库车坳陷克拉苏构造带巴什基奇克组储层中钠长石胶结物成因机制  

Genetic mechanism of albite cements in Bashijiqike Formation reservoirs of Kelasu Structural Belt,Kuqa Depression

作　　者：杨海军[1] 王健[2,3] 莫涛[1] 李振坤[4] 朱文慧 汪顺宇[2,3] 丁海燕 冉逸轩 YANG Haijun;WANG Jian;MO Tao;LI Zhenkun;ZHU Wenhui;WANG Shunyu;DING Haiyan;RAN Yixuan(PetroChina Tarim Oilfield Company,Korla 841000,China;State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao 266580,China;School of Geosciences in China University of Petroleum(East China),Qingdao 266580,China;Geophysical Research Institute,SINOPEC Shengli Oilfield Company,Dongying 257029,China)

机构地区：[1]中国石油塔里木油田分公司,新疆库尔勒841000 [2]深层油气全国重点实验室(中国石油大学(华东)),山东青岛266580 [3]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [4]中国石化胜利油田分公司物探研究院,山东东营257029

出　　处：《中国石油大学学报（自然科学版）》2024年第6期15-24,共10页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(42172146);国家重点研发计划(2022YFE0203400);山东省泰山学者青年专家项目(tsqn202312111);深层油气全国重点实验室基金项目(SKLDOG2024-ZYRC-05)。

摘　　要：通过偏光显微镜、扫描电镜、薄片鉴定资料分析、激光拉曼、激光微区分析多种手段,对钠长石胶结物的微观特征、分布特征以及成因机制进行系统研究。结果表明:偏光显微镜下钠长石胶结物十分干净,通常以加大边或长条状单晶体的形态发育,在正交光下常见聚片双晶。横向上,钠长石胶结物主要分布在克深段南部、大北段西部和南部以及博孜段东部和北部,在大北段北部和克拉3段北部几乎不发育;纵向上,钠长石胶结物在靠近不整合处含量较高。储层中的钠长石胶结物纯度极高,拉曼光谱特征显示为低温钠长石,其微量元素特征与发生溶解的长石颗粒相似。钠长石胶结物的物质来源为溶解的长石,亲缘流体为大气淡水。白垩纪末研究区构造抬升期,大气淡水淋滤溶解了大量长石而富含H_(4)SiO_(4)、Na^(+)、Ca^(2+)等物质,大气淡水在越靠近地表的部位作用越强烈,因此在靠近现今不整合处沉淀了较多钠长石。大气淡水中的Na^(+)、H+活度比和H_(4)SiO_(4)活度在低地貌地区较高,有利于钠长石发生沉淀,钠长石胶结物富集在古地貌较低的地区。开放环境下钠长石含量较低的不整合附近或古地势较高处为优质储层的有利发育区。This paper systematically investigates the microscopic characteristics,spatial distribution,and genetic mechanisms of albite cements using optical microscopy,electron microscopy,thin section analysis,laser Raman,and laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)microanalysis.Under an optical microscope,albite cements appear very clean,typically forming as overgrowths or elongated single crystals.Under cross-polarized light,polycrystals are common.Horizontally,albite cements are primarily distributed in the southern Keshen section,the western and southern parts of the Dabei section,and the eastern and northern parts of the Bozi section.However,albite cements are almost absent in the northern parts of the Dabei and Kela 3 section.Vertically,albite cements are more abundant near unconformities.These cements exhibit high purity,and Raman spectroscopy confirms that they are low-temperature albite,with trace element characteristics similar to those of dissolved feldspar particles.The source material for the albite cements is dissolved feldspar,and the associated fluid is atmospheric freshwater.At the end of Cretaceous,during the tectonic uplift,atmospheric freshwater leached large amounts of feldspar,becoming enriched in H_(4)SiO_(4),Na^(+),Ca^(2+),and other ions.Atmospheric freshwater played a stronger role closer to the surface,leading to the deposition of more albite cements near current unconformities.Higher activity ratios of Na^(+),H+,and H_(4)SiO_(4)in low-lying areas promoted albite precipitation,resulting in the enrichment of albite cements in areas with lower paleotopography.Conversely,regions near unconformitiesor higher ancient terrains,with low content of albite cements,are the favorable areas for high-quality reservoir development.

关 键 词：钠长石胶结物 成因机制 巴什基奇克组 克拉苏构造带 

分 类 号：TE122.1[石油与天然气工程—油气勘探]