嫩二段标志层套管损坏区进水域影响因素分析

Analysis on Influential Factors of Water Inflow Domain in Casing Failure Zone of Nen2 Member Marker Bed

分析了标志层进水域形成的力学机理,并根据水力压裂理论和Von-Mises屈服准则,确定了进水域形成的判定准则;基于建立的判定准则,采用有限元法模拟计算分析了注水压力、孔隙度、抗拉强度等因素对进水域面积的影响。计算结果表明:注水压力及孔隙度的增加会使标志层进水域面积增加,注水压力的作用效果更为明显;岩石抗拉强度和内聚力的增加,会使标志层进水域面积减小,但作用较小。了解嫩二段标志层进水域的影响因素及其作用对制订有效的套管损坏防控措施具有重要意义。

This paper analyzed the mechanical mechanism for the forming of marker bed water inflow domain,and based on the hydraulic fracturing theory and von- Mises yield criteria,ascertained the decision criteria for the forming of water inflow domain; furthermore,based on the built decision criteria,this paper used the finite element method( FEM) to have conducted simulation calculation and analyzed the effect of the factors like injection pressure,porosity and tension strength on the area of water inflow domain.The calculation results showed that the increase of injection pressure and porosity could increase the area of marker bed water inflow domain,and the effect of injection pressure was more obvious; the increase of tensile strength of rock and cohesion all could decrease the area of marker bed water inflow domain,but the effect was small. The understanding on the influential factors and their effect of water inflow domain of Nen2 Member marker bed are significant to the working out of effective casing failure prevention and control measures.