Coupling Analysis of Ion Characteristics and Genetic Relationships of Produced Water in the Kelasu Gas Field—A Case Study of Keshen 2 Block

In recent years, the water invasion situation in the Kelasu Gas Field has been severe. The productivity of gas wells and the ultimate recovery rate of the gas reservoir have been significantly affected by water invasion. The reservoir in this gas field is cut by fractures and cracks of different scales, resulting in extremely complex seepage laws. Traditional methods of seismic data analysis and dynamic monitoring data analysis have limitations such as long time consumption and high costs. To effectively explore the water invasion problem, this paper conducts a comparative analysis of the chemical test data of the produced water from water breakthrough gas wells, constructs a data model, summarizes the internal laws, and then deeply analyzes the genetic relationship of the produced water in the Kelasu Gas Field to accurately characterize the gas reservoir water invasion channels. Specifically, by comparing the ion content radar charts, sodium-chloride coefficients, desulfurization coefficients, and chloride ion contents of the produced water from each single well, a fine division of the genetic relationship of the produced water is achieved. The research findings show that there are differences in the formation water chemical patterns within the same block, and they exhibit characteristics of gradual evolution and a trend towards unification. At the same time, there are significant differences in the degree of water invasion, the direction of water invasion, and the source of water invasion among different blocks. The research results of this paper provide new ideas and reference bases for solving the water invasion problem in the Kelasu Gas Field.