页岩气增压生产模式下脱水装置适应性探讨

Discussion on adaptability of dehydration unit under pressure boosting mode of shale gas production

三甘醇(TEG)脱水工艺广泛应用于页岩气脱水处理,具有经济、可靠等优势。随着页岩气区块开发的深入,气井压力不断降低,需对原料天然气进行增压处理,增压后工况与脱水装置的设计工况出现偏离,可能导致产品天然气水露点无法达标。通过对增压生产模式下脱水装置适应性的分析,确定影响脱水装置产品天然气水露点的主要原因,是增压生产模式下进入脱水装置的原料天然气水含量增加。提出增加汽提气量、提高贫TEG质量浓度等调控措施调控产品气水露点,通过HYSYS软件模拟计算证明调控措施能够取得较好效果。研究结果对于指导实际生产具有借鉴意义。

The TEG(Tri-Ethylene Glycol) dehydration process is widely used in shale gas dehydration treatment and has good economic advantage and reliability. With the deepening of the development of shale gas blocks, the pressure of gas wells continues to decrease and the raw natural gas needs to have pressure boosting. The working conditions of dehydration unit deviate from design assumptions after raw natural gas is re-pressurized, which may result in higher water dew point of product gas that exceeds water dew point specification. By analyzing the adaptability of the dehydration unit in the pressure boosting production mode, it is found that the main reason affecting the water dew point of product gas leaving the dehydration unit is that in the pressure boosting production mode, compressed feed gas temperature increases resulting in higher water content in the raw natural gas entering the dehydration unit. This paper proposed control measures such as increasing the amount of stripping gas and increasing the concentration of lean TEG, and these measures are shown to have good effect by process simulation using HYSYS software. The research results can provide important guidance for actual production in similar situations.