Well tubing and tubing collar therefor

摘要

A well tubing includes an insert nipple for receiving a hold- down projection of an insert pump. The tubing includes a tubing collar threadingly interconnecting the upper end of the insert nipple with the next upper tubing section. The tubing collar includes a tapered inner bore which becomes progressively larger in cross-section in the upward direction to provide, around the outside of the hold-down projection, a space of gradually enlarged volume for receiving debris as the insert pump is lifted from the well tubing, thereby preventing the pump from becoming stuck.