| 摘要 |
<p>Retractable ball seats (20) having a housing (12), a seat, and a plug such as a ball (30) are disclosed. The seat has a retracted position that prohibits the ball from passing through the passageway (25) and an expanded position that permits the ball to pass through the passageway. A time delay material, such as a dissolvable material (40), maintains the seat in the retracted position. The time delay material disintegrates, degrades, or dissolves withi a known period of time such that the retractable ball seat can be placed in a desired location in the wellbore and the ball will be released through the passageway within a known period of time.</p> |
