核磁测井在火成岩储层解释评价中的应用研究

Study on NMR Log Application in Igneous Reservoir Evaluation

常规测井资料在辽河油田火成岩储层评价中存在储层识别率不高、储层参数计算精度低等问题.利用一种适用于低信噪比核磁测井弛豫信号的多指数反演方法,提高火成岩地层核磁测井处理解释精度,并在岩心实验分析基础上研究建立了火成岩核磁测井储层参数计算解释模型.应用结果表明,在16～64点对数均匀布点时,多指数反演方法明显优于传统算法,特别是在信噪比较低的情况下,该方法反演的弛豫谱连续性好,具有较好的谱分辨能力,能保证实际岩石、流体弛豫谱的真实性.利用核磁测井资料能较好地识别火成岩储层,划分火成岩的储层类型,提高孔、渗、饱储层参数计算精度及储层流体性质解释符合率.核磁测井在辽河油田火成岩储层测井解释评价中发挥了较好的应用效果.

There are a lot of problems to evaluate reservoir with conventional log data in igneous reservoir of Liaohe oilfield, such as low reservoir identification, poor computation precision for reserve parameters and so on. In this paper, a new multi-exponential inversion method is used to improve NMR logging interpretation in igneous bed at low ratio of signal to noise. New reserve parameter interpretation models are founded based on rock core experiment analysis. Log practice shows that multi-exponential inversion method is better than conventional method, especially at low ratio of signal to noise. The method may invert better continuity of relaxation spectrum, so, its resolving power is better and easy to acquire true relaxation characteristics of rock and liquid. Igneous reservoir can be identified finely with NMR logging data, types of igneous reservoir can be sorted and parameter precision of reservoir can be improved. Some good application effects are obtained for NMR logging in igneous reservoir evaluation, Liaohe oilfield.