玛西斜坡区风城组高含盐致密储集层流体识别

Identification of Fluid in Highly Saline Tight Reservoirs of Fengcheng Formation in Maxi Slope Area

准噶尔盆地玛西斜坡区二叠系风城组发育碱湖沉积的高含盐致密储集层,其油水关系复杂,流体识别难度大。利用岩性扫描测井资料构建饱含盐水地层热中子宏观俘获截面,并利用测井热中子宏观俘获截面与饱含盐水地层热中子宏观俘获截面的差值构建含油性敏感因子,再利用氯元素相对产额与总孔隙度比值构建含盐度敏感因子,将含油性敏感因子与含盐度敏感因子交会形成流体识别图版。实例应用表明,利用该流体识别图版可以对储集层流体性质进行准确判断,为试油选层提供依据。

The Permian Fengcheng formation in the Maxi slope area of the Junggar basin is characterized by highly saline tight reservoirs deposited in alkaline lakes,and the relationship between oil and water in these reservoirs is complicated,which leads to difficulties in fluid identification.A thermal neutron macroscopic capture cross⁃section of the highly saline formation was constructed by using lithoscanner logging data,and an oil⁃sensitive factor was constructed by using the difference between the thermal neutron macroscopic capture cross⁃sec⁃tion from logging and the thermal neutron macroscopic capture cross⁃section of the brine⁃saturated formation.Furthermore,a salinity⁃sensi⁃tive factor was constructed by using the ratio of chlorine element relative yield to total porosity.Then,a fluid identification chart was estab⁃lished by intersecting the oil⁃sensitive factor with the salinity⁃sensitive factor.The actual application shows that this fluid identification chart can accurately assess reservoir fluid properties and provide a basis for selecting formation test layers.