裂缝性边水气藏水侵机理及治水对策实验

针对裂缝性边水气藏主要治水措施建立了物理模拟方法并开展实验，系统测试了气藏内部动态压降剖面，对比分析了不同水体、不同治水措施下气藏开采动态及储量动用规律。结果表明：①水体能量不同时，相同的控气排水措施将导致完全不同的实际效果：30倍水体时，采收率可提高10.8%，而无限大水体时采收率反而降低15.6%。生产参数和动态压降剖面揭示无限大水体时，过分控制生产压差不仅难以减缓水侵，相反还会导致采速降低，延长水侵时间，加剧水侵对开发影响。②多井协同排水采气治水效果显著，裂缝性储层中的水会在自身弹性能和剩余气驱动下大量排出，大幅提升气相渗流能力，促使封闭气重新产出，采收率可再提高约10%~30%。水侵影响越严重的气藏，采取排水采气措施越早治水效果越好。③裂缝贯通水体和气井时，地层水主要沿裂缝向气井侵入，外围基质区含水饱和度增量低于5%，压降剖面显示基质区仍有大量封闭剩余气，这些未动用储量是后期开展排水采气等增产措施的重要物质基础。

Physical simulation of water invasion and water control for the fractured water-bearing gas reservoirs

Physical simulation experiment method is established and the experiments were carried out to investigate the main water control measures adopted in the development of fractured water-bearing gas reservoirs. The dynamic pressure drop profiles inside the gas reservoir are measured, the rules of gas well production regulation, reserves utilization mechanism and enhanced gas recovery efficiency under different water conditions and water control measures are compared and analyzed. The study shows that: (1)The same gas drainage measures may cause totally different practical results to the fractured water-bearing gas reservoirs with different water energy: to reservoir with 40 times water body, drainage measures can increase gas recovery by 10.8%, when the reservoir with infinite water body, it can reduce by 15.6%. (2)Multi well synergistic water drainage measures are effective, when the energy of the water body is blocked, the water in the fractured reservoir will be discharged from the gas well under the driving of its own elastic energy and residual gas. The large reduction of water saturation may greatly improve the gas phase seepage capacity and make the water sealing gas flowing again, and increase recovery degree by about 10%-30%.(3)When fractures penetrate water and gas wells, water invades mainly by fractures to gas wells, and the water saturation in the surrounding matrix area increases only by 5%. Because of water blocking damage, there is still a lot of residual gas in the matrix. These non-producing reserves are important material basis for carrying out measures to increase production.