沉积相控制下致密砂岩气藏分布特征——以四川盆地川西坳陷中段蓬莱镇组为例

针对致密砂岩气藏受沉积相影响控制作用不明晰的情况，综合利用野外露头、岩心分析化验、测井和地震等资料，对川西坳陷中段蓬莱镇组沉积相进行了深入研究，最后探讨了沉积相对致密砂岩气藏的控制作用。研究表明：蓬莱镇组可以划分为2个长期、4个中期及29个短期旋回；蓬莱镇组沉积体主要受来自北西部的龙门山短轴物源控制为主，东部长轴物源次之；从龙门山前至成都凹陷区依次发育冲积扇、冲积平原、辫状河三角洲和湖泊相等沉积体系，东部主要为一套河流相沉积体系；蓬莱镇组含气砂体主要分布在西部三角洲平原、前缘（水下）分流河道、河口坝砂体和东部的河道边滩和心滩砂体中，呈不连续条带状分布；有利的含气圈闭主要受砂体叠置关系与构造或斜坡背景联合控制。

Characteristics of tight sandstone gas reservoir distribution under control of sedimentary facies: A case study from the Penglaizhen Formation in the central western Sichuan Depression

To understand the influences of sedimentary facies on tight sandstone gas reservoirs,this paper studied in-detail the sedimentary facies and their control on tight sandstone gas reservoir distribution of the Penglaizhen Formation in the central western Sichuan Depression by using outcrop,core,logging and seismic data.The Penglaizhen Formation can be stratigraphically divided into 2 long-term,4 middle-term and 29 short-term sedimentary cycles.The deposition of Penglaizhen Formation is controlled primarily by the short-axis provenance in the northwestern Longmen Mountain and secondly by the long-axis provenance in the eastern part.Alluvial fan,alluvial plain,braided river delta and lacustrine depositional systems occur successively from piedmont of Longmen Mountain to Chengdu sag.The eastern area is dominated by a fluvial depositional system.The gas-bearing sand bodies of the Penglaizhen Formation mainly occur in the western delta plain,delta front distributary channels and river mouth bars,as well as the eastern fluvial point bars and mid-channel bars in the forms of discrete sands.The potential gas-bearing traps are jointly controlled by the superposition of sand bodies and slope structural setting.