致密油藏重复压裂前应力场分布研究

发布时间：2019-06-05 01:59

【摘要】：重复压裂技术是致密油藏增产增效的重要技术,其关键在于确定再次压裂时裂缝的重新定向,研究人工裂缝附近应力场分布至关重要。基于人工裂缝诱导应力和流体产出对原地应力场的影响,建立流固耦合离散模型和井眼-裂缝有限元力学模型,并利用FEPG开发软件对模型进行求解,定量分析致密油藏重复压裂前应力场分布情况。研究结果表明:人工裂缝附近会形成椭圆形压降区域,从生产边界到人工裂缝孔隙压力递减;平行裂缝方向裂缝影响的压降范围要小于垂直方向,并且裂缝影响范围仅略大于半缝长;裂缝附近致密储层有效应力要大于其他区域,平行裂缝方向有效应力整体上要大于垂直方向,并且在垂直裂缝方向出现了拉压应力变换区域。
[Abstract]:Repeated fracturing technology is an important technology to increase production and increase efficiency in tight reservoirs. The key lies in determining the reorientation of fractures when fracturing again, and it is very important to study the distribution of stress field near artificial fractures. Based on the influence of artificial fracture induced stress and fluid output on in situ stress field, the fluid-solid coupling discrete model and wellbore fracture finite element mechanical model are established, and the model is solved by FEPG development software. The distribution of stress field before repeated fracturing in tight reservoir is analyzed quantitatively. The results show that the elliptical pressure drop area will be formed near the artificial fracture, and the pore pressure will decrease from the production boundary to the artificial fracture. The pressure drop range of cracks in parallel fracture direction is smaller than that in vertical direction, and the influence range of cracks is only slightly longer than half fracture length. The effective stress of tight reservoir near fracture is larger than that of other areas, and the effective stress of parallel fracture direction is larger than that of vertical direction as a whole, and the tensile and compressive stress transformation area appears in the direction of vertical fracture.
【作者单位】：中国石油大学胜利学院油气工程学院;
【分类号】：TE357

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