川东北宣汉地区海相“新型杂卤石钾盐矿”的发现、突破与前景  

Discovery,breakthrough and prospect of“new type polyhalite potash deposit”in the Puguang area,northeastern Sichuan basin

作　　者：张永生[1,2] 邢恩袁[2] 郑绵平[2] 苏克露 桂宝玲[2] 仲佳爱 左璠璠 商雯君 牛新生[2] 苏奎[2] 王宁军 慎国强 唐兵 彭渊[2] 纪德宝 张兵[8] 盛德波 刘铸 王建波[3] 葛星 ZHANG Yongsheng;XING Enyuan;ZHENG Mianping;SU Kelu;GUI Baoling;ZHONG Jiaai;ZUO Fanfan;SHANG Wenjun;NIU Xinsheng;SU Kui;WANG Ningjun;SHEN Guoqiang;TANG Bing;PENG Yuan;JI Debao;ZHANG Bing;SHENG Debo;LIU Zhu;WANG Jianbo;GE Xing(SinoProbe Laboratory,Institute of Mineral Resources,CAGS,Beijing 100037,China;MNR Key Laboratory of Metallogeny and Mineral Assessment/Key Laboratory of Salt Lake Resources and Environment,Institute of Mineral Resources,CAGS,Beijing 100037,China;Sinopec Exploration Company,Chengdu,Sichuan 610041,China;The 2nd Geological Brigade of Sichuan,Chengdu,Sichuan 610042,China;Sichuan Hengcheng Potassium Salt Technology Co.,LTD.,Dazhou,Sichuan 636150,China;Sinopec Geophysical Institution of Shengli Oil Field,Dongying,Shandong 257031,China;Sichuan Geological and Mineral Resources Group Co.LTD.,Chengdu,Sichuan 610000,China;Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部深地科学与探测技术实验室,北京100037 [2]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室/自然资源部盐湖资源与环境重点实验室,北京100037 [3]中国石化勘探分公司,四川成都610041 [4]四川省第二地质大队,四川成都610042 [5]四川恒成钾盐科技有限公司,四川达州636150 [6]中石化胜利油田分公司物探研究院,山东东营257031 [7]四川省地质矿产(集团)有限公司,四川成都610000 [8]成都理工大学,四川成都610059

出　　处：《地质学报》2024年第10期2823-2846,共24页Acta Geologica Sinica

基　　金：国家重点研发计划项目(编号2023YFC2906503,2017YFC0602800);中国地质调查二级项目(编号DD20190172,DD20230037)联合资助的成果。

摘　　要：全球探明钾盐资源主体为古代海相可溶性固体钾盐矿床(氯化钾、光卤石),仅少量来自现代盐湖卤水钾矿。与国外不同的是,目前我国探明钾盐资源主体为现代陆相盐湖钾矿,古代海相可溶性固体钾盐找矿40余年,未获突破。四川盆地是我国主要大型海相成钾盆地之一,前人在中—下三叠统发现大量与硬石膏和白云石共伴生或互层的杂卤石,但绝大部分埋深超过2000 m,目前尚难以开发利用。2017年以来,笔者通过对四川盆地东北部宣汉盐盆普光地区卤水探井(恒成2、3井)岩芯复查,发现杂卤石主要与石盐共伴生,大量破碎的杂卤石碎屑颗粒分布于石盐基质中,KCl含量达边界工业品位以上,不同于钾石盐和光卤石,亦不同于前人发现的与硬石膏和白云石共伴生或互层的杂卤石(石膏型杂卤石),将之命名为“新型杂卤石钾盐矿”。小试和中试结果表明,该“新型杂卤石钾盐矿”可以采用对接井注水溶采,是能够得到规模化开发利用的“活矿”,是一种全新的硫酸盐+氯化物复合型海相可溶性固体钾盐矿床新类型。通过成钾条件、成矿规律综合研究,笔者提出了新型杂卤石钾盐矿“双控复合成矿”理论新认识、建立了“三高、两低、一大”综合测井识别新模型,创新理论技术指导设计部署“钾锂兼探”基准井——川宣地1井,探获厚29.46 m、氯化钾(KCl)平均含量12.03%(最高20.5%)的“新型杂卤石钾盐矿”厚层高品位工业矿层。与此同时,采用岩芯样品实测数据和测井解释数据拟合的方法,建立矿石K含量和密度参数的测井定量预测模型,结合“气钾兼探”,利用33口钻井数据,依据古代固体盐类勘查规范(2020),运用“几何法”,初步估算“新型杂卤石钾盐矿”氯化钾(KCl)资源规模:推断资源量2.45亿t(超大型)、潜在资源4.65亿t,合计7.1亿t,奠定了川东北达州市宣汉地区形成中国首个亿吨级海相Globally,the majority of proven potassium salt resources are ancient marine soluble solid deposits(sylvine,carnallite).In contrast,Chinas proven potassium salt resources mainly originate from modern salt lake brines.Despite decades of exploration,breakthroughs in marine soluble solid potassium salt prospecting in ancient salt basins have remained elusive.The Sichuan basin,a major marine potassiumforming basin in China,harbors significant polyhalite deposits associated with or interbedded with anhydrite and dolomite in the Middle and Lower Triassic series.However,these deposits are generally buried at depths exceeding 2000 m,posing significant challenges for development and utilization.Since 2017,core reviews from brine exploration wells(HC2 and HC3)in the Xuanhan salt basin of the Puguang area in the northeastern Sichuan basin have revealed a type of polyhalite-type potassium-bearing ore.This“new type polyhalite potassium ore”is characterized by the abundant fragmented polyhalite dispersed in the salt matrix and exhibiting a converted KCl content exceeding industrial grade thresholds.This type of polyhalite,known as“new type polyhalite potassium ore,”differs from sylvite,carnallite,and the polyhalite associated or interbedded with anhydrite and dolomite(anhydrite-type polyhalite)discovered by predecessors.Small-and medium-scale tests show that this“new type polyhalite potassium ore”can be dissolved by water injection through butt wells;therefore,it is a“live ore”that can be developed and utilized on a large scale.It is also a new type of sulfate-chloride composite marine soluble solid potassium salt deposit.A thick industrial layer of“new type polyhalite potassium ore”with a thickness of 29.46 m and an average KCl content of 12.03%(reaching a maximum of 20.5%)was discovered in the“potassium-lithium exploration”reference well CXD 1.This discovery,based on the“double controlled compound”metallogenic theory,marks a substantial breakthrough in marine soluble solid potassium salt prospectin

关 键 词：新型杂卤石钾盐矿 海相 固体钾盐矿床新类型 中—下三叠统 川东北普光地区 

分 类 号：P619.211[天文地球—矿床学]