鄂尔多斯盆地富县地区延长组长6储层特征

鄂尔多斯盆地富县地区长6油层组主要发育三角洲沉积,其中分流河道和水下分流河道是主要的油气储集层。长6油层组储集层岩石类型以岩屑长石细砂岩和长石细砂岩为主,颗粒间多为线、点—线接触,孔隙和薄膜式胶结,总体具有成分成熟度低、结构成熟度高的特征。粒间孔和长石溶孔是主要的储集空间,其中以小孔和微孔为主,渗透率小于3×10-3μm2,为特低渗储层和接近致密储层。研究区较强的压实作用、胶结作用是形成低孔低渗的主要因素,而溶蚀作用是储层物性改善的主要因素。

CHARACTERISTICS OF THE CHANG 6 RESERVOIR OF THE FUXIAN AREA IN THE ORDOS BASIN

Delta sediments are the main deposits in the Chang 6 oil beds of Yanchang Formation in Fuxian area of the Ordos Basin and the sand bodies of distributary channel and subaquatic distributary channels are main reservoirs for the hydrocarbon.Fine lithic arkose sandstone and fine arkose sandstone are main sandstones of the Chang 6 reservoir.They have line and point-line contact forms with pore and thin film cementation between rock grains.The Chang 6 reservoir is characterized by the low component maturity and high textural maturity.The main pore types are granular pore and secondary feldspar-dissolution pore which are mainly composed of small hole and micropore.The Chang 6 reservoir has super low permeability and is accessed densify reservoir of which the permeability is less than 3×10-3μm2.The strong compaction and cementation are the main factors which cause the low porosity and low permeability of the reservoir,while dissolution is the main factor for improving the physical property of the reservoir.