柴北缘仙西地区下干柴沟组测井流体识别方法适应性分析

Adaptability analysis of logging fluid identification method for Xiaganchaigou formation in Xianxi area of northern Qaidam basin

为了解决柴北缘仙西地区古近系下干柴沟组深层碎屑岩储层流体识别效果差、精度低等问题,在分析流体测井低敏感度特征因素的基础上,通过常规测井参数交会图法、P^(1/2)正态分布法、可动水饱和度法等多种方法对储层流体性质进行判别对比,建立并优选出适用于仙西地区储层特征的测井流体识别方法。结果表明:上述方法相结合能提高仙西地区下干柴沟组储层流体性质判别的精度,声波时差-电阻率及孔隙度-含水饱和度交会图法能有效识别气、水层;正态分布法在地层水高矿化度地区应用效果较差,但能有效识别气水同层;利用可动水饱和度辅以常规测井参数能够较好地识别仙西地区的气水同层和含气水层,气、水层的符合率为100%,基本解决了仙西地区深层碎屑岩储层流体识别困难的技术难题,可为该区下一步的勘探开发提供有力支撑。

In order to solve the problems of poor fluid identification effect and low accuracy in deep clastic reservoir of Paleogene Xiaganchaigou formation in Xianxi area of northern margin of Qaidam basin,based on the analysis of low sensitivity characteristic factors of fluid logging,this paper discriminates and compares reservoir fluid properties by conventional logging parameter crossplot method,P^(1/2)normal distribution method,movable water saturation method and other methods,and establishes and optimizes the logging fluid identification method suitable for reservoir characteristics in Xianxi area.The results show that the combination of the above methods can improve the accuracy of identifying the fluid properties of the lower Ganchaigou formation reservoir in Xianxi area.The crossplot method of acoustic time difference-resistivity and porosity-water saturation can effectively identify gas and water layers.The application effect of normal distribution method in high salinity area of formation water is poor,but it can effectively identify the same layer of gas and water.Using movable water saturation supplemented by conventional logging parameters can better identify gas-water layers and gas-bearing water layers in Xianxi area.The coincidence rate of gas and water layers is 100%,which basically solves the technical problems that restrict the fluid identification of deep clastic reservoirs in Xianxi area,and can provide strong support for the next exploration and development in this area.