文南油田低电阻率油层成因及测井评价方法

利用测井、岩心资料对文南油田低电阻率油层的成因进行了分析.文南油田的低电阻率油层主要由高束缚水饱和度、高地层水矿化度以及高泥质含量引起.提出了利用区域对比法和复合岩性混合地层水法评价该油田的低电阻率油层,克服了原解释时仅利用单井资料进行低电阻率油层评价过程中存在的不利因素;在资料标准化以后,利用回归分析技术建立岩电关系图版,包括孔隙度与声波、中子、密度测井的关系图版;渗透率与孔隙度的关系图版;根据试油分析资料和测井典型分析层段建立油气水判别标准.利用所建立的图版对文南油田75口井的疑难层段进行了重新处理,处理后共增加油层96个层,约214.1 m,油水同层63个层,约151.7 m.与试油结果相比符合率达90%,表明该方法是可靠的,地质效果明显.

The Genesis of Low Resistivity Pay Zone in Wennan Oilfield and Its Log Evaluation

With the logs and core data,the genesis of low resistivity pay zones in Wennan oilfield is analysed,which is caused by high irreducible water saturation,high formation water salinity and high shale volume.Proposed are regional correlation method and mixed formation water method of complex lithology for interpretating pay zones with low resistivities in this oilfield.Based on the analysis of regression technique,established are three litho-electric relationship charts of porosities versus sonic log / neutron log / density log;permeability versus porosity;discrimination criterium for identifying oil and water zones with testing & typical logging intervals data.The charts given are used to process some complex zones from 75 wells in Wennan Oilfield,the result shows that 96 pay zones are identified again,about 214.1 m,63 oil-water zones,about 151.7 m.The log interpretation agreement rate is up to 90%.