水平井分段分簇压裂缝间干扰和段间干扰建模——以昌吉油田吉7井区八道湾组油藏为例

Inter⁃Fracture and Inter⁃Section Interference Modeling for Staged and Clustered Fracturing Stimulation in Horizontal Wells:A Case Study on Reservoirs of Badaowan Formation in Wellblock Ji 7 in Changji Oilfield

昌吉油田吉7井区八道湾组油藏开发过程中直井水力压裂的储集层改造效果有限,产能受到限制,需要开展水平井多级压裂。针对吉7井区八道湾组的地质力学特征,采用扩展有限元法编制了非平面人工裂缝扩展模型,模型考虑了多簇裂缝同时扩展时的缝间干扰和分段压裂时邻近段的段间干扰,表征了吉7井区八道湾组水平井非平面裂缝扩展特征。结果显示,段内缝间干扰会抑制中间簇裂缝半长,使得外侧裂缝的缝宽更大、裂缝半长更长;缝间干扰和簇间干扰使得裂缝扩展呈现非平面特征,在几何形态上具有一定曲率。通过与压裂施工数据和微地震监测数据对比,认为裂缝数值模拟结果与现场数据拟合程度较好,模型在目标区域的应用效果较好。在吉7井区八道湾组开展水平井多级压裂实验,单井日产油量达到了同井区直井的7.8倍,取得明显成效。

In developing the reservoir of the Badaowan formation in Wellblock Ji 7 in Changji oilfield,the results of hydraulic fracturing stimulation in vertical wells are unsatisfactory,and the postfracturing productivity is limited,so that it is necessary to apply multistage fracturing stimulation in horizontal wells.According to the geomechanical characteristics of the reservoir in the Badaowan formation in Wellblock Ji 7,a nonplanar artificial fracture propagation model was established using the extended finite element method.By taking into account interfracture interference while multiple clusters of fracture propagating simultaneously and the intersection interference during staged fracturing stimulation,the model characterizes the nonplanar fracture propagation in horizontal wells drilled in the Badaowan formation in Wellblock Ji 7.The results show that the interfracture interference induced in a section inhibits the halflength of middle fracture clusters,but makes a wider and longer halflength of the fractures on both sides;the interfracture interference and the intercluster interference make fracture propagation nonplanar,and show a certain curvature in geometrical morphology.According to comparative analysis of fracturing data and microseismic data,the modeling results are consistent with the measured data,proving that good application results have been obtained in target zones.A multistage fracturing test was carried out in the Badaowan formation in a horizontal well in Wellblock Ji 7.The daily postfracturing oil production of the horizontal well was 7.8 times that of a vertical well in the same well block,indicating a significant development effect.