川西致密气藏二维核磁共振测井优化设计与应用

Optimal Design and Application of Two-Dimensional NMR Logging in Chuanxi Tight Gas Reservoir

二维核磁共振(NMR)测井在储层参数计算与流体性质判别应用中的作用逐渐受到重视.然而在川西致密气藏开展二维NMR测井应用之初,遇到了现有观测模式下资料采集效率较低、测井结果与地质条件不匹配等难题.通过对比两种常用的二维NMR测井方法,开展致密气藏二维NMR测井观测模式设计方法研究,结合致密气藏实际应用效果分析,明确了横向弛豫时间-纵向弛豫时间(T_2-T_1)方法比横向弛豫时间-自扩散系数(T_2-D)方法更适用于致密气藏,总结了一套致密气藏二维NMR测井观测模式设计流程与参数取值方法,设计出了适用于致密气藏的观测模式TGR01(tight gas reservoir 01).新设计的观测模式在致密气藏的应用效果优于现有的二维NMR测井观测模式,结合T_2-T_1方法可以有效识别储层中的流体信号,解决致密气藏综合评价难题.

Two-dimensional nuclear magnetic resonance （2D NMR） logging has been increasingly used in the reservoirmodeling and fluid identification. A series of problems were encountered when applying the technique in the Chuanxi gasfield, including poor efficiency in logging data collection and mismatch between the logging evaluation and reservoirproperties. By comparing two commonly-used 2D NMR logging intersection methods and analyzing in-field results, weoptimized the design. It was found the T2-T1 method was more suitable than the T2-D method for tight reservoir evaluation.The activation set TGR01 （tight gas reservoir 01） derived from the optimized method, was shown to be superior to theexisting method for the tight gas reservoir. At the same time, the T2-T1 intersection method was found to be able to identifydifferent fluids effectively, and applicable to the evaluation of tight gas reservoir.