“…The second type involves joint inversion methods based on statistical or empirical petrophysical relationships [e.g., Gardner et al, 1974;Lines et al, 1988;Li, 2015, 2016]. Other joint inversion methods are based on different physical property models with similar spatial distribution structures, such as cross-gradient joint inversion [e.g., Haber and Oldenburg, 1997;Gallardo and Meju, 2003;Fregoso and Gallardo, 2009;Vatankhah et al, 2022], correlation-analysis joint inversion [e.g., Oldenburg and Li, 1999;Lelièvre et al, 2012;Yin et al, 2018;Gao et al, 2019], and the joint inversion based on Gramian constraint [e.g., Zhdanov et al, 2012;Lin and Zhdanov, 2018]. In this case, the non-uniqueness can be effectively reduced by properly combining the correlation-analysis constraint with the joint inversion [e.g., Yin et al, 2018;Gao et al, 2019].…”