Optimum Oil Production With Intermittent Gas Lift

Intermittent gas lift is a cyclic operation where the wellbore fluids are produced in individual piston-type slugs. A design technique was developed for practical application in a South American oil field to produce fast depleting solution gas reservoirs. The design principle is based on controlled valve loading and is not affected by tubing size, thereby eliminating diminishing valve spacing with increased valve depth. An advantage of this type design is that it eliminates the possibility of not being able to work to bottom valve because of improper design. In most cases, especially in wells that have a low productive capacity, less gas lift valves can be utilized for unloading to the operating depth. Although proper gas lift design is the basis for any good intermittent gas lift operation, it is essential that the field personnel have a working knowledge of gas cost, usage and well operation. A simple trial and error testing procedure that can be used by field personnel to determine when a well is producing at a the maximum fluid rate for the minimum required lift gas usage, is a plot of producing rate versus the volume of gas injected per day. The point on the curve where the maximum fluid rate is attained with the least volume of gas injected should be the optimum intermittent gas lift operation. Therefore, optimum oil production by intermittent gas lift is a function of proper design and operation.