Analyzing the factors influencing the imbibition of tight oil based on orthogonal experiment

The stimulation effect of imbibition in the process of fracturing construction is influenced by a variety of factors, such as reservoir property and operation condition. To solve this problem, a quantitative study on the influences of different factors on imbibition recovery were carried out . Based on the imbibition theory, combined with reservoir characteristics and development situations of the M Block of tight oil in the Xinjiang Oilfield, laboratory contrast experiments were performed on 6 imbibition influencing factors by using the independently developed high-accuracy electronic static imbibition device. After the experimental process was simplified and the experimental accuracy was improved, the influential laws of imbibitions fluid system, permeability, crude oil viscosity, interfacial tension, wettability and antiswelling agent content on the recovery factor were clarified. In addition, based on L₉(3⁴) orthogonal list, orthogonal experiments were designed. And the influential degrees of 4 main factors on the imbibitions recovery were ranked on the basis of fewer experiments. From the largest to the smallest were: interfacial tension, permeability, crude oil viscosity and wetting angle. This conclusion not only provides some theoretical basis and technical guidance for the type selection of fracturing fluid and the optimization of formula on site in M Block so as to improve the imbibition recovery, but also provides the reference for fracturing construction and production and efficiency increase of other tight oil blocks.