温度和气体对稠油物性的影响

Effects of Temperature and Gas on the Physical Property of Heavy Oil

为明确多元热流体增产机理、优化多元流体组成,以便为科学编制多元热流体热采的工程方案提供技术支持,通过室内实验研究了温度和气体对渤海南堡油田稠油物性的影响。结果表明,在56数120℃范围内,含天然气稠油和脱气稠油黏度均随温度升高而迅速降低,温度升高到120℃时的原油降黏率约为92%,继续升高温度对稠油黏度的影响较小。在同等条件下,CO2比N2更易溶解到原油中,尤其是在温度较低的条件下。注入N2对改善稠油黏度的作用较小,只在100℃以下时略有降黏效果,温度超过120℃时稠油黏度增加。温度低于160℃时,注入CO2可以显著降低稠油黏度。将稠油加热至80℃并注入天然气和CO2体积比约为2∶1的混合气体至16.86MPa可使稠油黏度降低90%。通过升高温度和注入气体两种途径均可使稠油黏度大幅降低。考虑到注汽设备、热损失和注汽成本等因素,“适度加热,辅以注气”的开采技术可以达到较好的降黏效果,可用于海上稠油开采。

Laboratory experiments were performed to investigate the effects of temperature and inject gas on the physical property of heavy oil from an offshore oilfield,so as to clarify the mechanism of enhanced oil recovery by multi-components thermal fluid, optimize the composition of multi-components fluid,and provide technical support for the proper design of the engineering scheme of multi-components heat recovery. The results showed that in the range of 56℃ to 120℃,the viscosity of natural gas saturated oil and degassed oil decreased rapidly with the increase of temperature. The viscosity of heavy oil decreased by about 92% when it was heated to 120℃,while further raising the temperature had little effect on the viscosity. Under the same condition,CO2 dissolved into crude oil more easily than N2,especially at low temperature condition. Injection of N2 had little effect on the viscosity improvement of heavy oil. The viscosity could be reduced slightly with the injection of N2 when the temperature was below 100℃, and that increased with the injection of N2 when the temperature was over 120℃. When the temperature was below 160℃,the viscosity reduced obviously with the injection of CO2. The viscosity of heavy oil could be reduced by 90% at 80℃ with the injection of gas mixture including natural gas and CO2 in volume ratio of 2∶1 to the pressure of 16.86 MPa. The viscosity of heavy oil could be greatly reduced by raising temperature or injecting CO2. Taking into account the steam injection equipment,heat loss and the cost of steam injection etc.,the viscosity reduction effect could be achieved by the technology of“moderate heating,auxiliary gas injection”,which could be applied to the production of offshore heavy oil.