烟道气强化蒸汽驱提高稠油油藏采收率实验

为了搞清烟道气与蒸汽混合注入稠油油藏进一步提高采收率机理,进行了烟道气强化蒸汽驱模拟实验研究。利用PVT装置研究了不同温度、压力条件下,烟道气在原油中的溶解特性及原油物性变化特征,开展了烟道气强化蒸汽驱一维管式驱替实验与三维物理模拟实验。通过一维驱替实验,可确定不同温度条件下烟道气强化蒸汽驱比单纯蒸汽驱的驱油效率增加值,并优选了最佳注入温度;利用三维物理模拟实验,对比了蒸汽驱转烟道气强化蒸汽驱的生产动态变化规律及温度场扩展特征,分析了厚层油藏内热采过程中不同流体组分的分布特征。基于三维物理模拟实验结果,利用数值模拟方法优化设计了厚层稠油油藏水平井热采开发的布井模式。结果表明:高温降黏助驱、CO_2溶解降黏和N_2分压增容是稠油油藏烟道气强化蒸汽驱提高稠油采收率的机理。

EOR EXPERIMENT OF THE HEAVY OIL RESERVOIR BY THE TUNNEL GAS ENHANCED STEAM FLOODING

In order to ensure the mechanism of further enhancing the recovery of the heavy oil reservoirs injected by the mixture of the tunnel gas and steam,the experimental studies were conducted for the tunnel gas enhanced steam flooding simulation.By means of the PVT testing apparatus,the solubility of the tunnel gas in the crude oil and changed characteristics of the crude oil in the physical properties were researched under different temperature and pressure conditions,the one-dimension tube displacing experiment and 3D physical simulating experiment were launched for the tunnel gas enhanced steam flooding.For the first experiment,comparing with the simple steam flooding,the incremental values of the displaced efficiency of the tunnel gas enhanced steam flooding were determined under different temperature conditions,the injection temperature was optimized;with the help of the achievements of the 3D physical simulating experiment,the changed laws of the production performances and the spread characteristics of the temperature field were contrasted for the tunnel gas enhanced steam flooding inverted from the steam flooding,and furthermore the distribution features were analyzed for the different components of the liquids in the process of the thermal recovery in the thick oil reservoirs;with the help of the achievements of the 3D physical simulating experiment and the numerical simulating method,the well location patterns of the thermal-recovery horizontal well in the thick heavy oil reservoir were optimally designed.The results show that the high-temperature-assisted viscosity-reducing displacement,CO2-solubility viscosity lowering flooding and N2-partial-pressure volume increment are the EOR mechanisms of the heavy oil reservoir by means of the tunnel gas enhanced steam flooding.