Slidable sleeve plunger
An improved plunger lift mechanism comprises an internal hollow body having bypass orifices that, when exposed, allow fluid to pass through during plunger descent in a downhole tube to the bottom of a production well. A slidable sleeve slides along the hollow body to close the orifices, causing the plunger to rise and carry accumulated fluid to the well surface. In addition, the present apparatus comprises surface interfaces between a slidable sleeve and a mandrel to minimize a probability of mandrel and sleeve separation during the plunger's ascent phase and a risk of plunger stall. By integrating a plunger lift having a slidable sleeve with closer limits between the slidable sleeve and an internal hollow body, and a wider plunger surface area, the present apparatus can minimize radial movement which can occur during plunger drop and when impact occurs.
1. A plunger for unloading formation fluids in a high flow hydrocarbon well, said apparatus comprising:
a mandrel comprising a top end, a bottom end, and a mandrel orifice through which fluid passes during plunger descent to the well bottom;
said mandrel further comprising fluid entry means locatable circumferentially about its bottom end to allow fluid to enter said mandrel orifice, and fluid egress means locatable circumferentially about its top end to allow fluid to exit said mandrel orifice;
wherein said mandrel is movable in an axial direction internally within a slidable sleeve to a closed position, whereby said fluid entry means are blocked to fluid entering said mandrel orifice, thereby allowing said plunger to ascend the well and carry loading fluid to the surface;
said mandrel being rotatable within said slidable sleeve: and
wherein a flange surface of said slidable sleeve contacts a flange surface of said mandrel to form at least one circumferential flange seat positioned within the sleeve to maintain said closed position during plunger ascent, said plunger being driven up by a pressure of gas present within the well.
2. The apparatus of claim 1 , wherein a vertical surface of said slidable sleeve adjoins a vertical surface of said mandrel to effect a partial seal between the sleeve and the mandrel, said partial seal positioned within said sleeve to maintain said closed position during plunger ascent.
3. The apparatus of claim 1 , wherein said fluid entry means are located distally from the bottom end of the mandrel, thereby causing said entry means to be fully positioned within said sleeve in said closed position during plunger ascent.
4. The apparatus of claim 1 , wherein a well top plunger strike can cause said at least one circumferential flange seat positioned within the sleeve to disengage, thereby allowing the slidable sleeve to slide to an open position, whereby said fluid entry means are unblocked to fluid entering said mandrel orifice, thereby allowing said plunger to descend against flow in the well.
5. The apparatus of claim 1 , wherein a well bottom plunger strike can cause said at least one circumferential flange seat positioned within the sleeve to engage, thereby allowing the slidable sleeve to slide to said closed position whereby said fluid entry means are blocked to fluid entering said mandrel orifice, thereby allowing said plunger to ascend in the well.
6. The apparatus of claim 1 , wherein the top end of said mandrel further comprises a fishing neck.
7. The apparatus of claim 1 , wherein said top end of said mandrel further comprises a removable top plug to provide a means of controlling the rate of fluid egress during plunger descent.
8. The apparatus of claim 7 , wherein a removal of said top plug can provide additional means for fluid to exit said mandrel, thereby causing the plunger to fall at an increased rate of speed.
9. The apparatus of claim 1 , wherein said fluid entry means further comprises apertures positioned radially at about 120° intervals from one another.
10. The apparatus of claim 1 , wherein said fluid egress means further comprises apertures positioned radially at about 120° intervals from one another.
11. The apparatus of claim 1 , wherein an outer diameter of said plunger is sufficiently large to enable an external surface of said plunger to maintain contact with a casing of said well, thereby minimizing radial movement of said plunger and allowing the plunger to exert an axial force in a true vertical direction when the plunger strikes the well bottom.
12. The apparatus of claim 1 , wherein a distance between an inner diameter of said slidable sleeve and an outer diameter of said mandrel is sufficiently small enough that radial movement of said plunger is minimized, thereby allowing the plunger to exert an axial force in a true vertical direction when the plunger strikes the well bottom.
13. A plunger for lifting formation fluids in a hydrocarbon well, said apparatus comprising:
a hollow body comprising at least one entry orifice positioned near a bottom end, said at least one entry orifice allowing fluid to enter said body and commence a plunger bypass during plunger descent in said well;
at least one exit orifice positioned at a top end of said hollow body to allow fluid egress from said body and complete the plunger bypass;
a slidable sleeve operating to close the at least one entry orifice, thereby causing the plunger to rise and carry accumulated fluid to the well surface;
wherein an attachment means is formed at an internal interface between said sleeve and said hollow body, said attachment means functioning to minimize sleeve separation during plunger ascent in said well.
14. The apparatus of claim 13 , wherein the attachment means further comprises a circumferential flange seat positioned within said sleeve, said flange seat formed when a flange surface of said slidable sleeve contacts a flange surface of said mandrel.
15. The apparatus of claim 13 , wherein the attachment means further comprises a partial seal positioned within said sleeve, said partial seal formed when a vertical surface of said sleeve adjoins a vertical surface of said mandrel.
16. The apparatus of claim 13 , wherein said at least one entry orifice is distal from the bottom end of the hollow body, thereby causing said at least one entry orifice to be fully positioned within said sleeve in a closed position during said plunger ascent.
17. The apparatus of claim 13 , wherein an outer diameter of said plunger is sufficiently large to enable an external surface of said plunger to maintain contact with a casing of said well, thereby minimizing radial movement of said plunger occurring during plunger drop and when impact occurs.
18. The apparatus of claim 13 , wherein a distance between an inner diameter of said slidable sleeve and an outer diameter of said mandrel is sufficiently small that radial movement of said plunger is minimized during plunger drop and when impact occurs.
19. A plunger for lifting fluids in a hydrocarbon well, said apparatus comprising:
a slidable sleeve to slide axially along a hollow body, said hollow body comprising a first and a second end;
said first end comprising at least one entry through which fluid may enter said hollow body;
said second end comprising at least one egress through which fluid may exit said hollow body;
wherein said slidable sleeve operates to close said at least one entry, thereby preventing fluid from entering and bypassing said hollow body, whereby said plunger rises due to a pressure of accumulated gas, carrying accumulated fluid upward;
wherein said at least one entry is distal from said first end, thereby causing said at least one entry to be fully positioned within said sleeve during a plunger closure;
wherein a flange of said slidable sleeve contacts a flange of said hollow body to form a circumferential flange seated within the sleeve, said circumferential flange sustaining said plunger closure during plunger ascent; and
wherein a vertical surface of said slidable sleeve adjoins a vertical surface of said mandrel to form a partial seal between the sleeve and the mandrel, said partial seal positioned within said sleeve to sustain the plunger closure.
20. A plunger for lifting fluids in a hydrocarbon well, said apparatus comprising:
a hollow body comprising at least one entry through which fluid may enter said hollow body and at least one egress through which fluid may exit said hollow body;
a slidable sleeve to slide axially along said hollow body, wherein said slidable sleeve operates to open said at least one entry, thereby allowing fluid to enter and commence bypass of said hollow body, whereby said plunger falls against flow to the well bottom due to gravity;
said hollow body being rotatable within said slidable sleeve;
wherein a distance between an inner diameter of said slidable sleeve and an outer diameter of said hollow body is sufficiently small to minimize radial movement of said plunger during plunger descent and when impact occurs; and
wherein an outer diameter of said plunger is sufficiently large to enable an external surface of said plunger to maintain contact with a casing of said well, thereby minimizing said radial movement of said plunger occurring during plunger descent and when impact occurs at the well bottom.