摘要
为研究低煤阶煤储层的产气潜力,以彬长矿区大佛寺井田4号煤储层为例,引用临储压差、临废压差、有效解吸量、解吸效率等指标,并结合低煤阶储层含气量低、厚度大、渗透性好等特点,运用煤层气数值模拟软件对低煤阶煤储层产气潜力进行定量评价。研究结果表明:大佛寺井田4号煤层的临储压差为1. 27MPa、临废压差为0. 76~1. 26MPa、有效解吸量为1. 25~2. 35m^3/t,最大解吸效率为1. 99~2. 46m^3/(t·MPa),相对于中高煤阶煤储层都偏低;但由于4号煤层厚度大、渗透率高,抽采数值模拟显示5年平均日产气量达965m^3,具有形成工业气流煤层气井的产气潜力;现场单井排采实践也验证了4号煤层定量评价结果的可靠性。论文认为应将煤层厚度和渗透率指标纳入低煤阶煤储层定量评价指标体系中。
In order to study the gas production potential of low-rank coal reservoirs,taking No. 4 coal reservoir of Dafosi Mining Field in Binchang Mining Area as an example,the indexes of critical desorption pressure-reservoir pressure difference,critical desorption pressure-abandonment pressure difference, effective desorption quantity and desorption efficiency are quoted,and combining with the characteristics of low-rank coal reservoirs,such as low gas content,large thickness and good permeability,the numerical simulation software of coalbed methane is applied to low-rank coal reservoirs. Quantitative evaluation of reservoir gas production potential is carried out. The results indicates that the critical desorption pressure-reservoir pressure difference of No. 4 coal reservoir in Dafosi Mining field is 1. 27 MPa, the critical desorption pressure-abandonment pressure difference is 0. 76 ~ 1. 26 MPa,the effective desorption quantity is 1. 25 ~ 2. 35 m^3/t,the desorption efficiency is 1. 99 ~ 2. 463/( t·MPa),which is lower than that of medium and high rank coal reservoirs,but because of the thickness and permeability of No. 4 coal seam is large,the numerical model of extraction is drawn. The simulation result shows that the average daily gas production in 5 years is 965 m^3,which has the gas production potential of CBM wells with industrial gas flow. The field single well drainage and production practice also verifies the reliability of quantitative evaluation results of No. 4 coal seam. It is considered that the indexes of coal seam thickness and permeability should be included in the quantitative evaluation index system of low-rank coal reservoirs.
作者
汪万红
茹婷
李林
杨刚
降文萍
WANG Wan-hong;RU Ting;LI Lin;YANG Gang;JIANG Wen-ping(CCTEG Xi'an Research Institute,Xi'an 710077,China;Shaanxi CBM Development and Use Co.,Ltd.,Xi'an 710119,China)
出处
《煤炭工程》
北大核心
2020年第2期27-31,共5页
Coal Engineering
基金
国家自然科学基金(41972167)。
关键词
煤层气
低煤阶煤储层
产气潜力
定量评价
等温吸附曲线
大佛寺井田
coalbed methane
low-rank coal reservoirs
gas production potential
quantitative evaluation
isothermal adsorption curve
Dafosi Mining Field
