地下流体势的空间分布模式与油气运移聚集关系
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摘要
利用流体势分析系统(简称 FPAS)研究地下流体势分布模式,可克服井资料不系统的局限性,有效地大规模进行盆地地下流体流动系统的研究.该方法技术在西藏伦坡拉盆地得到了很好的应用,得出了伦坡拉盆地具有"双层"结构的流体势分布特征,反映了西藏伦坡拉盆地所存在的两大流体流动系统,即重力流系统和压实流系统.这两大系统在流体势内幕结构水化学场、地温场、流体流动方向等方面具明显不同的特征.它们对油气运移聚集起着不同的作用,重力流系统对早期形成的油气起着破坏分散和再分布的作用;压实流系统残存有流体压力封闭舱,流体作发散状离心式短距离运移.利用流体势平面切片分布特征,指出了油气运移途径和方向,得出了可供勘探的有利低势油气聚集区.
Fluid potential analysis system(FPAS)based on seismic velocity data is developed in this study.The use of this system in the studies of underground fluid potential distribution patterns can avoid the limitation of drilling data,thus,effectively favouring the study of underground fluid flow systems on a large scale in sedimentary basins.The applications of this analysis system to Lunpola Basin of Xizang (Tibet)show that the distributions of fluid potential in the sections are of"two-layer"structure characteristics in Lunpola Basin.This distribution pattern indicates this basin contains two main fluid flow systems,gravity flow system and compaction flow system.Their characteristics vary in the distributions of fluid potential,water chemical field,geothermal field and the direction,and they play dif- ferent roles for hydrocarbon migration and accumulation in Lunpola Basin.Gravity flow system dispersed and reaccumulated hydrocarbons generated in early period from Niubao Formation(En).Fluid migrated with centrifugation style and in short distance,and main hydrocarbons accumulated incompaction flow sys- tem.According to the sliced map of fluid potential in Niubao Formation(En),hydrocarbon migration path- ways and directions can be pointed out and hydrocarbon accumulation areas for exploration determined through the closed contours of low oil and gas potential range.
Fluid potential analysis system(FPAS)based on seismic velocity data is developed in this study.The use of this system in the studies of underground fluid potential distribution patterns can avoid the limitation of drilling data,thus,effectively favouring the study of underground fluid flow systems on a large scale in sedimentary basins.The applications of this analysis system to Lunpola Basin of Xizang (Tibet)show that the distributions of fluid potential in the sections are of"two-layer"structure characteristics in Lunpola Basin.This distribution pattern indicates this basin contains two main fluid flow systems,gravity flow system and compaction flow system.Their characteristics vary in the distributions of fluid potential,water chemical field,geothermal field and the direction,and they play dif- ferent roles for hydrocarbon migration and accumulation in Lunpola Basin.Gravity flow system dispersed and reaccumulated hydrocarbons generated in early period from Niubao Formation(En).Fluid migrated with centrifugation style and in short distance,and main hydrocarbons accumulated incompaction flow sys- tem.According to the sliced map of fluid potential in Niubao Formation(En),hydrocarbon migration path- ways and directions can be pointed out and hydrocarbon accumulation areas for exploration determined through the closed contours of low oil and gas potential range.
引文
1 Hubbert M K.Entrapment of petroleum migration.AAPG Bull,1953,37:1954～2026
2 Dahlberg E C.Applied hydrodynamics in petroleum exploration.New York:Springer-Verlag,1982．
3 Toth J.Cmss-formational gravity flow groundwater:a mechanics of the transport and.accumulation of petro leum,problema of petroleum migration.AAPG Studies in Geology,1980,10:121～167
4 England W A,Mackenzie A S,Mann D M,et al.The movement and entrapment of petroleum fluids in the subsurface.Journal of the Geological Society,1987,144:327～344
5 Bethke C M,Reed J D,Oltz D F.Long-range petroleum migration in the Illinois Basin.AAPG,1991,75(5) :925～945
6 Fillipone W R.On the prediction of abnormal pressured sedimentary rock form seismic data.Congreso panamericano de ingeria del petroled.[s.1． ]:[s.n.],1979．
7 Hunt J.Generation and migration of petroleum from abnormally pressured fluid compartments.AAPG,1990,74(1) :1～12
2 Dahlberg E C.Applied hydrodynamics in petroleum exploration.New York:Springer-Verlag,1982．
3 Toth J.Cmss-formational gravity flow groundwater:a mechanics of the transport and.accumulation of petro leum,problema of petroleum migration.AAPG Studies in Geology,1980,10:121～167
4 England W A,Mackenzie A S,Mann D M,et al.The movement and entrapment of petroleum fluids in the subsurface.Journal of the Geological Society,1987,144:327～344
5 Bethke C M,Reed J D,Oltz D F.Long-range petroleum migration in the Illinois Basin.AAPG,1991,75(5) :925～945
6 Fillipone W R.On the prediction of abnormal pressured sedimentary rock form seismic data.Congreso panamericano de ingeria del petroled.[s.1． ]:[s.n.],1979．
7 Hunt J.Generation and migration of petroleum from abnormally pressured fluid compartments.AAPG,1990,74(1) :1～12
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