新疆油田超低渗透油藏注水开发储层损害研究

超低渗透储层由于其特殊的孔喉特性,在注水开发过程中对外来流体的悬浮物含量与结垢性等都有很严格的要求,如何在注水开发过程中降低储层损害与有效保护储层孔喉成为高效开发超低渗透油藏的关键。以新疆油田某区块为例,通过储层敏感性评价与注入水结垢分析,明确了注水开发过程中储层的损害因素。结果表明：该区块储层具有中等偏强的水敏、较强的盐敏以及中等偏强的碱敏性损害;混合注入水容易产生以Ca2＋为主的不溶性结垢,导致堵塞注水管线及储层孔喉。因此,超低渗透油藏在注水开发过程中,不仅要注重储层保护措施,更要严格控制注入水水质,从而有效地保护储层,为长期高效的开发奠定基础。

Study on formation damage with water flooding for ultra-low permeability reservoir in Xinjiang Oiifield

Because of the special characteristics of pore throat, the suspended solids content and the scaling tendency of foreign fluids are strictly limited with water flooding for ultra-low permeability reservoir. How to reduce the degree of formation damage with water flooding to protect pore throat, that will be the critical to efficient development of ultra-low permeability reservoir. Taking a block of Xinjiang Oilfield as an example, by analyzing the reservoir sensitivities and scaling tendency, this paper defined the damage factors of formation with water flooding. The result shows that the reservoir exhibits medium to strong water sensitivity, serious salt sensibility and medium to strong alkali sensitivity, the scale is serious for oilfield injection water, injected water will produce insoluble that will damage the water injection pipeline and reservoir pore throat. Thus, in the water flooding development process of ultra-low permeability reservoir, we need to not only focus on reservoir protection, but also limit the quality of injected water so as to effectively protect reservoirs and lay the foundation for long-term efficient development.