Great efforts had been made to use indirect non-destructive tests in the geotechnical evaluation of rocks, especially sandstones, employing different empirical equations. However, most of these equations have been der...Great efforts had been made to use indirect non-destructive tests in the geotechnical evaluation of rocks, especially sandstones, employing different empirical equations. However, most of these equations have been derived from hard and compacted sandstones data</span><span style="font-family:"">;</span><span style="font-family:"">therefore, the focus of this research is on weak and weakly compacted sandstones, aiming firstly to obtain empirical equations for estimating their characteristics, secondly to demonstrate and visualize the correlations between the studied variables, and finally to cluster <span>the studied samples based on their characteristics. To attain these aims</span></span><span style="font-family:"">,</span><span style="font-family:""> twenty</span><span style="font-family:""> oriented block samples were collected from Nubia sandstone, central Eastern Desert, Golden Triangle area, Egypt. These samples were prepared and tested according to standard test methods, including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), Schmidt rebound number (SRN), porosity (<i><i>n</i></i>), bulk density (<span>ρ</span>), and ultrasonic P-wave velocity (UPV). The loss on ignition (LOI) was also employed as a physicochemical test for classifying the studied samples and indicating pores filling materials. The results revealed that these sandstones are characterized mainly by high <i><i>n</i></i>, low <span>ρ</span>, and low UPV values and these give an indication of weakly compacted and weakly cemented sandstone with shallow burial diagenetic conditions. Based on UCS and elastic modulus values, these sandstones are mainly classified as very low strength and highly yielding rocks. The results of regression analysis show satisfactory correlations between physical and mechanical characteristics, indicating the suitability of obtained empirical equations to deduce these properties. Principal component analysis revealed that the LOI, BTS, SRN, and USC have a positive correlation to each other and weakly correlated with <i><i>ρ</i></i> and UPV, which positively correlated to each other and negatively correlated to <i><i>n</i></i>. The results of agglomerative hierarchical clustering revealed that the studied samples can group into three main clusters depending on their USC, LOI, and <i><i>n</i></i><span> </span>values.展开更多
Steeply dipping prograding fan deltas possess high reservoir quality facies that could be excellent targets while exploring for hydrocarbons.Due to their complex stacking nature,and limited examples,delineating their ...Steeply dipping prograding fan deltas possess high reservoir quality facies that could be excellent targets while exploring for hydrocarbons.Due to their complex stacking nature,and limited examples,delineating their architectural elements is still challenging.In this paper we mainly performed sedimentary facies analysis;applying various disciplines e.g.sequence stratigraphy,seismic stratigraphy,GR-log motifs,and seismic waveform segmentation;so as to adequately depict the reservoir heterogeneity and quality of the Paleozoic Nubia clastics in West Esh El Mallaha Concession(southwest Gulf of Suez rift).Organic maturity prediction,to confirm the hydrocarbon charging from source units to reservoir intervals,was also of most importance in this study.Accordingly,1D basin model was established to define the past geologic events;subsidence,and thermal maturity;and their controls on sedimentary basin evolution and associated petroleum potential.We utilized several key-information scales;e.g.wireline logs,and seismic profiles.Linking different disciplines applied in this study points to a successful integrated reservoir characterization workflow capable of unfolding ancient environments and the associated hydrocarbon potential.The results show that Nubia Formation was built during the lowstandtransgressive phase of a 3rd order depositional sequence.It encompasses fluvio-lacustrine system with eight sedimentary facies associations;form source to sink.Fluvial channels and mouth bars,settled in subaerial and subaqueous settings respectively,represent the most significant reservoir facies in the area.Given best hydrocarbon-reservoir quality,the deltaic mouth bars ought to attract attention of further oilfield development plans and be considered while investigating similar settings.展开更多
文摘Great efforts had been made to use indirect non-destructive tests in the geotechnical evaluation of rocks, especially sandstones, employing different empirical equations. However, most of these equations have been derived from hard and compacted sandstones data</span><span style="font-family:"">;</span><span style="font-family:"">therefore, the focus of this research is on weak and weakly compacted sandstones, aiming firstly to obtain empirical equations for estimating their characteristics, secondly to demonstrate and visualize the correlations between the studied variables, and finally to cluster <span>the studied samples based on their characteristics. To attain these aims</span></span><span style="font-family:"">,</span><span style="font-family:""> twenty</span><span style="font-family:""> oriented block samples were collected from Nubia sandstone, central Eastern Desert, Golden Triangle area, Egypt. These samples were prepared and tested according to standard test methods, including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), Schmidt rebound number (SRN), porosity (<i><i>n</i></i>), bulk density (<span>ρ</span>), and ultrasonic P-wave velocity (UPV). The loss on ignition (LOI) was also employed as a physicochemical test for classifying the studied samples and indicating pores filling materials. The results revealed that these sandstones are characterized mainly by high <i><i>n</i></i>, low <span>ρ</span>, and low UPV values and these give an indication of weakly compacted and weakly cemented sandstone with shallow burial diagenetic conditions. Based on UCS and elastic modulus values, these sandstones are mainly classified as very low strength and highly yielding rocks. The results of regression analysis show satisfactory correlations between physical and mechanical characteristics, indicating the suitability of obtained empirical equations to deduce these properties. Principal component analysis revealed that the LOI, BTS, SRN, and USC have a positive correlation to each other and weakly correlated with <i><i>ρ</i></i> and UPV, which positively correlated to each other and negatively correlated to <i><i>n</i></i>. The results of agglomerative hierarchical clustering revealed that the studied samples can group into three main clusters depending on their USC, LOI, and <i><i>n</i></i><span> </span>values.
文摘Steeply dipping prograding fan deltas possess high reservoir quality facies that could be excellent targets while exploring for hydrocarbons.Due to their complex stacking nature,and limited examples,delineating their architectural elements is still challenging.In this paper we mainly performed sedimentary facies analysis;applying various disciplines e.g.sequence stratigraphy,seismic stratigraphy,GR-log motifs,and seismic waveform segmentation;so as to adequately depict the reservoir heterogeneity and quality of the Paleozoic Nubia clastics in West Esh El Mallaha Concession(southwest Gulf of Suez rift).Organic maturity prediction,to confirm the hydrocarbon charging from source units to reservoir intervals,was also of most importance in this study.Accordingly,1D basin model was established to define the past geologic events;subsidence,and thermal maturity;and their controls on sedimentary basin evolution and associated petroleum potential.We utilized several key-information scales;e.g.wireline logs,and seismic profiles.Linking different disciplines applied in this study points to a successful integrated reservoir characterization workflow capable of unfolding ancient environments and the associated hydrocarbon potential.The results show that Nubia Formation was built during the lowstandtransgressive phase of a 3rd order depositional sequence.It encompasses fluvio-lacustrine system with eight sedimentary facies associations;form source to sink.Fluvial channels and mouth bars,settled in subaerial and subaqueous settings respectively,represent the most significant reservoir facies in the area.Given best hydrocarbon-reservoir quality,the deltaic mouth bars ought to attract attention of further oilfield development plans and be considered while investigating similar settings.
