目前页岩气井间压窜问题突出,严重干扰邻井生产。以威远页岩气示范区某区块为研究对象,根据压窜后母井生产特征,提出以母井产量恢复速度为核心的压窜影响程度量化评价指标,并采用灰色关联分析法评价了10项地质、工程影响因素。结果表明,井间距离、母井生产时间、平均单簇用液规模、天然裂缝与压窜程度的灰色关联度较高。在此基础上,评价了子母井位置关系、母井生产时间、单簇用液规模、天然裂缝对压窜程度的影响规律。评价结果表明：①井间压窜以巷道平行模式为主,巷道错位/相对模式压窜次之;②随着母井生产时间增长,母井产量恢复速度、恢复程度趋于降低,建议子井压裂时间控制在母井生产300 d以内;③随着平均单簇用液规模增加,压窜影响程度趋于增强,建议根据母井生产时间和井间位置关系,针对性优化单簇用液规模;④对于贯穿型天然裂缝发育的井段,在设计和施工过程中需要严格控制用液规模、优化射孔参数和施工排量,避免压窜。现场试验表明,该研究成果对页岩气减小井间压窜影响具有指导意义。

Currently, the problem of intra-well frac hit is serious in shale gas, which disturbs the production of nearby wells. Taking the Weiyuan national shale gas demonstration area as the research object, and according to the production characteristics of parent wells, quantitative evaluation index of intra-well frac hit influence based on the recovery rate of parent well production has been put forward. Then ten key geological and engineering parameters affecting intra-well frac hit influence have been analyzed by grey correlation method. The result shows that the grey correlations of intra-well distance, parent well producing time, average fluid volume of single cluster and natural fracture are higher. On this basis, the influence of intra-well position, parent well production time and average fluid volume to intra-well frac hit extent has been evaluated to obtain the following results. Firstly, the main intra-well position of frac hit is parallel, while the secondary is the position of opposite and malposition. Secondly, as the producing time of parent wells increase, the impact of frac hit significantly increases. The suggested optimal operation time of child wells is within 300 produce days of parent wells. Thirdly, as the average fluid volume of single cluster of child wells increases, the impact of frac hit increases too, so that it is suggested to optimize the liquid scale of single cluster according to the production time of parent wells and intra-well position. Lastly, the fluids volume, perforations and slurry rate should be strictly optimized in the section with cut-through natural fracture in order to reduce frac hit risk. Field tests show that the result can provide a reference to reduce the impact of intra-well frac hit of shale gas.