广安地区有水气藏压力系统划分与控制原因分析

Division of Pressure System and Analysis of Controlling Reason for Water-Driven Gas Reservoir of the Guang'an District

广安地区须家河组有水气藏开发早期气水关系复杂,气井普遍产水。根据低渗有水气藏生产动态及渗流特征,分析利用储层地质方法、压力与埋深关系和区块内部地层压力场分布变化关系确定其压力系统情况;根据低孔低渗储层气水分异原理,通过储层物性对所需最小圈闭高度的控制分析认为,随着孔喉半径减小,毛细管力增大,对应区域含水饱和度高,气水过渡带高度增大,当气藏的闭合高度小于气水过渡带高度时,则形成气水同层气藏;储层的非均质性导致不同区域气水过渡带高度存在差异,是地层水控制压力系统划分的主要原因。分析结论为有水气藏的压力系统划分及其控制原因分析提供依据,对有水气藏的开发具有重要意义。

Xujiahe gas reservoir in Guang'an area is characterized by complex relationship between gas and water,and low natural productivity of gas wells,so diving pressure system gets difficult.From analysis of the production performance and percolating characteristics of low permeability water-driven gas reservoir,the characteristics of reservoir,pressure-elevation and pressure distribution of low permeability gas reservoir were studied.By way of the analysis of characteristics and mechanism of yielded formation water during the exploitation of Xujiahe gas reservoir in this paper,the reservoir is characterized by normal distribution of gas andwater,namely the gas located above the water;watertype is disserted;As the decreasing of pore throat radius,capillary force,water saturation and the high of gas water transition zone increase;gas and water reside in the same layerby the action of capillary force and gas watertransition zone exists;the reservoirheterogeneous conditions are the reasons of controlling reason and pressure system division.With real cases,itis demonstrated the analysismethods have important significance for the development of the water-driven gas reservoirs with low permeability.