Research On Frequency Expanding Method Of 3D Seismic Data Constrained By Well Logging Data

With the rapid development of science and technology,petroleum resources in areas of the energy industry play a more and more important role.We need to study on rolling development of old oilfield by investing more manpower and material resources,and enhance recovery factor of old oil field based on the old oil fine processing and interpretation and the effective exploitation of remaining oil.But now the resolution of 3D seismic data is still unable to meet the increasingly complex research on subsurface strata.In the process of fine interpretation of the old oil field,high resolution seismic data is particularly information.Improving resolution of seismic data plays an important role in the fine interpretation of geologic target,such as formation structure information,oil and gas reservoirs.Currently,seismic exploration technology provides abundant multi-scale geophysical data for exploration and development of oil and gas field.This brought infinite possibilities for the advancement of seismic exploration technology.On the premise of the known geological law,through the study on joint frequency expanding method of 3D seismic data,cross-well seismic,well logging data and so on,which named multi-scale geophysical data,we could broaden bandwidth and increase frequency of 3D seismic data.It has a new meaning for old field development and fine description.In order to obtain the high resolution seismic data and more detailed reservoir information,we often expand frequency by jointing well logging data and 3D seismic data.Well logging data with high frequency noise,better vertical resolution,but limited in horizontal direction,and wide frequency most of which is beyond the range of 3D seismic data,so we must downgrade frequency of well logging data into the level of seismic traces so that the logging well data can be matched with cross-well seismic data.We present a stepping iterative method constrained by well-side seismic traces to solve this problem.In the iterative process,convolution results of reflectivity(from well logging data)and estimated wavelet approaches well-side traces.Finally,we get a reflectivity series matched with well-side trace.The reflectivity series obtains both seismic information and high frequency components of well-logging data.The matching factor on well location can be extracted with the reflectivity and well-side traces,and processed with spatial algorithm.Based on the relationship between spatial matching factor and 3D seismic data,to establish 3D constrained data as constrains of frequency expanding method extends seismic data's frequency.By this method,we have realized that well logging data is used to guide and strengthen the effective signal in 3D seismic data,improved the resolution of seismic data.The feasibility of this method has been verified by processing the model and actual data.Through the research we can know:(1)The reflectivity series can be matched with surface seismic data in the mid and low-frequency range after stepping iterative process.After iteration,the reflectivity carries logging and seismic information at the same time.(2)By optimizing spatial algorithm of matching factor,matching factor can meet the requirements in the continuity and stability,more in line with geological characteristics of the geophysical data.(3)Matching constraint data can be constructed by spatial matching factor and 3D seismic data,and then we can get high resolution seismic through broadband constrained inversion on matching constraint data and 3D seismic data.Time-frequency analysis of the high resolution seismic data shows that the high frequency component of seismic data is improved,but the low frequency component has the loss.(4)The significance of low frequency component of seismic data is very important for the characterization of deep formation structure.Therefore the low frequency component should be protected in frequency expanding process.After low frequency compensation,the seismic data has been both expended high frequency and retained low frequency.Finally,we panoramically expand bandwidth and improve the quality of seismic data.