Ocean controllable source electromagnetic response calculating method based on actually-measured launcher morphology data

Abstract

The invention belongs to the technical field of geophysical exploration and relates to an ocean controllable source electromagnetic response calculating method. The method is characterized in that a GPS / depth sensor mounted on a launcher is used to measure the position deviation of the launcher and a preset measuring line, substituting the position deviation data into a geological calculation model, allowing an electric dipole to be equivalent to a finite line source and performing subsection calculation, breaking up a sectioned long straight wire of optional morphology into horizontal and vertical equivalent electric dipoles under an observation coordinate system, respectively calculating the electromagnetic response of each section, using an analytic formula to solve an ambient field, using a staggered finite volume method to solve an induction field, and superimposing vector fields to obtain sectioned wires and the ocean controllable source electromagnetic response based on the actually-measured launcher morphology data. The method has the advantages that launcher morphology parameters can be monitored precisely, the method can approach the actual operation working conditions to the maximum extent, and the accuracy of electromagnetic response calculation and inversion can be increased effectively by using a finite line source treatment method.

Description

technical field [0001] The invention belongs to the technical field of geophysical survey, and relates to a calculation method for the electromagnetic response of an ocean controllable source. Background technique [0002] Marine controlled source electromagnetic method is an effective marine geophysical survey method for detecting seabed oil and gas resources and mineral resources. It has played an important role in reducing the risk and ambiguity of deep water oil and gas exploration. It has become a developed country for deep water oil and gas exploration. important means. In offshore oil and gas exploration operations, seismic methods are generally used to find out favorable geological structures of reservoirs, and at the same time, controlled source electromagnetic methods are used to obtain existing high-resistance anomalies. The combination of the two can significantly improve the success rate of exploration. [0003] The electromagnetic response of the geological mo...

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Problems solved by technology

However, the current research on the electromagnetic response of marine controllable sources all adopts the processing method of using the emission source as a point electric dipole, which reduces the accuracy of calculation

[0005] At present, the measures taken for the shape change of the emission source are to record the dynamic position and track information of the emission source, and correct the influence of the field value in the subsequent data processing, but this method regards the emission source as a point electric dipole, The recorded information only includes the dynamic information of the electric dipoles at both ends of the emission source, and does not consider the change of the emission source shape during the detection process, so the accuracy is not high (Li Yuguo, Duan Shuangmin. Research on the preprocessing method of electromagnetic data of marine controllable sources[J] .Journal of Ocean University of China, 2014, 44(10): 106-112.)

Due to the complex and changeable submarine currents, the shape of the emission source changes randomly, and it is impossible to obtain the data of the shape change of the emission source by means of calculation and simulation. How to obtain objective and accurate dynamic information of the emission source and how to accurately calculate or correct the electromagnetic field of the controllable source based on the dynamic information Response is an important topic for current researchers

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