− | * '''Trap fluid'''s—physical and chemical contrasts—especially differences in miscibility, solubility, and density—between the common reservoir fluids (primarily water, gas, and oil) that allow hydrocarbons to migrate, segregate, and concentrate in the sealed reservoir. | + | * '''Trap fluids'''—physical and chemical contrasts—especially differences in miscibility, solubility, and density—between the common reservoir fluids (primarily water, gas, and oil) that allow hydrocarbons to migrate, segregate, and concentrate in the sealed reservoir. |