| 东营凹陷东辛2-4井上新世至全新世天文地层研究 |
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| 作者单位： | 中石化胜利油田有限公司地质科学研究院,中国地震局地质研究所,中国科学院国家天文台 |
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| 摘 要： | 东辛2-4井钻取岩芯0—530.1m,明化镇组上段的上亚段至平原组划分为18个层,其中,下更新统平原组一段(简称平一段)的底作为第四系下界;同时进行了古地磁研究,测定出布容、松山、高斯和吉尔伯特等4个极性时。由于天文地层研究的需要,对90年代古地磁的年龄与"国际地层表"(2004)对比,作了相应调整,确定井深242.5m处的年龄为781ka,274.5m处的为2581ka,452.0m处的为3596ka和529.5m处的为4493ka,井深242.5m和452.0m这两个界线的年龄值作为天文地层计时的标定。研究大致分为两步:①以磁化强度(MI)数值曲线的频谱和小波分析,选定平原组一段102.4m周期和明化镇组上段68.36m周期分别对应于天文偏心率404ka旋回,求出了堆积速率为0.1584mm/a和0.1692mm/a及其他各层位的年龄:井深274.5m处上新统明上(上)亚段顶界的年龄为2546ka,平一段底界的年龄是970ka,不整合的延续时间大约为1.6Myr。②推测明上(上)亚段顶2546—1806ka期间可能沉积了129m地层;而在1806—908ka期间,由于构造活动上升,把原沉积又剥蚀掉了,形成井深274.5m处的一个大的不整合面,对储层孔隙的扩张和压实有重要影响,成为最后二次烃源物质的卸载和封堵。
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| 关 键 词： | 磁性地层 沉积速率 天文地层 上新统 全新统 东营凹陷 山东 |
THE PLIOCENE-HOLOCENE ASTROSTRATIGRAPHIC STUDY OF WELL DONGXIN 2-4 IN THE DONGYING DEPRESSION |
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| Authors: | YAO Yi-min XU Dao-yi ZHANG Hai-feng HAN Yan-ben ZHANG Shou-peng YIN Zhi-qiang HE Qing-fang and BIAN Xue-mei Geological Scientific Research Institute of Shengli Oilfield Company SINOPEC Dongying Institute of Geology China Earthquake Administration Beijing National Astronomical Observatories Chinese Academy of Sciences Beijing |
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| Institution: | YAO Yi-min 1),XU Dao-yi 2),ZHANG Hai-feng 1),HAN Yan-ben 3),ZHANG Shou-peng 1),YIN Zhi-qiang 3),HE Qing-fang 1) and BIAN Xue-mei 1) 1) Geological Scientific Research Institute of Shengli Oilfield Company,SINOPEC,Dongying,257015, 2) Institute of Geology,China Earthquake Administration,Beijing,100029,3) National Astronomical Observatories,Chinese Academy of Sciences,Beijing,100012 |
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| Abstract: | Well Dongxing 2-4 is a shallow well drilled in 1990 and a core of 0—530.1 m was obtained from it. The strata from the Upper Submember of Upper Member of Minghuazhen Formation (shortened to U. Upper Submember of Ming) to the Pingyuan Formation are divided into 18 beds. The base of the First Member of the lower Pleistocene Pingyuan Formation (shortened to Ping 1) is used as the base of the Quaternary System. A paleomagnetic analysis was made and 4 Polarity epochs ( Brunhes, Matuyama, Gauss, and Gilbert) were recognized. Owing to the need for the astrostratigraphic study in recent years, correlations between the paleomagnetic dating in 1990s and the ages in International Stratigraphic Chart (2004) have been correspondingly adjusted. It has been determined that the age at a well depth of 242.5m is 0.781Ma, at 274.5m being 2.581Ma, at 452.3m being 3.596Ma. and at 529.5m being 4.493Ma. Of these, two boundary age values at 242.5m and 452.3m were used as the calibration of the astrostratigraphic dating in this paper. Studies were conducted in two stages: 1) based on the frequency spectrum of MI numerical curve and wavelet analysis, the period values of the Ping 1 (102.4 m) and the Upper Member of Minghuazhen Formation (68.36m) were selected respectively to respond to 404ka cycle of astronomic eccentricity, and accumulation rates of 0.1584mm/a and 0.1692mm/a as well as the ages of various beds were obtained, i.e. at 274.5m, the top boundary of the U.Upper Submember of the Pliocene Minghuazhen Formation is 2.546Ma in age, the basal boundary of Ping 1, is 0.970Ma in age and the duration of unconformity is about 1.6Myr; 2) it is deduced that during 2.546 to 1.806Ma, 129m of strata would be deposited on the top of the U.Upper Submember of Minghuazhen Formation. However, during 1.806 to 0.908Ma, owing to tectonic uplift, the original sediments were denuded. Therefore, a big unconformity plane was formed at 274.5m, having an important effect on the extension and compaction of pores of the reservoir and resulting in the unloading and plugging of the last two hydrocarbon source substances. |
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| Keywords: | astrostratigraphy magneto-stratigraphy accumulation rate Pliocene Holocene Dongying Depression Shandong Province |
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