Cup tool, cup tool cup and method of using the cup tool

1. A cup tool for providing a high-pressure fluid-tight seal in an annular gap between a high-pressure mandrel and a cased wellbore, the cup tool comprising:

a cup tool tube having a threaded upper end for connection to the high-pressure mandrel, the cup tool tube having an outer surface over which an elastomeric cup is slidably mounted for reciprocal movement from an unset position for entry of the cup tool into the wellbore to a set position in which the annular gap is obstructed to contain fluid pressure below the elastomeric cup, the outer surface of the cup tool tube having a lower portion of a first diameter and an upper portion with a second, larger diameter and a tapered region between the upper portion and the lower portion; and

the elastomeric cup including a lip seal that rides against the outer surface of the cup tool tube, and seals against the tapered region of the cup tool tube to provide a high pressure seal between the cup tool tube and the elastomeric cup when the elastomeric cup is in the set position.

2. The cup tool as claimed in claim 1 further comprising a gauge ring located at a top end of the cup tool tube, the gauge ring inhibiting movement of the elastomeric cup to the set position during entry of the cup tool into the well bore.

3. The cup tool as claimed in claim 2 wherein the gauge ring comprises at least two upward annular steps of increasing diameter to facilitate extrusion of the elastomeric cup into the annular gap.

4. The cup tool as claimed in claim 3 wherein the upward annular steps are right angle steps in the gauge ring.

5. The cup tool as claimed in claim 1 further comprising a bullnose connected to a bottom of the cup tool tube for protecting the elastomeric cup and guiding the cup tool through a wellhead.

6. The cup tool as claimed in claim 1 wherein the elastomeric cup is made of polyurethane.

7. The cup tool as claimed in claim 6 wherein the elastomeric cup has a Durometer of 80-100.

8. A cup tool for providing a high-pressure fluid-tight seal in an annular gap between a high-pressure mandrel and a tubing suspended in a wellbore, the cup tool comprising:

a cup tool tube having a threaded upper end for connection to the high-pressure mandrel, the cup tool tube having an outer surface over which an elastomeric cup is slidably mounted for reciprocal movement from an unset position for entry of the cup tool into the wellbore to a set position in which the annular gap is obstructed to contain fluid pressure below the elastomeric cup, the outer surface of the cup tool tube having a lower portion of a first diameter and an upper portion with a second, larger diameter and a tapered region between the upper portion and the lower portion; and

the elastomeric cup including a lip seal that rides against the outer surface of the cup tool tube, and seals against the tapered region of the cup tool tube to provide a high pressure seal between the cup tool tube and the elastomeric cup when the elastomeric cup is in the set position.

9. The cup tool as claimed in claim 8 further comprising a gauge ring located at a top end of the cup tool tube, the gauge ring inhibiting movement of the elastomeric cup to the set position during entry of the cup tool into the well bore.

10. The cup tool as claimed in claim 9 wherein the gauge ring comprises at least two upward annular steps of increasing diameter to facilitate extrusion of the elastomeric cup into the annular gap.

11. The cup tool as claimed in claim 10 wherein the upward annular steps are right angle steps in the gauge ring.

12. The cup tool as claimed in claim 8 further comprising a bullnose connected to a bottom of the cup tool tube for protecting the elastomeric cup and guiding the cup tool through a wellhead.

13. The cup tool as claimed in claim 8 wherein the elastomeric cup is made of polyurethane.

14. The cup tool as claimed in claim 13 wherein the elastomeric cup has a Durometer of 80-100.

15. A method of sealing an annular gap between a high pressure mandrel and a cased wellbore or a tubing suspended in a cased wellbore in order to isolate pressure-sensitive wellhead components from high-pressure fracturing and stimulation operations in a well, the method comprising:

connecting a cup tool tube to a bottom end of the high-pressure mandrel, the cup tool tube having an outer surface over which an elastomeric cup is slidably mounted for reciprocal movement from an unset position for entry of the cup tool into the wellbore to a set position in which the annular gap is obstructed to contain fluid pressure below the elastomeric cup, the outer surface of the cup tool tube having a lower portion of a first diameter and an upper portion with a second, larger diameter and a tapered region between the upper portion and the lower portion;

sliding an elastomeric cup over the cup tool tube, the elastomeric cup including a lip seal that rides against the outer surface of the cup tool tube, and seals against the tapered region of the cup tool tube to provide a high pressure seal between the cup tool tube and the elastomeric cup when the elastomeric cup is in the set position;

connecting a bullnose to a bottom end of the cup tool tube;

inserting the cup tool into the cased wellbore; and

injecting high pressure fluids through the high pressure mandrel and into the wellbore to force the elastomeric cup upwardly against a shoulder at a top of the cup tool tube, thereby forcing the lip seal against the tapered region, while extruding an upper end of the elastomeric cup into the annular gap, thus providing a high-pressure fluid-tight seal.

16. The method as claimed in claim 15 further comprising installing a gauge ring at a top end of the cup tool tube prior to sliding the elastomeric cup over the cup tool tube.

17. The method as claimed in claim 16 further comprising prior to connecting the bullnose, connecting another cup tool tube to a bottom end of the cup tool tube connected to the high pressure mandrel and repeating the step of sliding, followed by the steps of connecting, inserting and injecting.