基于核磁共振技术的致密储集层静态渗吸规律

中国致密油资源丰富,经济价值巨大,但因其储集层渗透率低、孔隙度小,致使其开发难度大,以毛细管力作用为基础的渗吸成为这类储集层的有效开采机理。基于核磁共振技术,阐明了流体在致密岩心中的静态渗吸流动规律。利用核磁实验的T2谱和成像图,研究了岩心渗透率、岩心长度和单向渗吸3个因素对静态渗吸采出程度的影响,并观测了流体在岩心中的二维空间流动和分布。通过对比,核磁共振实验T2谱法获得的渗吸采出程度与质量法获得的渗吸采出程度具有较高的一致性,从而验证了利用核磁共振实验研究致密储集层渗吸规律的适用性,为致密油开发提供可靠的理论依据。

Spontaneous Imbibition of Tight Oil Reservoirs Based on NMR Technology

China’s tight oil resources are rich in reserves and have huge economic value, but it is difficult to develop due to the features of low permeability and low porosity of tight oil reservoirs. The spontaneous imbibition principle based on capillary pressure becomes an effective production mechanism for such reservoirs. Combining with nuclear magnetic resonance(NMR) experiments, the paper clarifies the spontaneous imbibition flow law of fluids in tight core, studies the influences of core permeability, core length and one-way imbibition on the recovery percent of spontaneous imbibition based on T2 spectrum and imaging maps obtained from the nuclear magnetic experiment, and observes 2D fluid flowing and distribution in the core. The comparison result shows that the recovery percent of spontaneous imbibition obtained from T2 spectrum is consistent with that obtained from the mass method, which verifies the applicability using NMR experiments to study tight reservoir spontaneous imbibition and provides a reliable theoretical basis for tight oil development.