Stochastic Medium Modeling And Gravity Forward Modeling

Forward modeling plays an important role in gravity exploration.It is not only an important component of inversion,but also one of the means for geophysical staff to understand the gravity anomalies generated by geological profiles.The establishment of the density structure model is one of the keys to the gravity forward modeling.Constructing a good density model not only helps to obtain the ideal inversion results in the gravity exploration inversion,but also helps the geophysical exploration personnel to correctly understand the actual gravity anomaly of the geological section.And improve the reliability and accuracy of gravity data interpretation.For a long time,forward calculation models for gravity anomalies have been traditional uniform or block uniform models.Due to the uneven distribution of porosity,particle size,composition,and pressure of actual rock(mineral)media,the spatial distribution of density is random on a certain scale,and the diagenetic conditions and environment of adjacent spaces are consistent.So that the density has continuity in the local space.This randomness and continuity will inevitably affect the gravity anomaly,interfere with the interpretation of gravitational exploration data,and even lead to misinterpretation.This kind of interference is also difficult to eliminate by means of data processing.In the face of this problem,the stochastic modeling method in this paper uses random methods to generate disturbances,uses different correlation coefficients of related lengths to describe the local correlation,by controlling the random disturbance amplitude by the disturbance variance,this natural phenomenon can be described exactly.In order to better describe the characteristics of the actual strata and combine the characteristics of the actual stratum non-uniformity and gravity exploration,this paper introduces the basic principles of random media,using different autocorrelation lengths and disturbance variances to construct formation random medium model of density random distribution.It shows that the random medium theory can be used to construct a random medium model to describe various complex and non-uniform geological structures.Using the control variable method,the influence of different trait parameters on the random medium model was discussed.Based on a gravitational exploration profile in Dexing,Jiangxi,stochastic medium models with different autocorrelation lengths and different variances were constructed and compared with the traditional model.The results show that the stochastic model theory can effectively and flexibly describe the density distribution of underground actual media.Perform forward calculations on stochastic models and traditional models,and compare with the measured results,the actual formation characteristics parameters are estimated.The results show that the stochastic model can accurately reflect the actual section anomaly,and it has a certain guiding effect on the interpretation of measured gravity anomalies.Therefore,it is necessary to study the gravitational forward of density random distribution media to understand the characteristics of gravity anomalies in the random media model,to guide the practical application.