榆林气田二叠系山西组流动单元

Study on the flow units in Shanxi Formation of the Permian System in Yulin Gasfield

鄂尔多斯盆地东部榆林气田山西组储层具有低孔低渗、岩性复杂、孔隙结构复杂的特征.以层或层组为单元的砂体(岩性)、孔隙度和渗透率等参数的宏观分布研究已经达不到该区储层精细评价的要求,而储层的微观孔隙结构比储层宏观物性更能反映本区储层的本质特征.因此开展了该区储层流动单元测井评价研究.基于岩心和测井资料从孔隙几何学角度研究了工区储层的流动单元特征,采用FZI法把该区划分为5种类型的流动单元,同类流动单元的孔-渗关系呈现出规律性变化,其孔隙类型和结构趋于一致,表现出相似的测井响应特征,从而建立了研究区流动单元的划分及分类评价模式.

A flow unit is the minimum macroscopic geologic unit of oil-gas reservoirs,and it comprehensively reflects the lithology,property and microscopic pore throat feature of the oil-gas reservoirs.Shanxi Formation of Yulin Gasfield in the east of Ordos Basin has the feature of low porosity,low permeability,complex lithology and complex pore structure,and the reservoir features of quartz sandstone and lithic sandstone are different.Therefore,the study on the macroscopic distribution of the lithology,porosity and permeability of the reservoir unit of layer or layer set cannot meet the requirements of the fine reservoir evaluation in the studied area.The microscopic pore structure of reservoirs may better reflect the nature feature of the reservoirs than the macroscopic property distribution of them.For this reason,the study on the flow units of the reservoir is carried out.Firstly,the reservoir feature is studied.Then based on core data and logging data,the features of the flow units in the area are studied from the geometry of the pore,and the reservoir is divided into 5 flow units using FZI method.The flow units of the same type have the same porosity-permeability variation law,their pore type and structure are similar,and they have similar logging response characteristics.Finally,the modes of the flow unit division and evaluation of the studied area are established,and the grades of the reservoir is reasonably divided.