四川盆地开江—梁平海槽东侧三叠系飞仙关组鲕滩沉积特征  

Sedimentary characteristics of oolitic beach of Triassic Feixianguan Formation in eastern Kaijiang-Liangping trough,Sichuan Basin

作　　者：李阳 王兴志[1,2] 蒲柏宇 徐昌海[3] 杨西燕 朱逸青 黄梓桑 康家豪[1,2] LI Yang;WANG Xingzhi;PU Baiyu;XU Changhai;YANG Xiyan;ZHU Yiqing;HUANG Zisang;KANG Jiahao(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu 610500,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;Research Institute of Exploration and Development,PetroChina Southwest Oil and Gas Field Company,Chengdu 610041,China;Shale Gas Research Institute,PetroChina Southwest Oil and Gas Field Company,Chengdu 610051,China)

机构地区：[1]油气藏地质及开发工程国家重点实验室,成都610500 [2]西南石油大学地球科学与技术学院,成都610500 [3]中国石油西南油气田公司勘探开发研究院,成都610041 [4]中国石油西南油气田公司页岩气研究院,成都610051

出　　处：《岩性油气藏》2022年第2期116-130,共15页Lithologic Reservoirs

基　　金：国家科技重大专项“大型油气田及煤层气开发”的子课题“全球性海侵与气候变化对大型地层油气藏形成的控制作用”(编号:7ZX05001001-002);中国石油西南油气田分公司2019年开发前期评价项目“铁山坡、七里北、渡口河飞仙关组气藏鲕滩及优质储层分布规律研究”(编号:XNS勘研院JS2020-109)联合资助。

摘　　要：为了厘清四川盆地开江—梁平海槽东侧三叠系飞仙关组层序地层格架下鲕滩的时空分布特征,明确海平面变化对鲕滩迁移的控制机理,开展了岩性特征分析、沉积构造标志识别、层序界面层序地层格架划分等。结果表明:①开江—梁平海槽东侧飞仙关组在持续海退背景下发育2个三级层序(SQ1和SQ2),可进一步细分出5个四级层序(Ⅰ—Ⅴ)。②研究区飞仙关组鲕滩主要分布于Ⅰ—Ⅳ层序,Ⅱ层序内的鲕滩最为发育,单体厚度大、连续性好,而Ⅲ,Ⅰ和Ⅳ层序内的滩体发育程度依次减弱,最差呈不连续的零星状分布。③鲕滩在垂向加积的同时也具有明显的侧向迁移特征,整体由台地内部向斜坡方向迁移,其中Ⅰ层序至Ⅱ层序鲕滩侧向迁移特征最明显。④局部地貌高地发生的高频旋回与碳酸盐岩生产速率协同变化,导致研究区飞仙关组鲕滩呈现垂向加积和多期次叠置现象,而海平面下降到基准面以下时,适合滩体生长的水动力条件由局部高地向局部洼地变迁,使得鲕滩由垂向生长演化为侧向进积。⑤平面上,研究区飞仙关组鲕滩主要沿北西—南东(即台地边缘一带)方向展布,以铁山坡、普光地区最为发育,其次为渡口河、七里北以及罗家寨等地。该研究成果可为开江—梁平海槽地区飞仙关组优质滩相储层勘探提供依据。In order to clarify the temporal and spatial distribution characteristics of oolitic beach under the sequence stratigraphic framework of Triassic Feixianguan Formation in eastern Kaijiang-Liangping trough in Sichuan Basin,and the control mechanism of sea-level change on oolitic beach migration,lithologic characteristics analysis,identification of sedimentary structural markers and division of sequence stratigraphic framework of sequence boundary were carried out.The results show that:(1)Two third-order sequences(SQ1 and SQ2)are developed in Feixian‐guan Formation in eastern Kaijiang-Liangping trough under the background of continuous regression,which can be further subdivided into five fourth-order sequences(ⅠtoⅤ)(.2)The oolitic beach of Feixianguan Forma‐tion is mainly developed in sequenceⅠtoⅣ,and the oolitic beach in sequenceⅡis the most developed,with large single thickness and good continuity,while the sedimentary thickness of oolitic beach in sequenceⅢ,ⅠandⅣdecreases in turn,and the least developed oolitic beach is with discontinuous and sporadic distribution.(3)Besides vertical aggradation,oolitic beach has obvious lateral migration characteristics,migrating from the interior of the platform to the slope as a whole,and the lateral migration of oolitic beach in sequence I to is the most obvious.(4)The high-frequency cycles in local highlands and the production rate of carbonate rocks change synergistically,resulting in vertical aggradation and multi-stage superposition of oolitic beach of Feixianguan Formation in the study area.When the sea level drops below the base level,the hydrodynamic conditions suitable for beach growth change from local highlands to local depressions,resulting in the change of oolitic beaches from vertical growth to lateral progradation.(5)On the plane,the oolitic beach of Feixianguan Formation in the study area is mainly distributed along NW-SE direction(platform edge),most developed in Tieshanpo and Puguang areas,followed by Dukouhe,Qilibei and Luojiazhai areas.

关 键 词：鲕滩 层序 海平面升降 飞仙关组 三叠系 开江—梁平海槽 四川盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]