四川盆地普光地区三叠系杂卤石测井评价与发育规律  

Logging Evaluation and Distribution Rule of the Triassic Polyhalite in Puguang Area of Sichuan Basin

作　　者：王建波[1] 冯明刚[1] 王昆[1] 周依南 WANG Jian-bo;FENG Ming-gang;WANG Kun;ZHOU Yi-nan(Sinopec Exploration Company,Chengdu 610041,China)

机构地区：[1]中国石化勘探分公司,成都610041

出　　处：《科学技术与工程》2021年第1期61-67,共7页Science Technology and Engineering

基　　金：国家重点研发计划(2017YFC0602804)。

摘　　要：三叠纪是上扬子地区由海洋过渡为陆地的关键时期,四川盆地沉积了大套碳酸盐岩-蒸发岩。川东北地区是四川盆地三叠系含钾有利区,具有良好的成钾条件,钾盐矿资源丰富,以杂卤石为主。目前,杂卤石测井评价以传统型杂卤石的响应特征分析和定性识别为主要研究内容,定量评价方法和发育规律分析较少。近期,随着一种新型杂卤石盐矿——“盐晶颗粒杂卤石岩”的发现,基于“油钾兼探”思路,利用普光气田现有钻录井和测井资料,落实川东北普光地区6类主要岩性敏感信息和测井识别模式;提出了利用曲线重叠和交会图法、钾钍比值法等方法开展杂卤石定性识别,落实研究区杂卤石发育情况和分布规律,明确其横向变化大、局部富集的特点,同时,研究区二叠、三叠系几个基本构造单元均以北东向为主,二者一定耦合关系;提出采用“伽马能谱差值分析法”计算富钾矿物的模型,形成了定量计算方法。通过开展杂卤石测井评价和发育规律研究,明确了川东北地区深层钾盐矿产资源的潜力,为勘探开采提供技术支撑。The triassic reef in Sichuan Basin is the key period of the transition from ocean to land in upper Yangtze Area.It has deposited a large set of carbonate rocks and evaporite rocks.Northeast parts of Sichuan Basin are favorable area of triassic potassium,which has good potassium forming conditions and rich potash mineral resources,mainly of polyhalite.At present,the logging evaluation of traditional polyhalite mainly focuses on the response characteristic analysis and qualitative identification,while the quantitative evaluation method and analysis on regularities of distribution are few.With the discovery of a new type of polyhalite,the salt crystal grain polyhalite rock,and the idea of co-exploration of oil and potassium,six kinds of key lithological sensitive information and logging identification patterns were concluded in Puguang gas field of Sichuan Basin based on its existing drilling and logging data.The methods of curve overlap and crossplot,potassium-thorium ratio were proposed to carry out the qualitative identification of polyhalite,its development and regularities of distribution in the study area,which demonstrated the characteristics of large transverse variation and local enrichment.There was a certain coupling relationship with the regional structure.The model of calculating rich potassium mineral by gamma spectral difference analysis was proposed.The potential of sylvite mineral resources in northeast of Sichuan Basin has been identified through the research on the logging evaluation and regularities of distribution,providing technical support for exploration and exploitation.

关 键 词：四川盆地 普光地区 三叠系 杂卤石 测井评价 分布规律 定量计算 

分 类 号：P534.51[天文地球—古生物学与地层学]