火山岩相的岩屑识别——以松辽盆地南部东岭探区为例

Volcanic Facies Identification with Cuttings——A Case Study in Dongling,Southern Songliao Basin

以松辽盆地南部东岭探区为例,建立了用火山岩钻井岩屑来确定火山岩亚相的方法和工作流程。首先辨别真假岩屑,然后用真岩屑制片并进行薄片鉴定。根据火山岩显微镜下的岩性、结构和构造特征与火山岩岩相和亚相的对应关系确定其所对应的火山岩岩相和亚相。岩屑法对于厚度在一个采样间距(1 m)以上的火山岩层段可以准确定出火山岩亚相,与岩心鉴定结果的符合率大于90%。此外,该方法亦可校正录井岩性。用该方法对东岭地区15口探井火山岩段的录井岩性岩相进行了识别校正,提高了井间岩性岩相和储层对比的精度。

A new method is proposed here to identify the volcanic subfacies/facies with the cuttings. The general flowchart is true cuttings selection→cutting thin section preparation→thin section observation with microscope→subfacies/facies identification. The volcanic subfacies/facies finally is identified according to the typical characteristics of lithology, structure and texture observed under the microscope. The resolution equals to the cutting sampling interval （1 m, in general）. The accuracy is more than 90% compared to the core observation. This method was effective to verify the lithology as well as the volcanic facies. It has been proved as an effective way to promote the resolution of inter-well lithology and facies correlation based on the applications in 15 wells in Dongling, Southern Songliao Basin.