中拐凸起石炭系低自然伽马火山岩岩性测井识别

Logging Identification of Carboniferous Low Gamma Volcanic Lithology in Zhongguai Uplift

准噶尔盆地中拐凸起石炭系火山岩岩性复杂多样,横向变化快,纵向厚度大,岩性识别和多井对比困难;石炭系火山岩(包括酸性岩)均呈低自然伽马特征,利用自然伽马无法准确识别岩性。运用岩心标定测井,利用ECS测井进行成因、成分分析选取敏感矿物建立交会图进行火山岩化学成分划分,结合电成像测井反映的结构构造信息建立成像模式图版进一步从结构山对岩性进行识别;在特殊测井识别岩性的基础上,分析不同岩性、不同结构及矿物成分的火山岩常规测井相应特征,将特殊测井识别结果推广到常规测井中进行常规曲线敏感性分析,建立中子—密度交会图,实现利用常规测井曲线划分火山岩岩性。

The carboniferous volcanic lithology in Zhongguai uplift of Junggar basin is complex and variable with rapid lateral variation and large vertical thickness,which is difficult for lithological identification and multi-well comparison.The volcanic(including acid rock)shows low gamma characteristics,so gamma ray log can not accurately identify lithology.Core information is firstly used to calibrate logging data,then lithological identification chart based on chemical composition is established from ECS logging data,third imaging modalities plate is built by FMI logging reflecting texture and structure information,and finally lithology identification is performed by combing the conventional logging data,analysed is logging response sensitivity,and established is CNL—DENcross plot to identify lithology.