海相碳酸盐台地含钾层段旋回地层学响应和识别——以川中广安地区三叠系为例  

Identification of the Potassium-rich Member in Carbonate Platform and Its Response to the Gamma Ray Well Logging from the Perspective of Cyclostratigraphy:A Case Study in Triassic of Guangan Area,in the Central Sichuan Basin

作　　者：龚大兴[1] 周家云[1] 陈科贵[2] 李春梅[2] 李萌[3] 

机构地区：[1]中国地质科学院矿产综合利用研究所,成都610041 [2]西南石油大学,成都610500 [3]中国石油天然气股份有限公司勘探开发研究院,北京100083

出　　处：《高校地质学报》2014年第2期230-238,共9页Geological Journal of China Universities

基　　金：国家973项目"中国陆块海相成钾规律及预测研究"(2011CB403000);国家自然科学基金(41102060)资助

摘　　要：识别海相碳酸盐岩台地深部的成盐聚钾层段,主要依靠测井解译和钻井取芯验证。连续沉积的碳酸盐岩台地具有旋回性,记录着海相碳酸盐岩随古海平面旋回变化的信息。因此,利用测井数据模拟台地高频沉积旋回叠加样式,反演古海平面旋回,寻找海退地层序列的低水位沉积体系,进而快速锁定成盐聚钾层段的方法值得探索。文中以四川盆地川中广安地区三叠系为例,以等间距连续测量的自然伽马测井数据为对象,运用数值模拟技术,有效识别了三叠纪沉积时期的高频沉积旋回,并根据高频沉积旋回的累积厚度偏差变化,反演了古海平面的变化趋势,判断广安地区嘉陵江组5段至雷口坡组1段第1亚段沉积期,相对海平面长期处于较低水位,是最有利的成盐聚钾期,这与基于钻井岩芯划分的富钾层段极为吻合,表明这种方法能够有效识别碳酸盐岩台地含钾层段。To identify favorable salt-and potash-forming layer, we mainly rely on logging interpretation and coring verification. The continuously carbonate platform shows cyclical growing and recorded valuable information about the facies transition of carbonate rocks, which was synchronized with the relative sea-level cycles. This paper presents a method to preliminarily judge favorable potassium-rich intervals. By using natural gamma ray logging data and numerical simulation, high-frequency sedimentary cycles could be identified effectively from the sedimentary record. Then, we can inverse the distribution model and stacking patterns of these cycles, restore the ancient relative sea-level trends, and finally deduce the favorable salt-and potash-forming phases from the low-stand depositional system. On the basis of these principles, a case study has been taken in the Triassic strata of＆amp;nbsp;the Guang’an area, in the central Sichuan Basin. Our result show that the interval between the Fifth Member of the Jialingjiang Formation to the First Member of the Leikoupo Formation is the most potential salt-and potash-forming layer, which is consistent with the potassium-rich layer recognized in the drill cores. It shows that this method could effectively identify potassium rich layer from the marine carbonate platform.

关 键 词：海相碳酸盐岩台地 沉积旋回 含钾层段 测井响应 三叠系 川中地区 

分 类 号：P534.51[天文地球—古生物学与地层学]