Abstract:

As GOR (gas-oil ratio) and asphaltum content of Orinoco oil are high, the imitated oil used in reservoir development simulation is mixed with oil in tank and natural gas. The development characteristics of Orinoco oil are obtained using pressure depletion experiment in a long core model.(1)At the stage of pressure higher than bubbling point, the imitated oil shows an elastic characteristic with a very low recovery;(2)At the stage between bubbling point and pseudo-bubbling point, the imitated oil shows a very slow depletion characteristic that the recovery linearly increases with a slope of about 1, resulting in the highest profitability;(3)At the stage of pressure lower than pseudo-bubble point, gas production increases rapidly, while recovery increases slowly. Components of Orinoco oil are measured in detail. Based on it, imitated oil is mixed. Through the experimental research of Orinoco oil and imitated oil, it is found that GOR and light components have little influence on the relative volume of oil. Heavy components such as asphaltum help to stabilize the dissolved gas. The bubble point pressure and GOR have a linear relationship. The viscosity of degasified oil still has a value of 6 194 mPa·s at 60 ℃, the higher GOR can reduce the viscosity about 10 times. There is a slow increasing in viscosity below the pressure of bubble point, showing the special characteristic of Orinoco oil. Based on the research above, the development characteristics of imitated oil are still studied. The influence of light components (C₁-C₁₃) on the characteristic of oil is studied in the experiment. It shows that with the increasing of the kerosene content, the recovery increases to some degree.

Key words: foamy oil, imitated oil, pressure depletion, pseudo-bubble point