| 摘要 |
<p>A flow control device / sleeve valve for controlling the flow of fluid into a production tubing comprises an outer 13 and an inner sleeve 15 defining an annular chamber 20, and apertures 14 are provided on the outer sleeve 13, and apertures 16, 24 are provided on the inner sleeve 15. Seals 17, 18 and 19 are provided for isolating the apertures 14, 16 and 24. The seal 18 is seated on an annular insert 21 which forms a small annular passage 22 with the inner sleeve 15, and grooves 23 are also provided on the inner sleeve 15. Together the grooves 23 and the small annular passage 22 allows a small rate of fluid to bypass the seal 18 and enter the apertures 16, 24, thus reducing fluid pressure acting on the seal 18, and reducing erosion of the seal 18 and the apertures 16, 24. The apertures 16, 24 are arranged so that the rate of fluid flow has a predetermined relationship with the position of the sleeves 13, 15, so that the fluid pressure is balanced on both sides of the seal 18 prior to the opening of the flow control device / sleeve valve, thus reducing the problem of extrusion of the seal 18.</p> |
