油气藏中气态地层水的存在及其意义  

Occurrence and significance of gaseous water in reservoir

作　　者：郭望[1] 陈践发[1] 曹青[2] 赖长洁[1] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]西安石油大学地球科学与工程学院,陕西西安710065

出　　处：《油气地质与采收率》2013年第1期36-39,43,共5页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项"大型油气田及煤层气开发项目"(2011ZX05023-001-011)

摘　　要：油气藏中广泛存在烃—水及其他气体和矿物盐类的混溶体系,其相变特征十分复杂,但对油气勘探开发的作用至关重要。通过调研中外有关烃—水混溶体系的资料,着重分析了气态地层水的存在条件及含水烃类体系的相变特征,结果表明,局部突发性的温度上升、压力减小及混溶体系含烃量增加,均有利于烃—水混溶体系的气化。现今测得的束缚水膜厚度受控于束缚水饱和度的影响,为动态变化量,不适宜作为储层下限进行评估;真正稳定的束缚水膜厚度应约为1.6nm,在一定的温度和压力及溶解烃浓度下,现今测得的储层物性下限一定可以降低。地层水的气化引起的盐析作用会降低油气藏的渗透率,增大油水界面压力,在开采过程中要注意气态地层水的变化。The miscible systems, which are composed of hydrocarbon-water, other gases and mineral salts, are widely distributed in reservoir, with complicated phase transition attributes, and are also significant to the exploration and development of petroleum. After gathering domestic and international data about hydrocarbon-water miscible system and mainly analyzing conditions for occurrence of gaseous formation water and phases transition attributes of water bearing hydrocarbon system, this paper concludes that the regional sudden rising of temperature, reducing of pressure and increasing of hydrocarbon bearing content are all beneficial for the vaporization-to the hydrocarbon-water miscible system. The current measured thickness of irreducible water is a fluctuated value, which is dependent on irreducible brine saturation and ineligible for low limit of reserve, and then, the present measured low limit of reserve can be decreased undoubtedly under suitable values of temperature and pressure and content of dissolved hydrocarbon, the actual stable thickness should be about 1.6 nm. The salting out effect, which is caused by vaporization of water, will reduce the permeability of oil/gas field and increase interfacial tension of oil-water, so, it is necessary to inspect the gaseous water change during production.

关 键 词：气态地层水 烃-水混溶体系 束缚水膜厚度 盐析 相变特征 

分 类 号：TE37[石油与天然气工程—油气田开发工程]