2D bottom-cable operations
To acquire data in extremely shallow water areas, SeaRay®-100 or XZone® Marsh Line recording systems are used. These systems enable to obtain the signal which is similar in both offshore and onshore environment due to the displacement transducers (geophones and accelerometers). Streamers are manually deployed on land, using off-road vehicles.
According to this technology, specially developed sources are used.
To generate elastic waves in transition zone our engineers designed a special air-gun (analogous to downhole source) which is a vertical cluster of sources (as shown in the picture) mounted to the drill rod and supplied with a screw auger at the bottom. Compressed air and drilling liquid supply as well as sources running are controlled via special line/canal in the drill rod.
3-4m subsea source depth (the length of one drill rod) is optimal for 120-150 frequency range. The source is mounted on the off-road vehicle chassis, as depicted in the picture, which allows to easily move around the most unapproachable areas of the land and transition zones. The air-gun is currently being tested and improved.
This energy source and recording system will make it possible to tie-in both offshore and land-based acquisition geometry. |
