Reasearch On Picking Microeismic First Break Based On Fractal Dimension Of Image Automatically

In recent years, microseismic monitoring technology has been developed rapidly, and has made outstanding achievements in the field of low permeability oilfield exploitation. With the gradual depletion of high permeability oilfields, the importance of low permeability oilfield exploitation is obvious. Microseismic monitoring technology is a process that mainly acceptting process and analyze microseismic effective signal which comes from fracturing Wells. Then process and analyze signal. Finally according to these effective microseismic signals to analyze the progress of the fracturing operation. Precondition of optimizing fracturing is locating signal source, the strength of the signal energy, time of occurrence,etc. And obtained these the effective information is the basis of microseismic phase identification.Microseismic phase identification is mainly based on picking up the first Microseismic break from effective event waveform. After development of decades, there are as many as hundreds of methods for picking up Microseismic first break. In order to have a better understanding about the attributes and characteristics of microseismic signals, this thesis will make a simple introduction for perforating signal and the generation of microseismic signals in the fracturing operation. And it will introduce their respective using and characteristics. Firstly, the paper introduces several traditional methods of picking up Microseismic first break and realizes them by matlab programs. And it will make a simple induction and summary for various methods and describe advantages and disadvantages of themselves.In this paper, based on researching traditional correlation methods, it puts forward an improved correlation method automatically pick up Microseismic first break, and compares results with other methods. This idea is the reference of traditional method in actual Microseismic trace. The improved correlation method overcomes the disadvantages of traditional correlation method as referenced trace which can not be similar with other Microseismic traces. The results prove that it obtains a very good effect. Secondly, with the researches and implementation of traditional edge detection method in dealing with the actual datas and comparing, the paper puts forward a method which is called image fractal dimension. This method is compared with the method of one dimension, which prove that fractal dimension method can improve computing speed, picking precision and stability. And it has obtained the good effect in the dealing with aspect of noise suppression.