鄂尔多斯盆地中东部长6复杂低渗储层测井评价

开展复杂低渗储层特征、测井响应及其控制因素分析,有助于储层评价与油水层识别.鄂尔多斯盆地中东部长6期沉积具多物源供给、沉积相带频繁变化的特点,来自不同物源的沉积砂体岩石碎屑成分存在明显差异.长7、长6沉积期盆地周边的火山作用,致使一些地区的长6砂体具有相对高放射性特征.长6储层孔隙类型多样,孔隙结构特征复杂多变,再加上地层水系统的变化,致使一些油区长6低电阻率油层与常规油层、高电阻率水层与常规水层共存.研究结果表明,成藏动力与阻力的对比关系决定了在同一砂体中除存在常规油水分布外,还可能存在油水倒置分布.因此,加强钴前预测、钻井过程监督与调整、钻后综合研究、生产实践检验、解释模型与参数调整、老井复查等,有利于识别油水层,整体把握油水分布规律.

Logging evaluation of low permeability reservoirs in Chang 6,east-central Ordos basin

Analysis on the complex characteristics of low permeability reservoirs,log responses and the controlling factors,it is helpful for that the reservoir evaluation and oil-water layer recognition.Chang 6 Formation had the characteristics of multi sediment-source and the frequent variation of sedimentary microfacies in the eastern part of Ordos Basin.In sedimentary sand body from different material sources,the rock clastic components are obvious difference.In the depositional stage of interval Chang 7 and Chang 6,the volcanic event caused some oil areas had the relatively high radiation characteristics of sandstone in Chang 6 Formation.The reservoirs have the varieties of pore types and the complicated pore structure.Some areas have the normal well logging response characteristics of oil layers and the relatively low resistivity oil layers,the normal well logging response characteristics of water layers and the relatively high resistivity water layers.Low resistivity reservoir formation are mainly controlled by lithology,physical properties and pore structure,oil content,salinity of formation water,reservoir thickness,drilling fluid and control.The research results show that the relation between reservoiring dynamics and resistance determines the oil-water distribution characteristics in one sand body:normal and mode of distribution such as the inverted-"the upper part of the water,the lower oil".By predict before drilling,drilling process supervision and adjustment,comprehensive research after drilling,production results inspection,interpretation model and parameters adjustment,older well re-examination and others,it is help to identify oil-water layers and to know the oil-water distribution rule.