Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective
Multi-stage hydraulic fracturing combined with horizontal drilling has been widely implemented to enhance oil/gas production from shale reservoirs. One method of reservoir stimulation is to use low-salinity fracturing fluid that mixes with existing high-salinity formation brine. This process either...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Language: | English |
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ELSEVIER SCI LTD
2022
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| Online Access: | http://hdl.handle.net/20.500.11937/89528 |
| _version_ | 1848765236555808768 |
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| author | Zeng, Lingping Akhondzadeh, H. Iqbal, Muhammad Atif Keshavarz, A. Rezaee, Reza Xie, Sam |
| author_facet | Zeng, Lingping Akhondzadeh, H. Iqbal, Muhammad Atif Keshavarz, A. Rezaee, Reza Xie, Sam |
| author_sort | Zeng, Lingping |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Multi-stage hydraulic fracturing combined with horizontal drilling has been widely implemented to enhance oil/gas production from shale reservoirs. One method of reservoir stimulation is to use low-salinity fracturing fluid that mixes with existing high-salinity formation brine. This process either activates existing natural fractures or generates new fractures thus enhances reservoir communication. However, it is still unclear how the in-situ geochemistry change would affect shale surface energy and fracture/micro-fracture propagation, and far less research has investigated the effect of salinity on shale micromechanics. This impedes the proper evaluation of hydraulic fracturing influence on the stability of shale reservoirs with different mineralogy. In this study, the strength of shale samples with different composition at different saturation conditions were measured using nano-indentation techniques together with atomic force microscopy (AFM) and scanning electron microscopy (SEM). In addition, geochemical modelling with the combination of surface complexation and disjoining pressure isotherm were performed to examine the role of physicochemical reactions on shale micromechanical properties. Nano-indentation tests confirm that brine saturation can decrease samples’ indentation moduli regardless of mineralogy. We also found that decreasing salinity would further decrease indentation modulus of calcite-, quartz- and illite-rich shale samples by 43.8%, 19.2%, and 33.3%, suggesting that rock micromechanics are indeed affected by the geochemistry. Compared to dry condition, calcite- and quartz-rich shales have greater indentation moduli reduction after low salinity brine saturation (64.3% and 45.4%) than the illite-rich sample (32.2%), indicating that fluid-rock interactions associated with shale micromechanics are also influenced by mineralogy. Thermodynamics calculation shows that the shift of the disjoining pressure isotherm from strongly negative to positive likely plays an important role in shale weakening rather the mineral dissolution before and after water saturation. Taken together, these findings provide a new understanding of surface energy induced micromechanics of shale through geochemical modelling together with thermodynamics. |
| first_indexed | 2025-11-14T11:32:03Z |
| format | Journal Article |
| id | curtin-20.500.11937-89528 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:32:03Z |
| publishDate | 2022 |
| publisher | ELSEVIER SCI LTD |
| recordtype | eprints |
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| spelling | curtin-20.500.11937-895282023-01-18T06:39:38Z Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective Zeng, Lingping Akhondzadeh, H. Iqbal, Muhammad Atif Keshavarz, A. Rezaee, Reza Xie, Sam Science & Technology Technology Energy & Fuels Engineering, Chemical Engineering HYDRAULIC-FRACTURING-FLUID LOW-CLAY SHALE MECHANICAL-PROPERTIES PYRITE OXIDATION SURFACE-CHARGE PORE STRUCTURE WATER GAS SALINITY IMPACT Multi-stage hydraulic fracturing combined with horizontal drilling has been widely implemented to enhance oil/gas production from shale reservoirs. One method of reservoir stimulation is to use low-salinity fracturing fluid that mixes with existing high-salinity formation brine. This process either activates existing natural fractures or generates new fractures thus enhances reservoir communication. However, it is still unclear how the in-situ geochemistry change would affect shale surface energy and fracture/micro-fracture propagation, and far less research has investigated the effect of salinity on shale micromechanics. This impedes the proper evaluation of hydraulic fracturing influence on the stability of shale reservoirs with different mineralogy. In this study, the strength of shale samples with different composition at different saturation conditions were measured using nano-indentation techniques together with atomic force microscopy (AFM) and scanning electron microscopy (SEM). In addition, geochemical modelling with the combination of surface complexation and disjoining pressure isotherm were performed to examine the role of physicochemical reactions on shale micromechanical properties. Nano-indentation tests confirm that brine saturation can decrease samples’ indentation moduli regardless of mineralogy. We also found that decreasing salinity would further decrease indentation modulus of calcite-, quartz- and illite-rich shale samples by 43.8%, 19.2%, and 33.3%, suggesting that rock micromechanics are indeed affected by the geochemistry. Compared to dry condition, calcite- and quartz-rich shales have greater indentation moduli reduction after low salinity brine saturation (64.3% and 45.4%) than the illite-rich sample (32.2%), indicating that fluid-rock interactions associated with shale micromechanics are also influenced by mineralogy. Thermodynamics calculation shows that the shift of the disjoining pressure isotherm from strongly negative to positive likely plays an important role in shale weakening rather the mineral dissolution before and after water saturation. Taken together, these findings provide a new understanding of surface energy induced micromechanics of shale through geochemical modelling together with thermodynamics. 2022 Journal Article http://hdl.handle.net/20.500.11937/89528 10.1016/j.jngse.2022.104545 English ELSEVIER SCI LTD restricted |
| spellingShingle | Science & Technology Technology Energy & Fuels Engineering, Chemical Engineering HYDRAULIC-FRACTURING-FLUID LOW-CLAY SHALE MECHANICAL-PROPERTIES PYRITE OXIDATION SURFACE-CHARGE PORE STRUCTURE WATER GAS SALINITY IMPACT Zeng, Lingping Akhondzadeh, H. Iqbal, Muhammad Atif Keshavarz, A. Rezaee, Reza Xie, Sam Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective |
| title | Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective |
| title_full | Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective |
| title_fullStr | Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective |
| title_full_unstemmed | Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective |
| title_short | Effect of fluid-shale interactions on shales micromechanics: Nanoindentation experiments and interpretation from geochemical perspective |
| title_sort | effect of fluid-shale interactions on shales micromechanics: nanoindentation experiments and interpretation from geochemical perspective |
| topic | Science & Technology Technology Energy & Fuels Engineering, Chemical Engineering HYDRAULIC-FRACTURING-FLUID LOW-CLAY SHALE MECHANICAL-PROPERTIES PYRITE OXIDATION SURFACE-CHARGE PORE STRUCTURE WATER GAS SALINITY IMPACT |
| url | http://hdl.handle.net/20.500.11937/89528 |