Research On The Image Algorithms Of The Fracture Of The Microseismic Monitoring Oil Well

In the age of energy being shorted day by day, the need of oil source is increasing. Except the way of developing new oilfield , the use in the low permeability reservoir becomes important study direction more in more. But the aim to get more oil asks special technology, such as hydraulic fracture,importing the high temperature gas et al. Now hydraulic fracture is a common way in the more parts of oil field, it imports some kind of liquid to improve the pressure with the aim to crack the two side of oil well wall and ameliorate flow in the under-layer. So what the effect of fracturing is and what could be happened? It needs to estimate the procedure ,after compare with many kinds of detection scheme and choice the micro-seismic wave detection way which could be a much better way to gain the crack.All the time the seismic wave is the important trick to realize the earth exploring. In the modern industry, the ways of seismic wave exploration with introducing man-making earthquakes study the structure of the shallow earth , find any mineral resource or solve problems in the geology engineering. As the research on the theory of seismic wave develops and the technology on digital signal processing improves, the field-geophysicists apply the related technology on the drilling of the oilfiled and detect the resources with micro-seismic wave. Due to its high business value, so that the micro-seismic wave detection becomes one of the new directions on the geophysics technology development.Detect the micro-seismic wave and analyze the micro-seismic event which produced in the activities of the fracturing , aimed to monitor the activities result,get a better effect and make clearly the state of the underground. Especially on the engineering of development on oil-gas filed, such as oil recovery,water injection,gas breathed into et, all that kinds of work could induce seismic wave and provides the detection base. The effect on the oilfiled change is thought to more mature,more feasible and more dependent ,which compared with the man-feeling way.This article analyses the trait of the seismic wave when it spreads from the sources to the detection stations on the theory. In the mode of the sources location ,choice the way of same kind wave with time arrival differences as the basic location principles and at the same time make the required factors which is the complementary of the principles. It also makes the direct wave velocity model. Continuously, discuss the development state of micro-seismic detection at home and abroad, and find now the research on the theory of micro-seismic much but the completely instruments few. So introduce the micro-seismic monitor system made by our laboratory, which including the design scheme, the detail module and basic detection theories, at last contrasting two kinds of monitor system,(one are putting the monitor stations on the earth, but the other are underground). Combined the advantages of the two systems, make underground and earth monitors stations built up the detection system which increase the reliable of the signal and the seasonally of the explains.The next part analyses the signal collecting and processing software. It proposes many demands from the sides such as the principle of the software designing, operating function rules ,rational structure, high and stable running effect et al. Introduce on the overall software structure, and the clearly explanation in the relationship between modules'function by the software processing flow chart. This chapter presents the software architecture and prepares for the next part.So, in the forth part, give the full illustrate on the software processing program, the data processing module is explained clearly. The collected data from the ground, has been interferenced which may come from no-controllable environment, such as operating vehicles on the oilfield. the underground detector which throw in the water well aside the fracture well also collect the regular non-signal data. In that data ,the signal are not obvious, so must take some special measurements to filter the non-seismic wave.In the spread path of micro-seismic signal from source to ground ,the signal is attenuated by the soil absorption, the high frequency weaken faster than the low one ,so the most of detected data is low frequency. Take the frequency domain filter ,which change the time-domain signal to the frequency-domain by the FFT algorithm, keep the frequency part which takes the most energy, and filters out the frequency which include small energy; But in the course of frequency filter, the frequency area on the focused signal energy need the power spectral. When the seismic signal's mean is a zero due to the signal attenuation, the power spectral is a statistics trait and indicates the seismic wave feature. So after compared of different power spectral calculations, select welch power spectral and gain the main band for filter part by calculating the peak frequency on the spectral.After the one-dimensional frequency filter, the signal is still not clear and need the related processing to increase SNR. The principle of related use the signal similarity and add them, the energy of the same one increases, otherwise, the energy decreases, this also takes the noise's non-regular behavior into account. Simulate the sampling signal (SA function) and do the related function with the micro-seismic data, making the micro-seismic signal clearly; The other purpose of the related calculation is to pick up the arrival time of signal, using the rate between STA and LTA to receive the relative arrival time under some man-make threshold. The algorithm employs some simulated data and get a good result.In the end of this part, according to the image principle of same kind wave with time arrival differences ,solve out the 11 formulas , locate the micro-seismic sources dot and simulate the 3-dimensional image which includes three steps, such as the sources dot location-interpolation,surface fitting and 3D picturing. At last using the Mechanics to give the explanation of the 3d image and instructing the condition of the horizontal fracture and vertical crack .In order to get the results of the software, Takes some examples on processing the digital data of oilfield detected and show that the software works normally. At the same time ,discuss the problems appeared on the experiments and give the probable cause.Finally, make a summary on the all paper and with the aim to make the system perfect, some suggestions in the further research are given.