安塞油田长5储层注水对储层的影响研究

Influence of Water Injection on Chang5 Reservoir in Ansai Oilfield

注水开发过程中油层的主要伤害体现在注入水与地层岩石不匹配和注入水与地层流体不配伍方面上,且注水层渗流通道易受损害的部位是吼道。长期注水开发导致储层特性发生变化,注入水的长期水洗和冲刷会提高储层渗透率,改变储层的润湿性与孔隙结构,并使注水开发后期储层的微观复杂度增大。针对安塞油田长5的低渗、低压、低产的典型油藏,应在注入水中加入粘土防膨剂以及粘土稳定剂,并严格控制水中机械杂质的含量。以孔隙结构与喉道中值为依据控制水中的固体粒径,并对注入水进行过滤处理。在注入水中加入表面活性剂,使强亲水性的岩石转为弱亲水,有利于油在渗流通道中的流动。。

The main damage of water flooding development to oil reservoirs is reflected in the mismatch of injected water and formation rock and the incompatibility between injected water and formation fluid, and the vulnerable part of seepage aqueduct is roar. Long-term waterflooding results in changes of reservoir characteristics. Long-term water washing and scouring of injected water increase reservoir permeability, change reservoir wettability and pore structure, and increase the micro-complexity of reservoirs in the late waterflooding stage. For the typical reservoirs with low permeability, low pressure and low production in Chang 5 of Ansai oilfield, clay anti-swelling agents and clay stabilizers should be added into injected water and the content of mechanical impurities in water should be strictly controlled. Based on the pore structure and throat median value, the solid particle size in water should be controlled, and the injected water should be filtered. Surfactant should be added into the injected water to turn the strongly hydrophilic rock into a weakly hydrophilic one, facilitating the flow of oil in the seepage channel.