NMR Logging Environment Analysis and T2 Spectrum Oil Layer Identification Method in Low Permeability Reservoir

Low permeability conglomerate reservoirs are developed in Mahu sag, Junggar basin, and the nuclear magnetic resonance (NMR) T2 spectra of different formations have great differences in the identification results of these reservoir fluids. Based on geological, drilling, logging and oil testing data,...

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Bibliographic Details
Main Authors: CAO Zhifeng, LINGHU Song, MENG Xin, BAI Peng, SUN Zhenglong, ZHANG Kai
Format: Article
Language:zho
Published: Editorial Office of Well Logging Technology 2024-06-01
Series:Cejing jishu
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Online Access:https://www.cnpcwlt.com/#/digest?ArticleID=5602
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Summary:Low permeability conglomerate reservoirs are developed in Mahu sag, Junggar basin, and the nuclear magnetic resonance (NMR) T2 spectra of different formations have great differences in the identification results of these reservoir fluids. Based on geological, drilling, logging and oil testing data, the logging environment, NMR experiments and logging response characteristics of such formations have been studied. The results show that the pore structure of the near-wellbore reservoir is improved by drilling in the study area, and the broken zone, micro-fracture zone and undisturbed strata are developed successively from the near-wellbore to the undisturbed strata. Oil and gas invasion occurs in the negative pressure drilling environment. Oil and gas invasion can be divided into oil and gas enrichment zone (oil ring), oil and gas invasion zone and undisturbed strata in the radial direction, and the response mechanism of NMR logging is clarified. The existence of oil ring is verified by using the modular formation dynamics tester. The NMR T2 spectral volume relaxation spectra of core saturated with water, saturated with oil and saturated with water centrifugation are consistent with the NMR T2 spectral long relaxation time peak of formation crude oil, and the standard of NMR T2 spectra 100 ms is determined to identify oil and water layers. This method has achieved remarkable results in reservoir fluid identification, the results provide a reference for the identification of complex reservoir fluids by NMR T2 spectroscopy.
ISSN:1004-1338