Using Two Dimensional NMR Technology To Research Core Oil Saturation

There are several methods which can analyze core oil saturation, such as retorting, distillation extraction technique, chromatography and one dimensional NMR. But the oil got from cores during retorting is less than the actual oil because of evaporation, coking and cracking. It costs a long time to measure the cores especially the low-permeability cores when using distillation extraction technique. Oil bearing cores needed to be soaked in 1500mg/l MnCl2 solution when using one-dimensional NMR and need to cut cores into small pieces to measure quickly. All of the above experiments are irreversible.In order to achieve a solution to these questions, this paper, according to the basic theory of NMR and combining with limited two dimensional NMR documents, presents the fluid identification method by using two dimensional NMR. Due to different kinds of fluid having different diffusion coefficients, the interpretation model can be set up. This paper puts forward a method of analyzing the oil saturation by using two dimensional NMR. This technology can solve the irreversibility of the experiment and repeatedly measure cores free of damage.On the basis of theory and laboratory studies, first of all, the differences of NMR character between water and alkane must be studied, and then the oil saturation of mixed solution could be attained by measuring it with two dimensional NMR. The oil saturation is studied on the basis of acquiring the accurate porosity. The cores under the condition of saturating oil and irreducible water are measured by two dimensional NMR and accurate oil saturation can be acquired. Through the research for the porosity of each core by using slice scanning technology of two dimensional NMR, it is found that total porosity is not quite equal of porosity. The research also point that the distribution of the oil saturation, the end effect under the condition of saturating oil and irreducible water, and the variation of the oil saturation in the process of migration.The results show that using the two dimensional NMR can measure the oil saturation of cores quickly, accurately and no harmfully. Using the slice scanning technology can research the distribution of oil and water, fingering phenomenon, end effect and the process of migration of oil and gas.