摘要
CO_(2)增能压裂与常规水力压裂相比,具有压后增能、返排迅速、对储层伤害小以及单井产能高等优势,在非常规油气藏高效开发中发挥着重要作用。为优化CO_(2)辅助增能压裂过程中气体的注入时机,通过多孔介质气体扩散微观数值模拟、油藏数值模拟方法等分别从微观和宏观角度研究了不同注入时机下CO_(2)波及范围及地层压力分布规律,对比了不同储层物性及CO_(2)注入速度对CO_(2)增能效果的影响。研究结果表明:1)CO_(2)前置注入井筒附近含水饱和度低,CO_(2)伴注井筒附近含水饱和度高,CO_(2)前置注入扩散进入深部地层的CO_(2)量比CO_(2)伴注增加了约50%,深部地层压力上升更多;2)储层物性对CO_(2)增能效果有一定影响,CO_(2)注入过程中,随着孔隙度、渗透率由1%和0.003 mD变为10%和0.01 mD,地层压力进一步上升,最大地层压力可增加约8 MPa;3)在近井筒地带地层压力随CO_(2)注入速度的增加而上升,速度增量越大地层压力上升越明显,超过120 m后地层增能效果不显著。该结果可为非常规储层CO_(2)辅助增能压裂气体注入时机优选及注入方案设计提供参考。
Compared with conventional hydraulic fracturing,CO_(2) energized fracturing plays an important role in the efficient development of unconventional reservoirs due to its advantages of post-pressure energy increase,rapid flowback,less damage to the reservoir,and high productivity per well.CO_(2) injection timing of effect on the increased energy and the flowback efficiency has important influence.This article which is based on the numerical simulation of micro porous media and reservoir numerical simulation method,discussed from the point of view of micro and macro CO_(2) that CO_(2) sweep area and formation pressure distribution under different injection timing,analyzed the influence of reservoir physical properties and CO_(2) injection rate on CO_(2) energized fracturing effect.The results show that:1)Near the wellbore,the water saturation is low with the CO_(2) pre-injection,while the water saturation is high with the CO_(2) companying injection,The amount of CO_(2) diffusing into deep formation with CO_(2) pre-injection increased by about 50%compared with CO_(2) co-injection and the deep formation pressure increased more;2)The reservoir physical property has a certain influence on the CO_(2) enhancement effect.During the CO_(2) injection process,the formation pressure increases further as the porosity permeability changes from 1%and 0.003 mD to 10%and 0.01 mD,and the maximum formation pressure increases by about 8 MPa;3)In the near-hole zone,the formation pressure increases with the increase of CO_(2) injection rate,and the rise of formation pressure is more obvious with the increase of CO_(2) injection rate increment.The formation energy increase effect is not significant after 120 m.The results provide a reference for the injection timing optimization and injection scheme design of CO_(2) assisted energized fracturing gas in unconventional reservoirs.
作者
阳潇
陈星杙
董洁
程喜琨
陈泳洁
刘伟
李彦超
YANG Xiao;CHEN Xingyi;DONG Jie;CHENG Xikun;CHEN Yongjie;LIU Wei;LI Yanchao(School of Energy,Chengdu University of Technology,Chengdu 610059,China;Shale Gas Exploration and development Project Management Department,CNPC Chuanqing Drilling Engineering Company Limited,Chengdu 610051,China)
出处
《非常规油气》
2023年第3期135-142,共8页
Unconventional Oil & Gas
基金
国家自然科学基金项目“CO_(2)降黏剂在超稠油油藏中动态扩散传质规律研究”(51974038)
南充市科技项目“CO_(2)压裂液相态特征及流动规律研究”(19SXHZ0002)。
关键词
CO_(2)
增能压裂
扩散传质
注入时机
数值模拟
CO_(2)
energized fracturing
diffusion and mass transfer
injection timing
numerical simulation
