API RP 19G5-2019 pdf download.Operation, Maintenance, Surveillance, and Troubleshooting of Gas-lift Installations.
3.6 Gas-lift Valve Problems Typical problems with the unloading and operating gas-lift valves and recommended practices that should be performed are as follows. a) Unloading valve problems (see 7.2). — Check the gas-lift performance of each well to detect heading or valve operating problems. — Size the unloading valves to provide for enough gas passage to facilitate transfer to the deeper valves during kickoff and unloading or, use downstream chokes in IPO unloading valves to minimize throttling, avoid over- injection, and minimize damage to the valve port and seat during the unloading process. — Follow the unloading procedures in Section 12 to work down to the desired operating valve and avoid valve damage during unloading operations. b) Operating valve problems (see 7.3). — Use an orifice rather than a gas-lift valve in high productivity index (PI) wells [more than 0.5 B/D/psi (0.012 m 3 /D/kPa)] to prevent throttling and permit a wider range of gas injection rates. — Use an IPO gas-lift valve in low PI wells to prevent over-injection and low casing gas pressure, which causes hydrate formation at chokes or excessive gas withdrawal from the distribution pipeline; use of a PPO valve in this case is not recommended. — Use a choke downstream of the orifice to protect the orifice and avoid over-injection. — Resize and re-install the operating valve/orifice if well conditions change enough to disturb effective operation. 3.7 Well Equipment Problems Typical problems with gas-lift well equipment such as tubulars, completion equipment, and wellheads and recommended practices include the following. a) Tubing/Casing annulus problems (see 8.2). — Use a casing scraper during workovers to clean debris from the casing wall. — Circulate fluid to ensure that the annulus is clean. — Hydrostatically test to gas-lift injection pressure to verify casing integrity. — Avoid attempting to lift two well completions in one casing annulus. c) Completion problems (see 8.4). — Run flowing bottomhole pressure (FBHP) and static bottomhole pressure (SBHP) surveys at least annually to assess and track well performance and reservoir productivity. — Stimulate a well if its productivity becomes impaired and a pressure buildup test indicates that skin can be the problem. — Minimize pressure surges and heading in a well that has sand producing reservoir rock or a sand control screen or gravel pack. d) Wellhead problems (see 8.5). — Minimize flow restrictions such as bends, choke bodies, etc. — Provide safe and easy access for wireline work. e) Wellhead monitoring and control problems (see 8.6). — Measure the wellhead production pressure on a consistent basis. — Consider continuous measurement of the well’s production rate using multiphase metering or production flow rate estimating technology. 3.8 Gathering System Problems Typical problems with gathering system equipment, including the flowlines and manifold, and recommended practices that should be performed are as follows. a) Flowline problems (see 9.2). — Keep the flowline clean and avoid restrictions. — Use appropriate treatments if needed to remove scale deposits, paraffin, etc. — Avoid using one flowline for more than one well; this is to minimize excessive backpressure and avoid complications in monitoring the production of each well.
3.9 Well Testing Problems Typical problems with well production rate testing equipment and recommended practices that should be performed are as follows. a) Well test scheduling problems (see 10.2). — Test each well often enough to detect changes in performance. — Test each well long enough to obtain accurate results. — Coordinate well testing with other activities such as pressure surveys. — Use automatic or semi-automatic well testing to improve testing accuracy and reduce testing labor. b) Test separation problems (see 10.3). — Purge time is required to thoroughly flush the previous well’s production from the system. — Maintain the test separator backpressure consistent with the production system pressure. — Check and calibrate the well test meters. c) Test measurement problems (see 10.4) make well testing a high priority so it receives the attention it deserves. 3.10 Production Handling Problems Typical problems with production handling equipment and recommended practices that should be performed are as follows. a) Oil handling problems (see 11.2): measure total oil produced from each set of wells for comparison with estimates and for allocation and troubleshooting purposes. b) Water handling problems (see 11.3): measure or estimate total water production from each set of wells for comparisons and for allocation and troubleshooting purposes. c) Gas handling problems (see 11.4): measure gas production from each set of wells for comparisons and for allocation and troubleshooting purposes.