Research On Micro-seismic Signal Constraint-based Positioning Method

Micro-seismic monitoring technology plays an important role in the development of resources in oil and gas reservoirs. Micro-seismic monitoring techniques locate micro-seismic events by analysis of observation data to analyze underground morphology or guide the development of resources in oil and gas reservoirs. Micro-seismic positioning technology has always been the focus and difficulty of research in this field as a core part of micro-seismic monitoring technology. Existing micro-earthquake location methods have low locating precision, poor efficiency and high cost of production. So they can not meet the needs of actual production.Against the deficiencies of existing micro-earthquake location methods, the paper proposed a method of adaptive velocity model based on cross-validation and the GLI binding source scanning micro-seismic location method. The main work of the paper is as follows:1. The paper proposed a method of adaptive velocity model based on cross-validation. Establishing velocity model efficiently and accurately is a prerequisite to improve the micro-seismic location accuracy. Many existing micro earthquake location methods are used to manually adjust the parameters(such as the initial velocity, model parameters, etc.) to establish velocity model. In efficiency and accuracy it is unable to meet the needs of actual production. To this end, the paper proposed a method of adaptive velocity model based on cross-validation. This method each time selects different perforation points to establish velocity model and then uses the velocity model to locate the rest of the perforation points, repeated several times, and then weighted superimpose all groups of parameters with reciprocal positioning error as weights to achieve the adaptive adjustment of velocity model. Through theoretical and practical data, the results show that the adaptive velocity model can get better positioning results.2. The paper proposed the GLI binding source scanning micro-seismic location method. There are two types of micro-seismic location method: GLI and source scanning. GLI achieve speed, high precision horizontal orientation, but poor vertical orientation effect; source scanning search the position in three-dimensional space that can produce the most similar first arrival time to the observing first arrival time, the positioning accuracy is relatively high but inefficient. The paper proposed the GLI binding source scanning micro-seismic location method. The method uses GLI to solve the horizontal position of seismic source, and then uses source scanning method to solve the vertical position of the source. The method combines the advantages of both methods in efficiency and accuracy. It can efficiently obtain high accuracy results of micro-seismic event location. The paper tests the validity of the proposed method through actual data.In summary, the paper established the velocity model efficiently and accurately by using cross-validation approach to achieve adaptive adjustment of velocity model and located micro-seismic events accurately and efficiently by using the GLI binding source scanning micro-seismic location method.