CAJ | 학술논문

本文主要依据陕北盐盆地的镇钾1井等8口基干井，通过岩心观察、测井解释、镜下薄片鉴定，同时结合区域构造资料并参考前人研究成果，对陕北盐盆奥陶系马家沟组岩石类型、沉积相、沉积演化进行了研究。结果表明岩石类型以碳酸盐岩和蒸发岩为主，碎屑岩等其他沉积岩发育较少。主要发育碳酸盐岩台地相，可进一步划分出开阔台地和局限蒸发台地两种亚相，开阔台地可识别出灰泥丘微相；局限蒸发台地可识别出云坪、盐湖、膏湖、淡化泻湖等微相。沉积演化表明，马一期－马六期，陕北盐盆经历了三次海进－海退旋回，沉积演化为陕北盐盆及钾岩的形成创造了良好的成盐古地理环境，海进期，海水提供充足的成钾物质补给，海退期形成的继承性盐盆，四周隆起，又处在有利的低纬度干旱蒸发气候环境，十分有利于钾岩的形成。陕北盐盆奥陶系马家沟组五段六亚段沉积期，盆底总体表现为“两坳夹一隆”的构造样式，即自西向东依次为呈 NNE 向展布的西部盐坳、中部隆起和东部盐坳，“西部盐坳”可进一步分为3个次级盐凹，自北向南依次为“西一盐凹”、“西二盐凹”和“西三盐凹”；“东部盐坳”可进一步分为2个次级盐凹，即北部的“东一盐凹”和南部的“东二盐凹”，这5个盐凹的盐系地层厚度大于150m，是陕北盐盆最佳成钾盐凹，也是优先进行钾盐探井部署的有利目标区。
본문주요의거협북염분지적진갑1정등8구기간정，통과암심관찰、측정해석、경하박편감정，동시결합구역구조자료병삼고전인연구성과，대협북염분오도계마가구조암석류형、침적상、침적연화진행료연구。결과표명암석류형이탄산염암화증발암위주，쇄설암등기타침적암발육교소。주요발육탄산염암태지상，가진일보화분출개활태지화국한증발태지량충아상，개활태지가식별출회니구미상；국한증발태지가식별출운평、염호、고호、담화사호등미상。침적연화표명，마일기－마륙기，협북염분경력료삼차해진－해퇴선회，침적연화위협북염분급갑암적형성창조료량호적성염고지리배경，해진기，해수제공충족적성갑물질보급，해퇴기형성적계승성염분，사주륭기，우처재유리적저위도간한증발기후배경，십분유리우갑암적형성。협북염분오도계마가구조오단륙아단침적기，분저총체표현위“량요협일륭”적구조양식，즉자서향동의차위정 NNE 향전포적서부염요、중부륭기화동부염요，“서부염요”가진일보분위3개차급염요，자북향남의차위“서일염요”、“서이염요”화“서삼염요”；“동부염요”가진일보분위2개차급염요，즉북부적“동일염요”화남부적“동이염요”，저5개염요적염계지층후도대우150m，시협북염분최가성갑염요，야시우선진행갑염탐정부서적유리목표구。
Based on 8 wells(e.g.Zhenjia 1 well,etc)in the Northern Shaanxi salt basin,cores observation and well logging interpretation,identification of microscopic flakes,combined with regional tectonic data and previons research achievements,the Ordovician majiagou Formation rock types,sedimentary facies and sequence stratigraphy were studied.The rock types are mainly carbonates and evaporites,clastic rock and other sedimentary rocks less development.The main development of carbonate platform facies can be further divided into two subfacies:open platform and restricted evaporate platform.Open platform can identify limemud mound microfacie and the microfacies contain dolomitic flat,salt lake,gypsum lake. Sedimentary evolution shows that the salt basins in northern Shaanxi had experienced three timestransgressive-regressive cycles from Ma1 to Ma6 period.Sedimentary evolution created good salt palaeogeographic environment for Shaanxi salt basin and sylvite forming,and the sea-water supplied enough potassium material in the transgression.Inheritance of salt basins formed in the regressive period around the uplift at favorable evaporation low latitudes drought climate environment are was very favorable for the formation of potassium rock.Shaanxi salt basin showed the tectonic pattern of “two depressions and one lifting”,for west salt sags,middle uplift,east salt sags which are NNE-striking from west to east. west salt sags are made of “west 1 salt sags”,“west 2 salt sags”and “west 3 salt sags”from north to south;East salt sags were made of”east 1 salt sage”in the north and ”east 2 salt sage”in the south.The five salt sags with the thicknesses of more than 150 meters in this region are the best locations for potassium salt formation in Shaanxi salt basin,suggestion a priority targets for potash exploratory well deployment in the favorable area.