Fig. 1. Cross-section schematic of oil sludge and oil-containing soil. (a) Oil sludge; (b) oil-containing soil

Fig. 2. Schematic diagram of photon propagation inside porous media. (a) Theoretical schematic diagram; (b) program simulation diagram

Fig. 3. Schematic diagram of fluorescence statistics

Fig. 4. Simulation results of oil sludge and oil-containing soil. (a)(b) Oil sludge; (c)(d) oil-containing soil

Fig. 5. Simulation results of different porosities of oily soils. (a) Oil sludge contaminated by No. 1 oil product; (b) oil sludge contaminated by No. 2 oil product; (c) comparison of two types of oil sludges with a porosity of 70%; (d) oil-containing soil contaminated by No. 1 oil product; (e) oil-containing soil contaminated by No. 2 oil product; (f) comparison of two types of oil-containing soils with a porosity of 70%

Fig. 6. Simulation results of oil sludge at different incident angles. (a) 0°; (b) 15°; (c) 30°; (d) 45°; (e) 60°; (f) 75°

Fig. 7. Comparison of simulation results for different incident angles

Fig. 8. Simulation results under different pore densities. (a) Oil sludge; (b) oil-containing soil