Hybrid Gas-Lifting Method Optimizes High-GOR Production
The authors describe a hybrid gas-lift/rod-pump completion designed to reduce workover rig cost and production deferment and increase production efficiency in high-gas/oil-ratio environments in marginal fields.
The casing gas-pressure-operated rod-lift (CGPORL) system described in the complete paper consists of a sucker rod, pump, gas-lift valves, downhole gas anchor, and tubing string. The completion was invented to save workover rig cost, reduce production deferments, and increase production efficiency in high-gas/oil-ratio (GOR) environments in marginal fields.
CGPORL System Description
The hybrid-lift system includes gas-lift and rod‑lift modes, allowing operators to switch between two modes of artificial lift without costly workovers (Fig. 1 above). The key factor is the ability to isolate or communicate between the tubing and the annulus without pulling the tubing string out of the hole. Gas lift requires that the annulus should isolate tubing in order to inject gas through valves installed inside pocket mandrels, whereas rod pumps need communication between the tubing and annulus for passage of liberated free gas.
The gas-lift valve opens once annulus pressure develops over the valve-closing pressure.