3-D Apparant Density Inversion Based On Downward Continuation Of Regularization Methods

Gravity inversion uses some means to determine the density distribution underground through the distribution of the known gravitational,and it is an important means of geophysical exploration.The basic idea of this method is the inversion geological bodies on the underground for grid subdivision to calculate all the apparent density of subdivision grid unit through relentless inversion iteration until meeting precision requirement.However,the main problem with this approach is non-uniqueness of inversion:at first,observing gravity anomaly is the volume of underground space;the second,collection of data is discrete rather than continuous.How to reduce the multiple solutions and improve the accuracy of the inversion imaging has become the key to solve the problem of gravity inversion.In view of the multiple solutions,I have adopted to effectively extract more favorable prior information,increase the number of inversion data volume to improve the apparent density inversion imaging accuracy.It becomes the basic starting point of this article,that is how to effectively increase data inversion data volume.So I uses the research of downward continuation of regularizatio methods based on the depth change,and get the gravitational field at different depths(the three-dimensional gravity data volume)Then use the three-dimensional spatial data that downward slice at different depths extension field to inverse,the amount of data inversion method is far greater than the amount of data observation plane.This inversion method uses the golden section algorithm and adds to reasonable constraints to further reduce the inversion problem of multiple solutions,the aim to get close to the actual geological conditions of density distribution and geometrical morphology.At last,It improves imaging precision.Modeling computation studys on the feasibility of the method,and uses different geological model,by choosing different fields under the extension,compares with the apparent density imaging precision to come out the most reasonable extension of field.In the inversion process,compare various other parameters,join reasonable constraints,get the best inversion result,and improve inversion algorithm to improve imaging precision.Through the model test is summarized: this method does improve the apparent density of the imaging resolution in the longitudinal direction,The target of geological location is more accurate in the inversion,and improves different depths of geological imaging precision significantly,and greatly improves the inversion accuracy.This research method uses apparent density inversion to gravity anomaly on the north three regional.And according to the apparent density of the three-dimensional distribution interpretes igneous rocks,and compare actual drilling data with inversion results,and the result reaches the apparent density imaging accuracy requirements.It proves the method reliability and practicality.