Presentation on theme: "PRESSURE PULSE ANALYSIS OF GAS LIFT WELLS"— Presentation transcript:
1 PRESSURE PULSE ANALYSIS OF GAS LIFT WELLS J.S. Gudmundsson, I. DurgutNorwegian University of Science and Technology7491 TrondheimJ. Rønnevig, K. Korsan, H.K. CeliusMarkland AS7462 Trondheim2001 Fall ASME/API Gas Lift WorkshopNovember 12-13, 2001, Aberdeen
2 Contents of Paper Introduction Pressure Pulse Generation Mass Flow RateLine PackingMultiphase MixturesOperational IssuesWells and PipelinesLimited-Installation TestGas Lift AnalysisConcluding Remarks
6 Pressure Pulse Mass Rate No Calibration Needed Δp (Pa) = ρ u aa (m/s) = ΔL/ ΔtG (kg/s.m2) = ρ uw (kg/s) = G Aw (kg/s) = Δp A/a
7 Pressure Pulse FLOW CONDITION ANALYSIS A quick-acting valve stops the flow. The wellbore pressure drop needed to overcome wall friction during production, becomes available as static pressure at wellhead. This change in pressure propagates continuously at the speed of sound back to the wellhead. The resulting pressure-time log can be used in flow condition analysis. In-house rapid pressure transient and speed of sound models and commercial wellbore flow model used (convert to pressure-distance log).
9 Pressure Pulse Flow Condition Analysis Oil Producer Example 2476935108Reflections:1 = diameter change at 382 m2 = diameter change above SCSSV3 = diameter change below SCSSV4,5,6 = secondary reflections7 = Bubble point (2300 m)8 = secondary reflection from bubble point9 = diameter reduction before inflow zone10 = bottom hole1
10 Pressure Pulse Limited-Installation Test Offshore Well A Measured depth 4440 m, vertical depth 2270 mTubing ID reduced from 4.89” to 3.55” at 650 m depthOil gravity 35 API, gas gravity 0.89GOR 24.8 Sm3/m3, produced GOR 635 Sm3/m3Liquid production rate 1167 Sm3/day, WC 66.8%WHP 67 bar, BHP 234 barWHT 76 C, BHT 100 CVoid fraction at wellhead 0.63
13 Pressure Pulse Gas Lift Analysis Well B Vertical well 3500 m deepTubing ID 0.1 mGravity oil 32 API, gas 0.85, water 1.103GOR 50 Sm3/m3, WC 50%WHP 50 baraLiquid production rate 400 Sm3/dGas injection rate 100 MSm3/dValves 1100 m, 1750 m and 2100 m depth
17 Pressure Pulse Analysis of Gas Lift Wells CONCLUDING REMARKS Pressure pulse technology used for gas-liquid mass rate and wellbore flow condition analysis. On-demand testing.Technology is flexible, robust and gives highly-repeatable results. Limited and extensive-installations tested offshore.Location of active gas lift valve simulated for typical well using models of rapid transients, sound speed and wellbore flow models.Pressure pulse technology can be used for a range of applications, including gas lift optimisation (allocation of injection gas).