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Research Article
The Application of Dual Frequency IP Survey to Identify the Concealed Ore Body in Pilbara Craton, Australia: A Case Study from Calvert Gold Deposit
Zhangle Liu*
,
Yawen Zheng
Issue:
Volume 13, Issue 2, April 2024
Pages:
49-57
Received:
18 February 2024
Accepted:
8 March 2024
Published:
2 April 2024
Abstract: The Mallina Basin in Western Australia, situated in the central part of the Pilbara Craton which is one of the world's oldest cratons, is a structurally deposited basin subjected to multiple episodes of deformation and magmatic intrusion. The Calvert gold deposit in Mallina Basin is heavily covered by Quaternary, thus, it is hardly to identify any distinct mineralization indicators, and there is no any significant progress in exploration so far. The SQ-3C dual frequency induced polarization facility that is developed by China is introduced to carry out the dual frequency IP survey, the author’s team have tested all the types of different rock samples to collect the geophysical parameters in the Calvert area, and the selection of suitable facility and working frequency is based on the geological characters of the Calvert deposit and the geophysical parameters of rocks, and some processes are undertaken to weaken the interference triggered by the electromagnetic coupling, and an IP anomaly zone was delineated. Through the drilling program in the IP anomaly zone, a gold ore body that has the same orientation with the IP anomaly zone was controlled; this result demonstrated the dual frequency IP survey is effective in the local area and provide an efficient technical method for the mineralization prospecting, and this geophysical survey project sets an example for the familiar type of gold deposit in the local area.
Abstract: The Mallina Basin in Western Australia, situated in the central part of the Pilbara Craton which is one of the world's oldest cratons, is a structurally deposited basin subjected to multiple episodes of deformation and magmatic intrusion. The Calvert gold deposit in Mallina Basin is heavily covered by Quaternary, thus, it is hardly to identify any ...
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Research Article
Temporal and Spatial Distribution Characteristics of Torrential Flooding Disasters with Different Intensities in Tarim Basin
Issue:
Volume 13, Issue 2, April 2024
Pages:
58-66
Received:
3 March 2024
Accepted:
7 April 2024
Published:
29 April 2024
Abstract: As torrential flooding often cause huge economic losses and casualties, analyzing the spatio-temporal variation characteristics of torrential flooding events is of great significance to disaster prevention and reduction. Based on five indicators for torrential floodingin the Tarim Basin in 1990-2019, ratio weighting and non-dimensional linear summation were employed to calculate disastrous loss indicators that represent disaster intensity. Afterwards, percentile method was used to divide disasters into four levels, i.e., general, relatively severe, severe and extremely severe. The results showed that the regions where Level-1 to Level-4 disasters frequently and recurrently occur are concentrated in Kizilsu Kirghiz Autonomous Prefecture, Aksu Prefecture and Kashgar Prefecture and that such disasters often take place from April to July. The interannual variation of the frequency and intensity of Level-1 disasters presented a linear upward trend, and the frequency and disastrous loss indicator increased by 14.6 and 0.8 per 10a, respectively. The interannual variation of the frequency and intensity of Level-2 to Level-4 disasters did not show a linear increase or decrease trend. The threshold for 12-hour precipitation that may cause torrential flooding in the basin from March and October is 10mm. The annual frequency of 12-hour precipitation exceeding the threshold increased year by year, so did the frequency and intensity of Level-1 disasters.
Abstract: As torrential flooding often cause huge economic losses and casualties, analyzing the spatio-temporal variation characteristics of torrential flooding events is of great significance to disaster prevention and reduction. Based on five indicators for torrential floodingin the Tarim Basin in 1990-2019, ratio weighting and non-dimensional linear summa...
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Research Article
Classification and Prediction Method for Dolomite Reservoirs in the Permian Maokou Formation in the Sichuan Basin
Lu Yao*,
Wang Shize,
Li Haiyin,
Cui Xiaojie,
Zhao Jing,
Li Li,
Zou Wen,
Yan Qun
Issue:
Volume 13, Issue 2, April 2024
Pages:
67-75
Received:
18 March 2024
Accepted:
7 April 2024
Published:
29 April 2024
Abstract: The Lower Permian Maokou Formation in the Hechuan area is one of the key horizons for natural gas exploration in the Sichuan Basin, showing a low degree of exploration and great exploration potential. The Lower Permian gas reservoir is mainly controlled by the reservoir, therefore it is subject to the development of the Maokou Formation reservoir. However, due to the strong heterogeneity and significant variations in physical properties of the Maokou Formation dolomite reservoir in the Hechuan area, there are significant differences in seismic response characteristics of reservoirs with different porosities. Through comprehensive analysis of gas testing wells in the Maokou Formation, criteria for reservoir classification were established based on lithology, average porosity, plane porosity, and thickness of dolomite reservoirs. The effective reservoirs in the Maokou Formation were divided into two types: high-porosity reservoirs and medium-porosity reservoirs. On the basis of establishing a physical quantity model for the Lower Permian carbonate rock in the research area, the rock physical characteristics and seismic response characteristics of reservoirs with different pores are determined through model forward modeling, and appropriate methods are selected for prediction. By using the optimization processing method of gathers and wavelet decomposition to remove sidelobes, the issue of seismic abnormal response caused by lateral velocity changes in the underlying Maokou Formation has been solved. The relative strength relationship of seismic response amplitude can effectively characterize the true situation of reservoir development. Then, by using post-stack inversion and pre-stack simultaneous inversion methods, the high-porosity and medium-porosity dolomite reservoirs in the Maokou Formation are classified and predicted, thereby to effectively improve the prediction accuracy of reservoirs, ultimately providing a reliable basis for the exploration and development of the Maokou Formation in the Hechuan area in the later stage.
Abstract: The Lower Permian Maokou Formation in the Hechuan area is one of the key horizons for natural gas exploration in the Sichuan Basin, showing a low degree of exploration and great exploration potential. The Lower Permian gas reservoir is mainly controlled by the reservoir, therefore it is subject to the development of the Maokou Formation reservoir. ...
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Research Article
The Application and Effect of AI Fault Interpretation Technology in the Laoyemiao Area
Zeng Cheng,
Sun Lizhi*,
Bi Yongbin,
Xu Bo,
Duan Jian,
Xu Yingxin,
Qian Liping,
Zhang Wanfu,
Zhang Hao,
Ying Zijuan
Issue:
Volume 13, Issue 2, April 2024
Pages:
76-85
Received:
7 December 2023
Accepted:
8 April 2024
Published:
29 April 2024
Abstract: The complex faults, especially mid-deep faults, in the Laoyemiao area of the Nanpu Sag, the Bohai Bay Basin, are unclearly understood for their characteristics, constraining the structural and geological delineation of the area. The hydrocarbon enrichment in the Laoyemiao area is closely related to the faults, and thus the precise identification of mid-deep faults is of great significance for understanding the structural system and reservoir distribution in the area. In the past twenty years, artificial intelligence (AI) scholars developed new technologies and methods to solve engineering problems. Typically, the AI seismic data interpretation technology plays a critical role in improving the accuracy and efficiency of fault interpretation. In order to define the structural characteristics of the Laoyemiao area, the "2W1H" seismic data were processed by fault-constrained structure-oriented filtering, and then interpreted using the EasyTrack module of GeoEast independently developed by BGP. It is found that the imaging quality and accuracy of mid-deep faults are improved effectively. On this basis, the SN-trending strike-slip fault systems were discovered, and the structural pattern and evolution law of mid-deep faults in the Laoyemiao area were re-understood. The results are of great significance for the structural identification, reservoir evaluation and selection of exploration targets in this area.
Abstract: The complex faults, especially mid-deep faults, in the Laoyemiao area of the Nanpu Sag, the Bohai Bay Basin, are unclearly understood for their characteristics, constraining the structural and geological delineation of the area. The hydrocarbon enrichment in the Laoyemiao area is closely related to the faults, and thus the precise identification of...
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