特低渗透各向异性油藏井网加密储量动用规律

在特低渗透油藏中,由于高渗透条带的发育,通常使其表现出渗透率各向异性特征,导致注采井间的渗流规律与常规油藏不同,对井网加密形式的适应性也存在差异。基于各向异性油藏的渗流特点及井网调整形式,利用叠加原理,得到注采平面渗流场计算公式;引入线状排驱概念,对各向异性油藏井网加密形式进行适应性分析;用驱动压力梯度表征储量动用程度,提出无因次动用提高程度概念,建立定量表征注采井间储量动用规律的方法。结果表明,将初始正方形反九点井网系统地调整为排状加密井网,形成线状排驱,可有效提升特低渗透各向异性油藏的储量动用程度;初始井网井距大于400 m时,注采井间储量动用提升潜力较大。

Reserve producing law of extra-low permeability anisotropic reservoirs with infilled well pattern

There is permeability anisotropy due to the high-permeability channels in extra-low permeability reservoirs,which leads to the different percolation behaviors between injectors and producers compared with conventional reservoirs,and different adaptability of well pattern infilling.Based on the percolation behaviors of anisotropic reservoirs and infilled well pattern,the calculation formula of plane percolation field between injectors and producers is obtained by using the superposition principle.The linear displacement is introduced to analyze the adaptability of infilled well pattern in the anisotropic reservoir.The driving pressure gradient is used to characterize percentage of producing reserve,and the dimensionless incremental percentage of producing reserve is proposed.A quantitative characterization method for producing reserve between injectors and producers is established.The results show that the initial inverted nine-point well patterns are systematically infilled to row well patterns to form linear displacement,which can effectively improve the producing reserve in the extra-low permeability anisotropic reservoirs.When the initial well spacing is greater than 400 m,the potential of producing reserve between injectors and producers is improved significantly.