琼东南盆地YL8区基底潜山岩石类型及其录井识别特征  

Rock types and logging identification characteristics of basement buried hill in YL8 area of southeastern Hainan Basin

作　　者：陈沛 于小健 陈现军 郭书生 谭兵 瞿雪姣[4] CHEN Pei;YU Xiao-jian;CHEN Xian-jun;GUO Shu-sheng;TAN Bing;QU Xue-jiao(Hainan Branch,CNOOC China Limited,Haikou 570311,China;Geophysical Centre,China Geological Survey,Langfang 065000,Hebei,China;Zhanjiang Branch of China France Bohai Geoservices Co.,Ltd.,Zhanjiang 524057,Guangdong,China;School of Petroleum Engineering,Chongqing University of Science and Technology,Chongqing 401331,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海口570311 [2]中国地质调查局地球物理调查中心,河北廊坊065000 [3]中法渤海地质服务有限公司湛江分公司,广东湛江524057 [4]重庆科技学院石油与天然气工程学院,重庆401331

出　　处：《世界地质》2021年第3期613-623,共11页World Geology

基　　金：国家重大科技专项项目(2011ZX05025-002)。

摘　　要：琼东南盆地YL8区基底潜山天然气勘探潜力巨大,但基底潜山岩性复杂、现场资料和手段有限,录井岩性识别困难。笔者基于元素录井、X衍射录井结果,结合岩芯/壁芯、岩屑和薄片等资料,查明该区典型、高频岩性及其录井识别特征,建立录井岩性识别工作流程。YL8区基底潜山钻遇2大类4小类14种岩石类型,主要发育正长花岗岩、二长花岗岩、二长岩、脉岩和碎裂花岗岩。利用(K+Na)-Si图可将中性侵入岩从基底潜山岩石中分离出来,利用黏土总量-Si图可区分具风化特征的火成岩和酸性侵入岩,利用斜长石-Si图则可较好区分二长花岗岩与正长花岗岩。结合岩芯/壁芯、岩屑和薄片等观察、鉴定结果可以实现基底潜山岩性的录井快速识别。Basement buried hill in the YL8 area of the Southeast Hainan Basin has been confirmed with great exploration potential,but the lithology of the basement buried hill is complex.Due to poor field data and analysis tools,logging lithology identification has become one of the key technologies restricting the further gas exploration.Based on the element logging and X-ray logging,combined with the core,cutting and thin-section data,the typical and high-frequency rocks and their logging identification characteristics were determined,and the workflow of rock identification was further established.There are 14 types of rocks developed in the basement buried hill within the YL8 area,which can be summarized into 2 major categories and 4 subcategories,mainly including syenogranite,monzogranite,monzonite,dike and fractured granite.The(K+Na)-Si discriminant chart could separate intermediate intrusive rocks from the basement rocks,while the weathered igneous rocks and acid intrusive rocks can be distinguished using the total amount of clay-Si discriminant chart.The syenogranite and monzogranite could be separated according to the discriminant chart of plagioclase-Si.Finally,the rock types of basement buried hill in the YL8 area could be identified quickly in field drilling operation,combined with the results of the core,cutting and thin-section observation.

关 键 词：岩石类型 录井岩性识别 基底潜山 YL8区 琼东南盆地 

分 类 号：P618.13[天文地球—矿床学]