Abstract: An improved free piston assembly for use in combination with a plunger lift assembly is provided. The piston assembly includes a sleeve member, a retention sleeve, and a flow restriction member. The sleeve member has an inner surface defining an opening for the flow of formation fluids. The opening includes a first section and a second section. The retention sleeve is configured to be affixed to the first section of the opening. The flow restriction member is not latched to the sleeve member and is configured to have an interference fit with the retention sleeve. The interference fit provides a force that is sufficient to overcome the force of gravity on the flow restriction member when formation fluid forces acting on the flow restriction member are decreased or removed. The second section of the opening is configured to prevent the passage of the flow restriction member.

Abstract: The disclosure relates to an end fitting attachable to an end of a sucker rod. The end fitting includes a generally cylindrical body including a receptacle portion and a coupling portion along a longitudinal axis. The receptacle portion includes a receptacle extending inwardly from an open end surface of the body along the longitudinal axis for receiving the sucker rod end therein. The receptacle includes a plurality of wedge portions disposed therein and the coupling portion extends from a coupling end surface of the body opposite the open end surface. The wedge portions each have a peak portion, a first angled portion and a second angled portion. Each second angled portion has an angle with respect to the longitudinal axis wherein each angle of the second angled portions increases from the open end surface of the receptacle portion toward the coupling portion of the end fitting.

Abstract: The disclosure relates to an end fitting attachable to an end of a sucker rod. The end fitting includes a generally cylindrical body including a receptacle portion and a coupling portion along a longitudinal axis. The receptacle portion includes a receptacle extending inwardly from an open end surface of the body along the longitudinal axis for receiving the sucker rod end therein. The receptacle includes a plurality of wedge portions disposed therein and the coupling portion extends from a coupling end surface of the body opposite the open end surface. The wedge portions each have a peak portion, a first angled portion and a second angled portion. Each second angled portion has an angle with respect to the longitudinal axis wherein each angle of the second angled portions increases from the open end surface of the receptacle portion toward the coupling portion of the end fitting.