완전파형역산결과를 구조적 제약 조건으로 이용한 고해상도 전자탐사 복합역산 알고리듬 개발

초록

Compared with the separated inversion of electromagnetic (EM) and seismic data, a joint inversion using bothEM and seismic data reduces the uncertainty and gives the opportunity to use the advantage of each data. Seismic fullwaveforminversion allows velocity information with high resolution in complicated subsurface. However, it is an indirectsurvey which finds the structure containing oil and gas. On the other hand, marine controlled-source EM (mCSEM)inversion can directly indicate the oil and gas using different EM properties of hydrocarbon with marine sediments andcap rocks whereas it has poor resolution than seismic method. In this paper, we have developed a joint EM inversionalgorithm using a cross-gradient technique. P-wave velocity structure obtained by full-waveform inversion using planewave encoding is used as structure constraints to calculate the cross-gradient term in the joint inversion. When the jointinversionalgorithm is applied to the synthetic data which are simulated for subsea reservoir exploration, images havebeen significantly improved over those obtained from separate EM inversion. The results indicate that the developed jointinversion scheme can be applied for detecting reservoir and calculating the accurate oil and gas reserves.

키워드