Annular isolators for expandable tubulars in wellbores

A system for forming an annular isolator between tubing and a borehole, comprising:

• a section of expandable tubing,
• two annular rings of elastomeric material carried on the outer surface of said tubing whereby, when said tubing is installed in a borehole and expanded, said rings at least partially block flow of fluids in an annulus between said tubing and the borehole wall,
• a compartment carried with said tubing,
• a flow path from said compartment to the space between said rings,
• an annular isolator forming material in said compartment, and
• means for driving said material from said compartment into said space between said rings,
• wherein:
• said compartment is formed between a sleeve carried within said tubing and the inner wall of said tubing, and
• said flow path is a port from said inner wall to an outer wall of said tubing.

A system for forming an annular isolator between expandable tubing and a borehole comprising:

• a section of expandable tubing,
• two annular rings of elastomeric material carried on the outer surface of said tubing, whereby, when said tubing is installed in a borehole and expanded, said rings at least partially block flow of fluids in an annulus between said tubing and the borehole wall,
• a compartment formed in said expandable tubing,
• an annular isolator forming material carried in said compartment,
• a flow path from said compartment to the outer surface of said tubing between the two annular rings of elastomeric material, and
• an expansion device for expanding said tubing and driving said material from said compartment through said flow path and outside said tubing,
• whereby upon expansion of said tubing in a borehole, said material flows into an annulus between said tubing and said borehole and forms an annular isolator between the two annular rings of elastomeric material.

A method for forming an annular isolator between tubing and a borehole comprising:

• forming a compartment in a section of expandable tubing,
• filling the compartment with an isolator forming material,
• attaching two annular rings of elastomeric material to the outer surface of said tubing, whereby, when said tubing is installed in a borehole and expanded, said rings at least partially block flow of fluids in an annulus between said tubing and the borehole wall,
• installing the tubing in a borehole,
• expanding the expandable tubing in the borehole, and
• driving the isolator forming material from said compartment into the annulus between said tubing and said borehole between the two annular rings.