利用核磁共振资料改善低孔低渗油藏饱和度模型的精度

Enhancing accuracy of saturation model of low-porosity and low-permeability reservoirs by using nuclear magnetic resonance logging data

黄毅 赵军 程鹏飞 赵维新

Huang Yi Zhao Jun Cheng Pengfei Zhao Weixin

用核磁共振测井来评价孔隙结构较传统的压汞毛管压力法具有独特的优势。在低孔、低渗油藏中,孔隙结构的变化对饱和度指数具有较大的影响。大孔占优时,值越小;小孔占优时,值越大。利用核磁共振横向驰豫时间T的几何平均值与胶结指数和饱和度指数值之间良好的相关性求取,值,消除了因孔隙结构改变而造成的取值误差,从而在建立饱和度模型后,能求取到精确的含油饱和度S。通过对TZ111井的处理,计算得出的孔隙度消除了扩径的影响,含油饱和度更加接近试油结论,提高了饱和度模型的精度,在现场工作中得到了良好的验证。

Nuclear magnetic resonance logging has an edge on the evaluation of porosity structures over the traditional mercury-injection capillary pressure method.For oil reservoirs with low-porosity and low-permeability,the variations in pore structures have a significant impact upon the saturation index '',i.e.,when big pores dominate,the '' is small;and when small pores dominate,the '' is big.The good correlativity between '',the geometric mean of lateral relaxation time of nuclear magnetic resonance,'',the cementation index,and '',the saturation index,can be used to determine the values of '' and ''.The errors of value assignment caused by changes of pore structures are eliminated,thus a more accurate value for '.'(oil saturation) can be obtained from saturation model.The processing of the data in Well TZ111 yields a porosity free of influence of pore enlargement and a saturation closer to the testing results,greatly improving the accuracy of the saturation model.

10.11743/ogg20070313