Geophysics
Hamidreza Samadi; Roohollah Kimiaefar; Alireza Hajian
Abstract
One of the most important issues in seismology is to accurately determine the epicenter of earthquake, mainly because the accuracy of dependent studies such as seismic risk analysis, fault mechanism, depends on the accuracy of mentioned parameter. Double difference method is one of the conventional relative ...
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One of the most important issues in seismology is to accurately determine the epicenter of earthquake, mainly because the accuracy of dependent studies such as seismic risk analysis, fault mechanism, depends on the accuracy of mentioned parameter. Double difference method is one of the conventional relative earthquake relocation methods which is used vastly by seismological centers and it is used as the basis of an algorithm that relocates earthquake events about 0.004 second. In the proposed method, Adaptive Neuro-Fuzzy Inference System (ANFIS) is trained based on the former relocated events and generalized for new earthquakes. In the training procedure, the hypocentral information, for the main event and the nearest one (determined by K nearest neighbor search), and the velocity model of the region are considered as inputs and hypocentral information are set as target for the network. Here, with reference to the information of about 8000 earthquakes, as the training events, 490 earthquakes were relocated in about 0.1 (s) where RMS for predicating latitude and longitude of the events were 0.002 and for the depth parameter, RMS was 0.45. It is concluded that the proposed method could be considered as a powerful algorithm for near real time relocation of earthquakes.
Petroleum geology
kambiz Mehdizadeh farsad; davood Jahani; alireza hajian; Fereidoun Rezaei
Abstract
Hydraulic fracture is known as one of the effective methods for producing or being caused a change in the physical structure of a reservoir rock. In oil and gas reservoirs which have been fractured by a hydraulic approach, this method causes that a production well and the time of reservoir production ...
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Hydraulic fracture is known as one of the effective methods for producing or being caused a change in the physical structure of a reservoir rock. In oil and gas reservoirs which have been fractured by a hydraulic approach, this method causes that a production well and the time of reservoir production increase. In this research, fracture analysis have been comprised with the outputs produced by previous models. Its results show that the opening intersection produced by hydraulic fracture has been being changed in various time during pumpage, therefore, the fracture should be kept open by propanent substances. In the next stage, the amount of porosity pressure in the trend of the fracture is considered. In this survey, two parameters, i.e. the fracture measure and the change of pore pressure have been obtained using the hydraulic fracture modeled process under the actual condition of pay zone and its confining layers, and by the finite element approach. In this method, pumping processing has been assigned for fluid and propanent. At the end, by making a comparison between these result and the results obtained from previous studies, it can be found out that this approach is applicable and efficient.