The Dongfang1-1 gas field(DF1-1)in the Yinggehai Basin is currently the largest offshore self-developed gas field in China and is rich in oil and gas resources.The second member of the Pliocene Yinggehai Formation(YGH...The Dongfang1-1 gas field(DF1-1)in the Yinggehai Basin is currently the largest offshore self-developed gas field in China and is rich in oil and gas resources.The second member of the Pliocene Yinggehai Formation(YGHF)is the main gas-producing formation and is composed of various sedimentary types;however,a clear understanding of the sedimentary types and development patterns is lacking.Here,typical lithofacies,logging facies and seismic facies types and characteristics of the YGHF are identified based on high-precision 3D seismic data combined with drilling,logging,analysis and testing data.Based on 3D seismic interpretation and attribute analysis,the origin of high-amplitude reflections is clarified,and the main types and evolution characteristics of sedimentary facies are identified.Taking gas formation upper II(IIU)as an example,the plane distribution of the delta front and bottom current channel is determined;finally,a comprehensive sedimentary model of the YGHF second member is established.This second member is a shallowly buried“bright spot”gas reservoir with weak compaction.The velocity of sandstone is slightly lower than that of mudstone,and the reflection has medium amplitude when there is no gas.The velocity of sandstone decreases considerably after gas accumulation,resulting in an increase in the wave impedance difference and high-amplitude(bright spot)reflection between sandstone and mudstone;the range of high amplitudes is consistent with that of gas-bearing traps.The distribution of gas reservoirs is obviously controlled by dome-shaped diapir structural traps,and diapir faults are channels through which natural gas from underlying Miocene source rocks can enter traps.The study area is a delta front deposit developed on a shallow sea shelf.The lithologies of the reservoir are mainly composed of very fine sand and coarse silt,and a variety of sedimentary structural types reflect a shallow sea delta environment;upward thickening funnel type,strong toothed bell type and toothed funnel type logging facies are developed.In total,4 stages of delta front sand bodies(corresponding to progradational reflection seismic facies)derived from the Red River and Blue River in Vietnam have developed in the second member of the YGHF;these sand bodies are dated to 1.5 Ma and correspond to four gas formations.During sedimentation,many bottom current channels(corresponding to channel fill seismic facies)formed,which interacted with the superposed progradational reflections.When the provenance supply was strong in the northwest,the area was dominated by a large set of delta front deposits.In the period of relative sea level rise,surface bottom currents parallel to the coastline were dominant,and undercutting erosion was obvious,forming multistage superimposed erosion troughs.Three large bottom current channels that developed in the late sedimentary period of gas formation IIU are the most typical.展开更多
The kinetic parameters of hydrocarbon generation are determined through experimental simulation and mathematical calculation using four typical samples selected from the Cretaceous Nenjiang Formation in the northwest ...The kinetic parameters of hydrocarbon generation are determined through experimental simulation and mathematical calculation using four typical samples selected from the Cretaceous Nenjiang Formation in the northwest of Songliao Basin,Chang 7 Member of Triassic Yanchang Formation in the southwest of Ordos Basin,Paleogene in the southwest of Qaidam Basin,and Lucaogou Formation of Jimusar Sag in the east of Junggar Basin.The results show that activation energy of hydrocarbon generation of organic matter is closely related to maturity and mainly ranges between 197 kJ/mol and 227 kJ/mol.On this basis,the temperature required for organic matter in shale to convert into oil was calculated.The ideal heating temperature is between 270℃and 300℃,and the conversation rate can reach 90%after 50-300 days of heating at constant temperature.When the temperature rises at a constant rate,the temperature corresponding to the major hydrocarbon generation period ranges from 225 to 350℃at the temperature rise rate of 1-150℃/month.In order to obtain higher economic benefits,it is suggested to adopt higher temperature rise rate(60-150℃/month).The more reliable kinetic parameters obtained can provide a basis for designing more reasonable scheme of in-situ heating conversion.展开更多
基金The National Natural Science Foundation of China’s Major Project“Research on Geophysical Theories and Methods of Unconventional Oil and Gas Exploration and Development”,Task I:“China’s Tight Oil and Gas Reservoir Geological Characteristics,Classification and Typical Geological Model Establishment”under contract No.41390451。
文摘The Dongfang1-1 gas field(DF1-1)in the Yinggehai Basin is currently the largest offshore self-developed gas field in China and is rich in oil and gas resources.The second member of the Pliocene Yinggehai Formation(YGHF)is the main gas-producing formation and is composed of various sedimentary types;however,a clear understanding of the sedimentary types and development patterns is lacking.Here,typical lithofacies,logging facies and seismic facies types and characteristics of the YGHF are identified based on high-precision 3D seismic data combined with drilling,logging,analysis and testing data.Based on 3D seismic interpretation and attribute analysis,the origin of high-amplitude reflections is clarified,and the main types and evolution characteristics of sedimentary facies are identified.Taking gas formation upper II(IIU)as an example,the plane distribution of the delta front and bottom current channel is determined;finally,a comprehensive sedimentary model of the YGHF second member is established.This second member is a shallowly buried“bright spot”gas reservoir with weak compaction.The velocity of sandstone is slightly lower than that of mudstone,and the reflection has medium amplitude when there is no gas.The velocity of sandstone decreases considerably after gas accumulation,resulting in an increase in the wave impedance difference and high-amplitude(bright spot)reflection between sandstone and mudstone;the range of high amplitudes is consistent with that of gas-bearing traps.The distribution of gas reservoirs is obviously controlled by dome-shaped diapir structural traps,and diapir faults are channels through which natural gas from underlying Miocene source rocks can enter traps.The study area is a delta front deposit developed on a shallow sea shelf.The lithologies of the reservoir are mainly composed of very fine sand and coarse silt,and a variety of sedimentary structural types reflect a shallow sea delta environment;upward thickening funnel type,strong toothed bell type and toothed funnel type logging facies are developed.In total,4 stages of delta front sand bodies(corresponding to progradational reflection seismic facies)derived from the Red River and Blue River in Vietnam have developed in the second member of the YGHF;these sand bodies are dated to 1.5 Ma and correspond to four gas formations.During sedimentation,many bottom current channels(corresponding to channel fill seismic facies)formed,which interacted with the superposed progradational reflections.When the provenance supply was strong in the northwest,the area was dominated by a large set of delta front deposits.In the period of relative sea level rise,surface bottom currents parallel to the coastline were dominant,and undercutting erosion was obvious,forming multistage superimposed erosion troughs.Three large bottom current channels that developed in the late sedimentary period of gas formation IIU are the most typical.
基金Supported by the PetroChina Science and Technology Major Project(2016E-0101).
文摘The kinetic parameters of hydrocarbon generation are determined through experimental simulation and mathematical calculation using four typical samples selected from the Cretaceous Nenjiang Formation in the northwest of Songliao Basin,Chang 7 Member of Triassic Yanchang Formation in the southwest of Ordos Basin,Paleogene in the southwest of Qaidam Basin,and Lucaogou Formation of Jimusar Sag in the east of Junggar Basin.The results show that activation energy of hydrocarbon generation of organic matter is closely related to maturity and mainly ranges between 197 kJ/mol and 227 kJ/mol.On this basis,the temperature required for organic matter in shale to convert into oil was calculated.The ideal heating temperature is between 270℃and 300℃,and the conversation rate can reach 90%after 50-300 days of heating at constant temperature.When the temperature rises at a constant rate,the temperature corresponding to the major hydrocarbon generation period ranges from 225 to 350℃at the temperature rise rate of 1-150℃/month.In order to obtain higher economic benefits,it is suggested to adopt higher temperature rise rate(60-150℃/month).The more reliable kinetic parameters obtained can provide a basis for designing more reasonable scheme of in-situ heating conversion.
