Oriente盆地海相低阻油层成因机理及测井评价方法

Formation mechanism and log evaluation methods of marine low resistivity reservoir in Oriente Basin

海相油气藏的油层与水层电阻率对比度低,直接用阿尔奇方法难以实现对其束缚水饱和度和含水饱和度的精确计算。为了解决该问题,从地质因素分析入手,根据岩心、测井等资料,结合低阻油层的测井响应特征,探索海相低阻油层的成因机理,并在主控因素分析的基础上,建立了储层饱和度精细评价模型。研究结果表明:海绿石的束缚流体特性和附加导电性,是导致其形成低阻油层的主控因素;基于主控成因的束缚水饱和度计算模型和基于导电因素校正的含水饱和度计算模型所得出的低阻油层的饱和度,与岩心压汞实验分析得出的束缚水饱和度进行对比,吻合度较高。将基于导电因素校正的含水饱和度计算模型应用于Oriente盆地海相砂岩低阻储层综合评价中,提高了解释符合率和储层参数解释精度,取得了较好的应用效果,验证了该含水饱和度计算方法的有效性。

It is difficult to calculate the bound water saturation and water saturation directly by using Archie method in the low contrast of oil and water layers in marine reservoirs. In order to solve the problem,based on geologic factors,core and logging data,combined with logging response characteristics of low resistivity reservoir,the formation mechanism of marine low resistivity reservoir was studied,and the fine evaluation model of reservoir saturation was established by analyzing the main controlling factors. The results show that the bound fluid and additional conductivity characteristics of glauconite are the main cause of the formation of low resistivity reservoir. The low resistivity reservoir saturation calculated by bound water saturation calculation model based on the main controlling factors and the corrected water saturation calculation model based on conductive factor are consistent with bound water saturation analyzed by core mercury injection experiment. Applied to marine low resistivity reservoir evaluation in Oriente Basin,the corrected water saturation calculation model based on conductivity factor improved the coincidence rate of interpretation and reservoir parameter interpretation accuracy,and achieved goodapplication effect,verifying its effectiveness.