摘要
煤层气高产区的有效预测对提高煤层气单井产量和开发效益具有重要意义。为了实现煤层气储层产气能力的定量评价,基于煤层气开发机理,利用沁水盆地南部煤层气开发数据,通过理论和统计分析,定义了解吸效率指数和产气能力指数,从储层含气性、解吸效率和产出能力3个方面定量评价了各参数预测产气能力的可靠性。结果表明,储层含气性评价中去除含气饱和度,解吸效率指数中增加表征宏观解吸效率的地解压差,使含气性和解吸效率指数与日产气量的相关性大幅提升。煤层气井日产气量随含气量、解吸效率指数、渗透率增加而增加,当含气量大于15 m^3/t,解吸效率指数大于0.11(MPa·d)^-1,渗透率大于0.03×10^-3μm^2时,单井日产气量能够达到800 m^3以上。将含气量、解吸效率指数和渗透率的乘积定义为煤层气产气能力指数能够有效预测煤层气高产区。当产气能力指数分别大于0.05×10^-3μm^2·m^3·(t·d·MPa)^-1和1×10^-3μm^2·m^3·(t·d·MPa)^-1时,单井日产气量分别大于800 m^3和1 500 m^3。
The effective prediction of high production areas of CBM is of great significance to improve the production and the development benefits of single wells.In order to the evaluate the production capacity of CBM formation quantitatively,based on the development mechanism of CBM,the data of CBM in southern Qinshui Basin was used to define the absorption efficiency index and the gas production capacity index through the theory and statistical analysis.And the reliability of gas production capacity was quantitatively evaluated from 3 aspects of gas content ability,desorption efficiency and output capacity of the reservoir.The results showed that,in the evaluation of gas content,to remove gas saturation and increase the differential pressure of formation pressure and desorption pressure—which represented the macroscopic desorption efficiency—in the desorption efficiency index can greatly improve the correlation between daily gas production and gas content,desorption efficiency index respectively.The daily gas production increased with the increasing of gas bearing index,desorption efficiency index and the production capacity index.When the gas content,the desorption efficiency index and the permeability were respectively higher than 15 m^3/t,0.11(MPa·d)^-1 and 0.03×10^-3μm^2,the daily gas production could be more than 800 m^3.When the gas content,desorption efficiency index and production capacity index were defined as the gas production capacity index of CBM,high production areas of CBM could be effectively predicted.When the gas production capacity index was great than 0.05×10^-3μm^2·m^3·(t·d·MPa)^-1,the daily gas production was more than 800 m3,while the index was greater than 1×10^-3μm^2·m^3·(t·d·MPa)^-1,the daily gas production was more than 1 500 m^3.
作者
王镜惠
梅明华
梁正中
王华军
WANG Jinghui;Mei Minghua;LIANG Zhengzhong;WANG Huajun(School of Chemistry and Chemical Engineering,Yulin University,Yulin,Shaaxi 719000,China;No.2 Gas Production Plant,Changqing Oilfield Company,CNPC,Yulin,Shaaxi 719000,China)
出处
《油气藏评价与开发》
CSCD
2019年第4期68-72,共5页
Petroleum Reservoir Evaluation and Development
基金
陕西省自然科学基础研究计划“鄂尔多斯盆地东北部异常压力形成与页岩气富集机理研究”（2017JM4017）
关键词
沁水盆地
高煤阶
煤层气
储层评价
定量评价
产气能力指数
Qinshui Basin
high coal rank
coalbed methane(CBM)
formation evaluation
quantitative evaluation
gas production capacity index
