A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance
The porous and low-permeability characteristics of a shale gas reservoir determine its high gas storage efficiency, which is manifested in the extremely high breakthrough pressure of shale. Therefore, the accurate calculation of breakthrough pressure is of great significance to the study of shale ga...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/15/19/7223 |
| _version_ | 1827654584621858816 |
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| author | Juanjuan Xiao Yufeng Xiao Xinmin Ge Tianqi Zhou |
| author_facet | Juanjuan Xiao Yufeng Xiao Xinmin Ge Tianqi Zhou |
| author_sort | Juanjuan Xiao |
| collection | DOAJ |
| description | The porous and low-permeability characteristics of a shale gas reservoir determine its high gas storage efficiency, which is manifested in the extremely high breakthrough pressure of shale. Therefore, the accurate calculation of breakthrough pressure is of great significance to the study of shale gas preservation conditions. Based on a systematic analysis of a low-field NMR experiment on marine shales of the Longmaxi Formation in the Sichuan Basin, a shale gas breakthrough pressure determination technique different from conventional methods is proposed. The conventional methods have low calculation accuracy and are a tedious and time-consuming process, while low-field NMR technique is less time-consuming and of high accuracy. Firstly, the NMR T<sub>2</sub> spectrum of shale core sample in different states is measured through low-field NMR experiment. The NMR T<sub>2</sub> spectra of sample in water-saturated state and dry state are combined to model the mathematical relationship between shale gas breakthrough pressure and NMR T<sub>2</sub> spectrum. It is found that the gas breakthrough pressure is power-exponentially related to the geometric mean of NMR T<sub>2</sub> spectrum and positively related to the proportion of micropores. Accordingly, the shale gas breakthrough pressure is quickly and accurately calculated using continuous NMR logging data and then the sealing capacity of the shale caprocks is evaluated, providing basic parameters for analyzing unconventional hydrocarbon accumulation, preservation and migration. This technique has been successfully applied with actual data to evaluate the sealing capacity of shale caprock in a shale gas well in the Sichuan Basin. It can provide a good basis for the evaluation and characterization of shale oil and gas reservoirs. |
| first_indexed | 2024-03-09T21:46:47Z |
| format | Article |
| id | doaj.art-85c20042a5b3406abfa20f8d85d785de |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-09T21:46:47Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-85c20042a5b3406abfa20f8d85d785de2023-11-23T20:15:13ZengMDPI AGEnergies1996-10732022-10-011519722310.3390/en15197223A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic ResonanceJuanjuan Xiao0Yufeng Xiao1Xinmin Ge2Tianqi Zhou3PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, ChinaPetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, ChinaSchool of Geosciences, China University of Petroleum, Qingdao 266580, ChinaPetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, ChinaThe porous and low-permeability characteristics of a shale gas reservoir determine its high gas storage efficiency, which is manifested in the extremely high breakthrough pressure of shale. Therefore, the accurate calculation of breakthrough pressure is of great significance to the study of shale gas preservation conditions. Based on a systematic analysis of a low-field NMR experiment on marine shales of the Longmaxi Formation in the Sichuan Basin, a shale gas breakthrough pressure determination technique different from conventional methods is proposed. The conventional methods have low calculation accuracy and are a tedious and time-consuming process, while low-field NMR technique is less time-consuming and of high accuracy. Firstly, the NMR T<sub>2</sub> spectrum of shale core sample in different states is measured through low-field NMR experiment. The NMR T<sub>2</sub> spectra of sample in water-saturated state and dry state are combined to model the mathematical relationship between shale gas breakthrough pressure and NMR T<sub>2</sub> spectrum. It is found that the gas breakthrough pressure is power-exponentially related to the geometric mean of NMR T<sub>2</sub> spectrum and positively related to the proportion of micropores. Accordingly, the shale gas breakthrough pressure is quickly and accurately calculated using continuous NMR logging data and then the sealing capacity of the shale caprocks is evaluated, providing basic parameters for analyzing unconventional hydrocarbon accumulation, preservation and migration. This technique has been successfully applied with actual data to evaluate the sealing capacity of shale caprock in a shale gas well in the Sichuan Basin. It can provide a good basis for the evaluation and characterization of shale oil and gas reservoirs.https://www.mdpi.com/1996-1073/15/19/7223gas breakthrough pressurelow-field NMRshale caprockunconventional reservoirsealing capacity |
| spellingShingle | Juanjuan Xiao Yufeng Xiao Xinmin Ge Tianqi Zhou A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance Energies gas breakthrough pressure low-field NMR shale caprock unconventional reservoir sealing capacity |
| title | A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance |
| title_full | A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance |
| title_fullStr | A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance |
| title_full_unstemmed | A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance |
| title_short | A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance |
| title_sort | technique to determine the breakthrough pressure of shale gas reservoir by low field nuclear magnetic resonance |
| topic | gas breakthrough pressure low-field NMR shale caprock unconventional reservoir sealing capacity |
| url | https://www.mdpi.com/1996-1073/15/19/7223 |
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