模拟油藏条件下缔合聚合物溶液的黏弹性实验

Experiment study on viscoelasticity of associative polymer solution under simulated reservoir conditions

为了研究缔合聚合物溶液在实际油藏条件下黏弹性的好坏,在模拟大庆主力油藏条件下,研究了浓度和矿化度对缔合聚合物溶液黏弹性的影响。结果表明:浓度和矿化度对缔合聚合物溶液黏弹性的影响与对HPAM溶液的影响相同;缔合聚合物溶液黏弹性产生的原因与HPAM溶液不同,HPAM溶液的黏弹性是由分子链间的缠结作用引起的,而缔合聚合物溶液的黏弹性主要是由分子链间的缔合作用引起的;缔合聚合物溶液在相对比较低的浓度下表现出了明显的弹性;在低而宽的频率范围内缔合聚合物溶液的弹性明显大于HPAM溶液的弹性,说明缔合聚合物溶液在多孔介质中流动时,在比较小的剪切速率下就表现出弹性,这就意味着不需要很高的注入速度,即可达到利用缔合聚合物溶液的弹性来提高驱油效率的目的。

In order to determine whether the viscoelasticity of associative polymer solution(APS) is better or not under real reservoir conditions,the effect of concentration and salinity on the viscoelasticity of APS is analyzed by simulating major reservoir conditions of Daqing Oilfield.The result shows that the effect is the same as it is on HPAM solution.However,the viscoelasticity of HPAM solution is produced differently from that of APS.That is,the viscoelasticity of HPAM solution is generated from the entanglement of molecular chains,while the viscoelasticity of APS is mainly causes by the association reactions between molecular chains.APS viscoelasticity is obvious under much lower concentration.It is much higher than that of HPAM solution within low and wide frequency range.It is revealed that APS has viscoelasticity when it flows in porous media with lower shear rate.That means the purpose of improving oil displacement efficiency can be realized relying on APS viscoelasticity with lower injection rate.