塔河油田三叠系低阻油气层测井评价

塔河油田南部盐体覆盖区三叠系碎屑岩区域陆续发现一批低幅度构造、岩性圈闭油气藏，储层类型多样，既有高阻、低阻油气层，还有高阻水层。储层电性高低除受物性、含液性影响外，还明显受控于岩性变化的影响。低阻油气层的最大特点是与邻近水层电阻率值接近，难于识别。文中在岩心分析资料、地层水和核磁实验分析等资料的基础上分析了塔河油田三叠系油气储层的成因．发现黄铁矿在工区只是局部分布，且质量分数较少，因此可排除其导致低阻的可能，而地层水矿化度高、岩性细（粉砂、黏土质量分数高）、束缚水饱和度高、黏土附加导电性及储层岩性圈闭幅度小等因素是造成其油层电阻率低的主要原因、因此，采用岩性系数（黏土质量分数或泥质质量分数和阳离子交换浓度）、孔隙结构系数（孔喉半径）及电阻率值和电阻率侵入剖面可以识别低阻油层，并通过岩心分析资料和核磁实验数据标定，得到一系列如平均孔喉半径、阳离子交换计算及饱和度等参数模型，其应用于实际，取得了较好效果。

Logging evaluation of low resistivity reservoir in Triassic,Tahe Oilfield

Some low amplitude structure and lithologic reservoirs are found in Triassic clastic rocks in the salt bodies of southern Tahe Oilfield. There are various types of reservoirs, such as high resistivity reservoir, low resistivity reservoir and high resistivity water layer. The value of reservoir electrical property is obviously controlled by the impact of lithological change in addition to physical property and fluid property. The greatest feature of low resistivity reservoir is close to the resistivity value of adjacent water layer, being difficult to identify. The genesis of oil and gas reservoir is analyzed in Triassic of Tahe Oilfield based on the data analysis of core, formation water and NMR experiment. We discover that iron pyrites is locally distributed and the content is less. Therefore, the possibility that the conductivity of iron pyrites leads to low resistivity reservoir carl be excluded. High salinity of formation water, fine lithology （high silt and clay content）, high irreducible water saturation, additional conduction of clay and small trap range of reservoir lithology are the main reasons of low resistivity reservoir form. Therefore, the low resistivity reservoir can be identified through the method of resistivity combining with lithology factor （clay content or shale content and cation exchange concentration）, pore structure factor （pore throat radius） and resistivity value and resistivity invasion. The series parameter models, such as average pore throat radius, cation exchange calculation and saturation, are obtained by the analysis of core data and NMR experiment data. The models are applied to practical application and good effect is obtained.