伽马-伽马测井在鄂尔多斯盆地西南缘白垩系识别岩性的研究  

Gamma-gamma logging in the lithology identification of Cretaceous at the southwestern margin of Ordos basin

作　　者：王伟 武正乾 贺锋[2] 刘坤鹏 王晓鹏 李磊 喻腾 毛宁 张良 李西得[2] WANG Wei;WU Zhengqian;HE Feng;LIU Kunpeng;WANG Xiaopeng;LI Lei;YU Teng;MAO Ning;ZHANG Liang;LI Xide(Research Institute No.203,CNNC,Xi’an 710086,China;CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technolog Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]核工业二〇三研究所,陕西西安710086 [2]核工业北京地质研究院,中核集团铀资源勘查与评价技术重点实验室,北京100029

出　　处：《世界核地质科学》2024年第2期343-350,共8页World Nuclear Geoscience

基　　金：中国核工业地勘基金项目“鄂尔多斯盆地镇原—盐池地区铀矿资源调查评价”(编号:202115-2);中核集团集中研发项目“砂岩型铀矿多重耦合地质作用与时空定位”(编号:2021-143);中核集团青年英才项目“鄂尔多斯盆地西南部下白垩统厚大灰绿色砂体对铀成矿制约关系”(编号:地QNYC2301)联合资助。

摘　　要：近年来鄂尔多斯盆地西南缘白垩系砂岩型铀矿找矿取得突破,由于研究区白垩系特殊的沉积环境,环河组的泥岩和粉砂岩中广泛发育石膏类不导电矿物,导致常规测井曲线难以准确解释岩性。为了准确区分非渗透(泥岩、粉砂岩)和渗透砂岩,经过测量研究区岩石物性参数,发现泥岩、粉砂岩类岩石密度大于砂岩密度,伽马—伽马测井广泛应用在砂岩型铀矿地球物理测井工作中,用来计算地层密度,长、短源距测井参数为其中间测量参数,为了更好地发挥其作用,阐明了伽马-伽马测井原理,结合自然伽马与长、短源距拟合关系,优选了抗干扰强的短源距测井曲线,提出了自然伽马曲线消除长、短源距消除放射性矿层影响的校正方法。经钻孔岩性和测井曲线验证,伽马-伽马测井的短源距曲线可以较好地解释研究区白垩系岩性,对鄂尔多斯盆地西南缘白垩系砂岩型铀矿地球物理测井工作具有一定参考意义。In recent years,breakthroughs have been made in searching for Cretaceous sandstone type uranium deposit in the southwestern margin of Ordos basin.Due to the special depositional environment of Cretaceous in the study area,non-conducting gypsum-type minerals have been widely developed in the mudstones and siltstones of Huanhe formation,which makes it difficult to accurately interprete the lithology by the conventional logging curves.In order to accurately distinguish the difference between non-permeable(mudstone and siltstone)and permeable rocks,the physical parameters of the rocks in the study area were measured,it was found that the density of mudstone and siltstone is greater than that of sandstone.Gamma-gamma logging is widely used in sandstone-type uranium geophysical logging to calculate the density of strata,and the parameters of the long and short source distance logging are the parameters of its intermediate measurements.In order to better play its role,the principle of gamma-gamma logging was clarified,combined with the fitting relationship between the natural gamma and the long and short source distances,the short source distance logging curves with strong anti-interference were preferred,and the correction method of eliminating the influence of the radioactive layer by eliminating the natural gamma curves from the long and short source distances was proposed.The short source distance curve of gamma-gamma logging can better explain the Cretaceous lithology of the study area,which is of reference significance for the geophysical logging of Cretaceous sandstone uranium mines in the southwestern margin of the Ordos basin.

关 键 词：伽马-伽马测井 鄂尔多斯盆地 白垩系 识别岩性 

分 类 号：P619.14[天文地球—矿床学] P631.3[天文地球—地质学]