The attenuation of seismic waves reflects the elastic nature of the media within which the waves propagate.In this study,we calculate the Coda-Q(Qc),frequency dependence(η),Vp/Vs and Poisson's(υ)ratios by using ...The attenuation of seismic waves reflects the elastic nature of the media within which the waves propagate.In this study,we calculate the Coda-Q(Qc),frequency dependence(η),Vp/Vs and Poisson's(υ)ratios by using 2621 vertical component seismograms generated by 987 earthquakes recorded by 13 seismic stations in Eastern Anatolia,and creat a 2-D seismic tomographic Qc model for the region.The obtained model provides significant information for exploring the boundaries of adjacent tectonic units within the upper crust and interpreting their dynamic characteristics.The 2-D Qc model and the other parameters are consistent with the seismotectonic features of Eastern Anatolia.Highly heterogeneous Qc values are observed in the study area dividing it into north-south directed bands of low and high attenuation.The highestηvalues were obtained beneath the northwestern and eastern parts of the study region.Clear,high and lowυvalues are obtained in the western and eastern parts of the study area,respectively.The spatial variations in the measured parameters are consistent with many geophysical observations including low Pn velocities,efficient Sn blockage,high heat flow,and widespread volcanism.Different upper crustal thicknesses and inhomogeneous stress distribution along the East and North Anatolian Fault Zones may also contribute to the observed heterogeneities.展开更多
The interest of this research: there is oil seepage at the contact between coal seam-A and sandstone facies of Warukin Formation, so it is necessary to study where is the source rock. The correlation between HI and Tm...The interest of this research: there is oil seepage at the contact between coal seam-A and sandstone facies of Warukin Formation, so it is necessary to study where is the source rock. The correlation between HI and Tmax as result from rock eval pyrolysis shows that the shale of the Warukin Formation is immature while the correlation between HI and OI shows oil prone. The vitrinite (Ro) reflectance of Central Wara coal is between 0.48% up to 0.5% (immature), the content of the vitrinite group is 68.0 - 84.8 (% Vol.), Liptinite 3.0 - 14.0 (% Vol.) and inertinite 0.48 - 25.0 (% Vol.). The high content of liptinite mineral groups (14% Vol.) and the presence of exsudatinite maceral are as an initial indication of bitumenization of oil formation when there is a change in reflectance and fluorescence. Therefore, Central Wara coal plays an important role as the source rock of the Warukin Formation, although the maturity level is immature, the presence of exsudatinite maceral is believed to be the source of origin for producing oil, where the organic material comes from terrestrial.展开更多
The Kendeng Basin, the major depocenter of the East Java Basin, has been filled with deep-sea clastic volcanic deposits since the Middle Tertiary, which developed into volcanic deposits in the Quaternary. With thick Q...The Kendeng Basin, the major depocenter of the East Java Basin, has been filled with deep-sea clastic volcanic deposits since the Middle Tertiary, which developed into volcanic deposits in the Quaternary. With thick Quaternary volcanic deposits covering almost the entire basin, outcrops are only found in the north, forming a fold-thrust belt structure. The oldest known stratigraphic unit is the early Miocene Pelang Formation, which was deposited in the lower to the upper bathyal zone. Rocks older than the Pelang Formation have not been identified in this basin either from outcrops or drill-hole data. However, the geochemical analysis of oil seepage proves to be different because the oil source rock in Kendeng Basin was interpreted to be of older lithology than the Pelang Formation, indicating a potentially older stratigraphic unit in the Kendeng Basin that has not been revealed to date. Mud volcanoes transported rock material from the Kendeng Basin to the surface, uncovering the stratigraphy that has been an enigma. The material in question includes Nummulites limestones, conglomerates, and quartz sandstones. Paleontological analysis results on rock fragments indicate that they belong to the Middle Eocene age, so they are older than the Pelang Formation. Mud volcano also carried younger limestones to the surface identified as Miocene Age (equivalent with the Pelang Formation), which were deposited in a middle neritic environment, so they provided information that shallow areas possibly formed a horst-graben structure during the Miocene in the Kendeng Basin. The appearance of Eocene and Miocene rock fragments can be used to complement the stratigraphy and it also provides a potentially new concept of source-reservoir rock in the Kendeng Basin.展开更多
Kendeng Basin stretches in an E-W direction from the Quaternary Merapi-Ungaran Volcano range in the West to the Madura Strait East of Jawa Timur Province, Indonesia. With Quaternary volcanic deposits covering this bas...Kendeng Basin stretches in an E-W direction from the Quaternary Merapi-Ungaran Volcano range in the West to the Madura Strait East of Jawa Timur Province, Indonesia. With Quaternary volcanic deposits covering this basin, its subsurface configuration has not been accurately identified. Several scholars suggest that its configuration forms an asymmetrical basin deepening to the south as a result of volcanic deposits and extending E-W direction. This paper answers what configuration Kendeng Basin has, including whether it consists of a simple asymmetrical shape as previous studies have interpreted or other patterns due to tectonic processes that took place during its formation. The research employed Gravity and Magnetic method, and the results were processed by spectral and gradient analyses. Both analyses revealed that Kendeng Basin formed Horst-Graben structures extending in an E-W direction based on a response to compression and strain forces during its formation. A structure with an E-W direction controls the shape of the Horst-Graben and is transected by a structural pattern extending in a NE-SW direction or known as the Meratus pattern. These findings provide an alternative to the concept of oil and gas exploration, which, until today, is merely known from the emergence of oil seepages in Kendeng Basin.展开更多
Consider a typical situation where an investor is considering acquiring an unexplored oilfield.The oilfield has undergone a preliminary geological and geophysical study in which pre-discovery data such as lithology,de...Consider a typical situation where an investor is considering acquiring an unexplored oilfield.The oilfield has undergone a preliminary geological and geophysical study in which pre-discovery data such as lithology,depth,depositional system,diagenetic overprint,structural compartmentalization,and trap type are available.In this situation,investors usually estimate production rates using a volumetric approach.A more accurate estimation of production rates can be obtained using analytical methods,which require additional data such as net pay,porosity,oil formation volume factor,permeability,viscosity,and pressure.We call these data post-discovery parameters because they are only available after discovery through exploration drilling.A data-driven approach to estimating post-discovery parameters of an unexplored oilfield is developed based on its pre-discovery data by learning from proven reservoir data.Using the Gaussian mixture model,and a data-driven reservoir typology based on the joint probability distribution of post-discovery parameters is established.We came up with 12 reservoir types.Subsequently,an artificial neural network classification model with the resilient backpropagation algorithm is used to find relationships between pre-discovery data and reservoir types.Based on k-fold crossvalidation with k?10,the accuracy of the classification model is stable with an average of 87.9%.With our approach,an investor considering acquiring an unexplored oilfield can classify the oilfield's reservoir into a particular type and estimate its post-discovery parameters'joint probability distribution.The investor can incorporate this information into a valuation model to calculate the production rates more accurately,estimate the oilfield's value and risk,and make an informed acquisition decision accordingly.展开更多
文摘The attenuation of seismic waves reflects the elastic nature of the media within which the waves propagate.In this study,we calculate the Coda-Q(Qc),frequency dependence(η),Vp/Vs and Poisson's(υ)ratios by using 2621 vertical component seismograms generated by 987 earthquakes recorded by 13 seismic stations in Eastern Anatolia,and creat a 2-D seismic tomographic Qc model for the region.The obtained model provides significant information for exploring the boundaries of adjacent tectonic units within the upper crust and interpreting their dynamic characteristics.The 2-D Qc model and the other parameters are consistent with the seismotectonic features of Eastern Anatolia.Highly heterogeneous Qc values are observed in the study area dividing it into north-south directed bands of low and high attenuation.The highestηvalues were obtained beneath the northwestern and eastern parts of the study region.Clear,high and lowυvalues are obtained in the western and eastern parts of the study area,respectively.The spatial variations in the measured parameters are consistent with many geophysical observations including low Pn velocities,efficient Sn blockage,high heat flow,and widespread volcanism.Different upper crustal thicknesses and inhomogeneous stress distribution along the East and North Anatolian Fault Zones may also contribute to the observed heterogeneities.
文摘The interest of this research: there is oil seepage at the contact between coal seam-A and sandstone facies of Warukin Formation, so it is necessary to study where is the source rock. The correlation between HI and Tmax as result from rock eval pyrolysis shows that the shale of the Warukin Formation is immature while the correlation between HI and OI shows oil prone. The vitrinite (Ro) reflectance of Central Wara coal is between 0.48% up to 0.5% (immature), the content of the vitrinite group is 68.0 - 84.8 (% Vol.), Liptinite 3.0 - 14.0 (% Vol.) and inertinite 0.48 - 25.0 (% Vol.). The high content of liptinite mineral groups (14% Vol.) and the presence of exsudatinite maceral are as an initial indication of bitumenization of oil formation when there is a change in reflectance and fluorescence. Therefore, Central Wara coal plays an important role as the source rock of the Warukin Formation, although the maturity level is immature, the presence of exsudatinite maceral is believed to be the source of origin for producing oil, where the organic material comes from terrestrial.
文摘The Kendeng Basin, the major depocenter of the East Java Basin, has been filled with deep-sea clastic volcanic deposits since the Middle Tertiary, which developed into volcanic deposits in the Quaternary. With thick Quaternary volcanic deposits covering almost the entire basin, outcrops are only found in the north, forming a fold-thrust belt structure. The oldest known stratigraphic unit is the early Miocene Pelang Formation, which was deposited in the lower to the upper bathyal zone. Rocks older than the Pelang Formation have not been identified in this basin either from outcrops or drill-hole data. However, the geochemical analysis of oil seepage proves to be different because the oil source rock in Kendeng Basin was interpreted to be of older lithology than the Pelang Formation, indicating a potentially older stratigraphic unit in the Kendeng Basin that has not been revealed to date. Mud volcanoes transported rock material from the Kendeng Basin to the surface, uncovering the stratigraphy that has been an enigma. The material in question includes Nummulites limestones, conglomerates, and quartz sandstones. Paleontological analysis results on rock fragments indicate that they belong to the Middle Eocene age, so they are older than the Pelang Formation. Mud volcano also carried younger limestones to the surface identified as Miocene Age (equivalent with the Pelang Formation), which were deposited in a middle neritic environment, so they provided information that shallow areas possibly formed a horst-graben structure during the Miocene in the Kendeng Basin. The appearance of Eocene and Miocene rock fragments can be used to complement the stratigraphy and it also provides a potentially new concept of source-reservoir rock in the Kendeng Basin.
文摘Kendeng Basin stretches in an E-W direction from the Quaternary Merapi-Ungaran Volcano range in the West to the Madura Strait East of Jawa Timur Province, Indonesia. With Quaternary volcanic deposits covering this basin, its subsurface configuration has not been accurately identified. Several scholars suggest that its configuration forms an asymmetrical basin deepening to the south as a result of volcanic deposits and extending E-W direction. This paper answers what configuration Kendeng Basin has, including whether it consists of a simple asymmetrical shape as previous studies have interpreted or other patterns due to tectonic processes that took place during its formation. The research employed Gravity and Magnetic method, and the results were processed by spectral and gradient analyses. Both analyses revealed that Kendeng Basin formed Horst-Graben structures extending in an E-W direction based on a response to compression and strain forces during its formation. A structure with an E-W direction controls the shape of the Horst-Graben and is transected by a structural pattern extending in a NE-SW direction or known as the Meratus pattern. These findings provide an alternative to the concept of oil and gas exploration, which, until today, is merely known from the emergence of oil seepages in Kendeng Basin.
基金This research is supported and partially funded by Parahyangan Catholic University in Bandung,Indonesia.
文摘Consider a typical situation where an investor is considering acquiring an unexplored oilfield.The oilfield has undergone a preliminary geological and geophysical study in which pre-discovery data such as lithology,depth,depositional system,diagenetic overprint,structural compartmentalization,and trap type are available.In this situation,investors usually estimate production rates using a volumetric approach.A more accurate estimation of production rates can be obtained using analytical methods,which require additional data such as net pay,porosity,oil formation volume factor,permeability,viscosity,and pressure.We call these data post-discovery parameters because they are only available after discovery through exploration drilling.A data-driven approach to estimating post-discovery parameters of an unexplored oilfield is developed based on its pre-discovery data by learning from proven reservoir data.Using the Gaussian mixture model,and a data-driven reservoir typology based on the joint probability distribution of post-discovery parameters is established.We came up with 12 reservoir types.Subsequently,an artificial neural network classification model with the resilient backpropagation algorithm is used to find relationships between pre-discovery data and reservoir types.Based on k-fold crossvalidation with k?10,the accuracy of the classification model is stable with an average of 87.9%.With our approach,an investor considering acquiring an unexplored oilfield can classify the oilfield's reservoir into a particular type and estimate its post-discovery parameters'joint probability distribution.The investor can incorporate this information into a valuation model to calculate the production rates more accurately,estimate the oilfield's value and risk,and make an informed acquisition decision accordingly.
