Shale pore structure detection method based on nuclear magnetic resonance

Abstract

The invention provides a shale pore structure detection method based on nuclear magnetic resonance. The method comprises the steps that a sample is processed into a cylinder; the sample is saturated with water at normal pressure for 12h, and then is taken out; CPMG pulse sequence test is carried out on the sample to acquire a spin-echo-series attenuation signal; the spin-echo-series signal is inversed to acquire a T2 spectrum distribution diagram and the details of each peak; and the T2 spectrum of acquired same sample under water saturation and centrifugation is analyzed in a coordinate system to acquire the change of the volume and quantity of pores of the sample. The shale pore structure is mainly studied in a saturated water state in the prior art of nuclear magnetic resonance, and the problems that the study angle is single and limited; only pore distribution can be studied; and fracture prediction cannot be carried out are solved. The method provided by the invention belongs to the technical field of petroleum exploration and development.

Description

technical field [0001] The invention relates to reservoir prediction technology, in particular to a nuclear magnetic resonance detection method of shale pore structure, and belongs to the field of petroleum exploration and development. Background technique [0002] Shale is a weak rock with low porosity and ultra-low permeability, and there are few primary pores in the rock. Therefore, the original rock provides less reservoir space for shale gas, and the migration channel of shale gas is not smooth. However, in recent years, studies have found a large amount of shale gas in some shale rocks in Guizhou, indicating that there are a large number of secondary fractures in these shale layers. Therefore, microscopic pores in shale reservoirs not only provide space for the occurrence of shale gas, but also serve as channels for shale gas migration. The shale pore structure not only affects the occurrence state of gas in the pores, but also greatly affects the interaction between ...

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Problems solved by technology

[0004] The purpose of the present invention is to: provide a kind of shale pore structure detection method based on nuclear magnetic resonance, in order to solve the problem that the current nuclear magnetic resonance mainly studies the shale pore structure from the saturated state, the research angle is single, has certain limitations, and only Pore ​​distribution can be studied, but fracture prediction cannot be realized

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