靖边气田陕330井区储层微观特征研究

The Research on Reservoir Microscopic Characteristics of Shan330 Wellblock in Jingbian Gas Field

陕330井区是靖边气田东部扩边建产的重点区,储层微观特征认识不清。为此,利用薄片鉴定、压汞分析和物性测试等资料对储层岩石学特征、孔隙结构特征和物性特征进行系统研究,表明储层整体以白云石(82.2%)、方解石(13.5%)为主,陆源矿物较少;岩性以泥微晶-细粉晶云岩为主、占87.5%,晶粒细小;储集空间主要为晶间孔-溶孔、占90.1%;储层孔喉组合为细-微孔、小-微喉型,孔喉连通性差;分析认为,岩石晶粒细小、面孔率低、喉道半径小、孔喉连通性差是导致储层超低孔-超低渗的内因。研究成果具有实际意义,可作为储层沉积-成岩作用研究、储层分类评价以及后续开发选区的重要依据。

The reservoir characteristics of Shan330 wellblock,the key area of the edge extending and production enhancing project in Jingbian gas field,is not clearly determined,which slows down the process of rolled development of the whole field.The research on the weathered crust lithology,pore geometry and petrophysical property of the reservoir of Shan181-Shan400 wellblock is performed by the means of core observation,thin section identification,mercury analysis and petrophysical property test.The research result shows that the major mineral compositions of the reservoir are dolomite(82.2%)and calcite(13.5%)with little proportion of terrigenous minerals,reflecting marine chemical deposition.The lithology is mainly carbonate with cement crystals,which is mainly micrite to silty crystal:micrite-silty dolomite(87.5%).The storage space is the combination of vugular pore and intragranular pore(90.1%).The displacement pressure is high,with small median throat radius and poor pore connectivity.Pore and throat combination is fine-micro pore and medium-small throat.With poor petrophysical property,the reservoir has extra-low porosity and extra-low permeability,which is the direct consequence of fine crystal,low areal porosity,high displacement pressure,small median throat radius and the pore and throat combination of fine-micro pore and medium-small throat.The research acquires a more profound knowledge of the reservoir,and has a practical significance to the analysis of reservoir diagenesis characteristics,reservoir classification and develop area selection.