Study On The Features Of Gravi-Magnetic Field And The Sedimentary Structure In Mohe Basin

This study is based on national strategic oil and gas resources survey and evaluation of the constituency special down, surveying services for the oil and gas applications and basic research projects "around the Daqing Oilfield, Cenozoic rift basin evolution and future prospects "for the choice.As China's largest oil production base and an important oil and chemical industry base, the development of the past 40 years, Daqing has produced 1.624 billion tons of crude oil, accounting for the same period in the country's land-based oil output by 44.6%. However, the Daqing Oilfield in 24 consecutive high yields, recoverable reserves far from being able to meet with an annual output of 50 million tons of long-term needs. Therefore, identifying external Daqing, Cenozoic rift basin group of oil and gas potential, to favorable exploration strategy is a target zone problem to be solved.This study is the profile, magnetic data to obtain Moho depth, magnetic basement structure and depth distribution. According to the practical situation in the conventional treatment on the basis of Parker-Oldenburg depth inversion, Euler deconvolution structure inversion, DCT inversion.1.Parker-Oldenburg interface inversionThis method is targeting the rapid market anomaly Forward calculation. Parker interface inversion As a result of the fast Fouriertransform, so that the method is fast, strong function and other features. If the following formula for density is not constant. It can be variable density of Parker interface inversion formula. Currently, the method of the study of regional geophysical data inversion and interpretation to be widely applied.2. Euler deconvolution structure inversionEuler deconvolution inversion source depth ways to deal with the magnetic field inversion data source and level of depth location of the Act to homogeneous Euler equations based on theory, using equations for the structure to market sources inversion depth; On this basis, through the use of computers, analysis of the vertical veins, Magnetic vertical faults and simple contact with the different tectonic model for the depth and inversion; Euler method for three-dimensional inversion of magnetic data interpretation, derived from the theory of thin veins. Tilted magnetic inversion, and other contacts with the index value structure, describes the sphere, cylinder upright, Magnetic contact zone and vertical fault model inversion results of the plane.3. DCT inverseDCT method can identify faults. The use of gravity and magnetic field measurements to estimate the depth of the source and location has been developed for the many ways. With a strong magnetic anomaly and associated derivative of the curve and feature points to approximate estimates breakpoint to the horizontal position and attitude; Powerspectral slope of the curve estimation method is based on the statistical basis of the Act on the depth estimation errors; Normalized use of a gradient and the total phase of the market will determine the source of the fault and depth of the horizontal position breakpoint. The DCT will be applied to the interface unusual inversion of gravity anomaly and the derivative terms, calculation of infinite horizontal cylinder gravity anomaly vertical and level of a derivative with high accuracy. This paper will DCT Euler method used to determine the location of fracture is a method (called DCT).During this study found the following unresolved issues:(1) Euler deconvolution method is a commonly used method, but there are limitations. For example, it requires a parameter known as tectonic index; existing Euler deconvolution is confined to a window-a source of market (although there has been more than appropriate sources were used. But pending further development); Euler deconvolution calculation is more complicated.(2) Field data is the underground structure of a combination of body, in the study area when the structure is very difficult to deep anomaly from the stack together accurate information extracted, different filter window and classification standards will be different from the deep market information.(3) The effect of surface waves, DCT-based anomaly downward extension of the numerical calculation, there are still some problems, Therefore gravity cosine transform spectrum analysis and DCT-based Converter theory should be completed.(4) The current depth of the Moho inversion, the lack of deep seismic sounding and electric bathymetric information as a priori constraints, thus the calculation of the partial results generally 1-2 km deep. Extraction is the deep field different? Or because of a lack of depth control? Still requires further study. Finally, a note that the study of a region of deep crustal structure, to be combined with other geophysical methods for analysis and interpretation. Only in this way can the results better reflect the reality of the underground.Based on the above issues, the need for further study:(1) According to the main problems, although the gravity and magnetic exploration methods have made some progress, but because of gravity and magnetic Law itself is relatively mature, So much progress. Use gravity and magnetic response function strike effective magnetic angle is a new approach, pending further study. They should in gravity and magnetic inversion conducted more research.(2) Euler deconvolution method used to determine the deep structure of the plane location and depth of viable, but The quality of the results, treatment is the key parameter choice, therefore, how to choose the appropriate parameters and the process of dealing with how the need to continuously improve parameters, how to overcome Euler deconvolution limitations, the future of gravity and magnetic exploration of the important research direction.(3) Gravity and magnetic exploration in the oil and gas exploration and use of mineral resources which need further study. Current researchshows that gravity, magnetic field and hydrocarbon sediments between spatial correlations. In this regard, it should be further research and development using gravity and magnetic exploration of oil and gas deposits in a new way.