Abstract: A well tool has an elongate, metal outer tubing and an elongate, metal inner tubing received in the outer tubing to move axially with respect to the outer tubing. A metal annular seal assembly is provided between the outer and inner tubings residing in a seal chamber of the outer or inner tubing. The seal assembly has a center ring, a chevron seal ring on each side of the center ring and an end ring at each axial end of the seal assembly. The seal chamber is tight to the seal assembly.

Abstract: A rodless pump is disclosed which is connected to a pressure source via a conduit. In a common oilfield application the pump would be connected to the bottom of a tubing string within the reservoir fluid to be produced. A pressure source such as a hydraulic pump would be connected at the surface to the tubing string so as to selectively apply pressure via fluid in the conduit to the pump, raising the plunger assembly in the pump drawing reservoir fluid into the pump. When pressure via the surface pressure source is released, a gas source in the pump urges the plunger assembly downward in the pump urging the reservoir fluid in the pump into the tubing and to the surface. Preferably, the pump includes dampening mechanisms at both the top and bottom of the plungers stroke so as to reduce metal to metal impact within the pump. This dampening mechanism may include but is not limited to elastomer barriers, springs, and other dampening mechanisms such as discussed further below.