石油实验地质2026，Vol.48Issue(1)：89-98,10.DOI:10.11781/sysydz2026010089
陆相页岩凝析气衰竭及注气吞吐长岩心实验研究
Experimental study on depletion development and gas injection huff-n-puff in long cores for continental shale condensate gas
摘要
Abstract
During the development of continental shale condensate gas reservoirs,once the formation pressure falls below the dew point pressure,retrograde condensation occurs,leading to condensate oil retention.However,the depletion development characteristics and key parameters of gas huff-n-puff in such reservoirs remain poorly understood.This study aims to reveal the depletion development characteristics of shale condensate gas reser-voirs,clarify the oil enhancement mechanisms of gas huff-n-puff,and optimize key parameters through long-core physical simulation experiments.Using core samples from the well FY10HF and reconstituted formation fluids from Fuxing area,Sichuan Basin,depletion production experiments were conducted according to the orthogonal design method to systematically investigate production characteristics under different pressure decline rates.After depletion production,gas huff-n-puff experiments were performed to optimize parameters and improve condensate oil recovery degree.Throughout the experiments,pressure,oil and gas production,producing gas-oil ratio,and produced gas composition were monitored.After the experiments,nuclear magnetic resonance(NMR)was used to analyze the oil saturation distribution.The depletion experiments indicated that the producing gas-oil ratio exhibited a"hump"shape,confirming the participation of retrograde condensate oil in flow.Due to the gas stripping effect,rapid depletion achieved a higher condensate oil recovery degree(24.77%)than slow depletion(22.62%).In the gas huff-n-puff experiments,CO2 demonstrated significantly better oil enhancement performance than CH4,owing to its dual mechanisms of inhibiting retrograde condensation and strongly extracting heavy hydrocarbons.Under the constraint of total injection gas volume,a higher injection pressure led to a higher ultimate recovery factor,but required more huff-n-puff cycles.Starting gas injection at a lower pressure,while resulting in a slightly lower recovery factor,proved to be more economical.This study clarifies the dynamic characteristics of retrograde condensation during depletion development in continental shale condensate gas reservoirs,and demonstrates that CO2 huff-n-puff is an effective technical approach for enhancing condensate oil recovery.Its core advantages lie in suppressing retrograde condensation through phase behavior control and recovering retained hydrocarbons through strong extraction.Parameter optimization indicates that the timing of gas injection requires a trade-off between recovery factor and economic benefit.It is recommended to initiate CO2 huff-n-puff at lower formation pressures,combined with appropriate shut-in time,to achieve effective development.关键词
页岩凝析气/长岩心衰竭/注气吞吐/参数优化/陆相页岩Key words
shale condensate gas/long core depletion/gas injection huff-n-puff/parameter optimization/conti-nental shale分类
能源科技引用本文复制引用
郭艳东,胡小虎,刘华,汤勇,王东英,王妍妍,高铭翌..陆相页岩凝析气衰竭及注气吞吐长岩心实验研究[J].石油实验地质,2026,48(1):89-98,10.基金项目
国家科技重大专项"深层页岩气开发机理与开发关键技术"(2025ZD1404104)资助. （2025ZD1404104）
