Volcanic edifices play an important role in controlling the spatial distribution of volcanic reservoirs.Taking the volcanic rocks of the Yingcheng Formation as an example,the types of volcanic formations,seismic attri...Volcanic edifices play an important role in controlling the spatial distribution of volcanic reservoirs.Taking the volcanic rocks of the Yingcheng Formation as an example,the types of volcanic formations,seismic attributes and reservoir characteristics are studied in detail using drill cores and logging and seismic data. A volcanic edifice model is established. On the basis of lithology and internal flow unit,the volcanic edifices can be divided into 4 types,including acidic lava volcanic edifices( single flow units and composite flow units),rhyolitic lava debris volcanic edifices,and basaltic lava volcanic edifices. Among these types,the acidic lava volcanic edifices( single flow unit) consist of a single lava flow unit,and the seismic profile is characterized by a hill-like blank reflection. Additionally,this type of edifice shows a contiguous petal-like pattern in the waveform classification chart. The acidic lava volcanic edifices( composite unit) consist of several acidic lava domes and plate-like lava flows,and the seismic section is a combination of parallel and hill-like reflections. This type shows noise and short-line clutter in the waveform classification diagram. The rhyolitic lava debris volcanic edifices have multiple layers of stacked volcanic debris. The seismic section features a draping continuous parallel reflection over a large area,and this type of edifice is characterized by a ripple pattern in the waveform classification diagram. The basaltic lava volcanic structural seismic section shows a large area of parallel reflectors. The waveform classification phase diagram shows a single and continuous distribution. The volcanic edifices with better physical properties have the following characteristics: the primary porosity belt is well developed,the units in the volcanic edifices are superimposed,and the volcanic structure is not integrated. Acidic composite flow unit volcanic reservoirs have the best physical properties,and the acidic single flow unit volcanic reservoirs are the worst. This study provided some reference for volcanic exploration and reservoir study in areas with few or no wells.展开更多
On the basis of the shape and inner structure of volcanic edifice,the dip angle and coherence were selected to recognize the buried volcanic edifices in Songliao Basin.Five volcanic edifices were recognized in both tw...On the basis of the shape and inner structure of volcanic edifice,the dip angle and coherence were selected to recognize the buried volcanic edifices in Songliao Basin.Five volcanic edifices were recognized in both two methods in the first volcanic cycle of Yingcheng Formation and the prediction perfectly corresponds to the drilling results in well XS8 area.The results are satisfying when the prediction method were employed in the exploration and development of Qingshen gas field.展开更多
In this study,we present an artificial neural network(ANN)-based approach for travel-time tomography of a volcanic edifice under sparse-ray coverage.We employ ray tracing to simulate the propagation of seismic waves t...In this study,we present an artificial neural network(ANN)-based approach for travel-time tomography of a volcanic edifice under sparse-ray coverage.We employ ray tracing to simulate the propagation of seismic waves through the heterogeneous medium of a volcanic edifice,and an inverse modeling algorithm that uses an ANN to estimate the velocity structure from the“observed”travel-time data.The performance of the approach is evaluated through a 2-dimensional numerical study that simulates i)an active source seismic experiment with a few(explosive)sources placed on one side of the edifice and a dense line of receivers placed on the other side,and ii)earthquakes located inside the edifice with receivers placed on both sides of the edifice.The results are compared with those obtained from conventional damped linear inversion.The average Root Mean Square Error(RMSE)between the input and output models is approximately 0.03 km/s for the ANN inversions,whereas it is about 0.4 km/s for the linear inversions,demonstrating that the ANN-based approach outperforms the classical approach,particularly in situations with sparse ray coverage.Our study emphasizes the advantages of employing a relatively simple ANN architecture in conjunction with second-order optimizers to minimize the loss function.Compared to using first-order optimizers,our ANN architecture shows a~25%reduction in RMSE.The ANN-based approach is computationally efficient.We observed that even though the ANN is trained based on completely random velocity models,it is still capable of resolving previously unseen anomalous structures within the edifice with about 5%anomalous discrepancies,making it a potentially valuable tool for the detection of low velocity anomalies related to magmatic intrusions or mush.展开更多
The intact volcanic edifice had been formed and finalized during the depositional stage of Mesozoic Yixian Formation in the Bohai Sea.The residual body of the intact volcanic edifice after reformation was defined as t...The intact volcanic edifice had been formed and finalized during the depositional stage of Mesozoic Yixian Formation in the Bohai Sea.The residual body of the intact volcanic edifice after reformation was defined as the basement reformed volcanic edifice.Based on drilling,seismic,well logging and microscopic data in the study area,characteristics of the basement reformed volcanic edifice were well discussed,and its control on oil and gas was also investigated.Results showed that the basement reformed volcanic edifice was jointly controlled by magmatic property,paleo-geomorphology and late reformation,and the late fault cutting and differential denudation were major reformation ways of the volcanic edifice;strong and weak volcanic eruption patterns developed in the study belonged to the invertedsequence eruption,and the explosive facies and the intermediate-acidic or acidic effusive facies were the favorable reservoir facies;weathering,cycles and period boundaries controlled vertical distribution of high-quality lithofacies,and coupling between each periodic interface at different levels and residual high-quality lithofacies was the key to oil and gas enrichment.Major exploration targets of volcanic rocks were to find periodic interfaces in the volcanic edifice with the residual high-quality lithofacies within 150 m from the weathering crust or eruption surface.展开更多
The Mesozoic volcanic rocks of the Bodong Low Uplift in the Bohai Bay Basin have been studied and explored for years.In 2024,the LK7-A well drilled in this region tested high-yield oil and gas flows from volcanic weat...The Mesozoic volcanic rocks of the Bodong Low Uplift in the Bohai Bay Basin have been studied and explored for years.In 2024,the LK7-A well drilled in this region tested high-yield oil and gas flows from volcanic weathered crust.These volcanic rocks need to be further investigated in terms of distribution patterns,conditions for forming high-quality reservoirs,and main factors controlling hydrocarbon accumulation.Based on the logging,geochemical and mineralogical data from wells newly drilled to the Mesozoic volcanic rocks in the basin,and high-resolution 3D seismic data,a comprehensive study was conducted for this area.The research findings are as follows.First,the volcanic rocks in the LK7-A structure are adakites with a large source area depth,and the deep and large faults have provided channels for the emplacement of intermediate-acidic volcanic rocks.Second,volcanic rock reservoirs are mainly distributed in tectonic breccias and intermediate-acidic lavas,and they are dominantly fractured-porous reservoirs,with high-porosity and low-permeability or medium-porosity and low-permeability.Third,the dominant lithologies/lithofacies is the basic condition for forming large-scale volcanic rock reservoirs.Structural fractures and late-stage strong weathering are crucial mechanisms for the formation scale of reservoirs in the Mesozoic volcanic rocks.Fourth,the Bodong Low Uplift exhibits strong hydrocarbon charging by two sags and overpressure mudstone capping,which are favorable for forming high-abundance oil and gas reservoirs.The Mesozoic volcanic buried hills in the study area reflect good trap geometry,providing favorable conditions for large-scale reservoir formation,and also excellent migration and accumulation conditions.Areas with long-term exposure of intermediate-acidic volcanic rocks,particularly in active structural regions,are the key targets for future exploration.展开更多
Identifying volcanic reservoir types and their distribution patterns in volcanic edifices is important for accurate prediction and exploration of hydrocarbon reservoirs.Herein,we analyzed the distribution patterns of ...Identifying volcanic reservoir types and their distribution patterns in volcanic edifices is important for accurate prediction and exploration of hydrocarbon reservoirs.Herein,we analyzed the distribution patterns of different reservoir levels in volcanic edifices,discussed controlling factors,and reclassified reservoir types.This was done using core observations,whole-rock geochemistry,and reservoir physical property analysis,combined with logging,drilling,seismic,and oil-gas test data.Reservoirs can be divided into three classes based on their physical properties.The Mesozoic intermediate and basic rocks formed ClassⅠreservoirs,most lithologies formed ClassⅡreservoirs,and diabase intrusions and tight volcanic rocks formed ClassⅢreservoirs.Reservoirs form in different lithologies in the Huanghua depression due to weathering.Tectonic faults deepen the influence of weathering leading to the formation of reservoirs in tight.Additionally,volcanic rhythms and fractures control the vertical distribution of Cenozoic basaltic reservoirs.Volcanic reservoirs are classified into five types based on the main controlling factors and distribution patterns in volcanic edifices:tectonic-alteration,vesiclefracture,weathered-effusive,weathered-eruptive,and weathered-tectonic types.Among these,the weathered-eruptive type can easily form ClassⅠreservoirs,making it the best target for exploration.Whereas the weathered-tectonic and vesicle-fracture types tend to develop ClassⅡreservoirs and can be potential targets.The new classification takes into account the relationship between reservoir levels and their distribution in volcanic edifices,it is more conducive to igneous reservoir prediction in the Huanghua depression.This study provides a novel idea for the classification and comparative study of igneous reservoirs in petroliferous basins.展开更多
基金Supported by Project of National Natural Science Foundation of China(No.41430322)
文摘Volcanic edifices play an important role in controlling the spatial distribution of volcanic reservoirs.Taking the volcanic rocks of the Yingcheng Formation as an example,the types of volcanic formations,seismic attributes and reservoir characteristics are studied in detail using drill cores and logging and seismic data. A volcanic edifice model is established. On the basis of lithology and internal flow unit,the volcanic edifices can be divided into 4 types,including acidic lava volcanic edifices( single flow units and composite flow units),rhyolitic lava debris volcanic edifices,and basaltic lava volcanic edifices. Among these types,the acidic lava volcanic edifices( single flow unit) consist of a single lava flow unit,and the seismic profile is characterized by a hill-like blank reflection. Additionally,this type of edifice shows a contiguous petal-like pattern in the waveform classification chart. The acidic lava volcanic edifices( composite unit) consist of several acidic lava domes and plate-like lava flows,and the seismic section is a combination of parallel and hill-like reflections. This type shows noise and short-line clutter in the waveform classification diagram. The rhyolitic lava debris volcanic edifices have multiple layers of stacked volcanic debris. The seismic section features a draping continuous parallel reflection over a large area,and this type of edifice is characterized by a ripple pattern in the waveform classification diagram. The basaltic lava volcanic structural seismic section shows a large area of parallel reflectors. The waveform classification phase diagram shows a single and continuous distribution. The volcanic edifices with better physical properties have the following characteristics: the primary porosity belt is well developed,the units in the volcanic edifices are superimposed,and the volcanic structure is not integrated. Acidic composite flow unit volcanic reservoirs have the best physical properties,and the acidic single flow unit volcanic reservoirs are the worst. This study provided some reference for volcanic exploration and reservoir study in areas with few or no wells.
基金Supported by NSFC Project No 40372066,and SRFDP No 20030183042
文摘On the basis of the shape and inner structure of volcanic edifice,the dip angle and coherence were selected to recognize the buried volcanic edifices in Songliao Basin.Five volcanic edifices were recognized in both two methods in the first volcanic cycle of Yingcheng Formation and the prediction perfectly corresponds to the drilling results in well XS8 area.The results are satisfying when the prediction method were employed in the exploration and development of Qingshen gas field.
文摘In this study,we present an artificial neural network(ANN)-based approach for travel-time tomography of a volcanic edifice under sparse-ray coverage.We employ ray tracing to simulate the propagation of seismic waves through the heterogeneous medium of a volcanic edifice,and an inverse modeling algorithm that uses an ANN to estimate the velocity structure from the“observed”travel-time data.The performance of the approach is evaluated through a 2-dimensional numerical study that simulates i)an active source seismic experiment with a few(explosive)sources placed on one side of the edifice and a dense line of receivers placed on the other side,and ii)earthquakes located inside the edifice with receivers placed on both sides of the edifice.The results are compared with those obtained from conventional damped linear inversion.The average Root Mean Square Error(RMSE)between the input and output models is approximately 0.03 km/s for the ANN inversions,whereas it is about 0.4 km/s for the linear inversions,demonstrating that the ANN-based approach outperforms the classical approach,particularly in situations with sparse ray coverage.Our study emphasizes the advantages of employing a relatively simple ANN architecture in conjunction with second-order optimizers to minimize the loss function.Compared to using first-order optimizers,our ANN architecture shows a~25%reduction in RMSE.The ANN-based approach is computationally efficient.We observed that even though the ANN is trained based on completely random velocity models,it is still capable of resolving previously unseen anomalous structures within the edifice with about 5%anomalous discrepancies,making it a potentially valuable tool for the detection of low velocity anomalies related to magmatic intrusions or mush.
基金supported by National Science and Technology Major Project of China(2016ZX05024-003).
文摘The intact volcanic edifice had been formed and finalized during the depositional stage of Mesozoic Yixian Formation in the Bohai Sea.The residual body of the intact volcanic edifice after reformation was defined as the basement reformed volcanic edifice.Based on drilling,seismic,well logging and microscopic data in the study area,characteristics of the basement reformed volcanic edifice were well discussed,and its control on oil and gas was also investigated.Results showed that the basement reformed volcanic edifice was jointly controlled by magmatic property,paleo-geomorphology and late reformation,and the late fault cutting and differential denudation were major reformation ways of the volcanic edifice;strong and weak volcanic eruption patterns developed in the study belonged to the invertedsequence eruption,and the explosive facies and the intermediate-acidic or acidic effusive facies were the favorable reservoir facies;weathering,cycles and period boundaries controlled vertical distribution of high-quality lithofacies,and coupling between each periodic interface at different levels and residual high-quality lithofacies was the key to oil and gas enrichment.Major exploration targets of volcanic rocks were to find periodic interfaces in the volcanic edifice with the residual high-quality lithofacies within 150 m from the weathering crust or eruption surface.
基金Supported by the the National Natural Science Foundation of China(U24B2017)。
文摘The Mesozoic volcanic rocks of the Bodong Low Uplift in the Bohai Bay Basin have been studied and explored for years.In 2024,the LK7-A well drilled in this region tested high-yield oil and gas flows from volcanic weathered crust.These volcanic rocks need to be further investigated in terms of distribution patterns,conditions for forming high-quality reservoirs,and main factors controlling hydrocarbon accumulation.Based on the logging,geochemical and mineralogical data from wells newly drilled to the Mesozoic volcanic rocks in the basin,and high-resolution 3D seismic data,a comprehensive study was conducted for this area.The research findings are as follows.First,the volcanic rocks in the LK7-A structure are adakites with a large source area depth,and the deep and large faults have provided channels for the emplacement of intermediate-acidic volcanic rocks.Second,volcanic rock reservoirs are mainly distributed in tectonic breccias and intermediate-acidic lavas,and they are dominantly fractured-porous reservoirs,with high-porosity and low-permeability or medium-porosity and low-permeability.Third,the dominant lithologies/lithofacies is the basic condition for forming large-scale volcanic rock reservoirs.Structural fractures and late-stage strong weathering are crucial mechanisms for the formation scale of reservoirs in the Mesozoic volcanic rocks.Fourth,the Bodong Low Uplift exhibits strong hydrocarbon charging by two sags and overpressure mudstone capping,which are favorable for forming high-abundance oil and gas reservoirs.The Mesozoic volcanic buried hills in the study area reflect good trap geometry,providing favorable conditions for large-scale reservoir formation,and also excellent migration and accumulation conditions.Areas with long-term exposure of intermediate-acidic volcanic rocks,particularly in active structural regions,are the key targets for future exploration.
基金financially supported by the National Natural Science Foundation of China(No.42130309)the PetroChina Dagang Oilfield Company(No.DGTY-2018-JS-408)。
文摘Identifying volcanic reservoir types and their distribution patterns in volcanic edifices is important for accurate prediction and exploration of hydrocarbon reservoirs.Herein,we analyzed the distribution patterns of different reservoir levels in volcanic edifices,discussed controlling factors,and reclassified reservoir types.This was done using core observations,whole-rock geochemistry,and reservoir physical property analysis,combined with logging,drilling,seismic,and oil-gas test data.Reservoirs can be divided into three classes based on their physical properties.The Mesozoic intermediate and basic rocks formed ClassⅠreservoirs,most lithologies formed ClassⅡreservoirs,and diabase intrusions and tight volcanic rocks formed ClassⅢreservoirs.Reservoirs form in different lithologies in the Huanghua depression due to weathering.Tectonic faults deepen the influence of weathering leading to the formation of reservoirs in tight.Additionally,volcanic rhythms and fractures control the vertical distribution of Cenozoic basaltic reservoirs.Volcanic reservoirs are classified into five types based on the main controlling factors and distribution patterns in volcanic edifices:tectonic-alteration,vesiclefracture,weathered-effusive,weathered-eruptive,and weathered-tectonic types.Among these,the weathered-eruptive type can easily form ClassⅠreservoirs,making it the best target for exploration.Whereas the weathered-tectonic and vesicle-fracture types tend to develop ClassⅡreservoirs and can be potential targets.The new classification takes into account the relationship between reservoir levels and their distribution in volcanic edifices,it is more conducive to igneous reservoir prediction in the Huanghua depression.This study provides a novel idea for the classification and comparative study of igneous reservoirs in petroliferous basins.
