Fluid Density Acoustic Tool

General Description

The Fluid Density Acoustic Tool is a production-logging sensor designed to determine borehole fluid density based on acoustic-velocity principle. It is deployed in multi-sensor PLT assemblies to characterise multiphase fluids (oil, water, gas) inside casing or tubing.

Instead of radioactive gamma-density devices, this tool measures the speed of sound travelling through wellbore  fluid. Acoustic wave velocity varies significantly among oil, water and gas phases. The tool converts acoustic propagation speed into in-situ fluid density output. Combined with flowmeter, water-holdup and P-T data, it helps discriminate phase fractions and diagnose well flow behaviour. It avoids radioactive source handling, bringing operational safety benefits for field crews.

Working Principle

Ultrasonic transmitters emit acoustic pulses across the fluid measurement gap. Receivers capture the travelling signals. The tool calculates acoustic transit time to derive sound velocity of the mixed borehole fluid. Gas drastically reduces acoustic velocity; water yields high sound velocity, while oil gives intermediate values. On-board electronics convert velocity measurements into apparent fluid density. Under known pressure-temperature conditions, phase fractions can be further interpreted.

Key Features

◆  Non-radioactive acoustic density measurement; no radioactive source for improved operational safety.

◆ Distinguish oil-water-gas multiphase flow in cased-hole environments.

◆ Compact diameter for integration within standard PLT tool strings.

◆ Compatible with real-time surface readout and memory-mode logging.

◆ Work for vertical, deviated and horizontal wells, applicable for producers and injectors.

◆ Complementary dataset for holdup, flow rate and pressure-temperature measurements.

Typical Applications

    ◆ Estimate apparent fluid density for multiphase flow identification

    ◆ Detect gas presence and gas-liquid fraction variation along wellbore 

    ◆ Assist phase-fraction interpretation together with water-holdup data

    ◆ Diagnose inflow of different fluid zones in production profile logging 

    ◆ Monitor fluid density changes caused by water breakthrough or gas coning

    ◆ Safe alternative to radioisotope density tools for well-diagnosis surveys

Typical Technical Specifications