Table 2. Summary of the Research Related to the Prediction of Organic Matter in Shale.

refs	study conducted	technique	method type	input parametersa	geological field study
Tan et al.24	prediction of TOC	artificial intelligence	epilson-SVR, nu-SCR, SMO-SVR, and RBF	CNL, GR, AC, K, TH, U, PE, RHOB, and RT	Huangping syncline, China
Rui et al.25	prediction of TOC	artificial intelligence	SVM	wireline log data such as RHOB, GR, SP, RT, and DT	Beibu Gulf basin
Lawal et al.27	prediction of TOC	artificial intelligence	ANN	XRD data: SiO2, Al2O3, MgO, and CaO	Devonian Shale
Sultan28	prediction of TOC	artificial intelligence	self-adaptive differential evolution-based ANN	well logs: GR, DT, RT, and RHOB	Devonian Shale
Mahmoud56	prediction of TOC	artificial intelligence	ANN	well logs: GR, DT, RT, and RHOB	Devonian Shale
Zhao et al.50	prediction of TOC	regression	nonlinear	CNL	Ordos Basin in China and Bakken Shale of North Dakota
Wang et al.53	prediction of TOC	regression	nonlinear	DT and RT	Sichuan Basin, Southern China
Alizadeh et al.46	prediction of TOC and S2	artificial intelligence	ANN	DT and RT	Dezful Embayment, Iran
Handhal et al.45	prediction of TOC	artificial intelligence	SVR, ANN, KNN, random forest, and rotation forest	GR, RHOB, NPHI, RllD, and DT	Rumaila Oil Field, Iran
Wang et al.48	TOC, S1, and S2	artificial intelligence	ANN	RHOB, NPHI, RT, and DT	Bohai Bay Basin, China

^aGR = γ-ray, RHOB = bulk density, LLD = deep lateral log, LLS = shallow lateral log, MSFL = microspherical focused log, R_ILD = deep induction resistivity log, DT = compressional wave travel time, TH = thorium, U = uranium, K = potassium, RT = resistivity log, NPHI = neutron porosity, SP = spontaneous potential, CNL = compensated neutron log, PE = photoelectric index, SiO₂ = silicondioxide, Al₂O₃ = aluminiumdioxide, MgO = magnesium oxide, and CaO = calcium oxide.