低/特低渗透油藏压裂水平井布缝模式研究

针对目前商业软件模拟低/特低渗透油藏非达西渗流特性的局限性,建立了考虑启动压力梯度、地层应力敏感性及裂缝长期导流能力的三维两相数值模拟模型;并以某低渗透油田的数据为基础,验证了模型的有效性;同时进行了压裂水平井布缝模式分析。压力波及区域及累积产量协同优化结果表明:压裂水平井布缝时应避免缝间干扰;在相同裂缝间距条件下,裂缝对称分布模式波及面积最大、产量最高;其次为裂缝交错分布模式和裂缝不对称分布模式。为了提高低/特低渗透油藏的采收率,应采取维持裂缝长期导流能力、注水补充能量等有效措施。

Research of Fracture Distribution Pattern for Fractured Horizontal Wells in Low & Ultra-Low Permeability Reservoirs

According to the limitations of simulating non-Darcy flow in low and untra-low permeability reservoirs of the current commercial software, a three-dimensional and two-phases numerical model was established considering start-up pressure gradient, formation sensitivity and fracture conductivity decrement. The validity of the model was verified based on the data of a low permeability reservoir, and the fracture distribution pattern of the fractured horizontal well was analyzed. Considered both pressure sweep area and cumulative production, results show that, fracture interference should be avoided for a fractured horizontal well, on condition of same fracture interval, fractures distributed symmetrically leads to more pressure sweep area and cumulative oil production, and fractures distributed crossly and asymmetrically follow orderly. In order to improve the recovery efficiency of low and untra-low permeability reservoirs, effective treatments as maintaining long time fracture conductivity and water injection should be implemented.