Catcher for dropped objects

1. A catcher for use on a work string in a wellbore, the catcher comprising:

a housing having an upper end attachable to a first tubular member of a work string, a lower end attachable to a second tubular member of the work string, a housing outer wall of fixed diameter, and a housing inner wall defining a longitudinal bore, the housing inner wall having a first taper; and

an insert disposed within the housing, the insert having: an upper end; a lower end; an insert inner wall defining a longitudinal bore extending from the upper end to the lower end; a seat for catching an object dropped or pumped into the housing; and an insert outer wall having a second taper engaging the first taper, and wherein the second taper engaged with the first taper forms a self-locking taper connection.

2. The catcher of claim 1 , wherein the housing is made from metal, and the insert is made from a non-metallic material.

3. The catcher of claim 1 , wherein:

the first taper includes a first taper portion and a second taper portion; the second taper portion is located between the first taper portion and the lower end of the housing; and

the first taper portion defines a first angle with respect to a longitudinal axis of the housing, the second taper portion defines a second angle with respect to the longitudinal axis of the housing, and the first angle is different from the second angle.

4. The catcher of claim 3 , wherein:

the second taper includes a first taper portion and a second taper portion;

the second taper portion of the second taper is located between the first taper portion of the second taper and the lower end of the insert; and

the first taper portion of the second taper defines a first angle with respect to a longitudinal axis of the insert, the second taper portion of the second taper defines a second angle with respect to the longitudinal axis of the insert, and the first angle is different from the second angle.

5. The catcher of claim 4 , wherein the first taper portion of the first taper is engaged with the first taper portion of the second taper to form the self-locking taper connection.

6. The catcher of claim 4 , wherein the second taper portion of the first taper is engaged with the second taper portion of the second taper to form the self-locking taper connection.

7. The catcher of claim 1 , wherein:

the inner wall of the housing further includes a first section oriented parallel to a longitudinal axis of the housing;

the outer wall of the insert further includes a second section oriented parallel to a longitudinal axis of the insert; and

the first section is juxtaposed with the second section.

8. The catcher of claim 7 , further comprising a sealing member at an interface between the first section and the second section.

9. A catcher for use in a work string in a wellbore, the catcher comprising:

a metallic housing having an outer wall of fixed diameter, an inner wall including a first taper, the inner wall defining a longitudinal bore extending through the housing; and

a non-metallic insert disposed within the longitudinal bore of the housing, the insert having an inner wall defining a longitudinal bore extending through the insert, and an outer wall including a second taper engaged with the first taper of the inner wall of the housing, wherein the second taper engaged with the first taper forms a self-locking taper connection.

10. The catcher of claim 9 , wherein:

the inner wall of the housing further includes a first section oriented parallel to a longitudinal axis of the housing;

the outer wall of the insert further includes a second section oriented parallel to a longitudinal axis of the insert; and

the first section is juxtaposed with the second section.

11. The catcher of claim 10 , further comprising a sealing member at an interface between the first section and the second section.

12. The catcher of claim 9 , wherein the self-locking taper connection inhibits relative rotation of the insert with respect to the housing about the longitudinal axis of the insert.

13. A method of using a catcher in a work string in a wellbore, the method comprising:

disintegrating at least a first portion of a non-metallic first insert of a first catcher, the first insert defining a longitudinal bore therethrough, the first insert positioned within a longitudinal bore of a metallic first housing of the first catcher while the first insert is held rotationally stationary with respect to the first housing by a self-locking taper connection formed between a tapered outer wall of the first insert and a cooperating tapered inner wall of the first housing, and wherein the self-locking taper connection inhibits relative rotation of the insert with respect to the housing about a longitudinal axis of the insert.

14. The method of claim 13 , wherein:

the disintegrating at least a first portion of the first insert comprises rotating a bit relative to the first insert; and

after the first portion has been disintegrated, conveying the bit through a residue second of the insert remaining in the first housing.

15. The method of claim 14 , wherein an obturating object is landed on a seat of the first insert, and the method further comprises disintegrating at least a portion of the obturating object.

16. The method of claim 13 , further comprising:

prior to disintegrating at least a portion of the first insert:

releasing an obturating object into the wellbore; and

conveying the obturating object through the longitudinal bore of the first insert by pumping a fluid into the wellbore;

wherein the first insert hinders passage of the obturating object through the longitudinal bore thereof, thereby providing a first characteristic pressure signal.

17. The method of claim 16 , further comprising:

conveying the obturating object through a longitudinal bore of a second insert of a second catcher;

wherein the second insert hinders passage of the obturating object through the longitudinal bore thereof, thereby providing a second characteristic pressure signal.