Abstract:

A new method of suppressed conductivity ion chromatography for determination of four kinds of ions Cl^-, SO²-_4, Ca^2+, Na+ was developed. By analyzing the mass concentration variation of four ions, the fluid identification interpretation criteria of Sichuan Basin marine strata was established, which could accurately identify the fluid properties in carbonate formation and judge whether a gas layer or a water layer to be drilled. This criteria could also deduce the opening degree of underground structure by identifying the formation water type to determine the storage conditions of gas reservoir. The results showed that this method had high sensitivity and good accuracy, which could enrich the detection methods of geological exploration and could also provide scientific basis for Sichuan Basin gas drilling.

Key words:  ion chromatography, drilling, Sichuan Basin, carbonate, formation fluid recognition