井壁强化作用影响因素的数值模拟

发布时间：2018-06-22 16:03

本文选题：井壁强化 + 多孔弹性介质　；参考：《钻井液与完井液》2017年02期

【摘要】：近年来,井壁强化等先期封堵技术逐渐得到了应用和发展,但其相关影响因素及作用机理还未得到深入揭示。通过建立多孔弹性介质的有限元模型,考虑地应力各向异性、架桥位置、漏失速率及裂缝后端压力等因素的影响,对井壁强化机理及相关影响因素进行了分析。模拟结果表明,刚性封堵材料通过减缓裂缝后端由于压力下降所产生的形变,并将该形变向井壁周围传递,使架桥后裂缝附近的井壁周向应力增加,从而导致裂缝趋于闭合;地应力各向异性越小,裂缝闭合趋势越明显;漏失速率越大,越有利于封堵颗粒的快速架桥,井壁强化效果越好;封堵材料架桥时,架桥位置距离裂缝端口越近,架桥位置后端压力越接近地层孔隙压力,越有利于裂缝的闭合及抑制裂缝尖端的扩展。
[Abstract]:In recent years, early plugging techniques such as wellbore strengthening have been gradually applied and developed, but the related factors and mechanism have not been thoroughly revealed. Through establishing the finite element model of porous elastic medium, considering the influence of the anisotropy of in-situ stress, the position of bridge, the leakage rate and the pressure of the back end of fracture, the strengthening mechanism of borehole wall and the related influencing factors are analyzed. The simulation results show that the rigid sealing material reduces the deformation caused by the pressure drop at the back end of the fracture, and transfers the deformation to the surrounding of the shaft wall, which increases the circumferential stress of the shaft wall near the fracture after the bridge, which leads to the closure of the fracture. The smaller the in-situ stress anisotropy is, the more obvious the fracture closure trend is, the greater the leakage rate is, the better the strengthening effect of shaft wall is, and the closer the bridge position is to the fracture port, The closer the back-end pressure of the bridge is to the formation pore pressure, the more favorable to the closure of fractures and the suppression of crack tip expansion.
【作者单位】：中国石油大学(华东)石油工程学院;中石化中原石油工程有限公司;
【基金】：国家重点基础研究发展规划(973)项目(2015CB251205) 国家自然科学基金项目(51474236) 教育部创新团队(IRT1086)
【分类号】：TE28

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