基于井中微地震快速定位监测技术的煤系页岩气水平井压裂效果评价——以南华北地区J1HF井为例

Evaluation of fracturing effect of horizontal wells in coal shale gas based on borehole micro-seismic rapid location monitoring technology——take well J1HF in South North China as an example

井中微地震快速定位监测是评价非常规油气藏压裂效果的有效手段之一,鉴于研究区内压裂井和监测井距离较远,采集到的微地震数据信噪比低,纵横波初至拾取困难,直接影响微地震定位以及储层压后效果评价的准确性.针对该问题,本文对区内J1HF井的井中微地震事件的识别和初至拾取,采用了更具灵活布设、成本低廉的井中微地震快速定位技术,利用邻井埋设的三分量检波器组成的观测系统,采集了压裂井微地震信号,并对微地震信号进行数据精细处理,利用微地震快速定位算法,实现岩石破裂事件的有效监测.通过对压裂过程岩石破裂能量的时空特征分析,获得了压裂裂缝几何形态及扩展模式,认为本井采用的“暂堵球+纤维暂堵剂”双暂堵工艺较为合理,可有效提高压裂裂缝复杂程度,获得较理想的储层改造体积,研究成果对南华北地区煤系页岩气压裂改造具有一定的指导和借鉴作用.

In view of the long distance between the fracturing wells and the monitoring wells in the study area,the signal-to-noise ratio of the acquired micro-seismic data is low,it is difficult to pick up the first break of P and S waves,which directly affects the accuracy of microseismic location and evaluation of reservoir pressure.In order to solve this problem,this paper adopts the rapid location technology of micro-seismic events in J1HF well,which is more flexible and low-cost,to identify and pick up the first break of micro-seismic events in J1HF well,the micro-seismic signals of fracturing wells are collected by using the observation system composed of three-component geophone embedded in adjacent wells,and the micro-seismic signals are processed precisely,to achieve effective monitoring of rock fracture events.Based on the analysis of the space-time characteristics of the fracturing energy,the fracture geometry and propagation model are obtained.It is considered that the technology of“Temporary plugging ball+fiber temporary plugging agent”is more reasonable,it can effectively improve the complexity of fracture and obtain an ideal reservoir reconstruction volume.The research results have certain guidance and reference function for coal-bearing shale gas fracturing reconstruction in South China and North China.