GEOREC- Vertical Seismic Profile tool
Description
VSP (Vertical Seismic Profile) is the main link between time-based surface seismic imaging and depth/based well logs. It provides a high-resolution image of the structure in the vicinity of the instrumented well. One or several seismic sources on the surface are fired and recorded by the downhole receivers (GEOREC) positioned at different depth levels. The downhole receivers allow recording in lower noise conditions as well as recording direct arrivals and recording higher frequencies (->higher resolution) than the equivalent surface tools. GEOREC is a downhole digital receiver designed for seismic acquisition in HP & HT conditions. Each GEOREC single level includes 3 fixed or gimballed geophones. Pressure and temperature gauges, are optionally provided. Each downhole GEOREC level is provided with its own power supply and telemetry. Up to 48 GEOREC levels can be successively connected with a 7 conductors standard cable.
Features
Mechanics:
Maximum temperature : 180°C continuously (356°F)
Maximum pressure : 1,800 bar (27,000 psi)
Maximum number of levels : 48
Diameter : 80 mm (3.15’’)
Total tool length : 1,400 mm (55’’)
Compatible casing diameter : 3.75’’ to 16’’
Locking force ratio : 5:1 to 20:1
Maximum cable length : 6,000 m
Distance between levels : no limitations
Electronics:
Cable equalization : Fully automatic
Date rates : 1.5 Mbits/s (on 6000 m cable)
Sampling rates : 0.25, 0.5, 1, 2 ms
Input noise : 0.1microV rms
Gain settings : 12, 24, 36, 48 dB
Dynamic range : 120 dB
Digitalization : 24 bits
Sensors:
Fixed : Omni 2400 15Hz
Gimbaled : On request
Benefits
* Working temperature up to 180°C continuously (356°F), without active cooling.
* Working pressure up to 1,800 bar (27,000 psi)
* Independent power supply and telemetry - on each level - preventing from full breakdown