In order to research on the impact of imbibition effects, mechanisms and the correlation factors of the tight oil cores, the experimental devices of tight core imbibiton were established. The experiments of oil-water imbibition of tight sandstone were carried out. The effects of temperature, pressure and surfactant on the oil-water imbibition in compacted core were studied. The curves of imbibition efficiency versus time, characteristic points of curve and the influential factor of imbibition were analyzed. The imbibition law and characteristics of tight sandstone core were obtained. The results showed that the effect of imbibition was mainly occurred on the surface layer of the tight oil core. The temperature had a large effect on the second stage of imbibition. The oilwater imbibiton efficiency of the single tight oil core is about 10%, which is about 25% under the formation conditions.
There is usually a starting pressure gradient in the tight oil. This article considers the seepage law of the crude oil flowing from the matrix to the fractures in the formation under the premise of starting the pressure gradient and some assumptions. Through the establishment of numerical model, the relationship between the pressure, permeability, core size and other factors and the degree of failure recovery in the onedimensional space is analyzed, as well as the threedimensional plate is drawn. The results show that when the core scale is very small, the main factors affecting the degree of recovery are the failure pressure difference. At the same time when the scale increases, the relationship between the recovery degree and the core length and permeability is more and more significant. Then, based on the conclusion of the previous the paper put forward the empirical formula considering the degree of calculation and recovery under various factors, and extend the space to three dimensions. On the basis of one dimensional revise the formula, the empirical formula of the failure rate of three dimensional matrix failure is obtained. It provides some reference for production practice.