Figures (12)  Tables (3)

    • Figure 1. 

      Two typical well patterns for ISHG field application in heavy oil reservoirs[8,9] (Licence nos 6239381182856, 6239381372356). (a) Vertical-well mode. (b) Horizontal-well mode.

    • Figure 2. 

      The differences and connections between the three mechanisms.

    • Figure 3. 

      SEM image of pyrolyzed coke[26] (Licence no. 6239390127009). (a) Crude oil. (b) Oxidized heavy oil.

    • Figure 4. 

      Kapadia's improved bitumen pyrolysis model[35] (Licence no. 6239390397386). (a) Model improvement. (b) Pyrolysis pathway. (c) Multiphase component simulation results. (d) Gas production components.

    • Figure 5. 

      Reaction kinetics model and multi-component simulation results proposed by Ganji[36] (Licence no. 6244050832583). (a) Model 1. (b) Model 2. (c) Model 3. (d) Model 4. (e) Model 5. (f) Simulation results of Model 5.

    • Figure 6. 

      Multi-field physical coupling and molecular dynamics simulation methods[28, 37] (Licence no. 6239390806160, 6244051274881). (a) Multi-field coupling framework. (b) Grid generation. (c) Fitting results. (d) 3D results. (e) Component pyrolysis. (f) Atmosphere influence. (g) Gas conversion pathway.

    • Figure 7. 

      The transport path of the hydrogen element in aquathermolysis[38,39] (Licence no. 6239680877836, 6239681208274). (a) Chain reaction of alkyl deuteration. (b) Aquathermolysis of hydrogen migration in oil shale.

    • Figure 8. 

      The aquathermolysis model and simulation results applied to oilfield production[66] (Licence no. 6239681443442). (a) Model. (b) Fitting results. (c) Gas production results.

    • Figure 9. 

      The well locations, injection rate, and hydrogen concentration. (a) Well locations. (b) Hydrogen concentration of EX T4. (c) Hydrogen concentration of EX 4.

    • Figure 10. 

      The experimental equipment and hydrogen production characteristics during the ISHG process[79, 83,84] (Licence no. 502059445, 6239691210953, 6239691378567, 6239700073771, 6239700217452). (a) CT. (b) RTO. (c) RA. (d) Mineral-catalyzed and N2/Air/H2O-regulated hydrogen. (e) Coke-gasified and N2/H2O-regulated hydrogen. (f) Fixed-water-content oil oxidized hydrogen. (g) Mineral-catalyzed and multiple-round gasified hydrogen.

    • Figure 11. 

      The catalyst development of hydrogen generation from 1995 to 2024[86] (Licence no. 6239700454313).

    • Figure 12. 

      Differences of reaction models in the ISHG process.

    • StageChemical reactionHeat variationTemperature (°C)
      PyrolysisHeavy oil → Light oil + Gas + H2O + CokeEndothermic> 300
      Secondary crackingLight oil → H2O + H2 + CH4 + CnHm; Light oil + H2O → H2 + COEndothermic/
      Steam reforming reactionCnHm + 2nH2O → (2n + 0.5m) H2 + nCO2Endothermic> 700
      Water-gas reactionCO + H2O → H2 + CO2Exothermic300–600
      Methane formationCO + 3H2 → CH4 + H2O; CO2 + 4H2 → CH4 + 2H2OExothermic300–600
      Methane decompositionCH4 + H2O → 3H2 + COEndothermic> 500
      Boudouard reactionCoke + CO2 → 2COEndothermic> 700
      Coke gasificationCoke + 2H2O → 2H2 + CO2Endothermic> 700

      Table 1. 

      The typical pyrolysis reaction process.

    • Oil sample Viscosity, mPa·s (50 °C) Reaction time, h Catalyst CH4, wt% H2, wt% Gasification rate
      Heavy oil, Xinjiang, China 2,578.6 72 None 0.044 0.064 0.209%
      Heavy oil, Liaohe, China 183 72 NiO − − 0.157%
      Heavy oil, Cuba 9,963.7 24 None 1.257 (vol%) 0.06 (vol%) −
      Oil-soluble 1.401 (vol%) 0.01 (vol%) −
      Extra heavy oil, Liaohe, China 11,514–16,874 48 None 0.392 0.020 −
      Air-soluble 0.608 0.030 −
      Oil-soluble 0.582 0.025 −
      Water-soluble 0.467 0.024 −
      Heavy oil, Liaohe, China 124.3 36 None 0.677 0.026 −

      Table 2. 

      The hydrogen generation efficiency of aquathermolysis[57−60].

    • Year Reservoir Porosity Permeability (mD) Viscosity (mPa·s) Depth (m) Method Peak hydrogen
      1977 Utah Tar Sand 31% 600–700 > 106 107 ISC 14%
      1979 Marguerite Lake 30% 1,000–3,000 > 105 450 ISC 33%
      1985 Wolf Lake 32% 1,000–3,000 > 40,000 108–230 ISC 25%
      2006 Whitesands 36% 3,000–12,000 / / THAI 10%
      2009 Kerrobert 32% 2,000–6,000 > 21,000 789 THAI 7%

      Table 3. 

      The hydrogen concentrations reported from ISC sites.