“…2.1 Fluid feature extraction 2.1.1 Well log and rock physics parameters Tight reservoir evaluation is the practice of interpreting wellbore and well log data to detect and quantify lithology and fluid types [41]. The input parameters of fluid identification can be divided into two main categories: (1) Well log parameters include borehole diameter (CAL), gamma ray (GR), transverse velocity (S-wave velocity, SV), longitudinal velocity (P-wave velocity, PV), shallow lateral resistivity (LLS), compensated neutron log (CN), deep lateral resistivity (LLD), and acoustic log (AC), i.e., 𝐶 1 = {CAL, GR, SV, PV, LLS, CN, LLD, AC}; (2) Rock physics parameters are sensitive to reservoir fluids [42], and include Poisson's ratio ν, bulk modulus K, shear modulus μ, Young's modulus E, Lamé coefficient λ, and longitudinal-to-transverse velocity ratio 𝑉 𝑝 /𝑉 𝑠 (Eqs.…”