High-resolution reservoir impulse response estimation

Abstract

For a high-resolution inversion of elastic parameters at the target, preferably local full wavefield impulse responses need to be constructed. Along the target area, typically, these impulse responses are considered in the local CMP-(τ/p) domain. The success of these inversion schemes is highly dependent on the quality of this input data. Therefore, the wavefields at target level, estimated by Joint Migration Inversion (JMI) are good candidates, as all overburden effects are correctly taken into acount. Next, the Proximity Transformation in the standard JMI-based redatuming approach estimates the impulse responses in the shot-domain, which are later transformed to CMP-(τ/p) domain to be used as input for local inversion schemes. Here, we propose the direct estimation of CMP-(τ/p) domain impulse responses from the target level down-and upgoing wavefields, using a redefined Proximity Transformation as part of a modified JMI-based redatuming approach. The modified approach helps us to estimate high-resolution impulse responses with reduced artifacts and improved angle vs. ray parameter (AVP) characteristices at large plane-wave angles, which can directly be used as input for local inversion schemes. Moreover, the modified approach will be very well suited to estimate CMP-(τ/p) domain impulse responses in a 3D accquisition scenario, where we do not have sufficient sampling to apply explicit τ/px/py transform on shot-domain estimated impulse responses.