Method for nondestructive testing of source rock water content based on magnetic resonance imaging

Abstract

The invention provides a method for nondestructive testing of source rock water content based on magnetic resonance imaging, which includes steps of a, sequence selection: using a magnetic resonance imaging analyzer, and applying an S-MGE sequence to selectively collect a signal of proton in hydrone in a source rock sample, wherein the collecting process of the S-MGE sequence includes steps of applying multiple impulses at 90 degrees to magnetic resonance imaging signals of all hydrogen cores of a saturated source rock sample to form an exciting echo during the recovery process of the magneticresonance imaging signals of the hydrogen core, so as to acquire magnetic resonance imaging relaxing information of the hydrogen core in a water molecule in the source rock sample; finally, acquiringthe magnetic resonance imaging signal intensity of the hydrogen core in the water molecule in the source rock sample; b, building a standard curve; c, testing water content in the to-be-tested sampleof the source rock; d, calculating the water content of the to-be-tested sample of the source rock.

Description

technical field [0001] The invention relates to a method for non-destructive detection of water content of source rocks based on nuclear magnetic resonance, and belongs to the technical field of petroleum geological exploration. Background technique [0002] The water content in source rocks is one of the important indicators for studying hydrocarbon generation of source rocks, but source rocks generally have a denser pore structure, less water content and higher organic matter content. At present, the methods commonly used to measure the water content of rocks mainly include NMR method and drying method. Among them, the traditional nuclear magnetic resonance method (CPMG) is obviously affected by organic matter (kerogen). Using combined pulses, through a suitable phase cycle, the hydrocarbon signal in shale can be directly tested, and the oil-water signal cannot be distinguished, and the water content of the test is biased. big. However, the drying method takes a long tim...

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Problems solved by technology

Among them, the traditional nuclear magnetic resonance method (CPMG) is obviously affected by organic matter (kerogen). Using combined pulses, through a suitable phase cycle, the hydrocarbon signal in shale can be directly tested, and the oil-water signal cannot be distinguished, and the water content of the test is biased. Big

However, the drying method takes a long time to test, and if the temperature is too high, it will easily cause the organic components to volatilize. If the temperature is too low, the water will not evaporate completely, and the water content in the source rock is small. A small deviation may cause a large error, which cannot meet the test requirements. Accuracy requirements

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