一种预测水平井产能的新方法

A new method to predict productivity of horizontal well

水平井可以增加油气井的控制储量和产能,从而在复杂油气藏中得到了广泛应用。国内外学者建立了一系列经典的水平井产能公式,其中,解析法是研究水平井产能的重要方法,该方法从数学模型出发,通过假设条件,简化方程的初始、边界条件,利用保角变换、镜像映射、势的叠加原理,以及等值渗流阻力法等方法得到水平井的产能公式。文中把水平井渗流过程分为内、外两区,通过把外区水平井等效为与储层等厚的垂直裂缝,利用位势理论结合等值渗流阻力法推导出新的水平井产能公式。通过与常用水平井产能公式在经典算例下的对比表明,该公式合理可靠。储层有效厚度较小时,各公式计算结果差异较小;储层有效厚度较大时,要考虑多种方法,力求结果准确。

The horizontal well can increase the controllable reserves anti productivity of oil and gas well. In recent years, horizontal well has widely been applied in complex oil and gas reservoirs. Scholars at home and abroad have built some classical productivity formulas of horizontal well. Analytic method is an important approach to research the productivity of the horizontal well. It is based on the mathematieal model and through the appropriate assumption to simplify the initial equation and houndary conditions. The conformal mapping, image mapping, the prineiple of potential superposition and the equivalent flow resistance method are used to obtain the formula and analytical solution. The seepage process of the horizontal well is divided into inside and outside areas in this paper. The horizontal well in outside area is equivalent to a vertical fracture. Using potential theory and combined with the equivalent flow resistanc, e method, a new productivity formula of horizontal well is deduced. Contrast analysis on the commonly used productivity formula of horizontal well under the classic example shows that the formula is reasonable and reliable. When the effective thickness of reservoir is small, the difference of formula calculation result is small. When the effective thickness of reservoir is large, a variety of methods are needed to consider in order to get a more accurate result.