Wyniki wyszukiwania - BazTech

1

Fine detection on water abundance of sandstone by joint inversion of seismic and CSAMT: a case study in the western Ordos Basin, China

Dong Yi, Cheng Jiulong, Wen Laifu, Cheng Peng, Li Fei, Jiao Junjun, Huang Qisong

Acta Geophysica

|

2022

|

Vol. 70, no 5

2045--2056

EN

The Ningdong mining area in the western Ordos Basin, China, mainly mines coal seam in Yan'an group, where its overlying rock is a thick sandstone layer of the Middle Jurassic Zhiluo Formation. This rock layer poses a direct water hazard threat to the coal mining if it is water-rich. The water abundant rock layer in the upper strata of Zhiluo Formation forms a low-resistivity overburden layer, decreasing the resolution of controlled source audio magnetotelluric (CSAMT) method in detecting water-bearing in the lower part of Zhiluo Formation sandstone layer of coal seam direct roof. Therefore, under the influence of the low resistivity overburden of the upper sandstone, how to accurately detect the aquosity of the lower sandstone layer is of great importance to the safe mining of coal mines in the region. On the basis of CSAMT detection, combined with high-resolution seismic exploration method, the joint inversion of seismic and CSAMT is realized by using cross-gradient operation between the seismic wave impedance attributes clustered by particle swarm algorithm and CSAMT inversion model. The seismic data fitting term in the joint inversion objective function is discarded, and the pseudo-2D inversion method is used for CSAMT to reduce the calculation cost of the inversion. A 3D geological model conforming to the hydrogeological characteristics of the Ningdong mining area is established, and the joint inversion test between seismic and CSAMT is conducted, proving the feasibility and applicability of joint inversion to detect the water enrichment of sandstone in this area. The accuracy of the seismic and CSAMT joint inversion results is verified by combining the engineering example of water abundance detection in the sandstone layer in Maiduoshan coal mine that accorded with the typical hydrogeological characteristics of Ningdong mining area and the results of later downhole drilling exposures, which is remarkably better than the single method. The research shows that the joint inversion of seismic and CSAMT can accurately identify the water abundance of the lower sandstone layer and its range under the influence of the upper low resistance sandstone overburden and achieve the purpose of fine detection of the water abundances of the lower sandstone layer of the Zhiluo Formation. The joint inversion can provide important safety geological guarantee for the mining of coal seams in the Ningdong mining area in the western part of Ordos Basin.

2

Pareto Joint Inversion of 2D Magnetotelluric and Gravity Data – Towards Practical Applications

Miernik K., Bogacz A., Kozubal A., Danek T., Wojdyła M.

Acta Geophysica

|

2016

|

Vol. 64, no. 5

1655--1672

EN

In this paper, a Pareto inversion based global optimization approach, to obtain results of joint inversion of two types of geophysical data sets, is formulated. 2D magnetotelluric and gravity data were used for tests, but presented solution is flexible enough to be used for combination of any kind of two or more target functions, as long as misfits can be calculated and forward problems solved. To minimize dimensionality of the solution, space and introduce straightforward regularization Sharp Boundary Interface (SBI) method was applied. As a main optimization engine, Particle Swarm Optimization (PSO) was used. Synthetic examples based on a real geological model were used to test proposed approach and show its usefulness in practical applications.

3

Metody dekompozycji zadania odwrotnego na przykładzie wybranych zagadnień geofizyki

Pięta A., Bała J.

Przegląd Górniczy

|

2010

|

T. 66, nr 6

85-90

PL

W artykule zaprezentowano i porównano dwie metody dekompozycji zadania odwrotnego. Obliczenia przeprowadzono na przykładzie wybranych zagadnień z dziedziny geofizyki: lokalizacji współrzędnych hipocentrum wstrząsu górniczego oraz inwersji połączonej danych geoelektrycznych. Do rozwiązania zadania odwrotnego zastosowano algorytmy optymalizacji globalnej z grupy metod przeszukiwania siatki. W przedstawionych przykładach w przypadku obliczeń równoległych zastosowano dwie strategie podziału zadania sekwencyjnego: podział grubo- i drobnoziarnisty. Analizowano czas obliczeń, przyspieszenie i efektywność zaproponowanych schematów dekompozycji.

EN

The article presents two different kinds of parallel decomposition of the inverse problem. The computations were performed on the example of selected issues in the fields of geophysics: the location of mining tremors and the joint inversion of geoelectrical data. Global optimization algorithms from the group the grid search method were used to solve the inverse problem. For a parallel realization of this algorithm the fine and the coarse grid decomposition were proposed. Execution time, speed-up and efficiency of both kinds of parallel algorithms were presented and analyzed.

4

Zastosowanie inwersji połączonej dla wybranych metod geoelektrycznych.

Bała J.

Prace Naukowe Instytutu Górnictwa Politechniki Wrocławskiej. Konferencje

|

2007

|

Vol. 120, nr 49

37-46

PL

W metodach interpretacji danych geofizycznych jednym ze sposobów lepszej analizy informacji zawartych w pomierzonych wartościach jest połączenie interpretacji danych pomiarowych z różnych metod. W przypadku metod geoelektrycznych przykładem są wartości oporności pozornej mierzone w metodzie sondowań elektrooporowych i w metodzie dipolowych sondowań indukcyjnych. Jednym z problemów interpretacji danych jest niejednoznaczność rozwiązania w przypadku inwersji takich danych spowodowana ekwiwalencji. W artykule przedstawiono wyniki działania autorskiego programu pozwalającego wykonać inwersję sondowań elektrooporowych i dipolowych sondowań indukcyjnych oraz inwersję połączoną dla obu metod.

EN

In the methods of geophysical set of field data interpretation, one of the ways of better information analysis included in the measured data is joining the interpretation of data sets from different geophysical methods. In case of geoelectrical methods the example could be the data of apparent resistivity received by the vertical electrical sounding and dipole induction sounding which respond differently to the examined earth structures. The reason of the ambiguity of the interpretation in case of both methods is the measurement errors or equivalence phenomena. The use of the joint inversion for both methods can improve the measurement data analysis and geological interpretation of the given area. The example of the joint inversion was evaluated and example of the automatic ID inversion is presented and discussed.