鄂尔多斯盆地陕北斜坡中部延长组深部层系特低渗储层敏感性微观机理

Sensitivity microscopic mechanism study of super-low permeability reservoirs in depth of Yanchang Formation in central of Shanbei Slop Ordos Basin NW China

以2007年在鄂尔多斯盆地陕北斜坡中部新发现的三叠系延长组深部层系长101特低渗储层为研究对象,在野外露头及岩心观察的基础上,通过对室内敏感性实验、铸体薄片、物性测试、X线衍射、扫描电镜和压汞等大量测试资料的综合分析,对该储层的敏感性特征及其微观机理进行研究。研究结果表明:研究区长101储层具有弱速敏、弱水敏、中等偏弱—弱盐敏、弱—中等偏弱碱敏和强—中等偏强酸敏特征。敏感性的形成一方面与储层中绿泥石膜和浊沸石等敏感性矿物的存在有关,另一方面与成岩作用形成的复杂孔隙结构有关。

Triassic Yanchang Formation Chang 10 oil layer is a new oil-bearing layer which was found in the middle-east of Odors basin in 2007.Taking it as an example,on the basis of field outcrop and core observation combined with the indoor sensitivity test,sensitivity test,casting slice physical data,X-ray diffraction,SEM,mercury injection data and so on,the characteristics of reservoir sensitivity and its microscope mechanism were studied.The results show that the studied area Chang10 Reservoir possesses the characteristics such as slight water sensitivity and velocity sensitivity strata, medium-low to low saline sensibility,low-medium to low alkali sensitivity and high-medium to high acid sensitivity.The sensitivity is related to the existence of sensitive minerals such as chlorite-film,laumontite and the complex pore texture formed by diagenesis.