includes: placing an obstruction in a bore of an inner tubular string disposed in a wellbore; forming an opening through a wall of the inner tubular string above the obstruction; mixing a resin and a hardener to form a sealant; and squeezing the sealant into the bore, through the opening, and into an annulus formed between the inner tubular string and an outer tubular string, thereby repairing a cement sheath present in the annulus.

Description

BACKGROUND OF THE DISCLOSURE[0001]Field of the Disclosure[0002]The present disclosure generally relates to a method of sealing wells by squeezing a sealant into an annulus thereof.[0003]Description of the Related Art[0004]The hard impermeable sheath deposited in the annular space in a well by primary cementing is subjected to a number of stresses during the lifetime of the well. The pressure inside the casing can increase or decrease as the fluid filling it changes or as additional pressure is applied to the well, such as when the drilling fluid is replaced by a completion fluid or by a fluid used in a stimulation operation. A change of temperature also creates stress in the cement sheath, at least during the transition period before the temperatures of the steel and the cement come into equilibrium. As a result of pressure and temperature changes, the integrity of the cement sheath can be compromised. Thus, it can become necessary to repair the primary cement sheath, such as during...

AI Technical Summary

Benefits of technology

The present disclosure describes a method for sealing wells by squeezing sealant into the space between the inner and outer tubular strings. The method involves placing an obstruction in the inner string, forming an opening in the wall of the inner string above the obstruction, mixing resin and hardener to create the sealant, and then squeezing the sealant into the space between the inner and outer strings through the opening. This method can be used to repair any cement sheath that may be present in the space between the strings. The technical effect of this method is to provide a reliable and effective means for sealing wells.

Problems solved by technology

As a result of pressure and temperature changes, the integrity of the cement sheath can be compromised.

The use of conventional Portland cement for squeeze cementing has limitations, for instance, if the primary cement sheath is leaking fluid, such as gas, through micro-channels, squeeze cementing is not feasible, even using micro-fine ground Portland cement.

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