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本次研究主要依据龙探1井、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、沉积微相分析,结合区域构造资料并参考前人研究成果,对鄂尔多斯盆地奥陶系马家沟组沉积相进行了识别和划分,编制或修编了鄂尔多斯盆地马家沟一期至马家沟六期各时期的岩相古地理图。研究结果表明:鄂尔多斯盆地马家沟组主要发育碳酸盐岩台地相,包含开阔台地和局限蒸发台地两种亚相,与成盐成钾密切相关的局限蒸发台地可进一步划分为云坪、盐湖、膏湖、淡化泻湖等微相;平面上,马家沟组一段—六段主要发育陆(隆)、云坪、盐湖、膏湖、开阔台地及浅滩6个古地理单元,每个古地理单元在各段的分布情况有所不同。在半封闭的构造格局、华北古陆表海为主的预备卤水补给方式和奥陶纪极端干旱的古气候条件共同作用下,使有利成钾区最终定位在鄂尔多斯盆地东部盐坳绥德地区。
Based on the core observation, log interpretation, microscopic identification of thin slices, analysis of sedimentary microfacies, combined with regional tectonic data and reference to previous research results, The sedimentary facies of the Ordovician Majiagou Formation in the Ordos Basin have been identified and divided, and the lithofacies paleogeography maps of the first phase of the Majiagou Phase I to the Majiagou Phase 6 of the Ordos Basin have been compiled or revised. The results show that the Majiagou Formation in the Ordos Basin is mainly composed of carbonate platform facies, including two open facies and localized evaporites. The limited evaporites that are closely related to salt formation and potassium formation can be further divided into three types: , Plaster lake, desalination lacustrine and other microfacies. On the surface, the first section of the Majiagou Formation - the six sections mainly develop six paleogeographical units such as Lu (Long), Yunping, Salt Lake, Pasteur Lake, open platform and shallow bank. The distribution of cells in each segment is different. In the semi-closed tectonic framework, the preparation brine supply mode mainly dominated by the North China ancient land surface sea and the Ordovician extreme drought palaeoclimatic conditions, the favorable K-bearing zone is finally located in the salt Au-Suide area in the eastern Ordos Basin.