Inversion of the gravity data is one of the most interesting numerical tools for obtaining three dimensional geological images. In this paper 3D nonlinear inversion of the gravity data is used to determine the basement topography. The basement was juxtaposed with the re More
Inversion of the gravity data is one of the most interesting numerical tools for obtaining three dimensional geological images. In this paper 3D nonlinear inversion of the gravity data is used to determine the basement topography. The basement was juxtaposed with the regular array of rectangular prisms in which the thickness of each prism is determined by the inversion procedures. Prepared algorithm is based on singular value decomposition (SVD) method which ca modify the initial model by comparing observed and estimated gravity data. The SVD method is very popular with geophysical data analysts because it is mathematically robust and numerically stable. To illustrate effectiveness of the prepared codes and algorithm related to 3D inversion of gravity data, both synthetic and real data were tested by the mentioned algorithm. The real data were part of the gravity data which were acquired in Moghan area (located in the north-west of Iran). Because of being near to the Baku oil-rich regions and thick sedimentary rocks, the Moghan sedimentary basin is an interesting area from hydrocarbon exploration point of view. Determination of the sedimentary rocks thickness is an important factor in oil and gas exploration issues. The main goal of 3D inversion of the gravity data in the study area is to determine basement the sedimentary rocks thicknesses or the boundary of Ojagh-Gheslagh Formation and its volcanic basement. The modeled boundary of Ojagh-Gheshlagh Formation and its volcanic basement which is obtained by the inversion of gravity data, was previously confirmed by interpretation of seismic data.
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The image well theory was used in the study of no flow boundaries effects on the drawdown around pumping wells. Most studies are concentrated on the vertical no flow boundaries, while, in some cases these boundaries are not vertical and have inclinations. To the best of More
The image well theory was used in the study of no flow boundaries effects on the drawdown around pumping wells. Most studies are concentrated on the vertical no flow boundaries, while, in some cases these boundaries are not vertical and have inclinations. To the best of the authors knowledge, the problem of the inclined no flow boundaries has not been studied yet. The effects of the parallel no flow boundaries inclination on the drawdown around pumping wells in bounded aquifers is studied here. The time-drawdown data for vertical boundaries have used the numerical simulation and also the image well theory. The effects of inclination of the boundaries were only considered using the numerical simulation. The results of numerical simulations and image well theory for vertical no flow boundaries were matched completely. The computed drawdown for observation well in the models with inclined and vertical no flow boundaries used to compute the difference between them. The difference between these cases depends on the distance between the boundaries (width of the aquifer) and the inclination value. The results showed that in large widths and low inclinations, the computed drawdown in aquifers with vertical boundaries are almost similar with the computed drawdown in aquifers with inclined boundaries and the differences can be neglected. In the other words, the difference between the vertical and inclined cases in smaller widths is so high that even in the low inclinations, the differences can't be neglected. It can be concluded that the image well theory as we know, cannot be used in inclined no flow boundaries.
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