Quantitative evaluation for fluid components on 2D NMR spectrum using Blind Source Separation

During oil and gas exploration, it is difficult to quantitatively evaluate fluid components and accurately calculate the saturation of different fluids because of the overlapping of fluid components on 2D NMR spectrum. In this paper, Blind Source Separation (BSS) is proposed to separate fluid components, which utilizes the statistical independence of fluid signals on 2D NMR spectrum. Fast Independent Component Analysis (FastICA) is employed for the inverted NMR spectrums in an entire logged interval to obtain the residual information to determine the number of fluid components. Based on the determined number of fluid components, Nonnegative matrix factorization (NMF) is used to obtain the features of fluid components on NMR spectrum and the region on 2D NMR spectrum is divided into different regions. The overlapping regions are classified by distance or distance and T-1/T-2 to obtain the modified NMR spectrum. Through T-2-D and T-1-T-2 numerical simulation, the fluid saturations calculated by the proposed method and NMF are compared to verify the effectiveness of the proposed method. The results showed that the proposed method can be used to determine the number of fluid components effectively, and the calculated fluid saturations are more accurate than that obtained by NMF. (C) 2021 Elsevier Inc. All rights reserved.