CAJ | 학술논문

广安地区上三叠统须六段为辫状河三角洲平原分流河道的大套砂岩复合体沉积,以中-细粒长石岩屑砂岩、岩屑砂岩为主;孔隙度主要分布在3%～15%之间,渗透率主要分布在0.01×10~(-3)～1×10~(-3) μm~2之间.主、次分流河道为该区有效储层,复合砂体内渗透层与致密层交互分布形成了复杂的储层分布特征.在此基础上,结合成岩作用分析储层物性的影响因素认为,物源成分的不同影响储层发育富集区的分布,沉积演化特征控制储层发育层段,沉积微相控制层内非均质性.在煤系地层酸性环境下,强烈压实作用是形成普遍低渗的主要原因.主分流河道沉积的中、粗粒长石岩屑砂岩次生孔隙较发育,是主要的储层岩石类型.
엄안지구상삼첩통수륙단위변상하삼각주평원분류하도적대투사암복합체침적,이중-세립장석암설사암、암설사암위주;공극도주요분포재3%～15%지간,삼투솔주요분포재0.01×10~(-3)～1×10~(-3) μm~2지간.주、차분류하도위해구유효저층,복합사체내삼투층여치밀층교호분포형성료복잡적저층분포특정.재차기출상,결합성암작용분석저층물성적영향인소인위,물원성분적불동영향저층발육부집구적분포,침적연화특정공제저층발육층단,침적미상공제층내비균질성.재매계지층산성배경하,강렬압실작용시형성보편저삼적주요원인.주분류하도침적적중、조립장석암설사암차생공극교발육,시주요적저층암석류형.
The Xu-6 reservoir of Guangan gas field is a large scale sandstone complex of distributary channels of braided delta plain sub facies, and the sandstones of reservoir are mainly medium grained feldspar detritus sandstone and detritus sandstone. It has low porosity and ultra low permeability, with a porosity distribution range of 3% to 15% and permeability distribution range of 0.01×10~(-3) to 1×10~(-3) μm~2. Main and sub-main distributary channels are effective reservoirs, and the alternate distribution of permeable zones and compact layers in sand complex lead to complicated reservoir distribution. Based on above results, and combined with diagenesis, the controlling factors of reservoirs are discussed. The reservoir development is controlled by three sedimentary factors of different scales: distinctive rock composition of sandstones from different source regions which affects enrichment areas of reservoirs;sedimentary evolution which controls reservoir distribution sections;sedimentary micro facies which determines the heterogeneity in sandstones of favorable sections. Strong compaction of sandstones in acid environment of coal measures layer is the main cause of general low permeability. Medium and coarse grained feldspar detritus sandstones deposited in main distributary channels, which have relatively high secondary dissolved pores, are the main sandstone type of reservoirs.