CAJ | 학술논문

针对深部低渗透储集层水力压裂裂缝扩展问题，利用现场采集的深部低渗透岩芯样本开展了水力压裂模型试验，利用CT扫描技术和自行开发的三维重构算法，提取并分析了三轴应力和水压力作用下，低渗透岩石水力压裂裂纹的扩展与空间展布规律，探讨了不同岩性、地层应力对裂纹扩展与空间形态的影响。研究表明：岩性、水平应力比对裂纹起裂压力以及裂纹形态有显著的影响。起裂压力均比围压应力大；在最小水平应力相近的情况下，初始应力比越大，裂纹扩展越明显，起裂压力越小；岩石破裂时出现了一条与最大水平应力平行的主裂纹，伴随着明显的中断、扭曲和分叉现象。
침대심부저삼투저집층수력압렬렬봉확전문제，이용현장채집적심부저삼투암심양본개전료수력압렬모형시험，이용CT소묘기술화자행개발적삼유중구산법，제취병분석료삼축응력화수압력작용하，저삼투암석수력압렬렬문적확전여공간전포규률，탐토료불동암성、지층응력대렬문확전여공간형태적영향。연구표명：암성、수평응력비대렬문기렬압력이급렬문형태유현저적영향。기렬압력균비위압응력대；재최소수평응력상근적정황하，초시응력비월대，렬문확전월명현，기렬압력월소；암석파렬시출현료일조여최대수평응력평행적주렬문，반수착명현적중단、뉴곡화분차현상。
In order to expose the cracks propagation law induced by hydraulic fracturing in deep low-permeability reservoir stratum, a series of hydraulic fracturing physical tests of low-permeability core samples collected in situ are carried out. Using CT scanning technology and self-developed three-dimensional reconstruction algorithm, the cracks propagation and special distribution laws are featured in low-permeability rock subjected to triaxial stress and hydraulic pressure. The effects of li-thology and crustal stress on cracks growth distribution features are exposed. The results show that the lithology of rock and ratios of horizontal crustal stress have great influences on initiation stress and geometric distribution features of cracks growth. The initiation pressure is always greater than the con-fining pressure. When the minimum horizontal crustal stress is similar, the bigger ratio of horizontal crustal stress induces more fractured cracks and small initiation stress. The direction of failure main cracks is consistent with the direction of maximum horizontal crustal stress. The main cracks appear in the middle of samples accompanied by noticeable interruption, distortion and bifurcation.