Using A Transverse Marine Gradiometer (TVG) as submarine pipeline location tool
- INTRODUCTION
- THE METHOD
- SURVEY
- DEPTH ESTIMATIONS
IV. DEPTH ESTIMATIONS
I. INTRODUCTION
- Conventional sonar method is not successful.
- Most pipelines are made of steel, producing a magnetic field.
- Two Marine Magnetometers are used in transverse mode with 1.5 m separation.
- In the navigation channel, the TVG elevation above the seafloor was much higher than that in the shoal area.
- The overall estimated burial depth along the route mimics the bathymetry profile, showing 3-4 m burial depth in the shoal and 1-2 m depth in the channel.
- The TVG altitude does not correlate with the sea bottom profile, while the pipe burial depth does.
II. THE METHOD
Quasi-Analytic Signal (QAS)
Conclusion: 2D formula will work best in areas where the field has a minimal transverse gradient (both left and right magnetometer record similar field strengths).
III. SURVEY
survey area:
- a narrow deep channel in the North
- a large shoal in the middle
- a wide and deep navigation channel in the South