The Experimental Research On The Spontaneous Imbibition For Tight Reservoir

Tight oil resources,which are regarded as the dinner of the unconventional hydrocarbon resources in China and the black gold in western countries,exist to be great economic value.Tight oil resources are extensively distributed in China,but the researches are just at the beginning stage due to great challenges.Spontaneous imbibition mostly resulted from the capillary pressure is a very important and useful way for tight oil production because of small pore size and strong heterogeneity.It is essential to study the spontaneous imbibition for the tight reservoir,which is fundamental for further studying the water injection of tight reservoir.Xinjiang tight sandstones are selected as the research object to carry out the indoor spontaneous imbibition experiments.The characteristics and influencing factors of spontaneous imbibition for tight reservoirs are summarized and analyzed in order to decide the dominant factor.Nuclear magnetic resonance imaging can provide 2-dimensional(2D)reconstructions of in-situ oil phase inside a core plug,which is beneficial to analyze the development effectiveness of the spontaneous imbibition.Combined with the formula to judge the mechanism,it is further determined which functions would contribute the spontaneous imbibition and which conditions are beneficial to the field application.Based on the newly spontaneous imbibition recovery model,the relationship between different parameters and recovery factor is revealed,which can intensify the mechanism and law.Dimensio nless recovery factor is introduced and is related with dimensionless time,which can be used to predict the recovery efficiency of tight production on the field.This study also aims to provide the field operators with possible level of oil recovery from tight reservoirs and thus they can make positive plan by adjusting to more optimized parameters.