多层系边底水气藏生产动态特征及见水时间预测方法

Production performance characteristics and water breakthrough time prediction of multi-layer edge and bottom water gas reservoir

针对多层系气田不同层之间压力系统、水体能量、储层物性不同而导致的气藏生产动态规律差异明显的现象,以Z气田为例,分析了气井生产过程中凝析油含量变化规律,明确了影响凝析油含量变化的主控因素。研制了气井出水类型判别图版,通过计算井底与井口2种条件下天然气饱和水量的差值,能够判别气井出水类型。采用现代产量递减分析方法确定地层压力变化规律,基于气藏物质平衡方法,计算不同时刻气井的水侵量和水侵替换系数,明确了气井3种见水模式。建立了考虑储层倾角的边水气藏见水时间解析预测方法,研制了不同储层倾角、日产气量情况下的见水时间预测图版,为Z气田未投产气藏以及同类型气藏的高效开发提供了技术支撑。

The production performance of different gas reservoirs are obviously different due to the differences of pressure system,water energy and formation properties between different layers.Taking Z gas field as an example.In view of this situation,herein we analyzed the variation law of condensate content,and clarify the main controlling factors.The discrimination chart of water type of gas well was developed,which can be distinguished by calculating the difference of saturated water volume of natural gas under the conditions of bottom hole and wellhead.The modern production decline analysis method was used to determine the variation of formation pressure.Combined with the material balance method,the water influx and water influx replacement coefficient of gas wells at different times are calculated,and three water breakthrough modes of gas wells were defined.The analytical prediction method of water breakthrough time of edge water gas reservoir considering reservoir dip angle was established,and the prediction chart of water breakthrough time under different reservoir dip angle and daily gas production was developed.The findings in the present work provide technical support for the efficient development of unproductive gas reservoirs in Z gas field as well as similar gas reservoirs in other fields.