Because of generally high resistivity of the acidic volcanic reservoir, it is not easy to use conventional neutron-density crossplot and high-low resistivity to identify reservoir fluid types. Developed is a new fluid identification method based on new well logging technology, logging response curve that is sensitive to gas and little influenced by lithology and logging and well testing data. According to the characteristics of natural gas logging responses, three-porosity combination, ratio of transverse wave and longitudinal wave, nuclear magnetic resonance and integrated parameters are used to identify fluid types, results of which show that this method can only identify gas reservoir without identifying reservoir which contain gas and water. Resistivity is sensitive to the change of reservoir fluid types, but is not so for acidic volcanic reservoir. As viewed from the microscopic pore structure of reservoir, studied are influence factors on volcanic reservoir resistivity. The complicate pore structure is one of the reasons of high resistivity of acidic volcanic reservoir. On this basis, developed is a gradually fluid type identification method based on pore structure. Fluid types of 49 wells in Xushen gas field have been identified with this method. Through gas tests of 69 layers, identification accuracy is 94. 1%, increasing nearly 15%.%酸性火山岩储层电阻率普遍较高,应用常规的中子一密度测井曲线交会和电阻率已不能判断储层流体性质.在天然气测井响应特征分析基础上,应用三孔隙度组合、横纵波时差比值、核磁共振及综合参数识别流体性质.应用结果表明这些方法只能识别含气储层,对于气水同层的识别效果并不好.电阻率对储层流体性质变化反映灵敏,但对于酸性火山岩储层并不如此.从储层微观孔隙结构入手,对火山岩储层电阻率影响因素进行研究,孔隙结构复杂是酸性火山岩电阻率普遍较高的原因之一,提出基于孔隙结构的流体性质逐步判别法.应用该方法对徐深气田49口井流体性质进行判断,经69个层试气验证,识别准确率达89.1％,提高了近15％.
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