海拉尔盆地乌尔逊—贝尔凹陷铜钵庙组—大磨拐河组火山—碎屑沉

1、海拉尔盆地乌尔逊贝尔凹陷铜钵庙组大磨拐河组火山碎屑沉        【中文摘要】本文通过38口井的岩心描述和薄片分析确定了海拉尔盆地贝尔-乌尔逊凹陷铜钵庙-大磨拐河组的岩石类型主要有火山碎屑沉积岩、沉积岩、火山碎屑岩、沉积火山碎屑岩、火山熔岩五大类。在此基础上辅助粒度分析进行单井相分析,取得了较可靠的岩心沉积相分析结果,再配合含砂率等值线图分析,实现了对贝尔-乌尔逊凹陷铜钵庙-大磨拐河组的沉积相类型的熟悉,并对沉积相在平面上的展布特征进行了分析。研究区内目的层系共发育冲积扇、辫状河、曲流河、扇三角洲、三角洲、滨湖、

2、浅湖、半深湖、近岸水下扇、水下扇、污流等沉积,且研究区内火山碎屑与正常陆源碎屑的混积现象严重,火山岩以微相的形式存在于正常的沉积相带。最后对研究区内目的层位的油气显示进行统计,得知最有利的储集相带是扇三角洲,次为近岸水下扇、浊积扇、湖泊中的水下扇。而在这些相带中,最有利的沉积微相砂体是:扇三角洲相前缘的水下河道、河口砂坝、远砂坝和席状砂;近岸水下扇的水道砂体;浅湖-半深湖中的浊积砂体、水下扇砂体等。');【Abstract】 Hailaer basin is the biggest oil and gas basin on the periphery area of Songliao

3、basin. Wuerxun and Beier, two bigger sub-fault depressions lie in the south of Beier Lake sag with the potential of exploration and development on oil and gas. So far, Wuerxun and Beier depressions have been in relative higher stage in prospecting, with more than 70 wells for exploration and more th

4、an 50 wells for development evaluation. However, the lithology of this region is very complex. There are some conflicts in identifying rocks. This has made the logging interpretation and the reconstruction of sedimentary environments difficult and uncertain, affecting the following exploration going

5、 on well. It is necessary to study the lithology and do systemic sedimentary research, to provide advantageous exploration belts and targets.1.MethoLogy of The ResearchBased on the description of well cores, the identification of the thin section and the grain size analysis, we got the lithologies o

6、f the research area and did the well sedimentary facies analysis. As a result, dependable analysis of core sedimentary facies had been obtained, while the description of sedimentary features and facies types had been done with the precision to microfacies. Further, with the analysis of map of sand c

7、ontent rate isoline, the preponderant facies was defined to realize the plane distribution feature of sedimentary facies and to analyze the features of sedimentary facies and the directions of provenances. On the above researches and the related data, some analysis of reservoir rocks were given thro

8、ugh doing some statistics on the oil and gas shows in study well, to find out the relation between oil and gas shows and sedimentary facies, especially microfacies for the prediction of advantageous reservoir sands.2.Research on Types of RockThe lithology of Budate group- Damoguaihe formation in Wue

9、rxun-Beier depressions of Hailaer Basin is a set of rocks between volcanic lava and normal sedimentary clastic rock, mainly of volcanic lava, pyroclastic rock , sed pyroclastic rock, pyroclastic sedimentary rock, normal sedimentary rock. The abundance of types of rocks reduces in turn according to t

10、he following: pyroclastic sedimentary rock, sedimentary rock, pyroclastic rock, sed pyroclastic rock, volcanic lava. Abundance of pyroclastic sedimentary occupies the absolutely superiority.3.Particularity in The Growth of Sedimentary Facies and The Types of Sedimentary FaciesThe research area in th

11、at time was located in a part of volcanism deposition region and deposition region. There are seriously chaotic mélange of volcanic clasts and normal terrigenous clasts. Volcanic rock exists in forms of sedimentary microfacies in normal sedimentary belt. The special deposition of volcanic clast

12、 mainly displays in: volcanic clast channel, volcanic clast delta, volcanic ash in lacustrine environment, and so on.The target layers are sets of terrestrial deposits, including alluvial fan, braided stream, meandering river, fan delta, delta, nearshore subaqueous fan, turbidity current, subaqueous

13、 fan, coastal lake, shallow lake, half-deep lake. In the view of dispositional sequences, The episodic faulting is reflected in the depositional sequence (possibly exist conglomerate) of conglomerate - sandstone - mudstonesandstone. With the participation of volcanic activity, it will take on the de

14、positional sequence of conglomerate - pyroclastic rocks/sandstone - mudstone (possibly exist pyroclastic rocks) - sandstone (possibly exist conglomerate), also is the structure of deposition -volcano - deposition. This has reflected the control of structure - volcanism to the fills of the basin, cor

15、responding to the divisions: faulting, faulting - volcanism and post faulting stage. This kind of depositional evolution not only may be reflected in the 4-5 rank of depositional cycle, but also reflected in the high ranks, like group or formation cycles.4.The Plane Distribution of Sedimentary Facie

16、sWuerxun depression:The sedimentary facies belts of Tongbomiao formation distributed in north-east. There were alluvial fan, fan delta- nearshore subaqueous fan, fluvial facies, coastal-shallow lake, half-deep lake. Marginal facies grew very well, and provenances were from northwest and southeast. T

17、he sedimentary facies belts of the first member in Nantun formation still ditrbuted nearly north-east. There were alluvial fan, fan delta, shallow lake, half-deep lake facies. And shallow lake sediments were dominated. The provenances were from northwest and southeast. There were alluvial fan, fan d

18、elta, nearshore subaqueous fan, coastal lake, shallow lake, half-deep lake facies in the second member of Nantun formation. Half-deep lake sediments were dominated, and half -deep lake lay in the middle of the depression, took on nearly south-north in a shape of irregular ellipse. The provenances we

19、re from northwest, southwest and east. There were fan delta, shallow lake, half-deep lake facies in Damoguaihe formation. The sedimentary facies belts distributed in north-east. The provenances were from northwest and east.Beier depression:There were alluvial fan, fan delta, fluvial facies, shallow

20、-half-deep lake facies in Tongbomiao formation. Marginal facies grew very well, the provenances were from west in the south, south, east in the south and east in the north. There were alluvial fan, braided stream, fan delta, delta, alluvial plain-coastal-shallow lake, shallow -half-deep lake facies

21、in the first member of Nantun formation. Marginal facies grew very well, the provenances were from northwest, southwest, south and northeast. There were alluvial fan, braided stream, fan delta, shallow lake, half-deep lake facies in the second member of Nantun formation. Lake sediments were dominate

22、d, and there were two half-deep lake regions separately lying in south and north. The provenances were from west in the south and nearly southeast in the south. There were fluvial facies - delta, coastal lake, shallow lake facies in Damoguaihe formation. Shallow lake sediments were dominated. Provenance was from west.5. Di