疏松砂岩稠油油藏岩石应力敏感性对蒸汽驱的影响——以BZA油田为例

Effect of rock stress sensitivity on steam flooding in unconsolidated sandstone heavy oil reservoir——by taking BZA oilfield as an example

针对稠油油藏蒸汽驱过程中储层岩石变形会对开发效果产生影响这一问题,首次提出对疏松砂岩稠油油藏进行岩石应力敏感性实验,以及开展岩石应力敏感性对蒸汽驱油效率影响的物理模拟实验研究。结果表明,无论是高渗储层还是低渗储层,随着有效覆压的增加渗透率逐渐降低,且渗透率的变化具有不可逆性;有效覆压越高,岩心受到挤压加重,孔隙结构变形越严重,驱油效率越低;低渗储层岩石应力敏感性强于高渗储层;岩石的应力敏感性对蒸汽驱过程中的开发效果影响较大。研究成果对后期稠油油藏蒸汽驱开发及策略制定具有一定指导作用。

In order to solve the problem that rock deformation will affect the development effect in the process of steam flooding in heavy oil reservoir, the rock stress sensitivity experiment is proposed for the first time in unconsolidated sandstone heavy oil reservoir, and the physical simulation experiment research on the influence of rock stress sensitivity on steam displacement efficiency was carried out. The results of the study show that: whether it is a high-permeability reservoir or a low-permeability reservoir, the permeability gradually decreases with the increase of effective overburden, the sensitivity of the high-permeability reservoir is weaker than that of the low-permeability reservoir, and the change in permeability is irreversible. The higher the effective overburden pressure, the heavier the core is subjected to compression, the more serious the porestructure changes, and the lower the oil displacement efficiency. The stress sensitivity of rock has a great influence on the development effect of steam flooding. The research results have a certain guiding role for steam flooding development and strategy formulation in later heavy oil reservoirs.