綦江地区须家河组天然气勘探潜力分析

GAS EXPLORATION POTENTIAL OF XUJIAHE FORMATION,QIJIANG AREA

从綦江及邻区须家河组地层特征、沉积特征、储层特征及烃源岩特征等方面,分析了须家河组含油气地质条件及勘探潜力。研究表明:1綦江地区上三叠统须家河组发育辫状河三角洲平原沉积,岩性组合具有"砂包泥"的特点,整体上辫状河道砂体发育,具备形成规模储层的基础;2储层岩石致密-超致密,为特低孔、特低渗储层,裂缝和次生溶孔是储层发育的关键;3通过寻找相对低砂地比层系,叠合深大断裂沟通的须家河组构造,寻找混合气源的构造-岩性油气藏;4有深大断裂沟通深部海相气源的须家河组构造是有利的勘探目标。

For the Xujiahe Formation in Qijiang and surrounding areas,the petroleum geology and exploration potential were analyzed in terms of some features of formation,sedimentary,reservoir,and source rock.Results show that(1)braided-river deltaic plain deposits are developed in this formation which is featured by a lithological association of sand wrapping mud,and the developed braided-channel sandbody is the fundament to form reservoir;(2)the reservoirs are tight to extra tight,characterized by extra low permeability and porosity,and fracture and secondary dissolution pore are critical for reservoir development;(3) some structural-lithological reservoirs with compound gas source may be found after the Xujiahe Formation structure and some strata with relatively low net-to-gross ratio were discovered;and(4)the deep marine gas-source Xujiahe Formation,which is connected with deep fractures,is the favorable exploration target.