摘要
边、底水水侵是导致气藏采收率偏低的主要原因,明确边、底水气藏的水侵机理与规律,有利于改善气藏的开发效果。为此,运用全直径岩心模拟边、底水气藏开发过程,研究其水侵机理、动态与规律。实验结果表明:对于均质气藏,只有边、底水能量充足且储层渗透性较好,气藏开发过程中才有可能发生大规模水侵,降低气藏最终采出程度;对于均质低渗透致密储层,边、底水水侵速度十分缓慢,对生产效果几乎没有影响,而边、底水能量主要决定于流体(水和气)自身的弹性膨胀能力和孔隙空间的压缩性。在物理模拟实验认识的基础上,建立了均质、非均质气藏边、底水侵计算模型。数值模拟计算结果表明:均质气藏储层水侵均匀推进,水侵速度慢;非均质气藏储层水沿着高渗透条带或高角度裂缝向井底推进速度快,且非均质性越强,水侵推进速度越快,气井见水时间越早。该研究成果丰富了对边、底水气藏水侵机理、动态与规律的认识,并为边、底水气藏的合理有效开发提供了具体对策。
Edge and bottom water influx was the main reason for the low recovery efficiency of a gas reservoir, which can only be im- proved when a better understanding is obtained of the water influx mechanism and rules. Full diameter cores were used to simulate the development of gas reservoirs with edge and bottom water and to study the mechanism, dynamic state and rules of water influx into gas reservoirs. The results showed that： （1） for homogeneous gas reservoirs, the large-scale water influx would occur in reser voir development in the condition of plenty of edge and bottom water and high permeability, and decrease the ultimate gas reservoir recovery efficiency, （2） for homogeneous tight reservoirs with low permeability, the edge and bottom water influx velocity was too low and exerted little impact on production efficiency, but edge and bottom water energy was determined by the elastic expansion of the fluid （water and gas） and pore compressibility. Based on physical simulation results, a calculation model was established for edge and bottom water influx of homogeneous and heterogeneous gas reservoirs. The calculation results of numerical simulation showed that the water influx velocity of homogeneous gas reservoirs was uniform and slow, the water influx in heterogeneous gas reservoirs became faster from high-permeability stripes or high angle fractures to well bottom, and the greater heterogeneity the reservoir has, the higher the water influx velocity was and the earlier the water production would occur in a gas well. The research achievement en- riched the understanding of the mechanism, dynamic state and rules of water influx in the gas reservoirs with edge and bottom water and provided specific strategies for their efficient reasonable development.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2015年第2期47-53,共7页
Natural Gas Industry
基金
国家科技重大专项"低渗
特低渗油气田经济开发关键技术(二期)"(编号:2011ZX05013)
关键词
边
底水气藏
水侵机理
物理模拟
数学模型
均质储集层
非均质储集层
气藏有效开发
Gas reservoir with edge and bottom water
Water influx mechanism
Physical simulation
Mathematical model
Homo geneous reservoir
Heterogeneous reservoir
