Study Of Structural Characteristics And Oil-gas Perspective In Mohe Basin

Mohe basin is located in the North of Heilongjiang province, and Russia of the ushumun basin connected, in China area is about 21500km2, geographic coordinates: East longitude 121°30'-125°32', latitude 52°48'-53°28'. Mohe basin is in Ergun Caledonian fold belt on evolved basin, geological evolution of the historical complex. Argued, Mohe basin as the Daqing exploration area outside the rift basin, should have good potential, therefore residents for structural characteristics and petroleum potential analysis has very important practical significance. This article is to study the Mohe basin as an object, use the Daqing exploration area perimeter, Cenozoic rift basins evolution and petroleum potential analysis project gravity data, combined with other geological and geophysical data of a sedimentary basin of scope, structure, undulating and petroleum potential.This includes data processing methods and geological interpretations of two aspects, the main activities include the following:1. Bit field separation of Kalman filterGravity anomaly is underground density distribution uneven response, can effectively be bit field separation directly affects subsequent explanation. Usually we put the Bouguer gravity anomaly is divided into regional and local gravity anomalies, and the bit field separation can in the space field or you can wave number domains, this article focuses on that bit field separation of filtering methods. Briefly describes their principles, learn about each of these assumptions and implied subjective factors, and on the rise in recent years just for bit field separation of Kalman filter and Wiener filter for the simulation and modeling, through comparison, Kalman filtering method a Wiener filter method to better approximate truth value (expected value). But so far, all for bit field separation of filtering method has a drawback, and that is to be on average logarithmic power spectrum of recognition, this translates into increased filtering for human error, if you want to compare by filtering method to obtain the desired results, it must be as precise as possible to analyze logarithmic power spectrum. Therefore, actual data processing should be on gravity anomalies of logarithmic power spectrum careful analysis, to get more accurate results.2. Use the "multi-scale" inversion method of calculation field source distribution and determine the center of massPhysical view survey and Earth of a certain physical characteristics of the model can be contacted by mathematical abstraction, generally expressed as first class Fredholm integral equation. From known model of field effect this process is called forward, on the contrary, by observed physical field calculation field in the source model of the process is called inversion. They are closely related, and the latter than the former is much more difficult. For geophysical inversion problem, we must resolve solutions of unstable and not only the two basic problems. Over the past decade , about both questions of whether in theory or in its application have made much progress. Buckus and Gilbert established a system of inversion theory (i.e. B.G theory), a better solution to these two basic issues, in geophysical inversion get more and more applications. This article describes in detail the fundamental principles of B.G theory, model configuration and posed equation solving, and proposed a 2-dimensional gravity "multi-scale" inversion method.The"multi-scale"inversion is the last few years and is made of accelerating convergence, overcome local minimum values, search the global minimum of inversion policies. This method is the use of extension up to the different height of gravity field on the underground source distribution of physical parameters for inversion. Unlike a traditional bit field inversion, the"multi-scale"inversion method implements the gravity field of linear inversion, deferred to different height equivalent to increasing the inversion of the field in the source distribution of physical parameters required data dimension. Through the model analysis has the following conclusions:①Surface monolayer one-dimensional data from regularization inversion resulting model cells upper density is greater than the value of the value of a given model; While the density of the lower part of the density value is less than the given model density value.②With the upward extension of the increase in the number of layers, by gravity "multi-scale" inversion of the resulting model grid cell density values generally close to the given model density value, relative error.③Through gravity "multi-scale" inversion of the resulting model centroid ordinate as up extension layer number increases, gradually approaching the given model of mass ordinate.3. Density interface of inversion and interpretation program improvementIn the basin of the characteristics of the interface, density is an important research content, its basin plays inside the structure and constraining effects, geophysical methods is the calculation and analysis of the characteristics of the floor. This article details the density interface wave number linear inversion method and now applies broad Oldenburg-Parker inversion of the basic principles and implementation methods, experimental evidence, both good and bad of inversion is dependent on properly extracted from interface undulating gravity anomalies, and requires the interface of ups and downs to much less than the average depth of the interface. Based on the above theory, on gravity 2D, 3D and inverse program has been improved and optimized, through model calculation, optimized wave number 2D, 3D and inverse program calculation speed, accuracy and high, clearing the results to be stable, with strong practical value. But in dealing with practical work, it is important to note, interface depth cannot exceed the horizontal plane, and interface of fluctuations relative to the average depth of the interface. This is because the method in the derivation process took certain approximate; ignore the Taylor expansion of higher-order items or use of the differential.4. The inversion of faultsEuler deconvolution is a way to take advantage of a bit field grid data to determine geological location (boundary) and depth of automated calculation method, this method has the advantage that you do not need to known geological information of the control. It handles issues of the basic idea is based on the Euler homogeneous equation, application level anomalies, spatial derivative and different shapes to geological structure of a particular index to determine the source of the anomaly field general location. This article will Euler deconvolution and gravity "multi-scale" inversion method, is applied to the measured profile XB2, recognized by the size of the total fault, and obtains good results.Mutations in signal detection in digital signal processing have a very important role and function. In geophysical prospecting, when the fault caused rock horizontally changes, or you may experience when you rock with edge, because the physical changes, acquisition of signal mutates, detection signal, these mutations can fracture, contact make the correct interpretation of the geophysical. This article describes the wavelet detection method technology based model checking the technology to identify the faults in the viability, finally apply the Mohe basin fault Division, with comparative analysis of geological data, both have good anatomizes.5. The structural features of the Mohe basinFollow the process described above, and apply the above technique, on structural characteristics of the Mohe basin gives analysis, made the following understanding:①Mohe basin has four tectonic units, including three Ryuichi depressions, namely: Obama Heilongjiang uplift, ancient Lotus River uplift, Tahe uplift, a central depression.②Mohe basin of fracture press distribution direction can be divided into the Near East, North East-North East, North West and s four groups, and North-South and West, but a small number of large, usually the deepest base, control basin of structural pattern. One of the southern boundaries of the Mohe basin, as shown in Figure 3.20 fracture of F1, namely: Changying-Pangu depression belt of the southern boundary.6. Mohe basin of hydrocarbon potential predictionCombined with the structural features of the Mohe basin, igneous rocks distribution and basin endogenous, reservoir, cover conditions of think, Mohe basin Central depression is the most favourable hydrocarbon potential area, where in depression, Lin Hai-SAG and: Changying-Pangu depression as one level of petroleum potential area, engh SAG, baby forest SAG and Yilin SAG as secondary oil and gas potential. For small SAG basin, although for the mining area much less than the large depression, they take geological structure strongly, for oil and gas storage. But from another perspective, the Mohe basin belong to the comparison of faults, likely formed faulting closed constructed. This kind of closed constructed the resulting block raised or declining regions can also be formed good oil. From the Mohe basin geology and basin within IIB tectonic units feature analysis, in good health, oil conditions, basin within IIB tectonic units likely to form small and medium-sized oil and gas fields, recommended that further detailed exploration.To sum up, in data processing, this article uses some of the more advanced data processing methods, such as: Kalman filtering, gravity "multi-scale" inversion, wavelet detection point mutations and traditional techniques, on Mohe basin of gravity data carried out a series of processing, achieved results. In data interpretation, this article on the tectonic Mohe basin, basement characteristics and distribution in depth research, gets up and basin petroleum potential related geophysical evidence, on the basis of geological data provides a useful supplement to, and on the hydrocarbon potential of the Mohe basin compares the scientific evaluation.