【作者】 金惠；

【导师】 姜在兴；

【作者基本信息】 中国地质大学（北京） ， 能源地质工程， 2010， 博士

【摘要】 上三叠统须家河组是近年来四川盆地天然气勘探的重要领域,在川中地区的广安、潼南等构造不断获得新的突破,展现出良好的勘探前景。川中地区须家河组具有沉积砂体厚度大、分布广、砂地比值高的特点,但目前对须家河组的沉积相模式、分布格局以及有利沉积微相的展布等认识程度较低。本文在层序地层学、沉积学和储层地质学等理论、技术的指导下,综合利用露头、岩心、测井和地震资料,开展了川中地区须家河组层序地层学和沉积砂体特征及展布研究,精细描述了有利沉积微相的分布,预测了有利砂体的展布,为研究区须家河组近期的勘探提供了充分的地质依据。这些成果不仅提高了须家河组沉积砂体的认识程度,而且也成功地应用于勘探实践,体现了成果重要的理论意义和应用价值。通过研究,论文取得6方面的认识和新进展:1)充分应用露头、岩心和测井资料,在川中地区须家河组识别出3类沉积相(冲积扇相、三角洲相和湖泊相)、8类沉积亚相和水下分流河道、河口坝等17类沉积微相,建立了须家河组沉积相模式;2)对川中地区须家河组进行精细层序地层划分,将其划分为4个三级层序和12个体系域。其中低位体系域主要发育三角洲沉积体系,湖侵和高位体系域主要发育湖泊沉积体系,低位体系域是有利储集砂体的主要形成时期,预测了层序格架内有利沉积相的展布;3)对有利储集砂体(层序Ⅱ、Ⅲ、Ⅳ的低位体系域)以准层序组为单元进行精细刻画,共划分出7个准层序组,建立了川中地区须家河组低位体系域准层序组地层格架,精细预测了有利储集砂体的展布;4)应用沉积微相研究成果,设计多期叠加河道和河口坝地质模型,利用弹性波动方程进行模型正演,建立相应的地震相模式,确定河道砂体的地震反射特征,根据振幅、频率、连续性和形态等地震参数识别出席状相、透镜状等六大类九亚类地震相,其中最有利的地震相为透镜状-波状变振中连地震相;5)川中地区须家河组为低孔低渗性储层,以粒间、粒内溶孔和剩余原生孔为主要储集空间,储层类型为孔隙型与裂缝-孔隙型,沉积微相、岩石类型与储层的发育关系密切,水下分流河道为最有利沉积微相,中粗粒长石岩屑砂岩为最有利岩石类型,综合评价了有利储层的分布;6)依据上述成果将川中地区须家河组划分为4个有利勘探砂带,并通过储层地震反演对重点砂带进行了储层预测,优选了3个勘探区块和11个勘探目标。更多还原

【Abstract】 Recently, the Upper Triassic Xujiahe formation which is potential strata has been an important area of natural gas exploration in the Sichuan basin. The new breakthrough of exploration of Xujiahe formation has been achieved in Guangan, Tongnan area. The huge thickness, extensive distribution, high proportionality of sandstone and mudstone are the characteristics of Xujiahe formation in the center of Sichuan basin. The study about the sedimentary facies model, the distribution of sedimentary facies and sedimentary microfacies is lacked.Guided by the principles and the methods of sequence stratigraphy , sedimentology and reservoir geology, using the integrated data of outcrops,cores, well log,and seismic, the paper carried out the sequence stratigraphy and sandbody distribution of Xujiahe formation in the center of Sichuan basin, deiscribed the favorable sedimentary microfacies distribution, predicated the distribution of the favorable sandbody, which provided abundant basis for the exploration to Xujiahe formation in the center of Sichuan basin. It is important and valuable when these research findings not only were used to the exploration successfully but also improved the study level about sedimentary sandbody in these area.The research findings indicated that:1) By using of the data of outcrops,cores, well log,and seismic, 3 sedimentary facies , 8 sedimentary subfacies and 17 sedimentary microfacies were distinguished in Xujiahe formation in the center of Sichuan basin. And the sedimentary model was established for Xujiahe formation .2) Based on the careful identification to the sequence stratigraphy, Xujiahe formation can be divided into four third-order sequences with twelve systems tracts. Lowstand systems tract which is the major deposition time for favorable sandbody is rich in delta depositional system, trangressive systems tract and highstand systems tract are rich in lake depositional system. On the base of the research, the distribution of favorable sedimentary facies were predicted in the paper. 3)Seven parasequence sets were distinguished for sequenceⅡ, sequenceⅢand sequenceⅣwhich are rich in reservoirs. The isochronal framework of parasequence sets stratigraphy for lowstand systems tract of Xujiahe formation were established to predicted the favorable sandbody.4) By means of the results of sedimentary microfacies, the multiple superposed channels and mouth bar models were designed for establishing its seismic faceis model using forward modeling in elastic wave equation . According to seismic facies parameters such as interior structure, exterior shape of seismic reflection units, reflected wave termination types, frequency, amplitude, continuity, bed velocity, six group and nine sub-group seismic facies are identified, in which the seismic facies characterised by lenticular-wave, unstable amplitude and medium continuous event is most favorable.5) Xujiahe formation in the center of Sichuan basin is the reservoir with low porosity, low permeability, in which space is intergranular dissolved pore, intragranular dissolved pore and remaining primary pore. The reservoir type is porous reservoir and fractured reservoir. The reservoir development has close tie with sedimentary microfacies and rock category. Underwater delta distributary channels is the favorable sedimentary microfacies. Mesograin and macrograin arkose arenite is the favorable rock.6) Based on the results, four favorable sandbodies of Xujiahe formation were divided in the center of Sichuan basin, and 3 exploration blocks,11 exploration targets were prior seeked using seismic inversion predict the distribution of reservoir in the key sandbody.更多还原