高石梯-磨溪碳酸盐岩气藏斜井产能评价

Productivity Assessment for Inclined Wells in Gaoshiti-Moxi Carbonate Gas Reservoirs

针对高石梯-磨溪碳酸盐岩气藏应力敏感性强、斜井产能评价困难的问题,在储层类型描述的基础上,运用物理模拟实验方法,分析裂缝-孔洞型、孔隙-溶洞型及孔隙型储层的应力敏感特性和非达西渗流特征,采用曲线回归方法求取储层应力敏感和高速非达西渗流系数方程,在稳态渗流的条件下,建立考虑井斜、储层应力敏感和高速非达西的产能评价数学模型。根据储层岩石、流体特性与生产动态,应用现代产量递减分析方法,确定地层渗透率与单井控制半径,对模型进行求解计算。与矿场测试无阻流量相对比,计算结果平均误差小于6.0%,准确度较高。研究成果为应力敏感性碳酸盐岩气藏斜井产能评价提供了新的技术方法。

With high stress sensitivities, productivity assessments for inclined wells in Gaoshiti-Moxi carbonate gas reservoirs encountered significant challenges. On bases of reservoir descriptions, experimental techniques involving physical simulation have been used to determine stress sensitivity properties and non-darcy seepage features of res- ervoir formations of fracture-vug, pore-dissolved vug and pore types. Through curve regression, stress sensitivity and high-velocity non-darey seepage parameter equations for reservoir folmations can be established, in addition, the mathematic model for productivity assessment in reservoirs with consideration to well inclinations, reservoir stress sensitivity and high-speed non-darcy flow under steady seepage can be generated. With consideration to properties of reservoir rocks and fluids, together with production performances, state-of-art productivity reduction analysis techniques can be used to determine formation permeability and controlling radius of individual well. In this way, relevant calculations can be performed for the model. Compared with open-flow capacity determined on site, the calculation results have relatively high accuracy with average error less than 6.0%. Relevant research conclu- sions may provide an innovative technique for productivity assessment of inclined wells in carbonate gas reservoirs with high stress sensitivity.