Kleinberg R L
Schlumberger-Doll Research, Ridgefield, CT 06877, USA.
Magn Reson Imaging. 1996;14(7-8):761-7. doi: 10.1016/s0730-725x(96)00161-0.
Nuclear magnetic resonance magnetization decays are now used routinely to determine reservoir properties of economic significance to the oil and gas industry. Although individual features of relaxation time distributions are subject to degradation in the presence of measurement noise, integrated and average measures of those distributions are remarkably stable. Properties such as porosity, producible porosity, hydraulic permeability, and the capillary pressure curve can be measured rapidly and continuously. Laboratory comparisons of NMR T2 distributions with two different capillary pressure measurements enable the surface relaxivity parameter rho 2 to be determined for sandstones. Comparison with relaxivities of synthetic materials having well-defined surface areas strongly suggests that the NMR-effective internal surface area of rocks is closely connected with the hydraulic radius, and, surprisingly, is not greatly affected by the presence of clay, which dominates the pore space surface are as measured by gas adsorption.
核磁共振磁化衰减现在被常规用于确定对石油和天然气行业具有经济意义的储层特性。尽管弛豫时间分布的各个特征在存在测量噪声时会受到降解影响，但这些分布的综合和平均测量值却非常稳定。诸如孔隙度、可生产孔隙度、水力渗透率和毛细管压力曲线等特性可以快速且连续地测量。通过将核磁共振T2分布与两种不同的毛细管压力测量进行实验室比较，能够确定砂岩的表面弛豫率参数ρ2。与具有明确表面积的合成材料的弛豫率进行比较强烈表明，岩石的核磁共振有效内表面积与水力半径密切相关，而且令人惊讶的是，它不受粘土存在的很大影响，而粘土在通过气体吸附测量的孔隙空间表面积中占主导地位。
