摘要
超压储集体中的天然气往往以连续游离态、分散游离态和饱和溶解态三相混合形式共存,而后两者并未引起足够重视;针对上述现状,在精细解剖莺歌海-琼东南盆地典型压溶气和高温超压天然气溶解实验基础上,提出“压溶气”的概念,总结压溶气基本特征、形成条件和资源潜力。压溶气是指高压储集体内气水带和饱和溶解气带所赋存的天然气,其形成需要具备2个基本条件:压力系数通常大于1.5,储层具有较高含气饱和度(10%~35%)。压溶气以多期次叠置形式从浅到深存在于地层中,压溶气至少存在4种类型:多气顶压溶气组合类型、单气顶压溶气组合类型、无气顶含气水层组合类型和无气顶含溶解气水层组合类型。压溶气形成所需要的基本地质要素包括气源、储层、盖层、气水带和超压体,气源、储层及盖层条件控制压溶气带规模,高温高压和低渗储层控制天然气溶解度和气水带厚度,砂岩物性控制压溶气组合类型,压力变化控制压溶气不同赋存状态的转化。莺歌海-琼东南盆地压溶气具可观资源潜力,该领域一旦突破将开创超压盆地天然气勘探新局面。
In overpressure reservoirs,natural gas often coexists in a three-phase mixed form of continuous free state,dispersed free state and water-saturated dissolved state.However,the latter two have not received sufficient attention.In response to this situation,based on detailed characterization of typical overpressure dissolved gas in Yinggehai-Qiongdongnan basins and the experiment results of natural gas dissolution with high-temperature and overpressure,the concept of“overpressure-dissolved gas”was proposed and its basic features,formation conditions and resource potential were summarized.It refers to the natural gas present in the gas-water transitional zone and the saturated dissolved gas zone within the overpressure reservoirs.The formation of overpressure-dissolved gas requires two basic conditions:the pressure coefficient typically greater than 1.5,and a relatively high gas saturation in the reservoir(10%–35%).Overpressure-dissolved gas exists in the strata from shallow to deep with a multi-stage superimposed pattern;there are at least four combination types:overpressure-dissolved gas with multiple gas caps,overpressure-dissolved gas with single gas cap,gas-bearing water layer without gas cap,and dissolved gas-bearing water layer without gas cap.The basic geological elements required for the formation of overpressure-dissolved gas include the gas source,reservoir,cap rock,gas-water transitional zone and overpressure body.The conditions of gas source,reservoir and cap rock determine the scale of the overpressure-dissolved gas zone.High temperature,high pressure and low-permeability reservoirs control the solubility of natural gas and the thickness of the gas-water transitional zone.The physical properties of sandstone determine the combination types of overpressure-dissolved gas.Changes in pressure control the transformation of different existing states of overpressure-dissolved gas.The overpressure-dissolved gas in the Yinggehai-Qiongdongnan Basin has considerable huge resource potential.Once breakthrough is achieved in this area,it will usher in a new era of natural gas exploration in the overpressured basin.
作者
谢玉洪
XIE Yuhong(China National Offshore Oil Corporation,Beijing 100010,China)
出处
《石油勘探与开发》
北大核心
2025年第5期1211-1220,共10页
Petroleum Exploration and Development
基金
中国工程院科技战略咨询重点项目“海上能源一体化协同开发战略研究”(2025-HZ-30)。
关键词
压溶气
水溶解气
非常规天然气
高温超压
莺歌海盆地
琼东南盆地
overpressure-dissolved gas
dissolved gas in water
unconventional natural gas
high temperature and overpressure
Yinggehai Basin
Qiongdongnan Basin
