二氧化碳驱油返回气提质利用方案比选

Comparison and selection of return gas quality upgrading and utilization schemes in carbon dioxide enhanced oil recovery

为了更好地利用井口返回气中的二氧化碳和烃类,针对某油田二氧化碳驱油返回气的气源特征,结合油井装置现场实际情况,对二氧化碳和烃的分离及提质利用进行了研究,提出了2种二氧化碳驱油返回气的提质利用方案,对比了工艺脱水效果及膜分离效果,分析了应重点解决的问题。结果表明,直接对返回气进行压缩、预冷、干燥、脱水后再进行膜分离脱碳是较经济可行的方案,利用级间抽出气体的位能和减压冷量不足以弥补气体循环带来的压缩功耗。

In order to better utilize the carbon dioxide and hydrocarbons in the returned gas from the wellhead,the study is conducted on the separation and utilization of carbon dioxide and hydrocarbons based on the gas source characteristics of the return gas in carbon dioxide enhanced oil recovery in a oilfield,combined with the actual situation of the oil well.Two quality improvement and utilization schemes for the return gas are proposed,and the dehydration and membrane separation effects of the process are compared.The problems that should be focused on are analyzed.The results show that it is more economical and feasible to directly compress,precool,dry,dehydrate and then decarbonize it by membrane separation.The potential energy of interstage extracted gas and the reduced pressure cooling capacity are insufficient to compensate for the compression power consumption caused by gas circulation.