基于对应分析的丽水-椒江凹陷潜山岩性识别方法

A Lithology Identification Method for Buried Hills in the Lishui-Jiaojiang Sag Based on Correspondence Analysis

随着丽水-椒江凹陷油气勘探扩展至潜山油藏,钻井揭示花岗岩、片麻岩、灰岩等岩性地层;加之应用了钻井新工艺,录井岩屑细小、混杂,现场准确识别岩性难度较大。为了解决此问题,基于XRD衍射和XRF元素录井资料,利用ReliefF算法筛选了对潜山及上覆地层敏感的8种元素和4种矿物,将筛选出的元素、矿物作为原始数据集的特征参数进行对应分析,构建了花岗岩、片麻岩、灰岩等岩石岩性的H_(1)与H_(2)函数,并建立了复杂岩性的识别图版。其中,花岗岩的H_(1)和H_(2)分别为-3.0~1.0和1.0~3.0,片麻岩的H_(1)和H_(2)分别为-4.0~0和-2.5~1.0,灰岩的H_(1)和H_(2)分别为0.5~2.5和-9.0~-3.0,砂砾岩的H_(1)和H_(2)分别为2.5~10.0和-1.0~2.5,泥岩的H_(1)和H_(2)分别为-1.0~3.5和-1.0~0.5。丽水-椒江凹陷潜山油气区6口井应用了基于对应分析的岩性识别方法,识别复杂岩性的准确率达90.7%,可为钻井施工安全及潜山储层综合评价提供技术支持。

As oil and gas exploration in the Lishui-Jiaojiang Sag moves towards buried hills,drilling has encountered many lithology formations such as granite,gneiss,and limestone.In addition,with the application of new drilling technology,the cuttings for logging are fine and usually mixed together,and it is difficult to identify the lithology accurately on the well site.In order to solve this problem,based on X-ray diffraction(XRD) and X-ray fluorescence(XRF) element logging data,firstly,the ReliefF algorithm was used to identify eight elements and four minerals sensitive to buried hills and overlying strata,and then the selected elements and minerals were used as the characteristic parameters of the original data set for corresponding analysis.The H_(1and) H_(2) functions of granite,gneiss,limestone,and other complex lithologies were established,and the complex lithology identification chart was drawn.Specifically,the H_(1and) H_(2) of granite were-3.0~1.0 and 1.0~3.0,and those of gneiss were-4.0~0 and-2.5~1.0.The H_(1and) H_(2) of limestone were 0.5~2.5 and-9.0~-3.0,and those of sandstone were 2.5~10.0 and-1.0~2.5.In addition,the H_(1and) H_(2) of mudstone were-1.0~ 3.5 and-1.0~ 0.5.The lithology identification method based on corresponding analysis was applied to six wells in the oil and gas area of the Lishui-Jiaojiang Sag,and the identification accuracy of complex lithology reached 90.7%,which can provide technical support for drilling operation safety and comprehensive evaluation of buried hill reservoirs.