致密油藏孔喉细微、微裂缝发育,压裂水平井是开发的必要手段。由于受复杂地应力和天然裂缝影响,人工裂缝通常与井筒呈一定角度,使得角度缝压裂水平井产能预测变得十分复杂。基于天然裂缝等效渗透率张量理论,建立了考虑全渗透率张量的各向异性稳定渗流数学模型;根据势叠加原理,采用考虑应力敏感的半解析方法,构造了储层向人工裂缝流动的离散势函数单元,建立了考虑天然裂缝下任意角度人工裂缝有限导流能力压裂水平井产能预测模型。模型为致密油藏压裂水平井生产能力评估、合理工作制度制定提供了重要依据。
Tight oil reservoirs are characterized by tiny pores & throats and well-developed micro-fractures, the horizontal well fracturing is the necessary key to develop the reservoirs. Due to the influences of the complex in-situ stress and the natural fractures, there is usually a certain angle between the hydraulic fractures and the wellbore, which makes the productivity prediction of the angularly fractured horizontal well very complicated. Based on the theory of equivalent permeability tensor in the natural fractures, the heterogeneous steady-flow new mathematical model is established considering all permeability tensors; according to the potential stacking principle, by semi-analytic method considering the stress sensitivity, the discrete potential function units for the reservoirs considering the flow towards fractured/artificial cracks are established, the computing model for the fractured horizontal well is built taking the limited conducting capacity of the arbitrary angle's fractured cracks into the consideration under the condition of the natural fractures. The model has provided the important evidences for the productivity evaluation and determination of the reasonable operating system of the fractured horizontal well in the tight oil reservoirs.