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Woojin Lee - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Cementation of Jeju coastal sediments using in situ tests
Bulletin of Engineering Geology and the Environment, 2012Co-Authors: Moon-joo Lee, Sung-jin Hong, Raehyun Kim, Young-ho Chae, Woojin LeeAbstract:A series of SPT, CPT and SPS tests were performed for Jeju coastal sediments in order to investigate the possibility of detecting the Cementation of granular sediments by in situ tests. Plotting the in situ test results into the G_max/q_c–q_c1 and (G_max/p_a)/N_60–(N_1)_60 relations suggested by Schnaid et al. (Proceedings of 1st international conference on site characterization, Balkema Pub, Rotterdam 2004 ) indicates that the Jeju calcareous sediments are cemented. It is also observed that the q_c/N ratio of Jeju sediments is much higher than the (q_c/p_a)/N_60–D_50 relation suggested by Kulhawy and Mayne (Manual on estimating soil properties for foundation design, EPRI, Ithaca 1990 ). It is suggested a relative density >100 % obtained using the q_c–D_R–σ_v′ relation suggested for uncemented sands indicates Cementation of the in situ sediments. The G_max/q_c value of Jeju sediments was found to be 2–6 times larger than that of uncemented sands at the same normalized cone resistance. It is concluded that in situ penetration resistances are relatively insensitive to the Cementation of granular soil while the deformation moduli are significantly affected by the Cementation, and that the relative density and G_max of cemented sediments can be seriously misjudged unless the effect of Cementation on in situ penetration test results is considered. Une série de tests de pénétration SPT, CPT et SPS a été réalisée sur les sédiments côtiers calcaires de Jeju afin d’étudier la possibilité de détecter la cimentation de sédiments granulaires à partir d’essais in situ. Plaçant les résultats des essais dans un diagramme reliant G_max/q_c–q_c1 et (G_max/p_a)/N_60–(N_1)_60 proposé par Schnaid et al. (Proceedings of 1st international conference on site characterization, Balkema Pub, Rotterdam 2004 ), il apparaît que les sédiments de Jeju sont cimentés. On observe aussi que le rapport q_c/N des sédiments de Jeju est beaucoup plus fort que (q_c/p_a)/N_60–D_50, relation proposée par Kulhawy et Mayne (Manual on estimating soil properties for foundation design , EPRI, Ithaca 1990 ). Il est proposé qu’une densité relative supérieure à 100 % obtenue en utilisant la relation q_c–D_R–σ_v′ pour des sables non cimentés, rende compte de la cimentation de sédiments en place. Le rapport G_max/q_c des sédiments de Jeju a été trouvé 2 à 6 fois supérieur à celui de sables non cimentés avec la même résistance au cône normalisée. On conclut que les résistances à la pénétration in situ sont relativement insensibles à la cimentation de sols granulaires. Par contre, les modules de déformation sont significativement affectés par la cimentation. De plus, la densité relative et le module G_max de sédiments cimentés peuvent être sérieusement mal appréciés à moins que l’effet de la cimentation sur les résultats des tests de pénétration in situ ne soit considéré.
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Effect of artificial Cementation on cone tip resistance and small strain shear modulus of sand
Bulletin of Engineering Geology and the Environment, 2011Co-Authors: Moon-joo Lee, Hyunwook Choo, Jaejeong Kim, Woojin LeeAbstract:A series of cone penetration and bender element tests were performed on sands artificially cemented with gypsum in a calibration chamber to investigate the effect of Cementation on the cone tip resistance ( q _c) and small strain shear modulus ( G _max) of sand. It was found that both the q _c and G _max of cemented sand are significantly affected by the degree of Cementation while the effects of stress and density are reduced due to the Cementation bonds. As the degree of Cementation increases, the relationship between the $$ q_{{\text{c}}} {-}D_{{\text{R}}} {-}\sigma _{{\text{v}}}^{\prime } $$ of cemented sand is observed to be similar to that of quartz sand with low compressibility. As the density and stress level affect q _c more significantly than G _max, the G _max/ q _c of cemented sand decreases with increasing q _c. However, as the Cementation causes a larger increase in G _max than q _c, the G _max/ q _c ratio of cemented sand increases as the gypsum content increases. It was also observed from the $$ G_{{\max }} /q_{{\text{c}}} - (q_{{\text{c}}} /p_{{\text{a}}} )(p_{{\text{a}}} /\sigma _{{\text{v}}}^{\prime } )^{{0.5}} $$ relation that the G _max/ q _c ratio of cemented sand locates above the upper bound suggested by previous studies. Une série de tests de pénétration au cône et de flexion a été réalisée dans une chambre de calibration sur des sables artificiellement cimentés par du gypse afin d’étudier les effets de la cimentation sur la résistance de pointe ( q _c) et le module de cisaillement en faibles déformations ( G _max). Il a été trouvé que les deux paramètres q _c et G _max sont significativement affectés par le degré de cimentation tandis que les effets de contrainte et de densité sont réduits du fait des liens de cimentation. Alors que le degré de cimentation augmente, la relation entre $$ q_{{\text{c}}} {-}D_{{\text{R}}} {-}\sigma _{{\text{v}}}^{\prime } $$ de sables cimentés apparaît semblable à celle de sables quartzeux de faible compressibilité. Alors que la densité et le niveau de contrainte affectent q _c plus significativement que G _max, le rapport G _max/ q _c de sables cimentés décroît avec l’augmentation de q _c. Cependant, alors que la cimentation entraîne une plus forte augmentation de G _max que de q _c, le rapport G _max/ q _c de sables cimentés augmente avec l’augmentation de la teneur en gypse. Il a été aussi observé à partir de la relation $$ G_{{\max }} /q_{{\text{c}}} - (q_{{\text{c}}} /p_{{\text{a}}} )(p_{{\text{a}}} /\sigma _{{\text{v}}}^{\prime } )^{{0.5}} $$ que le rapport G _max/ q _c de sables cimentés est supérieur à une limite suggérée par de précédentes études.
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effect of artificial Cementation on cone tip resistance and small strain shear modulus of sand
Bulletin of Engineering Geology and the Environment, 2011Co-Authors: Moon-joo Lee, Hyunwook Choo, Jaejeong Kim, Woojin LeeAbstract:A series of cone penetration and bender element tests were performed on sands artificially cemented with gypsum in a calibration chamber to investigate the effect of Cementation on the cone tip resistance (q c) and small strain shear modulus (G max) of sand. It was found that both the q c and G max of cemented sand are significantly affected by the degree of Cementation while the effects of stress and density are reduced due to the Cementation bonds. As the degree of Cementation increases, the relationship between the $$ q_{{\text{c}}} {-}D_{{\text{R}}} {-}\sigma _{{\text{v}}}^{\prime } $$ of cemented sand is observed to be similar to that of quartz sand with low compressibility. As the density and stress level affect q c more significantly than G max, the G max/q c of cemented sand decreases with increasing q c. However, as the Cementation causes a larger increase in G max than q c, the G max/q c ratio of cemented sand increases as the gypsum content increases. It was also observed from the $$ G_{{\max }} /q_{{\text{c}}} - (q_{{\text{c}}} /p_{{\text{a}}} )(p_{{\text{a}}} /\sigma _{{\text{v}}}^{\prime } )^{{0.5}} $$ relation that the G max/q c ratio of cemented sand locates above the upper bound suggested by previous studies.
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Shear Strength of Artificially Cemented Sands
Marine Georesources & Geotechnology, 2009Co-Authors: Moon-joo Lee, Sung-kun Choi, Woojin LeeAbstract:In this study, a series of drained triaxial tests were performed in order to examine the effect of Cementation on the shear behavior of granular soil. It was observed that the brittle nature and dilative tendency of granular soil is dominant under a low confining stress level, while high confining stress results in a contractive behavior despite the strong Cementation bond. Based on experimental results, an idealized concept is suggested to define the shear strength of cemented sand in three distinctive zones: the Cementation control zone with a constant cohesion intercept at a low confining stress level, the transition zone in which the cohesion intercept is gradually reduced after a breaking point, and the stress control zone with almost zero cohesion intercept due to breakage of Cementation bonds at a high confining stress level. It was shown that the sitting pressures during Cementation have little effect on the strength parameters of cemented sand, while the increase of gypsum content and relative de...
Helge Hellevang - One of the best experts on this subject based on the ideXlab platform.
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diagenesis and reservoir quality of the lower cretaceous quantou formation tight sandstones in the southern songliao basin china
Sedimentary Geology, 2015Co-Authors: Yingchang Cao, Jens Jahren, Rukai Zhu, Knut Bjorlykke, Beyene Girma Haile, Lijing Zheng, Helge HellevangAbstract:Abstract The Lower Cretaceous Quantou Formation in the southern Songliao Basin is the typical tight oil sandstone in China. For effective exploration, appraisal and production from such a tight oil sandstone, the diagenesis and reservoir quality must be thoroughly studied first. The tight oil sandstone has been examined by a variety of methods, including core and thin section observation, XRD, SEM, CL, fluorescence, electron probing analysis, fluid inclusion and isotope testing and quantitative determination of reservoir properties. The sandstones are mostly lithic arkoses and feldspathic litharenites with fine to medium grain size and moderate to good sorting. The sandstones are dominated by feldspar, quartz, and volcanic rock fragments showing various stages of disintegration. The reservoir properties are quite poor, with low porosity (average 8.54%) and permeability (average 0.493 mD), small pore-throat radius (average 0.206 μm) and high displacement pressure (mostly higher than 1 MPa). The tight sandstone reservoirs have undergone significant diagenetic alterations such as compaction, feldspar dissolution, quartz Cementation, carbonate Cementation (mainly ferrocalcite and ankerite) and clay mineral alteration. As to the onset time, the oil emplacement was prior to the carbonate Cementation but posterior to the quartz Cementation and feldspar dissolution. The smectite to illite reaction and pressure solution at stylolites provide a most important silica sources for quartz Cementation. Carbonate cements increase towards interbedded mudstones. Mechanical compaction has played a more important role than Cementation in destroying the reservoir quality of the K 1 q 4 sandstone reservoirs. Mixed-layer illite/smectite and illite reduced the porosity and permeability significantly, while chlorite preserved the porosity and permeability since it tends to be oil wet so that later carbonate Cementation can be inhibited to some extent. It is likely that the oil emplacement occurred later than the tight rock formation (with the porosity close to 10%). However, thicker sandstone bodies (more than 2 m) constitute potential hydrocarbon reservoirs.
Moon-joo Lee - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Cementation of Jeju coastal sediments using in situ tests
Bulletin of Engineering Geology and the Environment, 2012Co-Authors: Moon-joo Lee, Sung-jin Hong, Raehyun Kim, Young-ho Chae, Woojin LeeAbstract:A series of SPT, CPT and SPS tests were performed for Jeju coastal sediments in order to investigate the possibility of detecting the Cementation of granular sediments by in situ tests. Plotting the in situ test results into the G_max/q_c–q_c1 and (G_max/p_a)/N_60–(N_1)_60 relations suggested by Schnaid et al. (Proceedings of 1st international conference on site characterization, Balkema Pub, Rotterdam 2004 ) indicates that the Jeju calcareous sediments are cemented. It is also observed that the q_c/N ratio of Jeju sediments is much higher than the (q_c/p_a)/N_60–D_50 relation suggested by Kulhawy and Mayne (Manual on estimating soil properties for foundation design, EPRI, Ithaca 1990 ). It is suggested a relative density >100 % obtained using the q_c–D_R–σ_v′ relation suggested for uncemented sands indicates Cementation of the in situ sediments. The G_max/q_c value of Jeju sediments was found to be 2–6 times larger than that of uncemented sands at the same normalized cone resistance. It is concluded that in situ penetration resistances are relatively insensitive to the Cementation of granular soil while the deformation moduli are significantly affected by the Cementation, and that the relative density and G_max of cemented sediments can be seriously misjudged unless the effect of Cementation on in situ penetration test results is considered. Une série de tests de pénétration SPT, CPT et SPS a été réalisée sur les sédiments côtiers calcaires de Jeju afin d’étudier la possibilité de détecter la cimentation de sédiments granulaires à partir d’essais in situ. Plaçant les résultats des essais dans un diagramme reliant G_max/q_c–q_c1 et (G_max/p_a)/N_60–(N_1)_60 proposé par Schnaid et al. (Proceedings of 1st international conference on site characterization, Balkema Pub, Rotterdam 2004 ), il apparaît que les sédiments de Jeju sont cimentés. On observe aussi que le rapport q_c/N des sédiments de Jeju est beaucoup plus fort que (q_c/p_a)/N_60–D_50, relation proposée par Kulhawy et Mayne (Manual on estimating soil properties for foundation design , EPRI, Ithaca 1990 ). Il est proposé qu’une densité relative supérieure à 100 % obtenue en utilisant la relation q_c–D_R–σ_v′ pour des sables non cimentés, rende compte de la cimentation de sédiments en place. Le rapport G_max/q_c des sédiments de Jeju a été trouvé 2 à 6 fois supérieur à celui de sables non cimentés avec la même résistance au cône normalisée. On conclut que les résistances à la pénétration in situ sont relativement insensibles à la cimentation de sols granulaires. Par contre, les modules de déformation sont significativement affectés par la cimentation. De plus, la densité relative et le module G_max de sédiments cimentés peuvent être sérieusement mal appréciés à moins que l’effet de la cimentation sur les résultats des tests de pénétration in situ ne soit considéré.
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Effect of artificial Cementation on cone tip resistance and small strain shear modulus of sand
Bulletin of Engineering Geology and the Environment, 2011Co-Authors: Moon-joo Lee, Hyunwook Choo, Jaejeong Kim, Woojin LeeAbstract:A series of cone penetration and bender element tests were performed on sands artificially cemented with gypsum in a calibration chamber to investigate the effect of Cementation on the cone tip resistance ( q _c) and small strain shear modulus ( G _max) of sand. It was found that both the q _c and G _max of cemented sand are significantly affected by the degree of Cementation while the effects of stress and density are reduced due to the Cementation bonds. As the degree of Cementation increases, the relationship between the $$ q_{{\text{c}}} {-}D_{{\text{R}}} {-}\sigma _{{\text{v}}}^{\prime } $$ of cemented sand is observed to be similar to that of quartz sand with low compressibility. As the density and stress level affect q _c more significantly than G _max, the G _max/ q _c of cemented sand decreases with increasing q _c. However, as the Cementation causes a larger increase in G _max than q _c, the G _max/ q _c ratio of cemented sand increases as the gypsum content increases. It was also observed from the $$ G_{{\max }} /q_{{\text{c}}} - (q_{{\text{c}}} /p_{{\text{a}}} )(p_{{\text{a}}} /\sigma _{{\text{v}}}^{\prime } )^{{0.5}} $$ relation that the G _max/ q _c ratio of cemented sand locates above the upper bound suggested by previous studies. Une série de tests de pénétration au cône et de flexion a été réalisée dans une chambre de calibration sur des sables artificiellement cimentés par du gypse afin d’étudier les effets de la cimentation sur la résistance de pointe ( q _c) et le module de cisaillement en faibles déformations ( G _max). Il a été trouvé que les deux paramètres q _c et G _max sont significativement affectés par le degré de cimentation tandis que les effets de contrainte et de densité sont réduits du fait des liens de cimentation. Alors que le degré de cimentation augmente, la relation entre $$ q_{{\text{c}}} {-}D_{{\text{R}}} {-}\sigma _{{\text{v}}}^{\prime } $$ de sables cimentés apparaît semblable à celle de sables quartzeux de faible compressibilité. Alors que la densité et le niveau de contrainte affectent q _c plus significativement que G _max, le rapport G _max/ q _c de sables cimentés décroît avec l’augmentation de q _c. Cependant, alors que la cimentation entraîne une plus forte augmentation de G _max que de q _c, le rapport G _max/ q _c de sables cimentés augmente avec l’augmentation de la teneur en gypse. Il a été aussi observé à partir de la relation $$ G_{{\max }} /q_{{\text{c}}} - (q_{{\text{c}}} /p_{{\text{a}}} )(p_{{\text{a}}} /\sigma _{{\text{v}}}^{\prime } )^{{0.5}} $$ que le rapport G _max/ q _c de sables cimentés est supérieur à une limite suggérée par de précédentes études.
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effect of artificial Cementation on cone tip resistance and small strain shear modulus of sand
Bulletin of Engineering Geology and the Environment, 2011Co-Authors: Moon-joo Lee, Hyunwook Choo, Jaejeong Kim, Woojin LeeAbstract:A series of cone penetration and bender element tests were performed on sands artificially cemented with gypsum in a calibration chamber to investigate the effect of Cementation on the cone tip resistance (q c) and small strain shear modulus (G max) of sand. It was found that both the q c and G max of cemented sand are significantly affected by the degree of Cementation while the effects of stress and density are reduced due to the Cementation bonds. As the degree of Cementation increases, the relationship between the $$ q_{{\text{c}}} {-}D_{{\text{R}}} {-}\sigma _{{\text{v}}}^{\prime } $$ of cemented sand is observed to be similar to that of quartz sand with low compressibility. As the density and stress level affect q c more significantly than G max, the G max/q c of cemented sand decreases with increasing q c. However, as the Cementation causes a larger increase in G max than q c, the G max/q c ratio of cemented sand increases as the gypsum content increases. It was also observed from the $$ G_{{\max }} /q_{{\text{c}}} - (q_{{\text{c}}} /p_{{\text{a}}} )(p_{{\text{a}}} /\sigma _{{\text{v}}}^{\prime } )^{{0.5}} $$ relation that the G max/q c ratio of cemented sand locates above the upper bound suggested by previous studies.
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Shear Strength of Artificially Cemented Sands
Marine Georesources & Geotechnology, 2009Co-Authors: Moon-joo Lee, Sung-kun Choi, Woojin LeeAbstract:In this study, a series of drained triaxial tests were performed in order to examine the effect of Cementation on the shear behavior of granular soil. It was observed that the brittle nature and dilative tendency of granular soil is dominant under a low confining stress level, while high confining stress results in a contractive behavior despite the strong Cementation bond. Based on experimental results, an idealized concept is suggested to define the shear strength of cemented sand in three distinctive zones: the Cementation control zone with a constant cohesion intercept at a low confining stress level, the transition zone in which the cohesion intercept is gradually reduced after a breaking point, and the stress control zone with almost zero cohesion intercept due to breakage of Cementation bonds at a high confining stress level. It was shown that the sitting pressures during Cementation have little effect on the strength parameters of cemented sand, while the increase of gypsum content and relative de...
Yingchang Cao - One of the best experts on this subject based on the ideXlab platform.
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diagenesis and reservoir quality of the lower cretaceous quantou formation tight sandstones in the southern songliao basin china
Sedimentary Geology, 2015Co-Authors: Yingchang Cao, Jens Jahren, Rukai Zhu, Knut Bjorlykke, Beyene Girma Haile, Lijing Zheng, Helge HellevangAbstract:Abstract The Lower Cretaceous Quantou Formation in the southern Songliao Basin is the typical tight oil sandstone in China. For effective exploration, appraisal and production from such a tight oil sandstone, the diagenesis and reservoir quality must be thoroughly studied first. The tight oil sandstone has been examined by a variety of methods, including core and thin section observation, XRD, SEM, CL, fluorescence, electron probing analysis, fluid inclusion and isotope testing and quantitative determination of reservoir properties. The sandstones are mostly lithic arkoses and feldspathic litharenites with fine to medium grain size and moderate to good sorting. The sandstones are dominated by feldspar, quartz, and volcanic rock fragments showing various stages of disintegration. The reservoir properties are quite poor, with low porosity (average 8.54%) and permeability (average 0.493 mD), small pore-throat radius (average 0.206 μm) and high displacement pressure (mostly higher than 1 MPa). The tight sandstone reservoirs have undergone significant diagenetic alterations such as compaction, feldspar dissolution, quartz Cementation, carbonate Cementation (mainly ferrocalcite and ankerite) and clay mineral alteration. As to the onset time, the oil emplacement was prior to the carbonate Cementation but posterior to the quartz Cementation and feldspar dissolution. The smectite to illite reaction and pressure solution at stylolites provide a most important silica sources for quartz Cementation. Carbonate cements increase towards interbedded mudstones. Mechanical compaction has played a more important role than Cementation in destroying the reservoir quality of the K 1 q 4 sandstone reservoirs. Mixed-layer illite/smectite and illite reduced the porosity and permeability significantly, while chlorite preserved the porosity and permeability since it tends to be oil wet so that later carbonate Cementation can be inhibited to some extent. It is likely that the oil emplacement occurred later than the tight rock formation (with the porosity close to 10%). However, thicker sandstone bodies (more than 2 m) constitute potential hydrocarbon reservoirs.
Lijing Zheng - One of the best experts on this subject based on the ideXlab platform.
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diagenesis and reservoir quality of the lower cretaceous quantou formation tight sandstones in the southern songliao basin china
Sedimentary Geology, 2015Co-Authors: Yingchang Cao, Jens Jahren, Rukai Zhu, Knut Bjorlykke, Beyene Girma Haile, Lijing Zheng, Helge HellevangAbstract:Abstract The Lower Cretaceous Quantou Formation in the southern Songliao Basin is the typical tight oil sandstone in China. For effective exploration, appraisal and production from such a tight oil sandstone, the diagenesis and reservoir quality must be thoroughly studied first. The tight oil sandstone has been examined by a variety of methods, including core and thin section observation, XRD, SEM, CL, fluorescence, electron probing analysis, fluid inclusion and isotope testing and quantitative determination of reservoir properties. The sandstones are mostly lithic arkoses and feldspathic litharenites with fine to medium grain size and moderate to good sorting. The sandstones are dominated by feldspar, quartz, and volcanic rock fragments showing various stages of disintegration. The reservoir properties are quite poor, with low porosity (average 8.54%) and permeability (average 0.493 mD), small pore-throat radius (average 0.206 μm) and high displacement pressure (mostly higher than 1 MPa). The tight sandstone reservoirs have undergone significant diagenetic alterations such as compaction, feldspar dissolution, quartz Cementation, carbonate Cementation (mainly ferrocalcite and ankerite) and clay mineral alteration. As to the onset time, the oil emplacement was prior to the carbonate Cementation but posterior to the quartz Cementation and feldspar dissolution. The smectite to illite reaction and pressure solution at stylolites provide a most important silica sources for quartz Cementation. Carbonate cements increase towards interbedded mudstones. Mechanical compaction has played a more important role than Cementation in destroying the reservoir quality of the K 1 q 4 sandstone reservoirs. Mixed-layer illite/smectite and illite reduced the porosity and permeability significantly, while chlorite preserved the porosity and permeability since it tends to be oil wet so that later carbonate Cementation can be inhibited to some extent. It is likely that the oil emplacement occurred later than the tight rock formation (with the porosity close to 10%). However, thicker sandstone bodies (more than 2 m) constitute potential hydrocarbon reservoirs.