摘要
为系统总结华北地区各煤类的主要物性特征,指导煤层气的勘探开发,对该区各种煤类共205件煤样进行了压汞实验,分析了各煤类孔径结构的比孔容、比表面积特征。基于180件煤样的高压等温吸附实验,探讨了朗格缪尔体积(VL,daf)、朗格缪尔压力与煤级的关系,发现朗格缪尔体积与煤级的关系呈现出两段式变化模式,即煤化程度在Ro,max<4%之前,VL,daf随Ro,max的增加而增大,当Ro,max>4%后,VL,daf随Ro,max的增加而减少,而朗格缪尔压力与煤级的关系复杂,数据十分离散。基于该区煤层气试井成果(170层次试井储层压力、204层次试井渗透率),划分了煤储层试井储层压力、试井渗透率类型:该区以欠压储层为主,占69.4%左右,正常压力储层占27.1%,超压储层仅占3.5%,储层压力梯度总体随埋深的增加呈现出增大的趋势;超低渗透储层占26.0%,低渗透储层占36.8%,中渗透储层占18.1%,高渗透储层占19.1%,试井渗透率总体随埋深的增加而减少。
In order to systematically summarize the petrophysical properties of coal layers with different ranks in North China and guide the CBM gas exploration and development,we performed mercury injection experiments on 205 coal samples from coal beds with different ranks,and analyzed the specific pore volume and specific surface area of their pore structures.Based on isothermal adsorption experiments under high pressure on 180 coal samples,the relationships are studied between Langmuir volume(VL,daf),Langmuir pressure(PL,daf) and coal rank respectively.The relationship between Langmuir volume and coal rank shows a two-stage variation pattern,i.e.VL,daf increases with the rising of Ro,max when Ro,max<4%,whereas it decreases with the rising of Ro,max when Ro,max>4%.In contrast,the relationship between Langmuir pressure and coal rank is more complex with very scattered data points.According to the test results of CBM wells in the study area(reservoir pressure test results of 170 layers and permeability test results of 204 layers),the types of coal beds is classified.Under-pressure reservoirs are predominant and account for about 69.4% of the total,normal pressure reservoirs account for 27.1%,and over-pressure reservoirs only account for 3.5%.As a whole,the reservoir pressure gradients increase along with the increasing of burial depth.Reservoirs with ultra-low permeability account for 26.0% of the total,those with low permeability account for 36.8%,those with moderate permeability account for 18.1%,and those with high permeability account for 19.1%.As a whole,the tested permeability decreases with the increasing burial depth.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2011年第12期72-75,128-129,共4页
Natural Gas Industry
基金
国家重点基础研究发展计划(973计划)"高丰度煤层气富集机制及提高开采效率基础研究"(编号:2009CB219600)
江苏省"青蓝工程"中青年学术带头人项目及新疆维吾尔自治区"天山学者"计划
关键词
华北地区
煤层气
储层
孔隙性
吸附性
朗格缪尔体积
储层压力
渗透性
North China,CBM,reservoir,porosity property,adsorption,Langmuir volume,reservoir pressure,permeability
