超低渗透油藏分段多簇压裂水平井渗流特征研究

Flow regimes of segmented multi-cluster fractured horizontal well in ultra-low permeability reservoir

基于鄂尔多斯盆地长8超低渗透油藏地质与流体特征,应用数值模拟方法和等效网格加密技术建立了分段多簇压裂水平井单井数值模拟模型.利用数值试井的手段,研究了分段多簇压裂水平井的渗流规律及影响因素.结果表明:分段多簇压裂水平井渗流主要分为6个阶段,且表现出双重介质的特性;井筒储集系数的大小决定着垂直径向流是否出现,驼峰峰值随表皮系数的增大而增大;主裂缝导流能力主要对前期和中期渗流阶段影响较大,裂缝半长对无因次压力和压力导数的影响较小;改造区渗透率对无因次压力和压力导数曲线位置及形状产生较大影响;应力敏感的存在会使无因次压力和压力导数曲线上移,但各个渗流阶段不会发生明显的变化.

Based on the geological and fluid proprieties of Chang-8 ultra-low permeability res-ervoir ,a single well numerical simulation model of segmented multi-cluster fractured hori-zontal is built by using the method of numerical simulation and the technology of equivalent local grid refinement （EQ-LGR） .Application of the model ,flow regimes and its affecting factors of segmented multi-cluster fractured horizontal well are studied by using numerical well test .The result shows that the segmented multi-cluster fractured horizontal well has six flow stages and show s the characteristic of double media .Whether the vertical radial flow ap-pears depends on the size of the wellbore storage coefficient .Hump peak increases with the increase of skin factor .Flow conductivity of main fractures mainly affects the early and mid-dle flow stages .Fracture half-length is less effect on the dimensionless pressure and pressure derivative .Permeability of simulated zone has great influence on the locations and shapes of dimensionless pressure and pressure derivative curve .The existence of stress sensitive can make the dimensionless pressure and pressure derivative curve upward ,but each stage hasn′t obviously changed .