Abstract: The foamy oil in the Orinoco Formation,Venezuela,is placed great attention to for its flow characteristic in development and lab research.Under different pressure,the research on the microscopic shape of the oil is important to search for the mechanism flowing through porous media.When the foamy oil is under bubble point pressure,it presents complex shape change,in lab research,by means of visualization model,the formation,growth,merging and separating of the bubble are observed and analyzed,it is found out the bubble,while passing through pores,is of unique migration characteristic,when the bubble comes close to or pass pore throats,its motion speed increases considerably.Deformation,overturning or absorbtion will occur in different diameter bubbles.Analysis of model surface roughness,pore and bubble size indicates the key factor influencing the number of bubbles is gas oil ratio,but the ration is not major factor gas/liquid interface interacting.The generation and motion of the bubble are controlled by both pressure drop and heavy weight components,high asphaltum and collidal matter content determine the characteristic flowing through porous media of foamy oil.

Key words: foamy oil, visualization model, bubble, throat, asphaltum, Venezuela