【摘要】 针对水力压裂井中监测方法易监测到不对称压裂裂缝及影响压裂评价的问题,提出不对称压裂裂缝解释方法。该方法利用微地震属性与储层的相关性,以表征储层特征的三维地震数据作为中间桥梁,综合区域地质认识,研究了储层对微地震事件空间分布的影响,分析不对称压裂裂缝形成原因,总结微地震事件分布规律,准确评价压裂改造效果,提高储层地质认识,验证地震、地质研究成果,指导油气开发;并从微地震事件震级、b值、压裂施工曲线、监测距离等角度验证分析结果,提高解释的可信度。辽河探区两个应用实例表明,对最大、最小水平主应力差较小的均匀储层,各段压裂裂缝走向大体一致,微地震事件发散,压裂波及宽度大,震级变化范围小;与主应力方向平行或近于平行的天然裂隙或断层可起到压裂诱导作用,促使压裂裂缝优先沿天然裂缝或断层发育,微地震事件集中分布,震级变化范围大。研究结果表明:为提高监测效果,应选择距离合适的监测井,或采用多井监测,避免因监测条件造成不对称压裂裂缝假象;如果监测距离在有效范围内,及时从储层角度查找不对称压裂裂缝形成原因,以指导压裂施工。更多还原

【Abstract】 Asymmetric fracturing fracture can be easily identified during borehole microseismic monitoring,thus affecting fracture evaluation.We propose an interpretation method for asymmetric hydraulic fracturing fracture to identify the causes of asymmetric hydraulic fracturing fractures.We also accurately reproduce fracture patterns and guide well placement and well pattern optimization.This study utilizes the relevance between microseismic attributes and reservoirs,and uses 3 D seismic data that can characterizes reservoir as an intermediate bridge.In this study,the effect of reservoirs on the spatial distribution of microseismic events is first examined,and the causes of asymmetric hydraulic fracturing fracture are determined.We then summarize the distribution law of microseismic events and evaluate the fracturing effect,thereby enhancing our understanding of reservoir geology.The development of oil and gas could be guided by integrating microseismic attributes,regional geological data,and other data.To improve the validity of interpretation in this study,the parameters of microseismic magnitude,b value,fracturing construction curve,and monitoring distance are used to verify the results of the analysis.Applications of this study in the Liaohe exploration area indicate that for uniform reservoirs with small horizontal principal stress differences,the trend of hydraulic fracturing fracture in each stage is approximately in the same direction.In addition,the microseismic events are divergent,the width of the fracturing spread is large,and the range of magnitude is small.Natural fractures or faults parallel(or nearly parallel) to the direction of the principal stress can act as a fracturing inducer to induce hydraulic fracturing fracture to develop preferentially along natural fracture.Moreover,microseismic events are distributed together and have a greater range of magnitude.A suitable observation well or multi-well monitoring should be used to avoid asymmetric fracturing caused by monitoring conditions and improve the microseismic monitoring effect.If the monitoring distance is within the effective range,the reasons for asymmetric fracturing should be determined from the reservoirs to guide fracturing construction.更多还原