摘要
由于膏盐岩层岩性、厚度横向变化大且盐下地层岩性组合变化较大,难以准确卡取盐底界线,为探讨适合膏盐岩层岩性识别和沉积环境判别的特征元素、矿物指标,通过XRF与XRD分析技术在塔里木盆地库车坳陷K 1A02井的综合应用,系统分析了盐间和盐下地层在矿物、元素组成、沉积环境方面的差异。研究表明,盐下泥岩对比盐间泥岩具有更高的石英、斜长石含量,并且方解石、石膏、石盐等含量更低;盐间泥岩与盐下泥岩常量、微量元素配分模式相似,主要区别在于盐间泥岩Na、Cl及微量元素含量更低;盐湖泥岩沉积期气候炎热干燥,由盐下到盐间泥岩干热程度增加,盐间泥岩主要沉积于咸水-超咸水水体;盐湖泥岩主要沉积于氧化-还原过渡环境,且盐下泥岩氧化程度更高。XRD分析技术可对岩性准确定名,XRF分析技术可较准确反演古沉积环境信息。XRD与XRF分析获得的沉积地球化学信息,可为膏盐岩层地质卡层提供理论支持;将岩屑录井与XRD、XRF分析技术相结合,可显著提高膏盐岩层盐底卡层的成功率,为准确卡取盐底提供依据。
It is difficult to accurately determinate the bottom boundary of gypsolith due to the great lateral change of lithology and thickness of gypsolith and the great change of formation lithology combination under gypsolith. In order to explore the characteristic elements and mineral indexes suitable for the lithology identification and depositional environment discriminant of gypsolith, through the comprehensive application of XRF and XRD analysis techniques to well K 1A02 of Kuqa depression in Tarim Basin, the formation differences of mineral, element composition and depositional environment within and under gypsolith are analyzed systematically. The results show that the mudstone under the gypsolith has higher content of quartz and plagioclase compared with the mudstone within the gypsolith, and the content of calcite, gypsum and rock salt is lower. The distribution patterns of macro and trace elements in mudstone within gypsolith and the mudstone under the gypsolith are similar, the main difference is that the content of Na, Cl and trace elements in mudstone within the gypsolith is lower. During the depositional stage of salt-lake mudstone, the climate was hot and dry, and the degree of dryness and heat increased from under the gypsolith to within the gypsolith, the mudstone within the gypsolith is mainly deposited in saline water -hypersaline water body. The salt-lake mudstoneis mainly deposited in the transitional environment of oxidation-reduction, and the mudstone under the gypsolith has a higher degree of oxidation. XRD analysis technique can accurately name the lithology, and XRF analysis technology can accurately invert the paleosedimentary environment information. The sedimentary geochemical information obtained by XRD and XRF analyses can provide theoretical support for the target bed determination of the gypsolith. Combining cuttings logging with XRD and XRF analysis techniques can significantly improve the success rate of determining the bottom boundary of the gypsolith, and provide the basis for accurately determining the bottom boundary of the gypsolith.
作者
卿元华
薛晓军
王晨
李秀彬
马树明
苑传江
QING Yuanhua;XUE Xiaojun;WANG Chen;LI Xiubin;MA Shuming;YUAN Chuanjiang(College of Energy,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Karamay Mud Logging Engineering Company,CNPC Xibu Drilling Engineering Company Limited,Karamay,Xinjiang 834000,China;Exploration Enterprise of PetroChina Tarim Oilfield Company,Korla,Xinjiang 841000,China)
出处
《录井工程》
2020年第1期108-115,共8页
Mud Logging Engineering
关键词
XRF
XRD
盐底
元素含量
泥岩
膏盐岩
盐度
沉积环境
XRF
XRD
the bottom boundary of the gypsolith
element content
mudstone
gypsum salt rock
salinity
depositional environment
