Tubing leak detection for wellbore leak localization: A coupled flow-acoustic simulation approach

Abstract

Wellbore tubing leakage poses severe threats to the operational safety and resource efficiency of oil and gas exploitation, and existing research suffers from insufficient understanding of flow-acoustic coupling mechanisms, lack of systematic analysis of multi-factor interactions, and oversimplified acoustic propagation models. To address these limitations, this study develops a bidirectional coupled flow-acoustic model matching the actual structural characteristics of wellbores, and conducts systematic simulations under adiabatic conditions considering different pressure differences (1–3 MPa), orifice diameters (1–5 mm), and three orifice shapes. Flow field results reveal that the fluid passing through the leak orifice exhibits a distinct “pressure drop-velocity increase” characteristic, with both pressure difference and orifice diameter exerting significant regulatory effects on fluid density and velocity distributions. Acoustic field results demonstrate a “laminar-like” distribution pattern of acoustic waves in the tubing; an increase in pressure difference elevates the sound pressure level (SPL) of leakage noise without causing peak frequency shift, while an increase in orifice diameter not only raises the SPL but also induces a significant shift in the peak frequency of the acoustic spectrum. This study further derives quantitative correlation formulas between SPL and pressure difference/orifice diameter, as well as between spectral peak frequency and orifice diameter, realizing the inversion of leakage working conditions from acoustic signals. The research findings optimize the non-intrusive leakage detection technology for high temperature-high pressure (HTHP) and high-sulfur wells, and provide a novel theoretical and technical basis for accurate wellbore leak localization.