低渗透储层水锁伤害机理核磁共振实验研究

客观准确地评价低渗透储层的水锁伤害是入井流体优选、增产改造措施和水锁防治解除措施合理运用的基础.对孔隙介质中水的赋存状态、储层伤害原因、黏土吸水伤害和水锁伤害微观机理进行了深入分析;利用低磁场核磁共振T2谱技术,结合常规流动实验手段,对同一性质岩心开展了黏土吸水伤害和水锁伤害实验,提出了水锁伤害核磁共振实验评价方法.通过实验,准确给出了水锁伤害程度;建立了束缚水增加量与黏土吸水伤害程度、可动水相滞留量与水锁伤害程度之间的对应关系;从而对引起水锁伤害的原因做出更精确的判断,实现了对水锁伤害的客观评价.

Experimental study on the water-blocking damage mechanism of low permeability reservoir by nuclear magnetic resonance

The existing form of water in porous media of low permeability reservoir,the causes of reservoir damage,the microscopic mechanism of water absorption damage of clay and the microscopic mechanism of water blocking are analyzed.The water-absorption damage of clay and the water blocking of the reservoir are evaluated with the cores of the identical property by means of nuclear magnetic resonance(NMR) T2 spectrum.The experiments can give the degree of the water blocking damage,the relationship between the increased amount of irreducible water and the water-absorption damage of clay and the relationship between the amount of movable water and the water blocking damage of reservoir,and according to which,the causes resulting in the water blocking damage can be judged.The accurate evaluation of the water blocking damage is the basis of the screening of the fluids to be injected into wells,the determination of simulation measures and the prevention and elimination of the water blocking damage.