莫西庄地区低阻油层成因分析与饱和度评价

Analysis on the forming of low-resistivity oil layer and evaluation of the water saturation in Moxizhuang area

(1.中国石油大学(北京),北京102249；2.中国石油化工股份有限公司石油勘探开发研究院,北京100083)

Chen Jihua,China University of Petroleum,Beijing 102249,China

莫西庄地区侏罗系储层具有低孔、低渗、低阻、强亲水特征。低阻油层饱和度评价是当前测井评价难题,而低阻油层成因分析是饱和度评价的基础。通过研究区储层粘土类型和粘土含量分析、多矿化度岩电分析实验、泥浆滤液侵入对地层电阻率影响的数值模拟、储层微毛细管发育情况及其它地质特征的深入研究,综合分析了各种因素对地层电阻率的影响,结果表明,微毛细管发育导致的高束缚水饱和度是造成本地区油层低阻的主要原因。根据微毛细管发育的低阻油层特征,分别采用导电岩石骨架(CRMM)模型和Archie公式对本地区低阻油层含水饱和度进行了计算,结果表明,CRMM模型的计算结果与地层真实情况吻合更好。

The Jurassic of Moxizhuang area is characterized by low porosity,low permeability,low resistivity and strong water wettability.Nowadays,the saturation evaluation of low-resistivity oil layer is a difficulty of logging evaluation,and is based on genesis analysis of low-resistivity reservoir.Through analysis of clay type and volume,litho-electric experiment in various salinity conditions,numerical simulation of mud filtrate invasion effects versus reservoir resistivity variation,analysis on development of micro-capillary in reservoir and other geological features,we studied the impact of different factors on the formation resistivity.The results show that the main cause of low-resistivity oil layer is high irreducible water saturation produced by the development of micro-capillary.Therefore,we calculated the water saturation of low-resistivity oil layer by Archie equation and conductive rock matrix model (CRMM) respectively.The result shows that CRMM is better for the calculation of water saturation.