LD油田高倍数水驱油效率实验研究

为探索介于热采开发界限的高孔高渗疏松砂岩稠油油藏在大液量提液冷采模式下的水驱油效率及其影响因素，以渤海辽东矿区LD油田样品为例，在实验流速分别为1.0、7.5、15.0 mL/min的情况下，开展了2 000 PV高倍数水驱油效率的实验研究，同时结合压汞、X衍射全岩和气测渗透率等实验数据对提液方式进行优化，分析各因素对此类型稠油油藏提液后的水驱油效率的影响。结果表明，微观孔喉结构、填隙物体积分数、渗透率等储层地质特征差异对提液后的驱替特征具有较大影响，微观孔喉结构越差、填隙物体积分数越高、渗透率越低，高倍数水驱油效率越低；相比于直接提液方式，分步提液方式能取得更高的水驱油效率。对处于热采界限内的该类型稠油油藏进行水驱冷采开发，为避免造成前缘突进、降低微观波及，提液幅度控制在7.5倍为宜。实验结果可以有效指导该类型稠油油藏在矿场利用水平井规模化大幅提高生产井产液量进行剩余油挖潜。

Experimental Study on Influence Factors for High PV Water Flooding Efficiency in LD Heavy Oil Reservoir

In order to explore the water displacement efficiency and its influencing factors of high porosity and high permeability unconsolidated sandstone heavy oil reservoir through the thermal production boundary in the mode of large volume liquid extraction and cold production,taking LD oilfield in Liaodong mining area of Bohai Sea as an example, the systematically study on oil displacement efficiency of 2 000 PV high multiple water was carried out with flow rates were 1.0,7.5,15.0 mL/min.At the same time,combined with mercury injection,X?ray diffraction,whole rock and gas permeability measurement,the liquid extraction system can be optimized,and the influence of various factors on the water oil displacement efficiency of this type of heavy oil reservoir after liquid extraction was analyzed as well.The experimental results show that the differences of reservoir geological characteristics such as micro pore?throat structure,interstitial content and permeability have a great influence on the displacement characteristics after liquid extraction. The worse micro pore?throat structure would induce a higher the interstitial content, inferior permeability and lower high PV water flooding efficiency.Compared with the direct liquid extraction method, the step?by?step liquid extraction method can achieve higher water flooding efficiency.For this type of heavy oil reservoir,it has the best liquid extraction range.If the amplitude is too large, it is easy to cause the front edge to burst, and reduce the micro sweep. It should be controlled at 7.5 times. The experimental results can effectively guide the exploitation of residual oil by using horizontal well extraction in heavy oil reservoirs.