摘要
为了解决鄂尔多斯盆地大牛地气田水平井开发动态特征差异影响因素不明的问题,对储层类型、沉积微相、生产动态等资料进行综合分析,应用不稳定流动分析法和数值模拟方法开展水平井生产达到拟稳态流动阶段所需时间及主要影响因素研究,分气藏建立了气井达到拟稳态流动阶段时间评价图版。研究结果表明:①气田水平井开发区自下而上发育上石炭统太原组障壁岛、下二叠统山西组分流河道和下二叠统下石盒子组辫状河等3种沉积类型储层;②水平井总体均呈3段式生产动态特征,即稳产阶段、快速递减阶段和长期低压低产缓慢递减阶段,不同气藏水平井开发动态特征差异大,太2气藏水平井初期产量高,稳产能力强,生产效果最好,盒1、山2气藏动态特征相近,稳产时间短,初期递减快,液气比高,生产效果一般;③气田水平井达到拟稳态流动阶段的时间平均为19 mon,对应气井平均累产气量为1235×10^(4) m^(3);④敏感性分析表明,渗透性越差、气层厚度越大、含水饱和度越低、孔隙度越高,达到拟稳态流动阶段所需的时间越长,影响大牛地气田水平井达到拟稳态流动阶段时间长短的主要因素为储层渗透率和含水饱和度。
So far,the factors affecting the development performance difference in horizontal wells,Daniudi gasfield,Ordos Basin,have not been made clear yet.Therefore,some data on reservoir types,sedimentary microfacies,production perfor⁃mance were analyzed comprehensively.Then,the time to reach the pseudo-steady state flow in a horizontal well and its main influential factors were studied by means of two methods,including unsteady-state flow analysis and numerical simu⁃lation.Finally,the chart to evaluate the time was established for different gas reservoirs.Results show that(1)in Daniudi gasfield,there are three kinds of reservoirs developed in the horizontal-well development area,from bottom to top includ⁃ing barrier island of Upper Carboniferous Taiyuan Formation,distributary channel of Lower Permian Shanxi Formation,and braided river of Lower Permian Lower Shihezi Formation;(2)as a whole the horizontal wells present the three-stage pro⁃duction performance,including stable production stage,fast decline stage,and long low-yield slow-decline stage with low pressure.For the horizontal wells in various gas reservoirs,their development performance is quite different,for example,the best production effect with high initial yield and stable production capacity for the horizontal wells in gas reservoirs of Taiyuan 2 Member whereas similar performance,not very good production effect,short stable production period,fast initial decline,and high liquid/gas ratio for those in gas reservoirs of both Shihezi 1 and Shanxi 2 members;(3)for these horizon⁃tal wells,their time to reach the pseudo-steady state averages 19 months,and the cumulative production for the corre⁃sponding wells averages 1235×10^(4) m^(3);and(4)sensitivity analysis indicates that the poorer the permeability,the greater the gas layer thickness,the lower the water saturation,the higher the porosity,and the longer time it takes to reach the pseu⁃do-steady state flow.In conclusion,the main factors influencing on this time are reservoir permeability and water satura⁃tion.
作者
孙华超
SUN Huachao(Exploration and Development Research Institute,Sinopec North China Company,Zhengzhou,Henan 450000,China)
出处
《天然气技术与经济》
2021年第2期7-10,26,共5页
Natural Gas Technology and Economy
关键词
大牛地气田
致密气藏
水平井
拟稳态
渗透率
含水饱和度
Daniudi gasfield
Tight gas reservoir
Horizontal well
Pseudo-steady state
Permeability
Water saturation
