| 摘要 |
An accumulator 100 for downhole application comprises a housing 150 for inline connection to a hydraulic system, an elastomeric bladder 115 separating gas 165 and fluid 170 compartments and a two position anti-extrusion device 107 initially positioned e.g. at the surface to prevent the bladder from extruding into the hydraulic system but moves, e.g. at depth to allow fluid communication between the system and bladder which then absorbs system pressure fluctuations without the anti-extrusion device moving. The anti-extrusion device may be a two part piston 105, 106 coupled to the bladder and axially biased by bladder gas pre-charge to close an extrusion gap 185 between the piston and a mandrel 160 shoulder. The piston is lifted axially towards the bladder and held against a stop by downhole pressure. Alternatively a piston may move a mandrel to uncover ports or a sleeve may move to a fluid communication position. May improve power output when used with a fluid hammer. |
