【作者】 王东；

【导师】 赵明国；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2009， 硕士

【摘要】 我国主力油田的主力油层大部分属于厚油层,主要采用注水开发。由于厚油层的储层岩性和物性上差异比较大,导致储层层内和平面的非均质性较强,在重力分异的作用下,目前的注水开发模式很容易造成水窜,底部水洗,顶部驱油效率低,层内矛盾突出,油田采收率比较低,目前的工艺还很难解决一整套大厚层水驱波及效率低的难题。根据国内外调研资料,美国加州Buena Vista油田、大庆油田实行水气交替注入能解决油层底部水洗,水驱效率低的问题,水气交替注入提高了水驱采收率。但是对于高渗厚油层,注气开发能否提高最终采收率还需要进行详细的研究。针对此问题,我们查阅厚油层的相关资料,制作人造岩心模拟储层,采用平面模型模拟基础井网(五点法),配制模拟油,先后进行了长岩心和平面模型水驱油、天然气驱油、水气交替驱油室内实验,以及三种驱替方式的驱油后饱和度分布实验等。对比不同驱替方式下的驱油效果,并对驱替过程中发生的现象及作用机理进行了深入剖析,最终选择最优的驱动方式和注入参数。通过实验结果可知,对于高渗厚油层油藏,水驱波及系数低,天然气驱采收率低,气体突破快,采用水气交替驱采收率高,水、气突破慢,含水率、生产气油比上升速度慢,而且水气交替驱时机越早,驱油效果越好。三种驱油方式对比,注水开发优于注气开发,水气交替驱采收率高于单独水驱和气驱,这主要是由于水气交替注入后,在油层中形成了油、气、水三相流动,增加了水的流动阻力,从而减少了层间(内)矛盾,改善了吸入剖面,增加了吸入厚度。同时由于注入气的重力分异作用,驱扫了顶部的剩余油。水气交替驱合理的气水比应为1:1,段塞为0.02PV。更多还原

【Abstract】 Most of main oil layers of main oil fields in China belong to thick oil layers and mainly adopt water injection development. Since the difference between the reservoir lithology and the physical property of the thick oil layers is bigger, the heterogeneity in the reservoirs and the plane is stronger, under the effect of gravitational differentiation, an existing mode of water injection development easily generates water breakthrough, the efficiency of washing the bottom with water and displacing oil on the top is low, the contradiction in the layers is prominent, an existing technique can not solve the problem of a whole set of big and thick layer that the efficiency of flood sweep is low.According to domestic and overseas investigation and study materials, America California Buena Vista Oil Field and Daqing Oil Field carry out water and gas alternate injection to solve the problems of washing the bottom of the oil layer with water and low water flooding efficiency, and the water and gas alternate injection increases the water flooding recovery efficiency. However, as for the hyperosmotic thick oil layers, whether the gas injection development can increase the final recovery efficiency also needs further investigating. Aiming at the problem, we consult relevant materials of the thick oil layers, artificial core simulated reservoirs are manufactured, plane models are adopted to simulate basic well patterns (a five-point method), simulated oil is prepared, and laboratory experiments of long core and plane model water driving oil, natural gas driving oil, water-gas alternate driving oil, saturation distribution experiments after the oil is driven of three displacement modes are carried out successively.Oil driving effects under different displacement modes are compared, phenomena which are generated in the displacement process and mechanisms of action are deeply analyzed, and finally an optimum driving mode and injection parameters are selected. The experimental results show that as for the hyperosmotic thick oil layers, the flood sweep coefficient is low, the natural gas driving recovery efficiency is low, the gas breakthrough is rapid, the recovery efficiency of adopting water-gas alternate driving is high, water breakthrough and gas breakthrough are slow, the ascending velocity of water content and production gas oil ratio is slow, and the water-gas alternate driving time is earlier, the oil driving effect is better.Three oil driving modes are compared, water injection development is better than gas injection development, the recovery efficiency of water-gas alternate driving is higher than single water driving and single gas driving since after water and gas are injected alternately, three-phase flow of oil, gas and water is formed in the oil layers, the flow resistance of the water is increased, thereby, the contradiction between and in the layers is reduced, the suction profile is improved, and the suction thickness is increased. Simultaneously, residual oil on the top is driven and swept due to the effect of gravitational differentiation of injected gas. The rational gas-water ratio of water-gas alternate driving should be 1:1, and the slug injection is 0.02PV.更多还原