Because multicomponent data furnishes a direct measurement of both compressional and shear wave information, it has the potential of providing improved imaging compared to conventional P-wave data alone, but also more reliable rock property information, better lithology discrimination and fluid identification, and improved stress and fracture characterization.
Processing of multicomponent data must focus on the joint use of both wave forms, while enhancing the quality of the shear wave output to match what we expect of P-wave processing and preserving the inherent properties of the data.
In most cases, we rely on a ‘converted shear’ wave for the shear wave data; that is a downgoing P-wave converted to an upgoing shear wave at the reflection boundary. This is called PS-wave data, but shear energy is being measured at the ground surface by the three geophone components. This is as opposed to PP data (normal l P-wave data measuring downgoing and reflected compressional waves) and SS data (downgoing shear waves generated by a shear wave source and reflected upgoing shear waves). Onshore, these data are recorded with a three component geophone, with three orthogonal axes. Offshore, a hydrophone is added along with a seafloor geophone. Different acquisition combinations give rise to different types of multicomponent data: 2C, 3C, 4C, and even 9C.
- 2C – In marine OBC, the combination of the hydrophone(P) and the vertical geophone component(Z); PZ data
- 3C – Land 3-component; PP and PS data
- 4C – Marine OBC 3-component geophone plus hydrophone; PP or PZ, and PS data
- 9C – A compressional and 2 polarized shear sources with three-component
geophones produce a three-by-three matrix of source-receiver combinations; PP, PS and SS data
The different data types require different assumptions and different processing routines, and provide different benefits. Geokinetics has capabilities for 2C (or PZ summation) and 4C marine OBC processing and 3C and 9C land processing.
SOLUTIONS DRIVEN / TECHNOLOGY FOCUSSED
- Wavefield separation
- “Ripple Migration” for downgoing wavefield imaging
- Shear wave static solution
- Detection of shear wave splitting
- Azimuthal anisotropy and fracture analysis
PP PS Integration
- Event registration
- Wavelet correction
- Joint depth migration
- Joint inversion