冀中地区高含水水平井治理工艺模式

Technologies of chemical plugging for high water-cut horizontal wells in Jizhong District

经过20多年的规模开发,冀中地区部分主力油藏水平井不同程度地出现含水上升过快、产油急剧下降甚至关井等状况。分析认为,边水或注入水沿正韵律沉积主河道底部突进和底水沿潜山缝洞锥进,是油田典型砂岩油藏和雾迷山裂缝性块状油藏的主要水淹特点。针对高渗条带状分布的砂岩储层,依据水电相似性设计模拟电桥电路,并改进了水平井深部堵水工艺决策方法。采用该方法对高渗条带深部（即渗透带到水平井边界距离20-40m）封堵,能够显著改善中、低渗透带的驱动压力场分布和流量,同时迫使液流转向至低渗透带,使其流量最高可增加55.3%。针对雾迷山碳酸岩盐裸眼完井水平井,借鉴潜山油井堵水工艺模式,封堵裸眼段下部出水层段,发挥上部含油层段的生产潜力。结合水平井堵水堵剂体系,设计了2种堵剂组合工艺模式,通过5井次水平井堵水先导应用,获得了显著的降水增油效果。由此形成的水平井堵水配套技术,对于改善油田开发后期高含水水平井的开发效果具有积极借鉴意义。

After 20 years development the horizontal wells of typical reservoirs in Jizhong District gradually expose serious problems such as fast water cut rising, sharp oil production decrease even shut-in. Analysis shows that the chief water output types of horizontal wells in sandstone reservoir with fluvial sedimentary is edged or injected water breakthrough along the bottom of ancient river course deposited by positive rhythm, whereas to carbonate reservoir of the Wumishan Formation that is the bottom water coning which penetrates into the seam or hole. Based on bridge-circuit simulation designed by distribution of high and low permeability zones, the technology decision of deep water plugging is developed. Results indicate that the driving pressure and seepage of midlow permeability channel could be greatly improved by strong in-depth water plugging in high permeability channel, and flow rates in low permeability channel compulsively increase to a maximum of 55.3%. Unlike in sandstone reservoir, the water plugging mode adopt by vertical well experience in buried hill is that sealing the water production layer below and tapping the potential production of oil layer section upward. Combined with two kinds of blocking agents, the successful field experiments show that new kinds of water-plugging technologies provide steps for the oil promotion and water reduction with single well, which can be used as guidance for development of horizontal wells during late period of oil exploit.