Basin modeling has become an important tool for analyzing sedimentary basins. The North Subbasin of the South Yellow Sea Basin is filled with thick Meso-Cenozoic terrigenous deposits during the rift evolution stage. T...Basin modeling has become an important tool for analyzing sedimentary basins. The North Subbasin of the South Yellow Sea Basin is filled with thick Meso-Cenozoic terrigenous deposits during the rift evolution stage. The accumulation of data and achievements of geological investigations in recent years have provided the preconditions for basin modeling. The necessary parameters and geological elements for simulations are collated and summarized. Modeling of tectono-thermal evolution is performed and the related trend in heat flow is reconstructed and calibrated. The heat flow value commences from an average level of 61 m W/m2during MiddleLate Jurassic, rises to about 80 m W/m2from circa 145 Ma to circa 74 Ma, and then undergoes a gradual decline to65 m W/m2until the end of Oligocene.Three evolutionary phases, namely, the initial rifting phase, syn-rifting phase, and post-rifting phase, have been identified. The modeling results show that the North Subbasin generally enters into a stage of strong rifting during Cretaceous and undergoes rapid subsidence until the Late Cretaceous,then follows by a stage of moderate rifting during the Paleogene. The input and general workflow involved in 3-D modeling are introduced. Reconstruction of the petroleum system in the North Subbasin reveals that the threshold depth of hydrocarbon generation is located near the top of the Paleogene Funing formation, and the underlying Jurassic and Cretaceous source rocks have reached or exceeded peak oil generation and have almost completed the generation and expulsion of hydrocarbons. The main generation and expulsion in the Jurassic source rocks take place during the syn-rifting and post-rifting phases, whereas the peak generation and expulsion in the Cretaceous and Paleogene source rocks take place during the post-rifting phase. Although the study area is still a relatively less explored sedimentary basin, the results of modeling can provide valuable information for exploration. A preliminary discussion of the main uncertainty factors is also presented.展开更多
The Eocene Niubao Formation is the primary research target of oil exploration in the Lunpola Basin.Crude oil was extracted from Well Z1 on the northern margin of the basin in 1993.In this study,an integrated evaluatio...The Eocene Niubao Formation is the primary research target of oil exploration in the Lunpola Basin.Crude oil was extracted from Well Z1 on the northern margin of the basin in 1993.In this study,an integrated evaluation of the source rock geothermal,and maturity histories and the fluid inclusion and fluid potential distributions was performed to aid in predicting areas of hydrocarbon accumulation.Due to the abundance of organic matter,the kerogen types,maturity,and oil-sources correlate with the geochemical data.The middle submember of the second member of the Niubao Formation(E2n^2-2)is the most favorable source rock based on the amount of oil produced from the E2n^2-3and E2n^3-1reservoirs.One-and twodimensional basin modeling,using BasinMod software,shows that the E2n^2-2source rock started to generate hydrocarbon at 35-30 Ma,reached a maturity of Ro=0.7%at 25-20 Ma,and at present,it has reached the peak oil generation stage with a thermal maturity of Ro=0.8%to less than Ro=1.0%.By using fluid inclusion petrography,fluorescence spectroscopy,and microthermometry,two major periods of oil charging have been revealed at 26.1-17.5 and 32.4-24.6 Ma.The oil accumulation modeling results,conducted by using the Trinity software,show a good fit of the oil shows in the wells and predict that the structural highs and lithologic transitions within the Jiangriaco and Paco sags are potential oil traps.展开更多
Great advancement has been made on natural gas hydrates exploration and test production in the northern South China Sea.However,there remains a lot of key questions yet to be resolved,particularly about the mechanisms...Great advancement has been made on natural gas hydrates exploration and test production in the northern South China Sea.However,there remains a lot of key questions yet to be resolved,particularly about the mechanisms and the controls of gas hydrates enrichment.Numerical simulaution would play signficant role in addressing these questions.This study focused on the gas hydrate exploration in the Shenhu Area,Northern South China Sea.Based on the newly obtained borehole and multichannel reflection seismic data,the authors conducted an integrated 3D basin modeling study on gas hydrate.The results indicate that the Shenhu Area has favorable conditions for gas hydrate accumulation,such as temperature,pressure,hydrocarbon source,and tectonic setting.Gas hydrates are most concentrated in the Late Miocene strata,particularly in the structual highs between the Baiyun Sag and the Liwan Sag,and area to the south of it.It also proved the existence of overpressure in the main sag of source rocks,which was subject to compaction disequilibrium and hydrocarbon generation.It also shown that the regional fault activity is not conducive to gas hydrate accumulation due to excess gas seepage.The authors conjecture that fault activity may slightly weaken overpressure for the positive effect of hydrocarbon expulsion and areas lacking regional fault activity have better potential.展开更多
This study aims to define the hydrocarbon generation potential of source rocks by assessing various factors including quantity of organic matter, types of kerogen, thermal maturity, and source of organic matter input....This study aims to define the hydrocarbon generation potential of source rocks by assessing various factors including quantity of organic matter, types of kerogen, thermal maturity, and source of organic matter input. Depositional conditions of source rocks from Thebes, Brown Limestone, and Matulla formations in Well G-9, Well GA-2 and Well GW-6, are assessed through pyrolysis, vitrinite reflectance and1D basin modeling. Results show the source rocks of Thebes and Brown Limestone formations exhibit favorable to excellent source rock characteristics with Type I-II kerogen and have the capacity to generate oil. Conversely, the source rocks of the Matulla Formation show fair to good source rock characteristics with Type II-III kerogen and have the capacity to produce both oil and gas. Thermal maturity shows the source rocks are at an immature stage. A 1D basin model is constructed for Well G-9to simulate multi-tectonic episodes, burial events, and the history of thermal maturity. Sedimentation rates of Cretaceous to Eocene deposits are characterized by a low burial rate, which contrasts with the high burial and sedimentation rates for Miocene and post Miocene(Pliocene-Recent) strata. Overall, the South Geisum oilfield petroleum system is found to be immature based on integration of source rock evaluation and petroleum basin modelling.展开更多
Jiaojiang sag in the East China Sea Basin is at the earlier exploration stage,where characterizing hydrocarbon generation of source rocks is important to understand oil-gas exploration potential.Utilizing geochemical ...Jiaojiang sag in the East China Sea Basin is at the earlier exploration stage,where characterizing hydrocarbon generation of source rocks is important to understand oil-gas exploration potential.Utilizing geochemical and basin modeling analysis,hydrocarbon generation capacity and process of the Paleocene E_(1)y,E_(1)l and E_(1)m formations were investigated.Results show that E_(1)y and E_(1)l mudstones are high-quality source rocks with Type Ⅱ kerogen,which is dominated by both aquatic organisms and terrestrial higher plants deposited in sub-reduced environment.E_(1)m mudstone interbedded with thin carbonaceous mudstone and coal is poor-quality source rock with Type Ⅲ kerogen,whose organic matter was originated from terrestrial higher plants under oxidized environment.Controlled by burial and maturity histories,E_(1)y and E_(1)l source rocks experienced two hydrocarbon generation stages,which took place in the Late Paleocene and in the Middle to Late Eocene,respectively,and had high hydrocarbon generation capacity with cumulative hydrocarbon volume of 363 and 328 mg/g,respectively.E_(1)m source rock only had one hydrocarbon generation process in the Late Eocene,which had low hydrocarbon generation capacity with cumulative hydrocarbon volume of only 24 mg/g.The future oil-gas exploration in the Jiaojiang sag should focus on hydrocarbon generation center and select targets in the central uplift formed before the Miocene with high-quality traps.展开更多
Lacustrine-fan deltas feature high reservoir-quality lithounits that are critical targets to hydrocarbon exploration and development.However,depicting their intricate sedimentary architectural elements is still challe...Lacustrine-fan deltas feature high reservoir-quality lithounits that are critical targets to hydrocarbon exploration and development.However,depicting their intricate sedimentary architectural elements is still challenging due to complex stacking-patterns and limited examples.In this study,both 3D-static geocellular reservoir modeling and 1D-basin modeling approaches were combined as an established effective workflow that is capable of efficiently delineating reservoir-heterogeneities and confirming hydrocarbon-charging.This integration was for the purpose of unlocking the ultimate petroleum potential of fluvio-lacustrine units,Nubia Formation,in the southwest of the Gulf of Suez rift(West Esh-ElMallaha Concession,Egypt).Pixel-based stochastic-simulation was applied,constrained by an established depositional-model developed after adequate integrated-facies analysis,upon geocellularly modeling rock and fluid properties of Nubia reservoir intervals;utilizing several key-information scales(seismic-profiles,well-logs).The results reveal a lowstand-transgressive systems tract encompassing fluvio-lacustrine depositional-systems subdivided into eight facies-associations,of which fluvialchannels and deltaic mouth bars represent significant reservoir-quality facies.Given efficient reservoir-quality,mouth sand-bars deserve special consideration,and testing,while running further oilfield development-endeavours and investigating similar-settings.展开更多
Unconventional natural gas in deep coal measures has become an exploration and research hotspot in recent years.The exploration breakthrough of deep coalbed methane and tight sandstone gas in Daning-Jixian Block in th...Unconventional natural gas in deep coal measures has become an exploration and research hotspot in recent years.The exploration breakthrough of deep coalbed methane and tight sandstone gas in Daning-Jixian Block in the eastern Ordos Basin has revealed huge resource potential and commercial prospects in the deep Upper Paleozoic Carboniferous-Permian coal measures.However,the ambiguity of gas accumulation in deep coal measures has restricted exploration and development.Based on a series of tests for fluid inclusions,including petrographic observation,Raman spectroscopy analysis,and microthermometry,combined with the burial-thermal evolution history recovered from basin modeling,this study aims to clarify the timing of gas accumulation in deep coal measures.The results show four types of secondary fluid inclusions in the deep coal measure sandstone layers of Daning-Jixian Block,including CH4-rich inclusions,C2+hydrocarbons-bearing inclusions,CO_(2)-bearing inclusions,and aqueous inclusions.The main formation stage of fluid inclusions corresponded to the mesodiagenesis stage of the deep coal measure sandstone,and the coeval assemblages of fluid inclusions vary due to the recording of gas charging in different maturity stages of coal measure source rocks.This study suggests that tight sandstone gas accumulation in deep coal measures was a continuous charging process with one period-multiple episodes in Daning-Jixian Block,and occurred mainly during the Early Cretaceous(137−127 Ma BP).The results of this study contribute to further understanding of gas accumulation mechanisms in deep coal measures.展开更多
In recent years,fueled by significant advancements in oil exploration technologies within the Ordos Basin,an increasing number of low-permeability or ultra-low-permeability reservoirs have been identified.Elucidating ...In recent years,fueled by significant advancements in oil exploration technologies within the Ordos Basin,an increasing number of low-permeability or ultra-low-permeability reservoirs have been identified.Elucidating their reservoir characteristics and formation mechanisms has become a critical priority for sustainable hydrocarbon development.The study focused on the Chang 6 Member of the Upper Triassic Yanchang Formation in the Heshui area of the Ordos Basin,systematically investigating its petrological features,porosity and permeability characteristics,diagenesis,and diagenetic evolution sequence.By integrating core observation,thin-section identification,and physical property measurements,a comprehensive quantitative evaluation of reservoir pore evolution was performed.These analytical outcomes were subsequently applied to simulate hydrocarbon migration and accumulation.These research results will provide a scientific basis for in-depth quantitative study of the pore evolution in ultra-low-permeability oil reservoirs and accurately constructing basin models.As indicated,the reservoir lithology in the study area predominantly comprises siltstone interbedded with mudstone or argillaceous siltstone,characterized by low porosity and permeability.Through diagenetic characteristics-based reconstruction constrained by the existing porosity data,pore evolution during diagenesis was quantitatively modeled.The simulated pore evolution aligns with actual geological observations,validating the reliability of the methodology.Furthermore,the quantified pore evolution results were applied to simulate hydrocarbon migration using PetroMod software,showing that hydrocarbon charging in the basin began at the end of the Late Jurassic(J3),peaking in hydrocarbon generation,expulsion,and accumulation by the end of the Early Cretaceous(K1)and maintaining high accumulation rates until the late Cretaceous,though significantly decreasing at the present stage.The simulation results were verified by comparison with actual drilling data,which confirms their reliability and applicability to other analogous oilfields.展开更多
An integrated study on source rock characterization and hydrocarbon generation potential modeling was conducted for the selected Dingo Claystone,Barrow Sub-basin,Australia.In this study,data were collected solely from...An integrated study on source rock characterization and hydrocarbon generation potential modeling was conducted for the selected Dingo Claystone,Barrow Sub-basin,Australia.In this study,data were collected solely from two wells represented by the Bambra-1 and Bambra-2 wells.The collected data include those from bulk geochemical analyses of cuttings and sidewall cores sampled from the Late Jurassic Dingo Claystone.Geochemical data obtained from Rock-Eval pyrolysis and gas chromatography(GC)of extracted organic matter were integrated for source rock characterization and the construction of burial history and hydrocarbon generation in the Dingo Claystone.To improve the accuracy of thermal maturity estimations,only samples with S2 greater than 1 were considered due to potential issues with peak integration and uncertainties of Tmax determination in samples with lower S2 values.Furthermore,Rock-Eval data from the Bambra wells may be unreliable due to the contamination of cuttings and sidewall core(SWC)samples by drilling mud additives and natural hydrocarbons,which could impact the reliability of the data for determining thermal maturity.This study reveals that the Dingo Claystone Formation has total organic carbon(TOC)contents ranging from 0.66%to 8.31%.A poor to good hydrocarbon generation potential is indicated,with a production yield(PY=S_(1)+S_(2))ranging from 1.37 to 10.44 mg HC/g rock.Hydrogen index values vary between 42 and 226 mg HC/g TOC,confirming that the Dingo Claystone is dominantly kerogen TypeⅢ,with minor contributions from typesⅡ/ⅢandⅣ.Thermal maturity ranges from immature to late mature and is mostly in the oil window.This is indicated by T_(max)values of 398-462℃and vitrinite reflectance(Ro,%)of 0.47-1.99.Some samples show suppressed T_(max)and a higher production index,which is typical for samples affected by drilling fluids during drilling operations.Additionally,gas chromatography(GC)analyses are used to interpret the paleodepositional environment showing mixed input between marine and terrestrial origins of the source rocks.One-dimensional basin modeling for the Bambra-1 and Bambra-2 wells was carried out to evaluate the burial and thermal history of the formation.The transformation ratio suggests that hydrocarbon generation has not reached its peak and is still in an ongoing phase.An indication of hydrocarbon migration can be observed in this formation based on the transformation ratio.The effects of contamination warrant further investigation,as it could significantly impact maturity estimates and data reliability.展开更多
The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes ...The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes of the whole region. Using molecular geochemistry, fluid inclusion techniques and basin modeling, we studied the oil filling process of the Bashituo Oilfield that is located in the west of the Markit Slope. The molecular migration indexes, such as the methyldibenzothiophene ratio （4-/1-MDBT）, trimethylnaphthalene ratio （TMNr） and pyrrolic nitrogen compounds content, decrease from west to east, indicating that the charging direction and migration pathways are from west to east. Lithological analysis and homogenization temperatures of saline fluid inclusions accompanied with oil fluid inclusions suggest that two charging periods occurred in the Devonian oil reservoir. Combining the burial history and heating history of well BT4, Basinmod 1D software modeling shows the two oil filling periods are from 290 Ma to 285 Ma and from l0 Ma to 4 Ma, respectively, and later oil filling dominates. This study may be helpful to understand the accumulation process and provide useful references for oil and gas exploration in the Markit Slope.展开更多
The Yitong（伊通） basin is a Late Mesozoic and Cenozoic continental sedimentary basin in Northeast China.On the basis of well tests and seismic data,we use the 2D modeling technique to rebuild the pressure evolution ...The Yitong（伊通） basin is a Late Mesozoic and Cenozoic continental sedimentary basin in Northeast China.On the basis of well tests and seismic data,we use the 2D modeling technique to rebuild the pressure evolution and hydrocarbon migration in the Moliqing（莫里青） fault depression of the Yitong basin.Based on the modeling results,four conclusions are drawn as follows.（1） The Eocene Shuangyang（双阳） Formation within the Moliqing fault depression had entirely undergone three epi-sodic cycles of pressure accumulation and release in geological history,and the three tectonic move-ments since the Middle Eocene played important roles in the episodic changes of excess pressure.（2） The present formation pressure distribution is characterized by normal pressure in almost the entire fault depression with some residual overpressure.The differential distribution of pressure results mainly from the difference in rock facies,sedimentation rate,hydrocarbon generation,and fault activi-ties.（3） The hydrocarbon migration is more active during the release of pressure in the Moliqing fault depression,which happened mainly in the Middle-Late Oligocene and provided the driving force for hydrocarbon migration.（4） The hydrocarbon migration was mostly directed to the Shuangyang For-mation within the Jianshan（尖山） uplift and the Kaoshan（靠山） sag.With the superior condition ofhydrocarbon accumulation and the higher de-gree of hydrocarbon concentration,the north-west part of Kaoshan sag is considered a favor-able area for oil and gas exploration in the Moliqing fault depression.展开更多
The problem that faults act as a conduit for hydrocarbon bearing fluid flow has been under debate for a long time. The southern boundary fault (F S) and No.2 fault belt in the Zhu Ⅲ subbasin in the Pearl River Mout...The problem that faults act as a conduit for hydrocarbon bearing fluid flow has been under debate for a long time. The southern boundary fault (F S) and No.2 fault belt in the Zhu Ⅲ subbasin in the Pearl River Mouth basin (PRMB) of South China Sea (SCS) are considered as the conduit of hydrocarbons for the oil and gas fields in the hydrocarbon generating half grabens. Based upon the basin modeling and seismic velocity inversion simulation, there are abnormal pressure compartments in the central part of half grabens. Wenchang, Enping and Zhuhai FormationⅡare seated within the abnormal pressure zone, while the Zhuhai Formation Ⅰ is within the pressure transition zone. The abnormal pressure was mainly caused by undercompaction due to the high rate of sedimentation for layers with an abnormal pressure. The increase of temperature of inclusions as the increase of depth supports vertical migration via faults in the study area.展开更多
The Sahul Platform where the Sunset-Loxton Shoals and Chuditch gas fields were discovered is located between the Timor Trough to the north and the Malita Graben to the south. These areas are located respectively 440 k...The Sahul Platform where the Sunset-Loxton Shoals and Chuditch gas fields were discovered is located between the Timor Trough to the north and the Malita Graben to the south. These areas are located respectively 440 km and 380 km northwest of Darwin in the northern Bonaparte Basin, Australia. Based on the structural evolution of the northern Bonaparte Basin, data from the wells Loxton Shoals 1, Sunset 1 and Chuditch 1 in the Sahul Platform and Heron 1 in the Malita Graben depocentre, and the Seismic Line N11606 were used to clarify the geological conditions and reconstruct the hydrocarbon accumulation processes in the study area. BasinMod 1-D, 2-D, and 3-D software was used for modeling. The Plover Formation source rock was a poor-to-good hydrocarbon generative potential and reached the middle to late mature oil window in the Sunset-Loxton Shoals field whereas in the Chuditch field, it was an overall fair-to-good hydrocarbon generative potential, and attained the Late mature oil window. The Flamingo, and the Echuca Shoals formations source rocks in the same field were a fair and good hydrocarbon generation potential respectively, and both reached mid-mature oil window. In the Malita Graben depocentre, the Petrel (Frigate) and the Echuca Shoals formations source rocks were a poor-to-very good hydrocarbon generating potential, and had attained wet gas window at the present day. The analyses of organic matter showed that the source rocks in the study area and Malita Graben were gas prone with kerogen types II2 & III and III predominantly. The Middle Jurassic Plover Formation sandstone reservoir in the Sunset-Loxton field was a poor-to-very good quality and potential for gas beds, and it was a very poor-to-very good quality and potential for gas beds in the Chuditch field. The intensities of gas generation and expulsion were more than of oil ones either in the Sahul Platform or in the Malita Graben. The Plover, Petrel (Frigate) and Echuca Shoals formations source rocks in the wells Chuditch 1 and Heron 1, except for the Flamingo Formation in the well Chuditch 1, had higher gas and oil expelling efficiencies than the Plover Formation source rock of the wells in the Sunset-Loxton Shoals field. The hydrocarbon migrated mainly from the Upper Jurassic Frigate Shale source rock in the Malita Graben depocentre (structurally lower) to the Plover Formation sandstone reservoir in the Sunset-Loxton Shoals field during the Late Cretaceous at 66 Ma. In the Chuditch field, the hydrocarbon migration to the Plover Formation sandstone reservoir was initiated during the Late Miocene at 7.5 Ma from the Middle Jurassic Plover Formation source rock in the well Chuditch 1. Nowadays, the main migration pathways are from the southeastward and southward of the Sunset-Loxton Shoals field, and from southward and eastward of the Chuditch field, precisely from the hydrocarbon source kitchens of the Malita Graben depocentre. The traps in the Sahul Platform have been effective to receive the migrated hydrocarbon.展开更多
Through natural gas exploration in the Changling Fault Depression,abundant natural gas flows were obtained and high-quality source rocks were also reveiled.Based on bulk analyses,organic matter abundance,organic matte...Through natural gas exploration in the Changling Fault Depression,abundant natural gas flows were obtained and high-quality source rocks were also reveiled.Based on bulk analyses,organic matter abundance,organic matter type and thermal maturity of the source rocks were studied systematically.At the same time,gas gener-ating intensity and gas generating quantity were quantitatively analyzed by using basin modeling technologies.The results indicated that gas source rocks of the Shahezi Formation are characterized by abundant organic matter and dark mudstone distributions and high-over thermal maturity.They possess high gas generating intensity with the biggest value surpassing 500×108 m3/km2,and large gas generating quantity,accounting from 74.40% of the total amount.The Yingcheng Formation has good gas-source rocks with moderate dark mudstone and relatively high organic matter.It has type-Ⅲ organic matter and low-over thermal maturity.The gas generating intensity is moderate,between 20×108 and 60×108 m3/km2.The gas generating quantity is 13.63% of the total amount.The Huoshiling Formation has relatively good source rocks with limited dark mudstone and low organic matter.It has type-Ⅲ kerogen and over-thermal maturity.The gas generating quantity is 7.10% of the total amount.The Denglouku Formation has poor-gas source rocks,and is characterized by undeveloped dark mudstone and low organic matter abundance.It has type-Ⅲ organic matter and low-high thermal maturity.Hydrocarbon gases in the Changling Fault Depression mainly originated from the Shahezi Formation,and secondarily from the Yingcheng Formation.The contribution of the Huoshiling Formation gas source rocks is relatively small.展开更多
Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded...Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded that (l)the Songpan-Garze fold belt has uplifted at least by 3-4 km with an uplift rate of no less than 0.3-0.4 mm/a since 10 Ma B.P.; (2) the Longmenshan thrust nappe belt has uplifted at least by 5-6 km with an uplift rate of more than 0.5- 0.6 mm /a since 10 Ma B.P.; (3) the Longmenshan detachment belt has uplifted by 1 - 2 km at a rate of 0.016-0.032 mm/a since 60 Ma B.P.; (4) the West Sichuan foreland basin has uplifted by 1.7-3 km at a rate of 0.028-0.05 mm/a since 60 Ma B.P.; (5) the uplift rate of the area on the west side of the Beichuan-Yingxiu-Xiaoguanzi fault for the last 10 Ma is 40 times as much as that on its east side; (6) the uplifting of the the Songpan - Garze fold belt and the subsidence of the West Sichuan foreland basin 60 Ma ago exhibit a mirro-image correlation, i.e. the rapid uplifting of the the Songpan-Garze fold belt was corresponding to the rapid subsidence of the basin;the Songpan-Garze fold belt has uplifted at a much greater rate than the West Sichuan foeland basin in the last 60 Ma;and (7) the palaeogeothermal gradient was 25℃ /km in the West Sichuan foreland basin.展开更多
A long-term simulation for the period 1990–2010 is conducted with the latest version of the International Centre for Theoretical Physics＇ Regional Climate Model（RegCM4）, driven by ERA-Interim boundary conditions a...A long-term simulation for the period 1990–2010 is conducted with the latest version of the International Centre for Theoretical Physics＇ Regional Climate Model（RegCM4）, driven by ERA-Interim boundary conditions at a grid spacing of 25 km. The Community Land Model（CLM） is used to describe land surface processes, with updates in the surface parameters,including the land cover and surface emissivity. The simulation is compared against observations to evaluate the model performance in reproducing the present day climatology and interannual variability over the 10 main river basins in China,with focus on surface air temperature and precipitation. Temperature and precipitation from the ERA-Interim reanalysis are also considered in the model assessment. Results show that the model reproduces the present day climatology over China and its main river basins, with better performances in June–July–August compared to December–January–February（DJF）.In DJF, we find a warm bias at high latitudes, underestimated precipitation in the south, and overestimated precipitation in the north. The model in general captures the observed interannual variability, with greater skill for temperature. We also find an underestimation of heavy precipitation events in eastern China, and an underestimation of consecutive dry days in northern China and the Tibetan Plateau. Similar biases for both mean climatology and extremes are found in the ERA-Interim reanalysis, indicating the difficulties for climate models in simulating extreme monsoon climate events over East Asia.展开更多
Morpho-tectonic study plays an important role in deciphering the effects of tectonic activity in the geomorphic evolution of the drainage basins.Romushi watershed forms one of the major watersheds of the intermontane ...Morpho-tectonic study plays an important role in deciphering the effects of tectonic activity in the geomorphic evolution of the drainage basins.Romushi watershed forms one of the major watersheds of the intermontane Karewa Basin of Kashmir Valley.The Karewa sediments are characterized by glacio-fluvio-lacustrine deposits capped by the aeolian loess.The geomorphic,morphometric and lithostratigraphic studies of these cap deposits have been carried out to elucidate the effect of tectonics on the geomorphic evolution of Romushi Watershed.Geomorphic mapping was carried out using GPS measurements,DEM at 30m resolution,Topographic Position Index(TPI) model,topographic maps,LANDSAT TM Imagery and field data.Morphometric and morphotectonic analyses in GIS environment were used to calculate various geomorphic indices(Mountain Front Sinuosity Index,Bifurcation Ratio,Asymmetry Factor,River Profile,etc).These indices reveal that the tectonic uplift observed in the region due to Himalayan orogeny coupled with mass movement and aeolian deposition have dominated the landscape evolution of intermontane Karewa Basin of Kashmir throughout the Late Quaternary Period.Additional data from lithostratigraphic measurements were analyzed to understand the geomorphic evolution of intermontane Karewa Basin.The data revealed that the basin has experienced differential uplift and erosion rates from time to time in the geological past.This was corroborated by the results from the morphometric and morphotectonic analysis.展开更多
In recent years, global reanalysis weather data has been widely used in hydrological modeling around the world, but the results of simulations vary greatly. To consider the applicability of Climate Forecast System Rea...In recent years, global reanalysis weather data has been widely used in hydrological modeling around the world, but the results of simulations vary greatly. To consider the applicability of Climate Forecast System Reanalysis（CFSR） data in the hydrologic simulation of watersheds, the Bahe River Basin was used as a case study. Two types of weather data（conventional weather data and CFSR weather data） were considered to establish a Soil and Water Assessment Tool（SWAT） model, which was used to simulate runoff from 2001 to 2012 in the basin at annual and monthly scales. The effect of both datasets on the simulation was assessed using regression analysis, Nash-Sutcliffe Efficiency（NSE）, and Percent Bias（PBIAS）. A CFSR weather data correction method was proposed. The main results were as follows.（1） The CFSR climate data was applicable for hydrologic simulation in the Bahe River Basin（R^2 of the simulated results above 0.50, NSE above 0.33, and ｜PBIAS｜ below 14.8. Although the quality of the CFSR weather data is not perfect, it achieved a satisfactory hydrological simulation after rainfall data correction.（2） The simulated streamflow using the CFSR data was higher than the observed streamflow, which was likely because the estimation of daily rainfall data by CFSR weather data resulted in more rainy days and stronger rainfall intensity than was actually observed. Therefore, the data simulated a higher base flow and flood peak discharge in terms of the water balance, except for some individual years.（3） The relation between the CFSR rainfall data（x） and the observed rainfall data（y） could berepresented by a power exponent equation： y=1.4789x0.8875（R2=0.98,P〈0.001）. There was a slight variation between the fitted equations for each station. The equation provides a theoretical basis for the correction of CFSR rainfall data.展开更多
Global solar radiation（GSR） is the most direct source and form of global energy, and calculation of its quantity is highly complex due to influences of local topography and terrain inter-shielding. Digital elevation...Global solar radiation（GSR） is the most direct source and form of global energy, and calculation of its quantity is highly complex due to influences of local topography and terrain inter-shielding. Digital elevation model（DEM） data as a representation of the complex terrain and multiplicity condition produces a series of topographic factors（e.g. slope, aspect, etc.）. Based on 1 km resolution DEM data, meteorological observations and NOAA-AVHRR remote sensing data, a distributed model for the calculation of GSR over rugged terrain within the Yangtze River Basin has been developed. The overarching model permits calculation of astronomical solar radiation for rugged topography and comprises a distributed direct solar radiation model, a distributed diffuse radiation model and a distributed terrain reflectance radiation model. Using the developed model, a quantitative simulation of the GSR space distribution and visualization has been undertaken, with results subsequently analyzed with respect to locality and terrain. Analyses suggest that GSR magnitude is seasonally affected, while the degree of influence was found to increase in concurrence with increasing altitude. Moreover, GSR magnitude exhibited clear spatial variation with respect to the dominant local aspect; GSR values associated with the sunny southern slopes were significantly greater than those associated with shaded slopes. Error analysis indicates a mean absolute error of 12.983 MJm-2 and a mean relative error of 3.608%, while the results based on a site authentication procedure display an absolute error of 22.621 MJm-2 and a relative error of 4.626%.展开更多
Estimation of base level changes in geological records is an important topic for petroleum geologists.Taking the Paleocene Upper Lingfeng Member of Lishui Sag as an example,this paper conducted a base level reconstruc...Estimation of base level changes in geological records is an important topic for petroleum geologists.Taking the Paleocene Upper Lingfeng Member of Lishui Sag as an example,this paper conducted a base level reconstruction based on Basin Filling Modelling(BFM).The reconstruction was processed on the ground of a previously interpreted seismic stratigraphic framework with several assumptions and simplification.The BFM is implemented with a nonlinear diffusion equation solver written in R coding that excels in shallow marine stratigraphic simulation.The modeled results fit the original stratigraphy very well.The BFM is a powerful tool for reconstructing the base level,and is an effective way to check the reasonableness of previous interpretations.Although simulation solutions may not be unique,the BFM still provides us a chance to gain some insights into the mechanism and dynamic details of the stratigraphy of sedimentary basins.展开更多
基金The National Special Project for Marine Geology of China under contract No.DD20160147the National Basic Research Program(973 Program) of China under contract No.2013CB429701the National Natural Science Foundation of China under contract No.41210005
文摘Basin modeling has become an important tool for analyzing sedimentary basins. The North Subbasin of the South Yellow Sea Basin is filled with thick Meso-Cenozoic terrigenous deposits during the rift evolution stage. The accumulation of data and achievements of geological investigations in recent years have provided the preconditions for basin modeling. The necessary parameters and geological elements for simulations are collated and summarized. Modeling of tectono-thermal evolution is performed and the related trend in heat flow is reconstructed and calibrated. The heat flow value commences from an average level of 61 m W/m2during MiddleLate Jurassic, rises to about 80 m W/m2from circa 145 Ma to circa 74 Ma, and then undergoes a gradual decline to65 m W/m2until the end of Oligocene.Three evolutionary phases, namely, the initial rifting phase, syn-rifting phase, and post-rifting phase, have been identified. The modeling results show that the North Subbasin generally enters into a stage of strong rifting during Cretaceous and undergoes rapid subsidence until the Late Cretaceous,then follows by a stage of moderate rifting during the Paleogene. The input and general workflow involved in 3-D modeling are introduced. Reconstruction of the petroleum system in the North Subbasin reveals that the threshold depth of hydrocarbon generation is located near the top of the Paleogene Funing formation, and the underlying Jurassic and Cretaceous source rocks have reached or exceeded peak oil generation and have almost completed the generation and expulsion of hydrocarbons. The main generation and expulsion in the Jurassic source rocks take place during the syn-rifting and post-rifting phases, whereas the peak generation and expulsion in the Cretaceous and Paleogene source rocks take place during the post-rifting phase. Although the study area is still a relatively less explored sedimentary basin, the results of modeling can provide valuable information for exploration. A preliminary discussion of the main uncertainty factors is also presented.
基金financially supported by the National Science and the Technology Major Project(Nos.2016ZX05024002-003,2017ZX05032-001-004,2016ZX05027-001-005)the National Science Foundation of China(No.41672136)the Branch of Exploration Project,SINOPEC(No.G0800-14-KK-169)
文摘The Eocene Niubao Formation is the primary research target of oil exploration in the Lunpola Basin.Crude oil was extracted from Well Z1 on the northern margin of the basin in 1993.In this study,an integrated evaluation of the source rock geothermal,and maturity histories and the fluid inclusion and fluid potential distributions was performed to aid in predicting areas of hydrocarbon accumulation.Due to the abundance of organic matter,the kerogen types,maturity,and oil-sources correlate with the geochemical data.The middle submember of the second member of the Niubao Formation(E2n^2-2)is the most favorable source rock based on the amount of oil produced from the E2n^2-3and E2n^3-1reservoirs.One-and twodimensional basin modeling,using BasinMod software,shows that the E2n^2-2source rock started to generate hydrocarbon at 35-30 Ma,reached a maturity of Ro=0.7%at 25-20 Ma,and at present,it has reached the peak oil generation stage with a thermal maturity of Ro=0.8%to less than Ro=1.0%.By using fluid inclusion petrography,fluorescence spectroscopy,and microthermometry,two major periods of oil charging have been revealed at 26.1-17.5 and 32.4-24.6 Ma.The oil accumulation modeling results,conducted by using the Trinity software,show a good fit of the oil shows in the wells and predict that the structural highs and lithologic transitions within the Jiangriaco and Paco sags are potential oil traps.
基金funded by Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0201,GML2019ZD0104)Finance Science and Technology Project of Hainan Province(ZDKJ202019).
文摘Great advancement has been made on natural gas hydrates exploration and test production in the northern South China Sea.However,there remains a lot of key questions yet to be resolved,particularly about the mechanisms and the controls of gas hydrates enrichment.Numerical simulaution would play signficant role in addressing these questions.This study focused on the gas hydrate exploration in the Shenhu Area,Northern South China Sea.Based on the newly obtained borehole and multichannel reflection seismic data,the authors conducted an integrated 3D basin modeling study on gas hydrate.The results indicate that the Shenhu Area has favorable conditions for gas hydrate accumulation,such as temperature,pressure,hydrocarbon source,and tectonic setting.Gas hydrates are most concentrated in the Late Miocene strata,particularly in the structual highs between the Baiyun Sag and the Liwan Sag,and area to the south of it.It also proved the existence of overpressure in the main sag of source rocks,which was subject to compaction disequilibrium and hydrocarbon generation.It also shown that the regional fault activity is not conducive to gas hydrate accumulation due to excess gas seepage.The authors conjecture that fault activity may slightly weaken overpressure for the positive effect of hydrocarbon expulsion and areas lacking regional fault activity have better potential.
基金express their gratitude to Petrogulf Misr Petroleum Company and Egyptian General Petroleum Corporation(EGPC)for their invaluable support and cooperation in providing essential data,which greatly facilitated the completion of this work.
文摘This study aims to define the hydrocarbon generation potential of source rocks by assessing various factors including quantity of organic matter, types of kerogen, thermal maturity, and source of organic matter input. Depositional conditions of source rocks from Thebes, Brown Limestone, and Matulla formations in Well G-9, Well GA-2 and Well GW-6, are assessed through pyrolysis, vitrinite reflectance and1D basin modeling. Results show the source rocks of Thebes and Brown Limestone formations exhibit favorable to excellent source rock characteristics with Type I-II kerogen and have the capacity to generate oil. Conversely, the source rocks of the Matulla Formation show fair to good source rock characteristics with Type II-III kerogen and have the capacity to produce both oil and gas. Thermal maturity shows the source rocks are at an immature stage. A 1D basin model is constructed for Well G-9to simulate multi-tectonic episodes, burial events, and the history of thermal maturity. Sedimentation rates of Cretaceous to Eocene deposits are characterized by a low burial rate, which contrasts with the high burial and sedimentation rates for Miocene and post Miocene(Pliocene-Recent) strata. Overall, the South Geisum oilfield petroleum system is found to be immature based on integration of source rock evaluation and petroleum basin modelling.
基金supported by the China National Science and Technology Major Project(Nos.2016ZX05024-002-003,2017ZX05032-001-004)the Foundation of Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education(China University of Geosciences),China(Nos.TPR-2022-11,TPR-2022-24)the Science and Technology Planning Project of Tangshan City,China(Nos.22130213H).
文摘Jiaojiang sag in the East China Sea Basin is at the earlier exploration stage,where characterizing hydrocarbon generation of source rocks is important to understand oil-gas exploration potential.Utilizing geochemical and basin modeling analysis,hydrocarbon generation capacity and process of the Paleocene E_(1)y,E_(1)l and E_(1)m formations were investigated.Results show that E_(1)y and E_(1)l mudstones are high-quality source rocks with Type Ⅱ kerogen,which is dominated by both aquatic organisms and terrestrial higher plants deposited in sub-reduced environment.E_(1)m mudstone interbedded with thin carbonaceous mudstone and coal is poor-quality source rock with Type Ⅲ kerogen,whose organic matter was originated from terrestrial higher plants under oxidized environment.Controlled by burial and maturity histories,E_(1)y and E_(1)l source rocks experienced two hydrocarbon generation stages,which took place in the Late Paleocene and in the Middle to Late Eocene,respectively,and had high hydrocarbon generation capacity with cumulative hydrocarbon volume of 363 and 328 mg/g,respectively.E_(1)m source rock only had one hydrocarbon generation process in the Late Eocene,which had low hydrocarbon generation capacity with cumulative hydrocarbon volume of only 24 mg/g.The future oil-gas exploration in the Jiaojiang sag should focus on hydrocarbon generation center and select targets in the central uplift formed before the Miocene with high-quality traps.
文摘Lacustrine-fan deltas feature high reservoir-quality lithounits that are critical targets to hydrocarbon exploration and development.However,depicting their intricate sedimentary architectural elements is still challenging due to complex stacking-patterns and limited examples.In this study,both 3D-static geocellular reservoir modeling and 1D-basin modeling approaches were combined as an established effective workflow that is capable of efficiently delineating reservoir-heterogeneities and confirming hydrocarbon-charging.This integration was for the purpose of unlocking the ultimate petroleum potential of fluvio-lacustrine units,Nubia Formation,in the southwest of the Gulf of Suez rift(West Esh-ElMallaha Concession,Egypt).Pixel-based stochastic-simulation was applied,constrained by an established depositional-model developed after adequate integrated-facies analysis,upon geocellularly modeling rock and fluid properties of Nubia reservoir intervals;utilizing several key-information scales(seismic-profiles,well-logs).The results reveal a lowstand-transgressive systems tract encompassing fluvio-lacustrine depositional-systems subdivided into eight facies-associations,of which fluvialchannels and deltaic mouth bars represent significant reservoir-quality facies.Given efficient reservoir-quality,mouth sand-bars deserve special consideration,and testing,while running further oilfield development-endeavours and investigating similar-settings.
基金supported by the National Natural Science Foundation of China(Grant Nos.42130802 and 42072198)the Fundamental Research Funds for the Central Universities(No.265QZ2021011)+1 种基金PetroChina Company Limited“14th Five Year Plan”Science and Technology Major Project(No.2021DJ2301)PetroChina Company Limited Science and Technology Project(No.2023-KJ-18).
文摘Unconventional natural gas in deep coal measures has become an exploration and research hotspot in recent years.The exploration breakthrough of deep coalbed methane and tight sandstone gas in Daning-Jixian Block in the eastern Ordos Basin has revealed huge resource potential and commercial prospects in the deep Upper Paleozoic Carboniferous-Permian coal measures.However,the ambiguity of gas accumulation in deep coal measures has restricted exploration and development.Based on a series of tests for fluid inclusions,including petrographic observation,Raman spectroscopy analysis,and microthermometry,combined with the burial-thermal evolution history recovered from basin modeling,this study aims to clarify the timing of gas accumulation in deep coal measures.The results show four types of secondary fluid inclusions in the deep coal measure sandstone layers of Daning-Jixian Block,including CH4-rich inclusions,C2+hydrocarbons-bearing inclusions,CO_(2)-bearing inclusions,and aqueous inclusions.The main formation stage of fluid inclusions corresponded to the mesodiagenesis stage of the deep coal measure sandstone,and the coeval assemblages of fluid inclusions vary due to the recording of gas charging in different maturity stages of coal measure source rocks.This study suggests that tight sandstone gas accumulation in deep coal measures was a continuous charging process with one period-multiple episodes in Daning-Jixian Block,and occurred mainly during the Early Cretaceous(137−127 Ma BP).The results of this study contribute to further understanding of gas accumulation mechanisms in deep coal measures.
基金funded by National Science and Technology Major Projects(Grant No.2016ZX05050,2017ZX05001002-008)China National Petroleum Corporation Major Projects(No.2021DJ2203)Key Laboratory of Petroleum Resources Exploration and Evaluation,Gansu Province(No.KLPREEGS-2024-22)。
文摘In recent years,fueled by significant advancements in oil exploration technologies within the Ordos Basin,an increasing number of low-permeability or ultra-low-permeability reservoirs have been identified.Elucidating their reservoir characteristics and formation mechanisms has become a critical priority for sustainable hydrocarbon development.The study focused on the Chang 6 Member of the Upper Triassic Yanchang Formation in the Heshui area of the Ordos Basin,systematically investigating its petrological features,porosity and permeability characteristics,diagenesis,and diagenetic evolution sequence.By integrating core observation,thin-section identification,and physical property measurements,a comprehensive quantitative evaluation of reservoir pore evolution was performed.These analytical outcomes were subsequently applied to simulate hydrocarbon migration and accumulation.These research results will provide a scientific basis for in-depth quantitative study of the pore evolution in ultra-low-permeability oil reservoirs and accurately constructing basin models.As indicated,the reservoir lithology in the study area predominantly comprises siltstone interbedded with mudstone or argillaceous siltstone,characterized by low porosity and permeability.Through diagenetic characteristics-based reconstruction constrained by the existing porosity data,pore evolution during diagenesis was quantitatively modeled.The simulated pore evolution aligns with actual geological observations,validating the reliability of the methodology.Furthermore,the quantified pore evolution results were applied to simulate hydrocarbon migration using PetroMod software,showing that hydrocarbon charging in the basin began at the end of the Late Jurassic(J3),peaking in hydrocarbon generation,expulsion,and accumulation by the end of the Early Cretaceous(K1)and maintaining high accumulation rates until the late Cretaceous,though significantly decreasing at the present stage.The simulation results were verified by comparison with actual drilling data,which confirms their reliability and applicability to other analogous oilfields.
文摘An integrated study on source rock characterization and hydrocarbon generation potential modeling was conducted for the selected Dingo Claystone,Barrow Sub-basin,Australia.In this study,data were collected solely from two wells represented by the Bambra-1 and Bambra-2 wells.The collected data include those from bulk geochemical analyses of cuttings and sidewall cores sampled from the Late Jurassic Dingo Claystone.Geochemical data obtained from Rock-Eval pyrolysis and gas chromatography(GC)of extracted organic matter were integrated for source rock characterization and the construction of burial history and hydrocarbon generation in the Dingo Claystone.To improve the accuracy of thermal maturity estimations,only samples with S2 greater than 1 were considered due to potential issues with peak integration and uncertainties of Tmax determination in samples with lower S2 values.Furthermore,Rock-Eval data from the Bambra wells may be unreliable due to the contamination of cuttings and sidewall core(SWC)samples by drilling mud additives and natural hydrocarbons,which could impact the reliability of the data for determining thermal maturity.This study reveals that the Dingo Claystone Formation has total organic carbon(TOC)contents ranging from 0.66%to 8.31%.A poor to good hydrocarbon generation potential is indicated,with a production yield(PY=S_(1)+S_(2))ranging from 1.37 to 10.44 mg HC/g rock.Hydrogen index values vary between 42 and 226 mg HC/g TOC,confirming that the Dingo Claystone is dominantly kerogen TypeⅢ,with minor contributions from typesⅡ/ⅢandⅣ.Thermal maturity ranges from immature to late mature and is mostly in the oil window.This is indicated by T_(max)values of 398-462℃and vitrinite reflectance(Ro,%)of 0.47-1.99.Some samples show suppressed T_(max)and a higher production index,which is typical for samples affected by drilling fluids during drilling operations.Additionally,gas chromatography(GC)analyses are used to interpret the paleodepositional environment showing mixed input between marine and terrestrial origins of the source rocks.One-dimensional basin modeling for the Bambra-1 and Bambra-2 wells was carried out to evaluate the burial and thermal history of the formation.The transformation ratio suggests that hydrocarbon generation has not reached its peak and is still in an ongoing phase.An indication of hydrocarbon migration can be observed in this formation based on the transformation ratio.The effects of contamination warrant further investigation,as it could significantly impact maturity estimates and data reliability.
基金supported by the Natural Science Foundation of China (Grant No.40972089)the Foundation of the State Key Laboratory of Petroleum Resources and Prospecting (Grant No.PRPDX2008-01)
文摘The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes of the whole region. Using molecular geochemistry, fluid inclusion techniques and basin modeling, we studied the oil filling process of the Bashituo Oilfield that is located in the west of the Markit Slope. The molecular migration indexes, such as the methyldibenzothiophene ratio （4-/1-MDBT）, trimethylnaphthalene ratio （TMNr） and pyrrolic nitrogen compounds content, decrease from west to east, indicating that the charging direction and migration pathways are from west to east. Lithological analysis and homogenization temperatures of saline fluid inclusions accompanied with oil fluid inclusions suggest that two charging periods occurred in the Devonian oil reservoir. Combining the burial history and heating history of well BT4, Basinmod 1D software modeling shows the two oil filling periods are from 290 Ma to 285 Ma and from l0 Ma to 4 Ma, respectively, and later oil filling dominates. This study may be helpful to understand the accumulation process and provide useful references for oil and gas exploration in the Markit Slope.
基金supported by the National Natural Science Foundation of China (No. 40172051)the Jilin Oil Field Scientific Project of China National Petroleum Corporation (No. 2006026157)the Special Fund for Basic Scientific Research of Central Colleges, China University of Geosciences (Wuhan) (Nos. 2010029056, CUGL10024)
文摘The Yitong（伊通） basin is a Late Mesozoic and Cenozoic continental sedimentary basin in Northeast China.On the basis of well tests and seismic data,we use the 2D modeling technique to rebuild the pressure evolution and hydrocarbon migration in the Moliqing（莫里青） fault depression of the Yitong basin.Based on the modeling results,four conclusions are drawn as follows.（1） The Eocene Shuangyang（双阳） Formation within the Moliqing fault depression had entirely undergone three epi-sodic cycles of pressure accumulation and release in geological history,and the three tectonic move-ments since the Middle Eocene played important roles in the episodic changes of excess pressure.（2） The present formation pressure distribution is characterized by normal pressure in almost the entire fault depression with some residual overpressure.The differential distribution of pressure results mainly from the difference in rock facies,sedimentation rate,hydrocarbon generation,and fault activi-ties.（3） The hydrocarbon migration is more active during the release of pressure in the Moliqing fault depression,which happened mainly in the Middle-Late Oligocene and provided the driving force for hydrocarbon migration.（4） The hydrocarbon migration was mostly directed to the Shuangyang For-mation within the Jianshan（尖山） uplift and the Kaoshan（靠山） sag.With the superior condition ofhydrocarbon accumulation and the higher de-gree of hydrocarbon concentration,the north-west part of Kaoshan sag is considered a favor-able area for oil and gas exploration in the Moliqing fault depression.
基金This study was supported by the National Natural Science Foundation of China (No.49732005-01)
文摘The problem that faults act as a conduit for hydrocarbon bearing fluid flow has been under debate for a long time. The southern boundary fault (F S) and No.2 fault belt in the Zhu Ⅲ subbasin in the Pearl River Mouth basin (PRMB) of South China Sea (SCS) are considered as the conduit of hydrocarbons for the oil and gas fields in the hydrocarbon generating half grabens. Based upon the basin modeling and seismic velocity inversion simulation, there are abnormal pressure compartments in the central part of half grabens. Wenchang, Enping and Zhuhai FormationⅡare seated within the abnormal pressure zone, while the Zhuhai Formation Ⅰ is within the pressure transition zone. The abnormal pressure was mainly caused by undercompaction due to the high rate of sedimentation for layers with an abnormal pressure. The increase of temperature of inclusions as the increase of depth supports vertical migration via faults in the study area.
文摘The Sahul Platform where the Sunset-Loxton Shoals and Chuditch gas fields were discovered is located between the Timor Trough to the north and the Malita Graben to the south. These areas are located respectively 440 km and 380 km northwest of Darwin in the northern Bonaparte Basin, Australia. Based on the structural evolution of the northern Bonaparte Basin, data from the wells Loxton Shoals 1, Sunset 1 and Chuditch 1 in the Sahul Platform and Heron 1 in the Malita Graben depocentre, and the Seismic Line N11606 were used to clarify the geological conditions and reconstruct the hydrocarbon accumulation processes in the study area. BasinMod 1-D, 2-D, and 3-D software was used for modeling. The Plover Formation source rock was a poor-to-good hydrocarbon generative potential and reached the middle to late mature oil window in the Sunset-Loxton Shoals field whereas in the Chuditch field, it was an overall fair-to-good hydrocarbon generative potential, and attained the Late mature oil window. The Flamingo, and the Echuca Shoals formations source rocks in the same field were a fair and good hydrocarbon generation potential respectively, and both reached mid-mature oil window. In the Malita Graben depocentre, the Petrel (Frigate) and the Echuca Shoals formations source rocks were a poor-to-very good hydrocarbon generating potential, and had attained wet gas window at the present day. The analyses of organic matter showed that the source rocks in the study area and Malita Graben were gas prone with kerogen types II2 & III and III predominantly. The Middle Jurassic Plover Formation sandstone reservoir in the Sunset-Loxton field was a poor-to-very good quality and potential for gas beds, and it was a very poor-to-very good quality and potential for gas beds in the Chuditch field. The intensities of gas generation and expulsion were more than of oil ones either in the Sahul Platform or in the Malita Graben. The Plover, Petrel (Frigate) and Echuca Shoals formations source rocks in the wells Chuditch 1 and Heron 1, except for the Flamingo Formation in the well Chuditch 1, had higher gas and oil expelling efficiencies than the Plover Formation source rock of the wells in the Sunset-Loxton Shoals field. The hydrocarbon migrated mainly from the Upper Jurassic Frigate Shale source rock in the Malita Graben depocentre (structurally lower) to the Plover Formation sandstone reservoir in the Sunset-Loxton Shoals field during the Late Cretaceous at 66 Ma. In the Chuditch field, the hydrocarbon migration to the Plover Formation sandstone reservoir was initiated during the Late Miocene at 7.5 Ma from the Middle Jurassic Plover Formation source rock in the well Chuditch 1. Nowadays, the main migration pathways are from the southeastward and southward of the Sunset-Loxton Shoals field, and from southward and eastward of the Chuditch field, precisely from the hydrocarbon source kitchens of the Malita Graben depocentre. The traps in the Sahul Platform have been effective to receive the migrated hydrocarbon.
基金supported by the National Science and Technology Major Project (2008ZX05002-006-007HZ)
文摘Through natural gas exploration in the Changling Fault Depression,abundant natural gas flows were obtained and high-quality source rocks were also reveiled.Based on bulk analyses,organic matter abundance,organic matter type and thermal maturity of the source rocks were studied systematically.At the same time,gas gener-ating intensity and gas generating quantity were quantitatively analyzed by using basin modeling technologies.The results indicated that gas source rocks of the Shahezi Formation are characterized by abundant organic matter and dark mudstone distributions and high-over thermal maturity.They possess high gas generating intensity with the biggest value surpassing 500×108 m3/km2,and large gas generating quantity,accounting from 74.40% of the total amount.The Yingcheng Formation has good gas-source rocks with moderate dark mudstone and relatively high organic matter.It has type-Ⅲ organic matter and low-over thermal maturity.The gas generating intensity is moderate,between 20×108 and 60×108 m3/km2.The gas generating quantity is 13.63% of the total amount.The Huoshiling Formation has relatively good source rocks with limited dark mudstone and low organic matter.It has type-Ⅲ kerogen and over-thermal maturity.The gas generating quantity is 7.10% of the total amount.The Denglouku Formation has poor-gas source rocks,and is characterized by undeveloped dark mudstone and low organic matter abundance.It has type-Ⅲ organic matter and low-high thermal maturity.Hydrocarbon gases in the Changling Fault Depression mainly originated from the Shahezi Formation,and secondarily from the Yingcheng Formation.The contribution of the Huoshiling Formation gas source rocks is relatively small.
基金the National Natural Science Foundation of china (poject No. 49070140)
文摘Based on fission track dating of apatite, and measurement of vitrinite reflectance of rock samples from the Longmenshan (Longmen Mountain)area and the West Sichuan foreland basin and computer modelling it is concluded that (l)the Songpan-Garze fold belt has uplifted at least by 3-4 km with an uplift rate of no less than 0.3-0.4 mm/a since 10 Ma B.P.; (2) the Longmenshan thrust nappe belt has uplifted at least by 5-6 km with an uplift rate of more than 0.5- 0.6 mm /a since 10 Ma B.P.; (3) the Longmenshan detachment belt has uplifted by 1 - 2 km at a rate of 0.016-0.032 mm/a since 60 Ma B.P.; (4) the West Sichuan foreland basin has uplifted by 1.7-3 km at a rate of 0.028-0.05 mm/a since 60 Ma B.P.; (5) the uplift rate of the area on the west side of the Beichuan-Yingxiu-Xiaoguanzi fault for the last 10 Ma is 40 times as much as that on its east side; (6) the uplifting of the the Songpan - Garze fold belt and the subsidence of the West Sichuan foreland basin 60 Ma ago exhibit a mirro-image correlation, i.e. the rapid uplifting of the the Songpan-Garze fold belt was corresponding to the rapid subsidence of the basin;the Songpan-Garze fold belt has uplifted at a much greater rate than the West Sichuan foeland basin in the last 60 Ma;and (7) the palaeogeothermal gradient was 25℃ /km in the West Sichuan foreland basin.
基金jointly supported by the National Key Research and Development Program of China(Grant No.2016YFA0600704)the National Natural Science Foundation(Grant No.41375104)the Climate Change Specific Fund of China(Grant Nos.CCSF201626 and CCSF201509)
文摘A long-term simulation for the period 1990–2010 is conducted with the latest version of the International Centre for Theoretical Physics＇ Regional Climate Model（RegCM4）, driven by ERA-Interim boundary conditions at a grid spacing of 25 km. The Community Land Model（CLM） is used to describe land surface processes, with updates in the surface parameters,including the land cover and surface emissivity. The simulation is compared against observations to evaluate the model performance in reproducing the present day climatology and interannual variability over the 10 main river basins in China,with focus on surface air temperature and precipitation. Temperature and precipitation from the ERA-Interim reanalysis are also considered in the model assessment. Results show that the model reproduces the present day climatology over China and its main river basins, with better performances in June–July–August compared to December–January–February（DJF）.In DJF, we find a warm bias at high latitudes, underestimated precipitation in the south, and overestimated precipitation in the north. The model in general captures the observed interannual variability, with greater skill for temperature. We also find an underestimation of heavy precipitation events in eastern China, and an underestimation of consecutive dry days in northern China and the Tibetan Plateau. Similar biases for both mean climatology and extremes are found in the ERA-Interim reanalysis, indicating the difficulties for climate models in simulating extreme monsoon climate events over East Asia.
文摘Morpho-tectonic study plays an important role in deciphering the effects of tectonic activity in the geomorphic evolution of the drainage basins.Romushi watershed forms one of the major watersheds of the intermontane Karewa Basin of Kashmir Valley.The Karewa sediments are characterized by glacio-fluvio-lacustrine deposits capped by the aeolian loess.The geomorphic,morphometric and lithostratigraphic studies of these cap deposits have been carried out to elucidate the effect of tectonics on the geomorphic evolution of Romushi Watershed.Geomorphic mapping was carried out using GPS measurements,DEM at 30m resolution,Topographic Position Index(TPI) model,topographic maps,LANDSAT TM Imagery and field data.Morphometric and morphotectonic analyses in GIS environment were used to calculate various geomorphic indices(Mountain Front Sinuosity Index,Bifurcation Ratio,Asymmetry Factor,River Profile,etc).These indices reveal that the tectonic uplift observed in the region due to Himalayan orogeny coupled with mass movement and aeolian deposition have dominated the landscape evolution of intermontane Karewa Basin of Kashmir throughout the Late Quaternary Period.Additional data from lithostratigraphic measurements were analyzed to understand the geomorphic evolution of intermontane Karewa Basin.The data revealed that the basin has experienced differential uplift and erosion rates from time to time in the geological past.This was corroborated by the results from the morphometric and morphotectonic analysis.
基金International Partnership Program of Chinese Academy of Sciences,No.131551KYSB20160002 National Natural Science Foundation of China,No.41401602+2 种基金 Natural Science Basic Research Plan in Shaanxi Province of China,No.2014JQ2-4021 Key Scientific and Technological Innovation Team Plan of Shaanxi Province,No.2014KCT-27 Graduate Student Innovation Project of Northwest University,No.YZZ15011
文摘In recent years, global reanalysis weather data has been widely used in hydrological modeling around the world, but the results of simulations vary greatly. To consider the applicability of Climate Forecast System Reanalysis（CFSR） data in the hydrologic simulation of watersheds, the Bahe River Basin was used as a case study. Two types of weather data（conventional weather data and CFSR weather data） were considered to establish a Soil and Water Assessment Tool（SWAT） model, which was used to simulate runoff from 2001 to 2012 in the basin at annual and monthly scales. The effect of both datasets on the simulation was assessed using regression analysis, Nash-Sutcliffe Efficiency（NSE）, and Percent Bias（PBIAS）. A CFSR weather data correction method was proposed. The main results were as follows.（1） The CFSR climate data was applicable for hydrologic simulation in the Bahe River Basin（R^2 of the simulated results above 0.50, NSE above 0.33, and ｜PBIAS｜ below 14.8. Although the quality of the CFSR weather data is not perfect, it achieved a satisfactory hydrological simulation after rainfall data correction.（2） The simulated streamflow using the CFSR data was higher than the observed streamflow, which was likely because the estimation of daily rainfall data by CFSR weather data resulted in more rainy days and stronger rainfall intensity than was actually observed. Therefore, the data simulated a higher base flow and flood peak discharge in terms of the water balance, except for some individual years.（3） The relation between the CFSR rainfall data（x） and the observed rainfall data（y） could berepresented by a power exponent equation： y=1.4789x0.8875（R2=0.98,P〈0.001）. There was a slight variation between the fitted equations for each station. The equation provides a theoretical basis for the correction of CFSR rainfall data.
基金National Natural Science Foundation of China,No.41175077 National Natural Science Foundation for Young Scholars,No.S0508016001 Guizhou Branch Major Projects[2011],No.6003
文摘Global solar radiation（GSR） is the most direct source and form of global energy, and calculation of its quantity is highly complex due to influences of local topography and terrain inter-shielding. Digital elevation model（DEM） data as a representation of the complex terrain and multiplicity condition produces a series of topographic factors（e.g. slope, aspect, etc.）. Based on 1 km resolution DEM data, meteorological observations and NOAA-AVHRR remote sensing data, a distributed model for the calculation of GSR over rugged terrain within the Yangtze River Basin has been developed. The overarching model permits calculation of astronomical solar radiation for rugged topography and comprises a distributed direct solar radiation model, a distributed diffuse radiation model and a distributed terrain reflectance radiation model. Using the developed model, a quantitative simulation of the GSR space distribution and visualization has been undertaken, with results subsequently analyzed with respect to locality and terrain. Analyses suggest that GSR magnitude is seasonally affected, while the degree of influence was found to increase in concurrence with increasing altitude. Moreover, GSR magnitude exhibited clear spatial variation with respect to the dominant local aspect; GSR values associated with the sunny southern slopes were significantly greater than those associated with shaded slopes. Error analysis indicates a mean absolute error of 12.983 MJm-2 and a mean relative error of 3.608%, while the results based on a site authentication procedure display an absolute error of 22.621 MJm-2 and a relative error of 4.626%.
基金the Initial Fund for Young Scholars of Qingdao University of Science and Technology and the National Natural Science Foundation of China(No.51804325)。
文摘Estimation of base level changes in geological records is an important topic for petroleum geologists.Taking the Paleocene Upper Lingfeng Member of Lishui Sag as an example,this paper conducted a base level reconstruction based on Basin Filling Modelling(BFM).The reconstruction was processed on the ground of a previously interpreted seismic stratigraphic framework with several assumptions and simplification.The BFM is implemented with a nonlinear diffusion equation solver written in R coding that excels in shallow marine stratigraphic simulation.The modeled results fit the original stratigraphy very well.The BFM is a powerful tool for reconstructing the base level,and is an effective way to check the reasonableness of previous interpretations.Although simulation solutions may not be unique,the BFM still provides us a chance to gain some insights into the mechanism and dynamic details of the stratigraphy of sedimentary basins.
