Orinoco地层油的开发特征及组分研究

Orinoco地层油具有较高的气油比和沥青质含量，在模拟油藏开发状况时，使用油罐油和天然气配制的模拟油。利用大直径长岩心模型进行压力衰竭实验，得到Orinoco地层油的流动特点及模拟开发效果。结果显示：(1)高于泡点压力阶段，模拟油显现弹性驱动特征，采收率很低；(2)在泡点和“拟泡点”之间的降压阶段，模拟油表现出缓慢的膨胀性能，采收率近似线性增加，斜率接近1，此时具有最大的开采效益;(3)低于拟泡点压力阶段，产气量增大，采收率增加缓慢。实验测定了Orinoco地层油的详细组分，并以此为依据配制模拟油。对模拟油PVT性质进行分析，结论是：气油比和少量的轻质组分对相对体积的影响很小，沥青等重质组分对气体保持稳定状态起主要作用；脱气状态的地层油在60 ℃时粘度仍高达6 194 mPa·s，而较高的气油比使地层油粘度陡降，特别在压力降低至泡点压力后，仍存在一个粘度缓慢变化的阶段，显示了Orinoco地层油的独特之处。

Development Characteristics of Orinoco Oil and Components Analysis

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.