四川盆地焦石坝地区页岩吸附特征室内实验  

Experiment study on shale adsorption properties for Jiaoshiba shale,Sichuan Basin

作　　者：杨文新[1] 李继庆[1] 苟群芳[1] 

机构地区：[1]中国石化江汉油田分公司勘探开发研究院,湖北武汉430023

出　　处：《天然气地球科学》2017年第9期1350-1355,共6页Natural Gas Geoscience

基　　金：国家科技重大专项"大型油气田及煤层气开发"项目"涪陵页岩气开发示范工程"(编号:2016ZX05060);中国石化股份公司科研项目"涪陵页岩气开发效果评价及开发技术政策研究"(编号:P2015139);中国石化江汉油田分公司项目"涪陵页岩气田气藏工程研究"(编号:JKK0016001)联合资助

摘　　要：页岩含气量对页岩气田储量计算至关重要,直接关系到页岩气的产量、递减规律等。页岩气以游离气和吸附气形式赋存,有重量法等温吸附、容量法等温吸附、现场含气量测试等不同方法测试吸附气、游离气。通过测试页岩气降压解吸过程中气体体积变化来测量吸附气量,首次建立了同时测试页岩吸附气、游离气的方法。该方法采用柱状页岩岩心,模拟不同温度、压力、含水、真实孔隙结构等条件,消除了等温吸附曲线的负吸附异常;分析了有机质含量、压力、温度、含水、气体组成等因素对页岩吸附量的影响。实验结果表明,页岩的甲烷吸附量随压力增加而增加,压力大于12MPa后达到吸附/解吸动态平衡,吸附量不再增加;有机质含量TOC增加时吸附量增加;温度增加时吸附量降低;页岩含水后吸附量降低;甲烷吸附量高于氮气吸附量;焦石坝龙马溪组主力层页岩在温度20℃、压力30MPa下页岩气吸附气量介于1.8~3.1m^3/t之间,总含气量介于5.1~6.5m^3/t之间,吸附气占总气量40%左右。Gas content is a key parameter for shale reserves estimation,production prediction and gas rate decline a- nalysis.The storage mechanisms in shale is contained free and adsorption, and there are many different gas content testing methods such as gravimetric isotherm method, volume isotherm method and traditional testing method in field.In this study, a new shale gas content lab testing method is proposed based on measuring the gas volume changes during shale gas desorption. In this new method, cylindrical shale cores are used for simulating the influ- ences of temperature, pressure, moisture content,real pore structure on total gas content, negative adsorption anom- alies are eliminated by using this method. The experimental results revealed that adsorption gas content increased with pressure and the volume of adsorption gas content is at equilibrium and does not increase while the pressure is up to ]2MPa.There is a positive relationship between adsorption gas content and TOC, and a negative relationship between adsorption gas content and temperature and moisture content.Adsorption of methane is higher than the ni- trogen adsorption in shale.At a temperature of 20℃, under pressure of 30MPa,the adsorption gas content of Long- maxi shale in Jiaoshiba is 1.8-3. l m^3/t and total gas content is 5.1-6.5m^3/t, and about 40 % of the total volume is adsorbed gas.

关 键 词：龙马溪组页岩 吸附气 游离气 等温吸附/解吸 压力 

分 类 号：TE311.1[石油与天然气工程—油气田开发工程]