陆相页岩层系岩心中气态烃井场测定技术初步应用及展望

Preliminary application and prospect of well site determination technology of gaseous hydrocarbon in continental shale cores

陆相页岩层系的流体分析是页岩油甜点评价的重要基础,针对岩心样品中气态烃易于散失的特性和页岩油钻井现场的需求,研发了井场岩心气态烃快速采集测定装置及方法,探讨了基于岩心气态烃分析和热解含油性分析资料快速计算视气油比和估算游离油损失的方法。研究表明,该装置适用于全直径岩心和块状样品的气态烃检测,既可以实现全直径岩心在常温、常压下逸散气态烃的采集测定,也可以测定块状岩心样品的气态烃总量,气态烃检测相对误差10%,测试结果可以转换为单位质量岩样气态烃含量。全直径岩心逸散气分析可实现岩心气态烃的非破坏式采集和测定,反映了页岩层系垂向上含油气性及其非均质性的变化特征。视气油比可反映页岩层系含油气性和可流动性的趋势,视气油比越大,代表相应页岩层系页岩油可流动性越好。利用视气油比可估算岩心经历降压降温脱气过程中游离烃的损失量,在建立岩心降温降压脱气过程的热解游离烃损失恢复方法中具有较大应用潜力。岩心气态烃井场测定技术丰富了适用于井场的岩心流体分析实验技术手段和方法,为陆相页岩层系流体评价及甜点确定提供数据支撑。

Fluid analysis of continental shale formations is an important basis for the evaluation of shale oil sweet spots.In view of the characteristics that gaseous hydrocarbons in core samples are easy to lose and the needs of shale oil drilling site,a device and method for rapid collection and determination of gaseous hydrocarbons in cores at well site are developed,and a rapid method for calculating apparent gas-oil ratio(AGOR)and estimating free oil loss based on gaseous hydrocarbon analysis and pyrolysis oil content analysis data of cores is discussed.The research shows that the device is suitable for the detection of gaseous hydrocarbons in full-diameter cores and bulk samples.It can not only realize the collection and determination of gaseous hydrocarbons in full-diameter cores at normal temperature and pressure,but also determine the total amount of gaseous hydrocarbons in bulk core samples.The relative error of gaseous hydrocarbon determination is 10%,and the test results can be converted into gaseous hydrocarbon content per unit mass of rock samples.The full-diameter core escape gas analysis can realize the non-destructive collection and determination of gaseous hydrocarbons in the cores,which reflects the change characteristics of vertical oil and gas bearing and heterogeneity of shale formations.AGOR can reflect the trend of oil-gas bearing and flowability of shale formations,and the higher AGOR,the better the flowability of shale oil of corresponding shale formations.AGOR can be used to estimate the loss of free hydrocarbon in the process of pressure and temperature reduction degassing,which has great application potential in establishing the recovery method of the loss of free hydrocarbon in the process of core temperature and pressure reduction degas-sing.The core gas hydrocarbon determination technology enriches the experimental technical means and methods of core fluid analysis suitable for well sites,and provides data support for fluid evaluation and sweet spot determination of continental shale formations.