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

Huang Yi; Zhao Jun; Cheng Pengfei; Zhao Weixin

doi:10.11743/ogg20070313

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Enhancing accuracy of saturation model of low-porosity and low-permeability reservoirs by using nuclear magnetic resonance logging data
Vol. 28, Issue 3, Pages: 390-394(2007)
Online First：25 June 2007，

Published：2007
DOI： 10.11743/ogg20070313
稿件说明：

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DOI：

Huang Yi, Zhao Jun, Cheng Pengfei, et al. Enhancing accuracy of saturation model of low-porosity and low-permeability reservoirs by using nuclear magnetic resonance logging data[J]. 2007, 28(3): 390-394. DOI： 10.11743/ogg20070313.

摘要

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n具有较大的影响。大孔占优时

n值越小;小孔占优时

n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m和饱和度指数n值之间良好的相关性求取m

n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。

Abstract

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 'n'

i.e.

when big pores dominate

the 'n' is small;and when small pores dominate

the 'n' is big.The good correlativity between 'T

the geometric mean of lateral relaxation time of nuclear magnetic resonance

'm'

the cementation index

and 'n'

the saturation index

can be used to determine the values of 'm' and 'n'.The errors of value assignment caused by changes of pore structures are eliminated

thus a more accurate value for 'S

.'(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.