Research And Design Of Marine CSEM Receiving System Sensors

MCSEM (marine controlled source electromagnetic methods, MCSEM) makesuse of electromagnetic waves which is emitted by the mobile horizontal electricdipole source mounted on board and electromagnetic signals from the seabed whichare collected by electromagnetic array receivers set under sea. By processing thecollected signals, we can get the resistivity distribution which is related with the oiland gas saturation closely leading to the direct detection of hydrocarbon potentialformations. The advantages can be concluded as, strong adaptability in the profoundlyzone, convenient for the continuous measurement, large range, low cost, highefficiency, short time, less affected by natural conditions, the strong anti-interferenceability. The most important is the controlled source electromagnetic detectionanomaly technology can improve the reliability of oil and gas detection, thedetermination the anomaly in relative position of oil and gas as well as the highresistivity anomaly depth. The sensor at the core of the received signal in theequipment device, it is good or bad will directly affect the result of submarine oil gasanalysis, finally affect the success or failure of the whole detection work. So how tochoose and create can satisfy the demand of sensor is particularly important.This paper mainly does research on CSEM method for sink type. It has this kindof advantage: receiving device can be placed on the seabed surface, emission source islocated on board within a distance of30to50m. In this way the electromagneticsignal performs strong penetrating ability, achieving high resolution of probe target inshallow stratum. The main research contents of this paper are as follows:1. Analysis the principle，classification，exploration equipment of MCSEM.2. Analysis and Research on the hardware design of MCSEM.The work focus onthe material’s selection of cabin equipment, safety pressure, the rationality of thestructure, the sinking and retrieving process of the receiving system.3. Research on the information acquisition technology of submarine electric field.Analysis on the working principle of electric field measurement under sea, as well ason the selection of electrode materials and basic manufacturing process to do analysisand research, end up with putting forward the structure design scheme.4. Research on the information acquisition technology of submarine magneticfield. In light of the principle of the magnetic field measurement, this paperinvolved the weak magnetic detection technology, the research of magnetic sensor, thedesign of oscillation circuit structure consists of coils, complete the relevantparameter formulas, do research on coil design and magnetic core design. In the research and design of magnetic sensor, this paper has also carried on thedetailed analysis. Firstly, overview the work principle, do the calculation and analysisof influencing factors on the three electrical parameters of coil circuit，giving designstandard of the relevant parameters and optimization analysis of the effectivepermeability of magnetic cores. Then finish the optimization design of magnetic coreand coils. At last, the study concluded that the core of submarine magnetic sensorworks in the best condition when the aspect ratio should be selected m=20~60and thewinding magnetic ratio should be selected A=0.4~0.7.