XRF元素录井技术在四川地区的地质应用研究

XRF元素录井技术是建立在x射线荧光光谱分析理论基础上，并结合岩石地球化学理论的一种创新技术。XRF元素录井岩性解释方法通过对元素含量、元素比值、定量岩性含量曲线随井深的变化特征与变化趋势进行分析，从而得到最终的解释结果：陆相地层的岩性识别主要根据Si、Fe的变化来判断砂岩、泥岩，海相地层主要根据Ca、Mg、S的变化来判断灰岩、白云岩、石膏岩，Ba、Ti的变化可以判断岩屑中的泥浆材料含量。该方法对样品要求低，能够很好地识别各种细碎岩性，建立地层剖面，划分地层界线。此外，XRF元素录井还可以用于判断沉积环境：Sr含量相对高、低分别指示海、陆沉积环境：在储层评价方面：陆相储层Si含量变大，说明储层质量变好，而Al、Fe、Ti等3种元素含量变大，预示着储层质量变差；海相储层S含量与溶孔发育程度具有正相关性。以上研究成果在川西4口井、川东北6口井现场应用后．岩屑剖面符合率达到90％。

The Geological Application of XRF Element Well Logging Technique in Sichuan Basin

XRF element well logging technique is innovative combined to lithogeochemistry theory with the basis of the X-ray fluorescence analysis theory.Variation features and trend of curves of the element content, element ratio and quantitative lithologic content along with the well depth are analyzed,and final interpreta- tion results may be gained by lithoiogic interpretation method of the XRF element well logging.For the terres- trial formations, the sandstone and mudstone may be known through the change of Si and Fe ;for the marine formations,limestone,dolomite rocks and gyprocks may be known through the change of Ca,Mg and S,the content of mud material in cuttings may be known through the change of Ba and Ti.This method may be applied to identifying various micro-lithology,establishing stratigraphic profile and classifying boundary strato- type under low demands of the samples.This method may be also applied to judging depositional environ- ment：relatively high or low value of the content of Sr may be the marine and terrestrial environment re- spectively.More content of Si in the terrestrial reservoirs indicates good quality of the reservoirs,and more content of Al,Fe ,Ti in the terrestrial reservoirs indicates bad quality of the reservoirs.The content of S in the marine reservoirs has positive correlation to development degree of the dissolved pore.After its field appli- cation in four wells in the west of Sichuan and six wells in the northeast of the Sichuan,coincidence rate of the cuttings profile is up to 90%.