煤系有机质演化过程中CO_2对流体密度的影响  

Impacts of CO_2 on fluid density during the evolution of organic material of coal series

作　　者：付德亮[1,2] 周世新[1] 马瑜[1,2] 李靖[1] 李源遽[1,2] 

机构地区：[1]中国科学院油气资源研究重点实验室/中国科学院地质与地球物理研究所兰州油气资源研究中心,兰州730000 [2]中国科学院大学,北京100049

出　　处：《岩性油气藏》2016年第2期41-46,63,共7页Lithologic Reservoirs

基　　金：国家自然科学基金面上项目“柴达木盆地北缘深层天然气形成和演化特征研究”(编号:41072105);国家重点基础研究发展计划(973)项目子课题“中国西部叠合盆地深部油气复合成藏机制与富集规律”(编号:2011CB201102);国家重大科技专项子课题“盆地深层流体性态及低渗砂岩储层的流体-岩石相互作用关系”(编号:2011ZX05008-004-01)联合资助

摘　　要：通过民和盆地侏罗系煤岩在黄金管封闭体系下热模拟实验,获得了煤系有机质各演化阶段的流体组成,应用PVT-sim软件中的PR状态方程计算了煤成烃的密度,同时就煤系有机质产生的CO_2对煤成烃密度的影响进行了研究,并认为煤成烃流体密度随演化程度的增加而减小。当压力为10~50 MPa,温度为25~125℃,EASY%R_o(通过计算得出的镜质体反射率)为0.86%~2.52%时,液相流体密度为0.51~0.85 g/cm^3,气相流体密度为0.05~0.85 g/cm^3。煤系有机质演化过程中会产生大量的CO_2,并直接影响煤成烃流体的密度。气相或液相流体密度均随着流体组成中CO_2含量的增加而增大。CO_2通过改变流体偏差因子(Z)和流体组分平均分子量的方式影响煤成烃的流体密度,随着热演化程度的增加,这2种控制因素的主次关系在逐渐改变。低演化阶段CO_2主要以降低流体偏差因子的方式增大流体密度,而高演化阶段CO_2含量的增加使流体平均分子量增大,造成流体密度增大。By the pressurized sealed gold tube pyrolysis experiments, the fluid composition of Jurassic coal series from Minhe Basin at different maturity was obtained, the fluid density was calculated by PR state equation in software PVT-sim, and the impact of CO2 from the evolution of coal on fluid density was discussed particularly. The result shows that the fluid density of coal generated hydrocarbon decreases with the increasing of maturity. At 10-50 MPa, 25-125 ℃ and EASY%Ro at 0.86%-2.52%, the density of liquid phase and the vapor phase was 0.51-0.85 g/cm3 and 0.05-0.85 g/cm3 respectively. Large quantity of CO2 would generate during the evolution of the coal, which will impact the petroleum density directly. In this study, the density of liquid and vapor fluid both increases with the increasing of CO2 content. The density was changed with the change of deviation factor and average molecular weight. At low of the increasing of average molecular weight

关 键 词：煤系有机质 密度 气相 液相 CO2含量 

分 类 号：TE122.3[石油与天然气工程—油气勘探]