Abstract: A tubular downhole tool, representatively a sliding sleeve valve, coaxially supports within its interior an annular plug ball seat formed from a series of rigid, arcuate segments that circumferentially overlap one another in various representatively disclosed manners. The seat is expandable from a diametrically compressed orientation, toward which it is resiliently biased, to a diametrically expanded orientation by a plug ball pumped through the seat. Due to the circumferential segment-to-segment overlap, each segment is blocked by its two circumferentially adjacent segments from being axially separated from the overall seat assembly by operational pressure forces.

Abstract: A tubular downhole tool, representatively a sliding sleeve valve, coaxially supports within its interior an annular plug ball seat formed from a series of rigid, arcuate segments that circumferentially overlap one another in various representatively disclosed manners. The seat is expandable from a diametrically compressed orientation, toward which it is resiliently biased, to a diametrically expanded orientation by a plug ball pumped through the seat. Due to the circumferential segment-to-segment overlap, each segment is blocked by its two circumferentially adjacent segments from being axially separated from the overall seat assembly by operational pressure forces.

Abstract: A composition for a ball that disintegrates, dissolves, delaminates or otherwise experiences a significant degradation of its physical properties over time in the presence of hydrocarbons and formation heat. The ball may be used in methods and apparatus for hydraulically fracturing a subterranean zone in a wellbore.