Nutrient Stimulation of Indigenous Microorganisms for Oil-in-Water Emulsion in a Medium Temperature Petroleum Reservoir with Ca²⁺-Rich Brine

Table 2

Chemical characteristics in the six formulas.

Ingredient (%)	OC	OCN	ONP1	ONP2	FN1	FN2
Ammonium nitrogen	0.2500	0.2513	0.2590	0.2520	0.0090	0.2590
Inorganic phosphorus	0	0	0.0011	0.0003	0.0011	0.0011
Total phosphorus	0	0.0001	0.0036	0.0018	0.0036	0.0036
Organic phosphorus	0	0.0001	0.0025	0.0015	0.0025	0.0025
OP/N ratio	0	0.0004	0.01	0.006	0.28	0.01

OP/N ratio refers to organic phosphorus divide by ammonium nitrogen.