元素录井技术在长庆油田岩性识别中的应用

Application of Element Logging Technology in Lithology Identification in Changqing Oilfield

鄂尔多斯盆地作为中国第二大沉积盆地,根据盆地构造-沉积发育特征可将其划分为六个二级构造单元。复杂的构造背景导致区内岩性多样,同一种岩性由于沉积环境不同其成分也有所变化,地层错综复杂,给录井现场岩性识别带来困难。在该区引入XRF元素录井技术,通过对230口井样品的统计分析,确定了5种特殊岩性的元素组合特征,有效解决了粉末状岩屑的岩性定名难题。通过全面梳理长庆油田各标志层岩性特征、元素特征和测井特征,制作标准剖面,结合所钻井地层进行对比,进行标志层识别,利用识别出的标志层完成了元素录井小层划分工作。12口井的应用表明,其结果比现场录井地层划分结果更详细、准确,剖面符合率提高了6.55个百分点。

As the second largest sedimentary basin in China,Ordos Basin can be divided into six secondary tectonic units according to the tectonic-sedimentary development characteristics of the basin.The complex tectonic background leads to the diversity of lithology in the area.The composition of the same lithology varies due to different sedimentary environments,and the formation is complicated,which brings difficulties to lithology identification in logging site.XRF element logging technology was introduced in this area,and through the statistical analysis of 230 well samples,the element combination characteristics of five special lithologies were determined,which effectively solved the problem of lithologic naming of powdery cuttings.By comprehensively sorting out the lithologic characteristics,element characteristics and logging characteristics of each marker layer in Changqing oilfield,the standard profile is made,and the identification of marker layer is carried out based on the comparison of the drilled strata.The identification of marker layer is completed by using the identified marker layer to divide the small layer of element logging.The application of 12 Wells shows that the results are more detailed and accurate than the results of field logging,and the coincidence rate of profile is increased by 6.55 percentage points.