摘要
CO_2相态变化直接影响其注入过程,CO_2相态变化分析是CO_2-ECBM成功实施的关键。基于柿庄北区块储层特征,结合实际CO_2注入参数,分析了CO_2-ECBM注入过程中参数对CO_2的相态影响及全过程相态变化。结合CO_2吸附置换能力试验,优化了研究区CO_2注入模式。结果显示:注入压力和地面温度对井下CO_2的状态影响较小。注入过程中井底温度在30℃附近,井底压力变化大。注入过程中,地面管汇中CO_2为液态,注入前期,从井筒到井底,CO_2相态从液态变为气态;注入20d后,井口压力和井底压力均大于7.3 MPa,注入CO_2将不会变为气态,而是一直以液态的形态存在。建议在开发中后期实施CO_2-ECBM增产措施。综合考虑地层破裂压力及置换效果,注入压力最优为2.5 MPa,为CO_2-ECBM技术推广提供依据与指导。
The CO_2 phase change directly affects the injection project and its analysis is the key to the successful implementation of CO_2-ECBM.Based on the reservoir features of Shizhuang north block,in combination with the injection process,the effect of the injection parameters on the CO_2 phase change was described,the dynamic process was analyzed during CO_2-ECBM engineering.Combined with experiment results for replacement of CH_4 by CO_2,the injection pattern of the study block was optimized.The study results showed that the injection pressure and temperature had little impact on CO_2 phase change.The temperature stabilized around 30℃,but the bottom hole pressure varied quickly with CO_2 injection.The CO_2 was liquefied in surface equipment.The CO_2 phase changed from liquid to gas in the wellbore during the former injection.After 20 days' injection,the well head pressure and the bottom hole pressure went higher than 7.3 MPa and the CO_2 existed in liquid form with no change.Taking into consideration the formation fracture pressure and displacement effect,CO_2-ECBM should be operated in the middle-late period of gas field development and the optimal injection pressure was 2.5 MPa,providing good reference for CO_2-ECBM technology popularization.
出处
《非常规油气》
2018年第1期80-85,共6页
Unconventional Oil & Gas
基金
国家科技重大专项资助项目"深煤层注入CO2置换甲烷技术研究及装备研制"(2011ZX05042-003)资助
关键词
CO2-ECBM
相态变化
注入参数
吸附置换
柿庄北
CO2-ECBM
phase change
injection parameters
adsorption and displacement
Shizhuang north block
