Ingeniero

Gas Lift
Types of Gas Lift Systems Continuous – Mainly used for the production of oil. Intermittent – Used for the removal of slugs fluid in oil and gas wells. Commonly used to de water gas wells.Open systems, The tubing and annulus are open to each other, no packer is used. Semi closed system, The tubing and annulus are connected only through the gas lift valves, packer is used. Closed system,A standing valve is set in the tubing, closing off flow from the tubing to the formation. Gas Injection Rates There are four significant gas injection rates 1) Injection rate of no flow – the amountof gas that is injected is insufficient to lift the fluid. 2) Injection rate of maximum efficiency – the minimum volume of gas is required to lift a barrel of fluid. 3) Injection rate of maximum flow– the maximum production is achieved. 4) Injection rate of no flow due to excess gas – the friction of the gas prevents fluid from entering the tubing.

Limitations of Continuous and Intermittent gasLift Liquid output for continuous is 200 to 20,000 bbls per day and less than 500 bbls per day for intermittent. A Productivity Index of > .45 bbls/day/psi for continuous and < .45 for intermittentlift. The intermittent lift is the only method possible for good producers with very low bottom hole pressures. Injection GLR of 50 to 250 ft3 /bbl for 1000 ft of lift for continuous and forintermittent it is 250 to 300 ft3/bbl for 1000 ft of lift.

Well Characteristics that effect behavior of producing well 1) Bottom hole pressure 2) Productivity Index 3) Formation gas oil ratio 4) Water cut5) Depth 6) Size of the tubulars 7) Type of producing mechanisms Equipment Characteristics 1) Back pressure held on the formation 2) Gas consumption

Four Categories of Wells and systems High PI andHigh BHP High PI and Low BHP Low PI and High BHP Low PI and Low BHP

cont. open and semi open cont. int. closed cont. int. semi and closed int. closed

Gas Lift Valves

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