Patent ID: 9476264
Filing Date: 2016-10-25
CPC Classification: E21B

Claim Text:
1. A coiled tubing lift frame assembly comprising: a frame having an upper frame section adapted for attachment to a top drive system and a lower frame section adapted to interface with a flowhead assembly; a pair of hydraulic cylinders spaced apart from one another, the hydraulic cylinders having a respective cylinder barrel and a piston rod translatable therein, a free end of the piston rods being fixed to the upper frame section; a single piston accumulator, the single piston accumulator disposed adjacent to a first of the hydraulic cylinders and in fluid communication therewith via a hydraulic fluid line; an air accumulator disposed adjacent to a second of the hydraulic cylinders and in fluid communication with the piston accumulator via a pneumatic fluid line; wherein the single piston accumulator and the air accumulator are both supported by the upper frame and section and wherein the piston rods in the cylinders remain stationary at a mid-stroke position when an axial load on the riser is within a predetermined range of operating loads, the piston rods extending on an upheave of the floating vessel when the axial load exceeds a predetermined upper operating load threshold and retracting on a down heave of the floating vessel when the axial load falls below a predetermined lower operating load threshold.