LG地区雷口坡组风化壳储层气水分布规律与测井识别

LG地区雷口坡组风化壳储层气水关系复杂,常规测井识别气、水层可靠性差,一定程度上影响了该区的勘探开发工作。为此,对气水组分特征、气水分布规律与气水测井识别方法等进行了系统研究。结果表明:天然气以甲烷为主,不含或微含H2S,气源来自上覆须家河组;地层水矿化度较高、变化范围较大,为封闭条件下与外界隔绝的残余水;气水关系复杂,无统一的气水界面;纵向上气水关系与所处地腹构造部位有关;气水分布规律受储层残余厚度与地腹构造的双重影响;常规电阻率绝对值法、三孔隙度交会法识别流体性质存在局限性,采用纵横波速度比值法、判别分析方法能有效识别气、水层,新的气、水层识别技术基本可以满足生产需要。

Researches on Gas-Water Distribution Law and Log Identification of Leikoupo Formation Weathering Crust Reservoir in LG Region

The complicated gas-water relationships in weathering crust reservoir of Leikoupo Formation of LG region caused a poor reliability of conventional logging in gas-water identification,which greatly affected the exploration and exploitation in this area to some extent.Therefore,the characteristics of gas and water components,the gas-water distribution and gas-water layer well logging identification were systematically studied.The results showed that natural gas was mainly consist of methane,contains none or little H2S,and gas supply came from the overlying Xujiahe Formation.The salinity of formation water was high and varied in a wide range,which was the residual water in a closed and isolated condition.The gas-water relationships were complex,without a unified gas-water interface.The relationships between water and gas were related to tectonic positions in longitudinal.The gas-water distribution was affected by both residual thickness of reservoir and tectonic positions.The conventional absolute value of resistivity method and the three fluid porosity intersection methods were limited in gas and water layer identification.The compressional and shear wave velocity ratio method and the discriminant analysis method identified gas and water layer more effectively,which can meet the production needs.