白云凹陷北坡珠江组沉积体系分析
发布时间：2018-08-28 08:12
【摘要】：位于珠江口盆地南部的白云凹陷油气资源十分充沛,储集条件很好,同时具有良好的运聚匹配条件及保存条件,因此白云凹陷及其周边地区具有非常良好的油气成藏条件,是最具有潜力的勘探区域之一。其中白云凹陷内珠江组地层每个层段中都勘探出油气,因此本文选取白云凹陷北坡珠江组为研究对象,这为今后整个珠江口盆地的砂体分布、有利区块的划分以及隐蔽油气藏的勘探起到指导意义。本文以层序地层学、沉积学及地震沉积学理论为依据,综合运用各种信息及资料,通过分析与预测相结合,在建立白云凹陷北坡珠江组等时地层格架的基础上,在等时地层格架内对每个层序的平面沉积体系展布及沉积演化规律研究之后,最后确定沉积相模式。第一步,对岩心资料的分析及观察之后,共划分出了12种岩石相并划分出7种主要的岩石相组合。然后在此基础上综合考虑测井资料等分析了该区的单井沉积相。认为白云凹陷北坡珠江组沉积体系主要发育3种沉积相、3种沉积亚相及7种沉积微相,同时,总结了白云凹陷北坡珠江组的测井相及测井响应特征。其次,本论文参考IODP1148站与珠江口盆地的可对比性,借助其连续取心的优势,客观的的反映出渐新世-中新世的海平面变化,为白云凹陷北坡珠江组层序地层研究起到了指导作用。同时综合考虑区域内地球化学资料、古生物资料和全球气候的变化,结合整个珠江口盆地十七万平方公里的地震资料,寻找上超、顶超、削截等不整合特征与单井所划分的层序和体系域进行结合,共识别出六个三级层序界面,以及五个三级层序。通过由点(单井)一线(连井)一面(平面)的方式,在层序地层格架内,对白云凹陷北坡珠江组沉积体系组合分析,研究了沉积体系时空分布演化特征。研究认为NSQl:23.8-21Ma层序发育时期,南部番禺低突起以南至白云凹陷可见小面积的斜交前积反射特征,反映了前积式的三角洲沉积。由于高位时相对海平面下降速率极大,陆架边缘三角洲发育。在番禺低隆起以南,白云凹陷北坡,发育低位盆底扇、斜坡扇及前积楔状体(低位三角洲)。NSQ2:21-18.5Ma在白云凹陷北坡PY34.PY35井区附近均发育有低位楔状体—低位三角洲砂体,及海侵三角洲砂体。NSQ3:18Ma-17.5Ma时期,相对海平面下降速率较小,由于近源区截留,物源供应不充分,陆架边缘三角洲不发育,高位虽有前积反射特征,但以富泥沉积为主,陆架边缘三角洲不发育。NSQ4:17.5-17Ma此时沉积主要以浅海-半深海沉积为主,层序主要沉积海相泥岩。NSQ5:17-16.5Ma层序则砂岩明显增多。地震反射同相轴多以平行亚平行居多—陆架边缘三角洲发育。最后,对沉积体系砂体平面展布和内部构成特征进行精细刻画,总结出白云凹陷北坡珠江组沉积体系组合的沉积模式。预测白云凹陷北坡珠江组沉积体系组合的有利相带,认为NSQ1三角洲前缘河口砂坝、远砂坝或席状砂沉积,是由于海平面的上升。该类有利区由三角洲前缘过渡到浅海陆棚相。三角洲前缘发育有较且物性较好的砂岩,为良好的储集体,而浅海陆棚的泥岩则是极好的盖层。NSQ2层序一方面为三角洲前缘的沉积,其相序叠置关系和岩性变化特征与NSQ1相似,所不同的其发育范围明显增加,这是由于海平面逐渐上升的结果；另一方面有利区域内的储集层是发育在厚层海相泥岩中的重力流沉积,该类型广泛分布在陆架坡折带上,其储集物性好,且由于是发育在厚层泥岩中,储盖组合较为有利。NSQ3时期有利区的储集层是前期沉积的三角洲前缘砂体受后期潮流作用的改造而重新沉积的潮汐砂脊(或陆架砂脊)。NSQ4时期该时期的有利区域与前一层序基本一致。略有不同的是随着海平面逐渐的下降,三角洲与陆棚交互区以及滨岸与陆棚交互区略微向南偏移。NSQ5时期随着海平面的持续下降和碳酸盐台地的逐渐萎缩,在17.1-16.5Ma时期,三角洲与陆棚的交互带为有利区域。
[Abstract]:Baiyun sag, located in the south of Pearl River Mouth Basin, has abundant oil and gas resources, good reservoir conditions, good migration and accumulation matching conditions and preservation conditions. Therefore, Baiyun sag and its surrounding areas have very good oil and gas accumulation conditions, which is one of the most potential exploration areas. The Pearl River Formation on the northern slope of Baiyun Depression is selected as the research object in this paper, which will guide the distribution of sand bodies, the division of favorable blocks and the exploration of subtle reservoirs in the whole Pearl River Mouth Basin in the future. Based on the isochronal stratigraphic framework of the Pearl River Formation on the northern slope of Baiyun Sag, the distribution of the planar sedimentary system and the law of sedimentary evolution of each sequence are studied in the isochronal stratigraphic framework. Finally, the sedimentary facies model is determined. The first step is to divide the core data after analysis and observation. On this basis, the sedimentary facies of the single well in this area are analyzed comprehensively considering logging data. It is considered that the sedimentary system of the Pearl River Formation in the northern slope of Baiyun Sag mainly develops three sedimentary facies, three sedimentary subfacies and seven sedimentary microfacies. At the same time, the survey of the Pearl River Formation in the northern slope of Baiyun Sag is summarized. Secondly, this paper objectively reflects the Oligocene-Miocene sea-level changes by referring to the comparability between IODP 1148 and Pearl River Mouth Basin and by virtue of its advantages of continuous coring, which plays a guiding role in the sequence stratigraphic study of the Pearl River Formation on the northern slope of Baiyun Sag. According to the data, palaeobiological data and global climate change, combined with the seismic data of 170,000 square kilometers in the whole Pearl River Estuary Basin, the unconformity characteristics such as super, super-top and truncation are searched and combined with the sequence and system tract divided by single well. Six third-order sequence boundaries and five third-order sequences are identified. In the sequence stratigraphic framework, the temporal and spatial distribution and evolution characteristics of the sedimentary system in the Pearl River Formation on the northern slope of the Baiyun Sag are studied. The delta deposits are developed on the continental shelf margin due to the great rate of relative sea-level decline at high altitudes. In the south of Panyu low uplift and the north slope of Baiyun sag, there are low-lying basin floor fan, slope fan and fore-cumulus wedge (low-lying delta). NSQ2:21-18.5Ma, there are low-lying wedge-low-lying wedge bodies near the PY34.PY35 well area on the northern slope of Baiyun sag. Delta sandbodies and transgressive Delta sandbodies. In the period of NSQ3:18Ma-17.5Ma, the relative sea level declined at a relatively low rate. Due to the close source interception, the source supply was insufficient, the continental shelf margin delta was not developed, although the high position had the characteristics of pre-accumulated reflection, the main deposit was mud-rich sediments, and the continental shelf margin delta was not developed. The sequence of NSQ5:17-16.5Ma is markedly more sandstones. Most of the seismic reflection events are parallel sub-parallel with the development of the continental shelf margin delta. Sedimentary model of sedimentary system assemblage. It is predicted that the favorable facies zone of sedimentary system assemblage of Pearl River Formation on the northern slope of Baiyun Sag is attributed to the rise of sea level in the estuary bar, distal bar or sheet sand deposits in the delta front. The favorable areas transit from delta front to shallow shelf facies. The NSQ2 sequence is delta front deposit on the one hand, its facies sequence superimposition relation and lithologic change characteristics are similar to NSQ1, and its development range is obviously increased, which is due to the gradual rise of sea level; on the other hand, the favorable reservoir in the area. It is a kind of gravity current deposit developed in thick marine mudstone, which is widely distributed in shelf slope break zone. It has good reservoir property and favorable reservoir-cap assemblage because it is developed in thick mudstone. The favorable areas of the period are basically the same as the previous sequence. The slightly different is that the delta-shelf interaction area and the coastal-shelf interaction area migrate slightly southward with the gradual decrease of sea level. In the period of NSQ5, with the continuous decrease of sea level and the gradual shrinkage of carbonate platforms, the favorable areas are between 17.1 and 16. In the period of 5Ma, the interaction zone between Delta and continental shelf is favorable area.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13
本文编号：2208808
[Abstract]:Baiyun sag, located in the south of Pearl River Mouth Basin, has abundant oil and gas resources, good reservoir conditions, good migration and accumulation matching conditions and preservation conditions. Therefore, Baiyun sag and its surrounding areas have very good oil and gas accumulation conditions, which is one of the most potential exploration areas. The Pearl River Formation on the northern slope of Baiyun Depression is selected as the research object in this paper, which will guide the distribution of sand bodies, the division of favorable blocks and the exploration of subtle reservoirs in the whole Pearl River Mouth Basin in the future. Based on the isochronal stratigraphic framework of the Pearl River Formation on the northern slope of Baiyun Sag, the distribution of the planar sedimentary system and the law of sedimentary evolution of each sequence are studied in the isochronal stratigraphic framework. Finally, the sedimentary facies model is determined. The first step is to divide the core data after analysis and observation. On this basis, the sedimentary facies of the single well in this area are analyzed comprehensively considering logging data. It is considered that the sedimentary system of the Pearl River Formation in the northern slope of Baiyun Sag mainly develops three sedimentary facies, three sedimentary subfacies and seven sedimentary microfacies. At the same time, the survey of the Pearl River Formation in the northern slope of Baiyun Sag is summarized. Secondly, this paper objectively reflects the Oligocene-Miocene sea-level changes by referring to the comparability between IODP 1148 and Pearl River Mouth Basin and by virtue of its advantages of continuous coring, which plays a guiding role in the sequence stratigraphic study of the Pearl River Formation on the northern slope of Baiyun Sag. According to the data, palaeobiological data and global climate change, combined with the seismic data of 170,000 square kilometers in the whole Pearl River Estuary Basin, the unconformity characteristics such as super, super-top and truncation are searched and combined with the sequence and system tract divided by single well. Six third-order sequence boundaries and five third-order sequences are identified. In the sequence stratigraphic framework, the temporal and spatial distribution and evolution characteristics of the sedimentary system in the Pearl River Formation on the northern slope of the Baiyun Sag are studied. The delta deposits are developed on the continental shelf margin due to the great rate of relative sea-level decline at high altitudes. In the south of Panyu low uplift and the north slope of Baiyun sag, there are low-lying basin floor fan, slope fan and fore-cumulus wedge (low-lying delta). NSQ2:21-18.5Ma, there are low-lying wedge-low-lying wedge bodies near the PY34.PY35 well area on the northern slope of Baiyun sag. Delta sandbodies and transgressive Delta sandbodies. In the period of NSQ3:18Ma-17.5Ma, the relative sea level declined at a relatively low rate. Due to the close source interception, the source supply was insufficient, the continental shelf margin delta was not developed, although the high position had the characteristics of pre-accumulated reflection, the main deposit was mud-rich sediments, and the continental shelf margin delta was not developed. The sequence of NSQ5:17-16.5Ma is markedly more sandstones. Most of the seismic reflection events are parallel sub-parallel with the development of the continental shelf margin delta. Sedimentary model of sedimentary system assemblage. It is predicted that the favorable facies zone of sedimentary system assemblage of Pearl River Formation on the northern slope of Baiyun Sag is attributed to the rise of sea level in the estuary bar, distal bar or sheet sand deposits in the delta front. The favorable areas transit from delta front to shallow shelf facies. The NSQ2 sequence is delta front deposit on the one hand, its facies sequence superimposition relation and lithologic change characteristics are similar to NSQ1, and its development range is obviously increased, which is due to the gradual rise of sea level; on the other hand, the favorable reservoir in the area. It is a kind of gravity current deposit developed in thick marine mudstone, which is widely distributed in shelf slope break zone. It has good reservoir property and favorable reservoir-cap assemblage because it is developed in thick mudstone. The favorable areas of the period are basically the same as the previous sequence. The slightly different is that the delta-shelf interaction area and the coastal-shelf interaction area migrate slightly southward with the gradual decrease of sea level. In the period of NSQ5, with the continuous decrease of sea level and the gradual shrinkage of carbonate platforms, the favorable areas are between 17.1 and 16. In the period of 5Ma, the interaction zone between Delta and continental shelf is favorable area.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13
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