东营凹陷沙四下盐湖相沉积序列

Sedimentary sequences of salt-lake facies in Lower Es_4 of Dongying Depression

根据岩心、岩屑和测井等资料,依据沉积学理论和马尔科夫链方法,对东营凹陷东部沙四下盐湖相沉积特征、沉积序列和对比模式进行研究。结果表明:东营凹陷东部沙四下沉积时期盐湖同时存在深水、浅水两种蒸发岩的沉积特征;深水蒸发岩主要与近岸水下扇砂砾岩和深水深灰色泥页岩共生,发育在湖盆中心和北部陡坡带,以石膏和石盐沉积为主;浅水蒸发岩主要与漫湖三角洲粉、细砂岩和紫红色泥岩共生,发育在湖盆南坡的浅水沉积环境中,发育石膏、石盐和碳酸盐岩沉积;第一套膏盐层存在4种对比模式,第二和第三套膏盐层存在两种对比模式。

Using rock cores, rock fragments and well logs, we studied the sedimentary characteristics, the sedimentary se-quences and the correlation methods of lower Es4 in the eastern Dongying Depression, based on the theories of sedimentation and Markov chain method. The results reveal the existence of shoal and deep water evaporates in the Es4 salt-lake. The deep water evaporates, mainly gypsum and halite, are associated with glutenite of the near-shore subaqueous fan and charcoal grey deep-water shale, and are mostly in the center of the lake basin and the north steep slope. The shoal evaporates, mainly gyp-sum, halite and carbon rock, are associated with sand and purplish red mudstone of the over-lake delta, and are mostly in the south gentle slope. There are four correlation methods in the first gypsum-salt layer and two correlation methods in the second and third gypsum-salt layer.