摘要
超临界CO_(2)压裂具有降低起裂压力、低伤害等特点,并兼顾温室气体埋存等优势,在非常规油气资源的开发中具有广阔的应用前景。为弄清超临界CO_(2)侵入条件下的储层起裂机制,基于岩石的拉伸破坏机理,考虑CO_(2)侵入地层引起的近井地层温度和孔隙压力变化对储层岩石切向应力的影响,建立了热流固耦合的超临界CO_(2)压裂起裂压力模型,并应用致密气井超临界CO_(2)压裂现场数据进行了模型验证。结果表明:超临界CO_(2)压裂可显著降低起裂压力,且起裂压力随着排量增大而降低;井底压力的波及速度高于井底温度,排量对波及速度影响不大;切向应力最小值位于井壁处,地层温度和孔隙压力引起的井壁切向应力方向相反,前者大于后者;泊松比增大、弹性模量增大、井底温度降低均可使储层起裂压力降低。
Supercritical CO_(2) fracturing technology has the advantages of reducing fracture initiation pressure,low damage to the formation and greenhouse gas storage,so it has broad application prospects in unconventional reservoir development.To investigate the fracture initiation mechanism with supercritical CO_(2) invasion,considering the influence of variation of formation temperature and pore pressure near the well caused by CO_(2) invasion on rock tangential stress,a fracture initiation pressure model of supercritical CO_(2) fracturing with thermo-fluid-solid coupling is established based on the tensile failure mechanism of rock.And supercritical CO_(2) fracturing field data for tight gas well is applied to verify the model.The results show that supercritical CO_(2) fracturing can significantly reduce the initiation pressure,and the initiation pressure decreases with pump rate increasing.Moreover,the propagation velocity of bottom hole pressure is higher than that of bottom hole temperature,and pump rate has little effect on the propagation velocity.The minimum tangential stress is at the borehole wall,and the tangential stress at the borehole wall caused by formation temperature and pore pressure are in opposite direction and the former is larger.With the increase of Poisson′s ratio and Young modulus,and the decrease of bottom hole temperature,the initiation pressure decreases.
作者
马建民
马可欣
张富美
李小娜
杜玉昆
赵博
赵玉明
MA Jianmin;MA Kexin;ZHANG Fumei;LI Xiaona;DU Yukun;ZHAO Bo;ZHAO Yuming(Oil Industry Training Centre,China University of Petroleum,Qingdao 266580,China;Engineering Training Centre,Ocean University of China,Qingdao 266100,China;No.1 Oil Production Plant,Qinghai Oilfield Company,PetroChina,Haixi 817000,China;School of Petroleum Engineering,China University of Petroleum,Qingdao 266580,China)
出处
《断块油气田》
CAS
CSCD
北大核心
2022年第3期295-301,共7页
Fault-Block Oil & Gas Field
基金
国家自然科学基金青年科学基金项目“多场多相条件下超临界二氧化碳粒子射流破岩及井筒携岩机理研究”(51404287)。
关键词
超临界CO_(2)
水力压裂
起裂压力
温度应力
热流固耦合
supercritical CO_(2)
hydraulic fracturing
fracture initiation pressure
thermal stress
thermo-fluid-solid coupling
