准噶尔盆地深层煤岩气赋存特征及游离气饱和度定量表征方法OA
Occurrence characteristics of deep coal-measure gas in Junggar Basin and a quantitative characterization method for free gas saturation
针对准噶尔盆地深层煤岩气储层孔隙结构精细化表征及气体赋存机理认识不足的问题,提出一种基于孔隙类型与气体赋存空间的游离气饱和度定量表征方法,建立了煤岩不同孔隙类型(微孔、介孔、宏孔)与不同赋存状态气体(吸附气、游离气)的对应关系,定量划分微孔主导的吸附空间与介孔-宏孔构成的游离空间,突破传统方法对孔隙类型与气体赋存状态缺乏针对性关联的局限;结合实测含气量、等温吸附、覆压孔渗等多源实验数据,针对性校正实测含气量中由于气体吸附—解吸—脱附动态变化带来的游离气含量偏差及储层条件下对游离空间的压缩效应,实现原位游离空间与原位游离气所占空间的精准量化,最终建立游离气饱和度计算模型.该方法首次将孔隙类型与气体赋存状态进行系统性耦合,并引入游离气饱和度作为核心评价参数.应用结果表明:滴煤与彩煤井区游离气饱和度低于 35%,属于中等生气能力-较强储集空间-较低游离气饱和度模型;齐新井区孔隙发育程度较低,但游离气饱和度多高于75%,属于强生气能力-中等储集空间-高游离气饱和度模型.该方法有效揭示了不同孔隙类型对气体赋存的控制机制,深化了气体赋存及产出机理认识,构建的生气能力-储气能力-游离气饱和度组合评价模式可为后期开采方案优化提供依据,提升煤岩气开采效率.
In view of the inadequate understanding of the pore structure refined characterization and gas occurrence mechanism in deep coal-measure gas reservoirs of the Junggar Basin,a quantitative characterization method for free gas saturation was proposed based on pore types and gas occurrence space.A correspondence was established be-tween different pore types in coal rock(micropores,mesopores and macropores)and different gas occurrence states(adsorbed gas,free gas).The adsorption space do minated by micropores and the free gas space composed of meso-pores-macropores are quantitatively delineated,overco ming the limitation of traditional methods lacking targeted linkage between pore types and gas occurrence states.By integrating measured gas content,isothermal adsorption,o-verburden porosity-permeability and other experimental data,targeted corrections were made for the bias in free gas content caused by dynamic adsorption-desorption-diffusion changes in measured total gas,as well as for the com-pression effect on free space under reservoir conditions.This achieved accurate quantification of in-situ free gas space and the space occupied by in-situ free gas,and ultimately established a calculation model for free gas satura-tion.This method,for the first time,systematically couples pore types with gas occurrence states and introduces free gas saturation as a key evaluation parameter.Application results show that in Dimei Well and Caimei Well areas,free gas saturation is below 35%,belonging to the model of moderate gas generation capacity-relatively strong stor-age space-relatively low free gas saturation;in Qixin Well area,despite lower pore development,free gas saturation is mostly above 75%,belonging to the model of strong gas generation capacity-moderate storage space-high free gas saturation.This method effectively reveals the controlling mechanism of different pore types on gas occurrence,deep-ens the understanding of gas occurrence and production mechanisms.The combined evaluation model of gas genera-tion capacity-gas storage capacity-free gas saturation can provide a basis for optimizing future development plans and improve the production efficiency of coal-measure gas.
杨潇;胡正舟;潘拓;姚卫江;陈国辉;谢菲;付基友
北京润泽创新科技有限公司,北京 100120中国石油新疆油田分公司,新疆 乌鲁木齐 830013中国石油新疆油田分公司,新疆 乌鲁木齐 830013中国石油新疆油田分公司,新疆 乌鲁木齐 830013北京润泽创新科技有限公司,北京 100120中国石油大港油田分公司,天津 300280中国石油西部钻探工程有限公司,新疆 克拉玛依 834000
能源科技
煤岩气气体赋存吸附空间游离空间游离气饱和度生气能力储气能力
coal-measure gasgas occurrenceadsorption spacefree gas spacefree gas saturationgas generation capacitygas storage capacity
《特种油气藏》 2026 (1)
22-32,11
中国石油攻关性应用性科技专项"深地煤岩气赋存特征及成藏机理研究"(2023ZZ18YJ02)
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