PRESSURE PULSE ANALYSIS OF FLOW IN TUBING AND

PRESSURE PULSE ANALYSIS OF FLOW IN TUBING AND CASING OF GAS LIFT WELLS ”New Generation of Flow Measurements” J. S. Gudmundsson, I. Durgut Norwegian University of Science and Technology 7491 Trondheim J. Rønnevig, K. Korsan, H. K. Celius Markland AS 7462 Trondheim NTNU ASME/API Gas Lift Workshop February 5 -6, 2002, Houston

Contents of Paper Introduction Rapid Pressure Pulses Field Tests (offshore wells) Flow Condition Analysis Gas Lift Analysis Flow on tubing-side Flow on casing-side Conclusions NTNU

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Pressure Pulse Technology NTNU • • • Production Testing Flow Condition Analysis Wells and Flowlines Field Tested Offshore On-Demand Testing Quick-Acting Valve Pressure Transducers Patented World-Wide Licensed to Markland

A B Pressure LAB NTNU B B A A Time

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Pressure Pulse Production Testing No Calibration Needed Δp (Pa) = ρ u a a (m/s) = ΔL/ Δt NTNU G (kg/s. m 2) = ρ u w (kg/s) = G A w (kg/s) = Δp A/a

Pressure Pulse FLOW CONDITION ANALYSIS A quick-acting valve stops the flow. The wellbore pressure drop needed to overcome wall friction 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). NTNU

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Wellbore Flow Condition Analysis NTNU

Pressure Pulse Gas Lift Analysis • • NTNU Vertical well 3500 m deep Tubing ID 0. 1 m Gravity oil 32 API, gas 0. 85, water 1. 103 GOR 50 Sm 3/m 3, WC 50% WHP 50 bara Liquid production rate 400 Sm 3/d Gas injection rate 100 MSm 3/d Valves 1100 m, 1750 m and 2100 m depth

production gas injection 1100 meters 1750 meters 2100 meters NTNU 3500 meters

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gas injection 2100 meters 2600 meters (a) NTNU 3500 meters (b) 3500 meters (c)

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CONCLUSIONS ”New Generation Flow Measurements” • In pressure pulse flow condition analysis, pressure-distance log obtained from expert analysis of measured pressure-time log. • Simulations presented for detection and monitoring of deposits in pipes and wells, and to identify depth to bubble point in wellbore. • Simulations presented of pressure-distance logs (pressure surveys) obtained on tubing-side and casing-side. • Operating gas lift valves (1100, 1750 and 2100 m) identified and liquid level (2100, 2600 and 3500 m) determined. NTNU