Depth Estimation of Sedimentary Basins Basement from Gravity Data Via Competitive Swarm Optimization

The thickness of sediments in sedimentary basins with hydrocarbon sources potential is one of the primary factors in determining the thermal maturation of these basins. This research has been done with the aim of two-dimensional modeling of the basement geometry of a sedimentary basin using the inversion of the gravimetric data. A common way for this problem consists in discretizing the basin using polygons (or other geometries), and iteratively solving the nonlinear inverse problem by local optimization. This procedure provides a solution that is highly dependent on the initial model and on the prior information that are used. Moreover, due to non-linearity of this inverse problem, local optimization methods would fail whenever there is no reliable initial model. Global optimization methods are promising alternative to classical inversion methods because the quality of their solutions does not depend on the initial model; also, they do not use the derivatives of the objective function. This research investigates the design and implementation of the CSO (competitive swarm optimization) algorithm as a novel algorithm in global optimization, for two-dimensional non-linear modeling of gravity data as a substitute for the local response methods such as Marquardt-Levenberg and Gauss-Newton. In first steps, designing and implementing the proposed algorithm were verified on synthetic model data. For evaluating the validation of this developed algorithm, it was tasted by both synthetic example include free noise data and data with presence of white Gaussian noise. Also, the results of application of this applying on noisy data show that this approach is robust to the presence of noise in data. Finally, reliability of proposed method to the inversion of a real gravity data was confirmed by applying it on a real gravity profile in the Moghan sedimentary basin. Results of this modeling agree well with previously published works on this Area.