| The deepening understanding of the geological architecture of large-scale paleouplift within the basin is often accompanied by great discoveries in oil and gas exploration.A wealth of oil and gas exploration results in the early stage show that the Luzhou paleo-uplift is one of the most important oil and gas structural units in the Sichuan Basin.Meanwhile,the formation and evolution of Luzhou paleo-uplift has been influenced by many geological process,it is the joint response of the intra-plate deformation of the Yangtze block and the Indosinian orogeny of the peripheral block,it is considered as a natural laboratory for studying basin-mountain coupling and basin evolution.By means of a large number of seismic reflection profiles and drilling data,combined with the field survey data,the temporal and spatial distribution characteristics and tectonic-sedimentary evolution history of Luzhou paleo-uplift are described in detail.Based on the tectonic background of the study area,the dynamic process and characteristics of the formation and evolution of the Luzhou paleo-uplift were further analyzed,and its genetic mechanism model was proposed.Based on the fault-related folding theory,the seismic profile in the study area was interpreted in detail,the late period superposed deformation patterns of the Luzhou paleo-uplift were analyzed in detail,and the superposed deformation process of the Luzhou paleo-uplift was restored by using the method of balanced cross section and forward modeling of the geological model.After fully understanding the process of the formation,evolution,and superimposed deformation of the Luzhou paleo-uplift,through the analysis of typical oil and gas accumulation model in the region and the periphery of Luzhou paleo-uplift,the controls effect of the dynamic evolution process of the paleo-uplift on hydrocarbon accumulation is explored.This study got to the following basic conclusions:(1)The Indosinian Luzhou paleo-uplift in the southeastern Sichuan Basin was identified,its long-axis is trending in the northeast-southwest,which is a typical squeezing and superimposed paleo-uplift.Its formation and evolution has obvious periodic characteristics,and almost throughout the entire Triassic period.(2)The formation of Luzhou paleo-uplift is controlled by the Indosinian orogeny in the peripheral block,which can be regarded as the crustal uplifted zones in the front of the piedmont depression during the migration and squeeze period from east to west of the Xuefeng orogen on the southeastern margin of the Yangtze block.(3)The core area of the Luzhou paleo-uplift was involved in the late tectonic deformation zone,and was mainly controlled by four sets of detachment zones such as basement metamorphic rock,Cambrian gypsum and salt,Silurian mudstone and Triassic gypsum and salt.Four sets of corresponding structural deformation layers have been developed,with typical characteristics of stratified deformation.(4)The superimposed structural deformation in the later period resulted in the transformation of the original shape of the paleo-uplift,and the superimposed deformation of the core area gradually increased from south to north.The original shape of the core area of the Luzhou paleo-uplift was more similar to a symmetrical ellipse.Its long axis is parallel to the eastern edge of the basin and trending NE-SW.(5)The process of formation and evolution of the Luzhou paleo-uplift has important controlling effects upon the ocurrence of the combination of source and reservoir and cap rocks in the study area.The early hydrocarbon accumulation,adjustments and redistribution of hydrocarbon were controled by the inherited development of the paleo-uplift.The structural superposition and reconstruction of the later stage has played a dual role in the transformation and destruction of hydrocarbon reservoirs in the study area. |
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