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临南洼陷沙四上沉积体系研究及勘探潜力评价
The Investigation of the Depositional System in Linnan Low-laying upper E2S4 and the Evaluation of Exploration Potential
【作者】 田振环;
【导师】 李巍然;
【作者基本信息】 中国海洋大学 , 海洋地质, 2007, 硕士
【摘要】 临南洼陷位于济阳坳陷的西部,属于惠民凹陷的次级构造单元。洼陷北侧的临商断裂构造带聚集了丰富的油气,洼陷内部的火成岩构造和南侧的斜坡带也形成了工业油气田。随着油气勘探工作的逐步深入,在洼陷中发现大、中型构造油气藏的机率越来越小,发现隐蔽油气藏的比重逐渐增大,勘探重点也由大中型构造油气藏转向中小型构造岩性隐蔽油气藏。临南洼陷沙四段主要沉积了一套滨浅湖相的粉砂、细砂岩与泥岩互层和火山碎屑岩,由于深层钻井揭示较少,是否存在深湖相生油岩系一直是人们关心的问题。从沙四段形成的沉积环境分析,临南洼陷具备形成生油岩的有利条件。本文采用层序地层学的方法研究沙四上亚段的沉积体系架构,弄清砂体的空间分布,揭示其生烃潜力,为临南洼陷隐蔽性油气藏的勘探提供依据。本文的研究方法是,首先根据地震反射特征,结合测井、古生物和岩心资料,识别地层边界,划分出层序和体系域,建立层序地层格架。然后,根据自然电位、视电阻率等测井资料划分准层序叠加方式,识别出进积、加积和退积准层序组,并以准层序边界为标志进行井间对比标定。最后,运用岩心、测井、粒度分析、薄片分析等各类资料对关键井进行单井相分析,借助准层序组的沉积相、亚相分析,进行沉积体系研究,并对地层的生烃条件和成藏条件做出评价。根据地震、测井等资料将临南洼陷沙四上划分为一个三级层序,层序类型为T-R旋回层序,包含湖进、湖退两个体系域。临南洼陷沙四段暗色泥岩主要分布在沙四上亚段,属滨浅湖-半深湖沉积,有机质类型为较好-好烃源岩。临南地区沙四上亚段烃源岩从洼陷边缘向洼陷中心依次发育低成熟、成熟和高成熟带,可分别形成低熟油、正常原油和轻质油甚至凝析油和湿气。沙四上亚段暗色泥岩在沙一-东营期和晚第三纪均有生烃过程,早期生成低熟油,数量较少,后期生成的是成熟到高成熟的油气,为主要的生烃时期。沙四上亚段烃源岩确实出现了原油的排烃过程。通过盆地模拟计算,得到石油资源量0.8367×108t,天然气资源量47.1074×108m3,油气总资源量为0.8838×108t。得到结论是临南洼陷沙四段具有充足的油源、多种储集体、发达的疏导体系等有利成藏条件,是下步勘探的一个重要目标层系。
【Abstract】 The Linnan low-laying which is on the westward of Jiyang Depression ,is the hypo-grade tectonic cell of Huimin sag .In northern of the low-laying the tectonic zone of Lin-Shang fault assembled abundant oil & gas ,meanwhile the igneous rock structure and the southern slope of the Low-laying also formed industrial oil & gas field . Along with the of oil gas prospecting , the rate of finding big and middling oil gas reservoirs become less and less , moreover the proportion of subtle reservoirs will be more and more . Therefore the empresses of prospecting turn from big and middling constructional oil gas reservoirs to medium and little sized structural-lithologic subtle reservoirs .The E2S4 of Linnan low-laying mainly develops clastic volcanic and a suit of siltstone and thin sandstone / mudstone interbeds which is shore shallow lake sedimentary facies . Because of the less well exploration ,it is an issue being cared whether there is good source rocks sediment in the pass. On the face of the sedimentary environment of E2S4, there are good conditions for forming valuable source rocks in Linnan low-laying .This text using the sequence stratigraphic methods do research to the depositional system framework.,make clear the distributing of sand body in room and open out the generation potential ,so that to provide instruction for the subtle reservoirs in Linnan low-laying.The researching method of this investigation is that ,fist of all , basing on the seismic reflection character and uniting the well log data ,ancient biology data ,and core data ,identify the sequence boundaries , make off sequences and tracts and found the sequence stratigraphic framework .Secondly, according to the well log data such as spontaneous potential and apparent resistivity , divide the parasequence adding manner ,distinguish RST(regressive system tract),HST(highstand system tract),TST(transgressive system tract),do well contrasting sign with the parasequence boundaries .Finally using core data, well log data, granularity analysis data , and flick analysis data to do single well facie analysis in pivotal well . Relying on the analysis of the sedimentary facies , parafacies of every parasequence set , investigate the depositional system and do analysis to the hydrocarbon generation condition and formation conditions of reservoir in the stratum.According to the seismic data and well log data divide the upper E2S4 of Linnan low-laying into a third class sequence whose type is T-R cyclic sequence–including lake transgression and lake regression tracts. The dark mudstone of E2S4 in Linnan low-laying mainly distribute in the upper E2S4 which is shore shallow lake-semi crater lake sedimentary facies. Organic matter type is moderate to good source rocks. From the edge of depression to the center of depression the upper E2S4 source rocks divide into low maturity zone, normal maturity zone, high maturity zone, differently form immature oil, normal oil, light oil indeed condensate and moisture . The dark mudstone of E2S4 has the course of hydrocarbon generating both in S1-Dongying period and later tertiary. It is the primary hydrocarbon generating period in which in prophase generated a little low maturity and in anaphase generated normal maturity and high maturity. And base oil generating is really appearing in E2S4 source rocks. Through basin simulative account, we can know the oil resource quantity is 0.8367×108t and the gas resource quantity is 47.1074×108m3 ,oil gas resource quantity is 0.8838×108t . We can get the conclusion that there are many formation conditions of reservoir such as plenteous oil sources, multi reservoir and advantaged leading system. And it is the most important aim tier for prospecting in future.
【Key words】 The upper E2S4 of Linnan low-laying; sequence stratigraphic framework; sedimentary facies; tracts; organic matter type;
- 【网络出版投稿人】 中国海洋大学 【网络出版年期】2009年 02期
- 【分类号】P618.13
- 【被引频次】1
- 【下载频次】217