PLUNGER FOR LIFITING FLUIDS WITHIN A TUBING STRING

摘要

There is disclosed a rotary-pad gas lift plunger. In an embodiment, the pads rotate around the mandrel. This rotation movement results from two features. The first one is the assembly of the mandrel and the pad retaining rings. The second one is the shape of the wearing pad. The rotation movement results from the plunger travel up and down within the tubing. Rotation with uniform wearing helps to maintain the sealing effect between the wearing pads and the inside of the tubing. This uniform wearing on the surface of pads improves efficiency to displace oil and water from oil and gas wells. The uniform wearing also causes a significant increase in the service life of the plunger. Because of the rotation movement, this gas lift plunger can operate in deviated wells where a typical gas lift plunger is restricted.

主权项

1. A plunger for lifting fluids within a tubing string of a hydrocarbon well, comprising:
an elongated mandrel having a mandrel axis and a circumferential surface;at least 2 arcuate pads having each a pad upper end and a pad lower end and disposed circumferentially around the mandrel to form a pad set, each arcuate pad having a wear surface cooperating to form a substantially contiguous cylindrical seal against an inner surface of the tubing string;
at least one spring disposed between the mandrel and the arcuate pad for biasing the arcuate pad outwardly radially such that the wear surfaces are moveably in contact with the inner surface of the tubing string; at least one circular guide disposed on the mandrel and each engaging a complementary receptacle of the arcuate pad for substantially restricting the motion of the arcuate pad to be circumferential around the mandrel axis;an annular retainer disposed around the mandrel and positioned to enclose one of the pad upper end, the pad lower end, the pad upper end of one pad set and the pad lower end of another pad set, the annular retainer limiting outward radial movement of the arcuate pad; and
wherein the at least one circular guide, the complementary receptacles, the springs, and the annular retainers cooperate to allow rotation of the arcuate pads about the mandrel axis while radially biasing the arcuate pads against the inner surface of the tubing string, thereby lifting fluids within the tubing string.