气田开发中“气藏整体治水”技术理念的形成、发展及理论内涵

The formation development and theoretical connotations of "overall water control of gas reservoir" technology in gas field development

全球气田开发过程中,气井产水具有普遍性和复杂性,气藏水侵、水封、水淹、甚至暴性水淹等,会导致气藏采收率大幅降低。为了提高气藏采收率,支撑气藏科学高效开发,基于四川盆地“九五”以来有水气藏开发的技术攻关和实践,逐渐形成以提高采收率为核心的“气藏整体治水”重大技术理念,并建立了“气藏整体治水”的理论内涵和技术模式,保障了四川盆地天然气大开发的高质量发展和可持续发展。研究结果表明:(1)气藏治水实现了“气井排水采气”向“气藏整体治水”的系统性、科学性技术转变,技术模式总体可归纳为“早期防水、中期控水、晚期治水”;(2)综合采用动态分析、数值模拟和排水采气等技术,准确预判了水侵特征和水侵模式,科学制订了具有系统性、全生命周期和差异化特点的治水方案,减缓非均匀水侵程度,减少封闭气规模,降低气藏废弃压力,实现气藏储量最大限度地均匀动用;(3)中坝须二、沙坪场石炭系和磨溪龙王庙组等有水气藏的开发实践证明,“气藏整体治水”大幅提升了有水气藏开发效果,逐渐成为气田开发中最重要的技术之一。结论认为,“气藏整体治水”技术理念的形成和发展具有极其重要的意义,为国内外深层—超深层有水气藏及其他复杂有水气藏高效开发提供理论技术指导和有益借鉴。

In the process of gasfield development all over the world, gas wells have universality and complexity in water production,and gas reservoirs suffer water invasion, water plugging, water flooding and even violent water flooding, which can lead to the great decrease of recovery factor of gas reservoirs. In order to improve the recovery factor of gas reservoirs and support the scientific and efficient development of gas reservoirs, the major technical concept of "overall water control of gas reservoir" with enhanced oil recovery(EOR) as the core is gradually formed based on the technical research and practice in the development of water-bearing gas reservoirs in the Sichuan Basin since the 9th Five-Year Plan. In addition, the theoretical connotation and technical mode of "overall gas control of gas reservoir" are established, which ensures the high-quality development and sustainable development of large-scale natural gas development in the Sichuan Basin. And the following research results are obtained. First, by virtue of the water control of gas reservoirs,the "drainage and gas recovery of gas well" is transformed systematically and scientifically into "overall water control of gas reservoir",and the technical mode is overall summarized as "early water prevention, middle water control and later water governance". Second,water invasion characteristics and modes are predicted accurately by using dynamic analysis, numerical simulation and drainage and gas recovery technologies comprehensively, which is beneficial to formulate systematic, lifecycle and customized water control plans scientifically, slow down the non-uniform degree of water invasion, reduce the scale of sealed gas and decrease the abandonment pressure of gas reservoirs, so that the reserves of the gas reservoir can be produced uniformly to the uttermost. Third, the development practices of water-bearing gas reservoirs in the second Member of Xujiahe Formation in Zhongba, in the Carboniferous in Shapingchang and in the Longwangmiao Formation in Moxi prove that "overall water control of gas reservoir" significantly improves the development effect of water-bearing gas reservoirs and has gradually become one of the most important gasfield development technologies. In conclusion,the formation and development of the technical concept of "overall water control of gas reservoir" is of great significance and provides theoretical and technical guidance and valuable reference for the efficient development of deep and ultra-deep water-bearing gas reservoirs and other types of complex water-bearing gas reservoirs at home and abroad.