致密气藏分段压裂水平井产能研究

A Study on Production Analysis of Multi-Fractured Horizontal Wells in Tight Gas Reservoirs

建立了致密气藏分段压裂水平井产能模型,使用伽辽金有限元方法对模型进行求解,最后通过编程计算绘制了产能及产能导数曲线,并对曲线的形态特征及影响曲线形态的因素进行了分析。研究结果表明:产能曲线主要分为6个流动阶段;水力裂缝导流能力主要影响压裂水平井早中期产能大小,导流能力越大,产能越大;裂缝半长越大,裂缝径向流持续的时间越短,但裂缝径向流及椭圆流阶段的产能越大;裂缝条数对整个生产阶段的产能都有重要影响,压裂裂缝条数越大,压裂水平井产能也越大;裂缝间距越大,压裂裂缝之间发生干扰的时间就越晚,裂缝径向流结束的就越晚,而且产能越大。研究结果可为致密气藏分段压裂水平井产能分析提供科学依据。

A new production analysis model of multi-fractured horizontal wells in tight gas reservoir is es-tablished, the solution is obtained by Galerkin finite element method. The dimensional production and its derivative curves are plotted by computer programming, and a sensitivity analysis is conducted to study impacts on production curves. The results show that there are six different flow regimes observed in production curves. The hydraulic fracture conductivity mainly affects the early-to-mid flow regimes, and the bigger the value is, the higher the production is. With the increase of hydraulic fracture half-length, the fracture radial flow becomes shorter, but the production is bigger in fracture radial flow and elliptical flow regimes. The number of hydraulic fractures has great effect on the whole flow regimes, and the production will be bigger for more hydraulic fractures. With the increase of hydraulic fracture spacing, the time of interference between the hydraulic fractures will be latter, then the occurrence of hydraulic fractures radial flow regime will postpone, and the production will be bigger in the corresponding flow regimes. The new model and obtained results can play a guiding role in analyzing production for multi-fractured horizontal well in tight gas reservoirs.