复兴地区高含黏土页岩凝析气藏渗吸排驱及液体渗流特征研究
Characteristics of Imbibition,Displacement,and Fluid Seepage in High Clay Content Shale Condensate Gas Reservoir in the Fuxing Area
乔润伟 1张士诚 1李凤霞 2王飞 1李宁2
作者信息
- 1. 中国石油大学(北京)石油工程学院,北京 102249
- 2. 中国石化石油勘探开发研究院,北京 102206
- 折叠
摘要
复兴地区凉高山组为高含黏土页岩凝析气藏,体积压裂改造后闷井和返排期间易出现反凝析和液锁现象,影响开采效果.为准确了解高含黏土页岩凝析气藏的渗吸排驱和液体渗流特征,优化闷井转排驱时机,选取储层岩心,开展了气水渗吸排驱试验和三相渗吸排驱试验,采用核磁共振、恒压驱替相结合的方式,量化了渗吸排驱过程中压裂液的水锁伤害特征及凝析油的可流动特征;建立了液锁伤害表征方法,并模拟了矿场尺度闷井过程中的水锁特征.研究结果表明:该页岩储层压裂渗吸阶段岩心的渗吸采收率在 50.22%～57.14%;渗吸液矿化度越低,返排率越低,水锁伤害率越高;油锁伤害率低于水锁伤害率;存在束缚水时,凝析油的临界可流动饱和度约可降低 20%;若以闷井后解除近裂缝水锁伤害为目标,闷井时间以 20～30 d为宜.研究结果为复兴地区高含黏土页岩凝析气藏高效开发提供了理论依据.
Abstract
The Lianggaoshan Formation in the Fuxing Area is a high clay content shale condensate gas reservoir,which is subject to retrograde condensation and liquid locking during well soaking and flowback after volumetric fracturing,which affects the production performance.In order to accurately understand the characteristics of imbibition,displacement and fluid seepage in high clay content shale condensate gas reservoir,and the timing of switching soaking to displacement was optimized,the experiments of gas and water imbibition,flowback and three-phase imbibition and displacement were carried out by selecting the reservoir core.Nuclear magnetic resonance and constant pressure displacement were both used to quantify the water lock damage characteristics of fracturing fluid and the flowable characteristics of condensate oil during the imbibition and displacement process.A liquid lock damage characterization method was established,and reservoir-scale water lock characteristics during well soaking were simulated.The results show that the imbibition recovery of the core in the shale reservoirs during the fracturing imbibition stage is between 50.22%and 57.14%;the lower salinity of the imbibition fluid indicates a lower flowback rate and higher water lock damage rate.The oil lock damage rate is lower than the water lock damage rate.When irreducible water exists,the critical flowable saturation of condensate oil can be reduced by about 20%.With the mitigation of water lock damage near fractures after well soaking as the goal,the recommended well soaking time is 20 to 30 days.The research results provide a theoretical basis for the efficient development of high clay content shale condensate gas reservoir in the Fuxing Area.
关键词
黏土/页岩/凝析气藏/渗吸/压裂液/液体渗流特征/闷井时间/复兴地区Key words
clay/shale/condenstate gas reservoir/imbibition/fracturing fluid/fluid seepage characteristics/well socking time/Fuxing Area引用本文复制引用
出版年
2024
NETL
NSTL
万方数据