【摘要】 四川盆地东部志留系小河坝组/石牛栏组同时发育碳酸盐岩与海相碎屑岩沉积，下伏龙马溪组优质烃源岩，成藏条件优越。然而，目前对小河坝组/石牛栏组沉积格局与储层特征认识不足，制约了油气勘探进程。综合露头、钻井及地震资料，开展沉积与储层特征研究，结果表明：（1）川东地区小河坝组/石牛栏组发育开阔台地、三角洲与陆棚等沉积相，进一步可划分出8种沉积微相。沉积相空间分布受古地貌控制，其中川中古隆起南斜坡高地貌区发育开阔台地及高能台内礁滩体；川南泸州与川东石柱—万州两个深水洼地发育深水陆棚沉积；川中古隆起东斜坡及川东的高地貌区发育三角洲沉积。（2）小河坝组发育致密砂岩储层，石牛栏组发育滩相石灰岩储层，二者具低孔低渗特征，受岩溶与裂缝改造时储层物性改善。储层分布受沉积相及古地貌控制，环川中古隆起高地貌区发育的礁滩体及三角洲前缘砂体易受多期岩溶控制，从而形成优质储层。（3）基于储层分布及烃源岩、断裂等成藏要素综合分析，提出3个有利勘探区。有利区Ⅰ和Ⅱ分别位于南川—石柱和达州一带，为致密砂岩勘探有利区。有利区Ⅲ位于荣昌—重庆—邻水一带，为滩相石灰岩勘探有利区。更多还原

【Abstract】 The carbonate and marine clastic sediments were deposited in the Silurian Xiaoheba/Shiniulan Formation in the eastern Sichuan Basin, showing superior conditions for hydrocarbon accumulation together with the underlying high-quality source rock in Longmaxi Formation. However, there is insufficient understanding of sedimentary and reservoir characteristics in Xiaoheba/Shiniulan Formation, which hinders the exploration progress. By integrating outcrop, well drilling and seismic data, the sedimentary and reservoir characteristics have been studied. The results indicate that:(1) Xiaoheba/Shiniulan Formation strata were deposited in open platform, delta, and shelf facies zones in the eastern Sichuan Basin, which can be further subdivided into eight types of microfacies zones. The spatial distribution of these facies zones was predominantly controlled by paleogeomorphology, among which open platform and high-energy intra-platform reef beach deposits were developed in the highland area of the south slope of Central Sichuan Paleo Uplift, deep-water shelf deposits were developed in the two deep-water subsags in southern Sichuan Luzhou and eastern Sichuan Shizhu-Wanzhou areas, and delta sediments were deposited in the east slope of Central Sichuan Paleo Uplift and the highland area in the eastern Sichuan Basin.(2) The tight sandstone reservoir in Xiaoheba Formation and beach facies limestone reservoir in Shiniulan Formation are generally characterized by low porosity and low permeability, with the reservoir quality significantly improved after karstification and fracture reconstruction. The reservoir distribution was controlled by sedimentary facies and paleogeomorphology, and reef beach and delta front sandstones in the highland area in the circum Central Sichuan Paleo Uplift were frequently subjected to multi-stage karstification, forming high-quality reservoirs.(3) Based on comprehensive analysis of hydrocarbon accumulation elements such as reservoir distribution, source rocks, and faults, three favorable exploration zones have been proposed, in which Zones Ⅰ and Ⅱ(Nanchuan-Shizhu and Dazhou areas) are prospective for tight sandstone exploration, while Zone Ⅲ(Rongchang-Chongqing-Linshui area) is prospective for beach facies limestone exploration.更多还原