天然气勘探与开发2025，Vol.48Issue(5)：81-90,10.DOI:10.12055/gaskk.issn.1673-3177.2025.05.008
中江气田沙溪庙组气藏地层水化学特征及溯源
Chemical characteristics and provenance of formation water in Shaximiao Formation gas reservoir,Zhongjiang gas field
摘要
Abstract
In order to identify the provenance of the formation water in the Middle Jurassic Shaximiao Formation gas reservoir of the Zhongjiang gas field,located in the Western Sichuan Depression of the Sichuan Basin,and its implications for gas reservoir preservation conditions,24 samples of formation water screened out from 34 wells were investigated systematically for their chemical characteristics,water types,typical chemical coefficients,Novk phase diagram,isotope testing and provenance by means of multiple analysis methods.The following results are obtained.(i)The formation water is of the CaCl2 type,with the total dissolved solids(TDS)ranging 6 942.0-77 289.1 mg/L,and an average pH value of 6.7,indicating weak acidity.Among the conventional ions,Cl-is the most abundant.(ii)The characteristics of the typical chemical coefficients(metamorphic coefficient,salification coefficient,desulfurization coefficient,and cation exchange coefficient)suggest that the formation water exists in a well-sealed reducing environment,favorable for gas accumulation and preservation.(iii)The Novk phase diagram characteristics of formation water samples from different wells are very similar,pointing to a common provenance.The comparison with the Novk phase diagram corresponding to the standard section of the Sichuan Basin reveals that the formation water is sourced from the second to fourth members of the Upper Triassic Xujiahe Formation.(iv)The analysis on hydrogen-oxygen and strontium isotopes shows that the formation water is primarily composed of paleometeoric water modified by crust-derived rocks.It is concluded that the research results are helpful for deeply understanding the chemical characteristics and provenance of the formation water,as well as the preservation conditions and accumulation process in this gas reservoir,and provide a theoretical basis for related researches;the technical idea of multi-method combination applied in this study can offer a reference for further researching the chemical characteristics of formation water based on conventional water sample analysis.关键词
四川盆地中江气田/侏罗系中统沙溪庙组/地层水/化学系数/同位素分析/洛瓦克相图/封闭性/气藏保存条件Key words
Zhongjiang gas field of the Sichuan Basin/Middle Jurassic Shaximiao Formation/Formation water/Chemical coefficient/Isotope analysis/Novk phase diagram/Sealing capacity/Gas reservoir preservation condition分类
能源科技引用本文复制引用
高伟,杨松林,黄文元..中江气田沙溪庙组气藏地层水化学特征及溯源[J].天然气勘探与开发,2025,48(5):81-90,10.基金项目
中国石化西南油气分公司科技攻关项目"中江气田沙溪庙组气藏气水分布特征及开发对策研究"(编号:KJ-685-2203). （编号:KJ-685-2203）
