Experimental study on the long-term conductivity of self-support fracture in deep shale reservoirs
Abstract Reservoir modification fracturing technology is one of the key technologies for the effective development of deep shale gas reservoirs. But the low initial production and fast decreasing after fracturing deep shale gas wells restrict the efficient development of deep shale gas. Many stratif...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2025-05-01
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| Series: | Journal of Petroleum Exploration and Production Technology |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s13202-025-01981-1 |
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| Summary: | Abstract Reservoir modification fracturing technology is one of the key technologies for the effective development of deep shale gas reservoirs. But the low initial production and fast decreasing after fracturing deep shale gas wells restrict the efficient development of deep shale gas. Many stratification fracture surfaces and tensile fracture surfaces were prepared by using a high-precision 3D morphological scanner and carving machine. How the flat fracture surfaces’ long-term hydraulic conductivity was affected by temperature and closure pressure was investigated. Additionally, the influence of closure stress and fracture surface type on the long-term hydraulic conductivity of self-supported fracture surfaces was examined by using a self-developed high-temperature and high-pressure fracture conductivity tester. The patterns of change and main control factors of the long-term hydraulic conductivity of fractures in deep shale reservoirs are aimed to be clarified. The results of the study show that the long-term flow infiltration capacity of self-supported fracture surface was affected by the closure stress and temperature. In experiments examining the impact of closure stress on the long-term infiltration capacity of flat plate cracks, there remains a pattern in the infiltration capacity. Initially, the crack infiltration capacity decreases relatively quickly before 20 h. This rapid decrease slows down as time progresses from 20 to 50 h. Beyond 50 h, the infiltration capacity of the cracks essentially stabilizes. When comparing the results under the same proppant conditions, it’s clear that a higher closure stress leads to a more rapid decrease in crack infiltration capacity. Furthermore, the final stable infiltration capacity of cracks in the experimental group subjected to large closure stress is notably smaller compared to that of the group with small closure stress. This indicates that closure stress plays a significant role in determining the long-term infiltration performance of flat plate fractures. In the experiments of supported cracks and self-supported cracks, the higher the temperature, the smaller the inflow capacity, and the decrease is gradually reduced; the conductivity of self-supported cracks decreases rapidly, and at 20 h, the inflow capacity decreases to about 1% of the initial value. Under the same conditions, the infiltration capacity of stratification fracture surface is higher than that of tensioned crack surface. The results of this paper can provide certain reference significance for the design and construction of oilfield site fracturing, and then provide certain contribution to the improvement of oil and gas recovery. |
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| ISSN: | 2190-0558 2190-0566 |