• 应用地球物理 •

### 微地震监测定位精度分析

1. 川庆钻探工程有限公司地球物理勘探公司, 成都 610213
• 收稿日期:2012-04-09 修回日期:2012-05-10 出版日期:2013-04-20 发布日期:2013-04-20
• 作者简介:尹陈,女,1982年生,四川省遂宁市人,工学硕士,工程师,现从事微地震监测技术研究.(E-mail:yinch_wt@cnpc.com.cn)
• 基金资助:

中国石油集团公司项目《微地震监测技术研究及应用》,项目编号:2011A-3605.

### The precision analysis of the microseismic location

YIN Chen, LIU Hong, LI Ya-lin, WU Fu-rong, HE Guang-ming, CHEN Chun-hua

1. Sichuan Geophysical Company of CNPC Chuanqing Drilling Engineering Company Limited, Chengdu 610213, China
• Received:2012-04-09 Revised:2012-05-10 Online:2013-04-20 Published:2013-04-20

Abstract:

With the exploitation of the unconventional reservoirs such as tight sand and shale, fracturing technique plays an important role in the reservoir reconstruction. Through inverting the microseismic(MS) location effectively, it can forecast the development tendency of manmade fracture and becomes one of the key and immediate techniques to provide the evaluations for the post-fracture response, directions for the exploitation and designs for the re-fracturing. The key role of the MS monitoring is both inverting the location of the microfracture which triggers the MS signal and describing the geometry of the fracture system effectively, therefore, it is important to get a high precision location. The location precision directly affects the distribution of the manmade fracture, and the false or low precision location will result in the misjudgment of the fracture tendency. However, it is very difficult to get a high precision MS location because it is very sensitive to the first arrival, velocity, inversion algorithm and so on. This paper firstly discusses the first arrival influence on the location precision. Through the numerical simulation it can get that the first arrival has a strong effect on the location precision, and there exists a proximate proximatey linear relation between the first arrival error and the location error. The paper discusses the influences of rock property, the calibrated velocity, anisotropy velocity, the layer dip, multi-stage fracture on the velocity and location precision. Before the fracturing, the bulk and shear modulus can be considered to be constant. With the liquid and filling material injection, the density and the modulus increase and they may result in the change of velocity. The static velocity model may result in the location error because a static velocity is used in the location. In addition, a horizontal isotropy velocity is usually used in the location and may result in the location error because of dip and anisotropy in the real layer. Moreover, it is easy to ignore that a fixed velocity model is used in multi-stages fracture and may result in the location error. Finally, the paper analyses the location algorithm influence on the location error. The inversion is the universal location method, but the inappropriate option function and criteria which may result in the local extremum. Meanwhile, the azimuth also has a strong effect on the location precision. Through the theoretical analysis and numerical simulation, the first arrival error, velocity error and location algorithm have a tight relationship with the location precision. Some kinds of location errors are controllable, and some errors are systematic. Through differentiating the controllable and systematic errors, it can give some suggestions for the high precision processing flow research and the actual data processing.