IDENTIFYING THE PHENOMENA OF WATER FLOOD IN OIL FIELDS USING NOBLE GAS ISOTOPE——EXAMPLED BY THE HUANGSHATUO OILFIELD IN THE LIAOHE BASIN

The source water for water injection,source water after procession,water of an injection well,and oil crude of a production well were sampled and degassed.The ³He/⁴He,⁴He/²⁰Ne and ⁴⁰Ar/³⁶Ar of the gases from the waters and oils were analyzed.We found that they can be used for identifying the phenomena and degree of water flood of a production well.Our research shows that the ³He/⁴He,⁴He/²⁰Ne and ⁴⁰Ar/³⁶Ar of the source water for water injection,source water after procession and water of an injection well characterize an atmosphere source.The ⁴⁰Ar/³⁶Ar of crude oil in the Huangshatuo oil field is near that of the air in an error range,indicating that it was flooded by water and can be used as a tracer of water flood in an oil field,however it has no relation with ⁴He/²⁰Ne and can not be used for reflecting the degree of water flood.The ⁴He/²⁰Ne and ³He/⁴He of the oil from the Huangshatuo oil field were larger than those of air and they have a better liner relation,indicating they can be used for tracing water flood and its degree of an oil bed in a production well.