古地貌对礁滩储层的控制作用——以四川盆地元坝地区二叠系长兴组为例  

Effect of palaeogeomorphology on reef-shoal reservoirs: A case study on Permian Changxing Formation, Yuanba area, Sichuan Basin

作　　者：王明筏 肖伟[1] 秦绪乾 张桂权 潘泽雄 叶晓斌 Wang Mingfa;Xiao Wei;Qin Xuqian;Zhang Guiquan;Pan Zexiong;Ye Xiaobin(Sinopec Exploration Company, Chengdu, Sichuan 610041, China)

机构地区：[1]中国石化勘探分公司

出　　处：《天然气勘探与开发》2018年第2期22-28,共7页Natural Gas Exploration and Development

基　　金：国家科技重大专项"海相碳酸盐岩层系大中型油气田分布规律及勘探评价"(编号:2011ZX05005-003-010HZ)

摘　　要：近年,四川盆地在环开江—梁平陆棚的上二叠统—下三叠统礁/滩型储层中获得了重大勘探突破,发现开江—梁平陆棚的形成与消亡控制着礁滩相展布,即沉积相发育受古地形、地貌的控制。为进一步探讨古地貌对储层的控制作用,以元坝地区长兴组为例,运用印模法恢复了长兴组末期古地貌,分析古地貌的展布特征。结果表明:研究区可划分为古台地、古斜坡、古陆棚3种二级古地貌类型,其中古台地又可细分为台地边缘高地、台地内部洼地2个三级古地貌类型,古陆棚可以划分为浅水和深水2个三级古地貌类型。通过对比古地貌与沉积相及储层的平面分布,认为:(1)不同类型古地貌控制着不同沉积相,不同沉积相控制着储层的展布;(2)储层之间物性差异较大,台地边缘礁滩为有利的储层发育区,优质储层的分布与台地边缘高地的展布相吻合。Recently, the reel-shoal reservoirs of Upper Permian-Lower Triassic around Kaijiang-Liangping continental shelf, Sichuan Basin, have made significant exploration breakthrough. It is demonstrated that the distribution of reef-shoal facies is controlled by the formation and extinction of this shelf, i.e., the sedimentary-facies development is controlled by palaeotopography and palaeogeomorphology. In this study, the late palaeogeomorphology of Changxing Formation in Yuanba area was restored by using the impression method to analyze its distribution, so as to further clarify its effect on reservoirs. It is shown that the study area can be divided into 3 types of second-order palaeogeomorphology, including palaeo-platform, palaeo-slope, and palaeo-shelf. The palaeo-platform is also subdivided into 2 types of third-order palaeogeomorphology, i.e., high at platform margin and depression inside platform whereas the palaeo-shelf is subdivided into 2 types of third-order palaeogeomorphology of both shallow water and deep water. The paleogeomorphological comparison of the plane distribution of sedimentary facies and reservoirs reveals that various paleogeomorphologies control different sedimentary facies and different sedimentary facies also affect reservoir distribution. Moreover, the physical properties vary greatly from one reservoir to another. The reef-shoal facies at platform margin are favorable for reservoirs developed, and the distribution of high-quality reservoirs is coincident with that of the high at platform margin.

关 键 词：四川盆地 元坝地区 晚二叠世 印模法 古地貌恢复 礁滩相储层 平面展布 

分 类 号：P618.13[天文地球—矿床学]