油气田水力压裂地面微地震监测技术研究

水力压裂地面微地震监测技术,是低孔低渗油气藏及非常规天然气开发过程中描述水力压裂诱发裂缝几何形态及评价压裂效果的主要技术,在我国尚处在工业试验阶段,在技术应用层面上存在认识不足。在介绍了地面微地震监测发展历史可行性证明、地面检波器排列类型的基础上,探讨了微地震数据处理反演定位方法以及地面监测定位精度。结果认为,采用稀疏台站检波器排列布设的地面微地震监测技术成本较低、施工方便且反演定位精度在横向和纵向上(一定监测距离以外)优于井中监测,对此观测系统采集的微地震数据进行走时反演和能量反演,都能获得准确可靠的结果,因此,是未来微地震监测的发展方向。

Locating microseismic sources based upon L-shaped single-component geophone array:A synthetic study

We have developed a type of L-shaped single-component geophone array as a single station(L-array station)for surface microseismic monitoring.The L-array station consists of two orthogonal sensor arrays,each being a linear array of single-component sensors.L-array stations can be used to accurately estimate the polarization of first arrivals without amplitude picking.In a synthetic example,we first use segmentally iterative ray tracing(SIRT)method and forward model to calculate the travel time and polarization of first arrivals at a set of L-array stations.Then,for each L-array station,the relative delay times of first arrivals along sensor arrays are used to estimate the polarization vector.The small errors in estimated polarization vectors show the reliability and robustness of polarization estimation based on L-array stations.We then use reverse-time ray-tracing(RTRT)method to locate the source position based on estimated polarizations at a set of L-array stations.Very small errors in inverted source location and origin time indicate the great potential of L-array stations for source localization applications in surface microseismic monitoring.

黄土塬区高信噪比地震数据采集方法研究

合水地区属陇东黄土高原,地貌主要由黄土塬、河谷阶地和低山丘陵组成。全区地形复杂,相对高差最大320m。黄土层巨厚、潜水位深,干燥、松散的黄土对地震波的吸收衰减作用强烈,导致激发、接收条件差。通过大量的试验工作,确定了在黄土塬区采用大排列和多检波器接收,多井组合和大药量激发等技术的地震数据采集方法和采集参数,取得了较好的地震资料,查明了主要可采煤层的赋存情况及构造复杂程度。