Anti-extrusion device for downhole applications

An anti-extrusion ring for a packer assembly having a resilient sealing sleeve, the anti-extrusion ring comprising:

• first and second ring portions divided into a plurality of discrete arcuate segments for movement between a retracted position wherein each segment is in contact with adjacent segments, and an expanded position wherein gaps are formed between the segments, with at least one of the ring portions being adapted to face the sealing sleeve, the plurality of discrete arcuate segments comprising a first set of discrete arcuate segments that forms the first ring portion and a second set of discrete arcuate segments that forms the second ring portion, the first and second sets of arcuate segments being circumferentially offset, each arcuate segment of the first set comprises one of a guide pin and a slot and each arcuate segment of the second set comprises the other of the guide pin and the slot, the slot including an end stop, each guide pin extends into the elongate slot of a first offset segment such that movement of the first and second sets of arcuate segments toward the expanded position causes each guide pin to ride in its respective slot and contact the end stop to thereby arrest further movement of the segments toward the expanded position and control the size of each gap;
• wherein the first ring portion is circumferentially offset from the second ring portion such that at least one of the first and second ring portions extends across the gaps during movement of the segments toward the expanded position to thereby prevent extrusion of the sealing sleeve through the gaps.

A downhole packer assembly for use in a well bore, the downhole packer assembly comprising:

• an elongate mandrel adapted for positioning in the well bore;
• an expander adapted for sliding movement along the mandrel;
• a sealing sleeve disposed around the mandrel for engaging the well bore;
• and
• at least one anti-extrusion ring disposed between the expander and the sealing sleeve, the at least one anti-extrusion ring comprising:
• first and second ring portions divided into a plurality of discrete arcuate segments for movement between a retracted position wherein each segment is in contact with adjacent segments, and an expanded position wherein gaps are formed between the segments, with one of the ring portions contacting the sealing sleeve, an elongate slot associated with each of the segments, the elongate slot having an end stop;
• and
• a guide pin extending from each of the segments and into the elongate slot of another segment, such that movement of the segments toward the expanded position causes each guide pin to ride in its respective slot and contact the end stop to thereby arrest further movement of the segments toward the expanded position and control the size of each gap,
• wherein the first ring portion is circumferentially offset from the second ring portion such that at least one of the first and second ring portions extends across the gaps during movement of the segments toward the expanded position to thereby prevent extrusion of the sealing sleeve through the gaps.

A downhole packer assembly for use in a well bore, the downhole packer assembly comprising:

• an elongate mandrel adapted for positioning in the well bore;
• an expander adapted for sliding movement along the mandrel;
• a sealing sleeve disposed around the mandrel for engaging the well bore;
• and
• at least one anti-extrusion ring disposed between the expander and the sealing sleeve, the at least one anti-extrusion ring comprising:
• first and second ring portions divided into a plurality of discrete arcuate segments for movement between a retracted position wherein each segment is in contact with adjacent segments, and an expanded position wherein gaps are formed between the segments, with one of the ring portions contacting the sealing sleeve, the plurality of discrete arcuate segments comprises a first set of discrete arcuate segments that forms the first ring portion and a second set of discrete arcuate segments that forms the second ring portion, with the first and second sets of arcuate segments being circumferentially offset, each arcuate segment of the first set comprises one of a guide pin an a slot and each arcuate segment of the second set comprises the other of the guide pin and the slot, the slot including an end stop, and each guide pin extends into the elongate slot of a first offset segment, such that movement of the first and second sets of arcuate segments toward the expanded position causes each guide pin to ride in its respective slot and contact the end stop to thereby arrest further movement of the segments toward the expanded position and control the size of each gap,
• wherein the first ring portion is circumferentially offset from the second ring portion such that at least one of the first and second ring portions extends across the gaps during movement of the segments toward the expanded position to thereby prevent extrusion of the sealing sleeve through the gaps.