Study On Characteristics And Distribution Of Permian Igneous Reservoirs In Western Sichuan

This paper under volcano petrology,reservoir geology,seismology and digenesis etc,based on the full digestion and absorption of previous research results,taking structural genesis of igneous rocks-lithology-lithofacies-volcanic bodies-diagenesisreservoir development-earthquake prediction as main line,with anatomy of typical well and outcrop profile and combination of point-line-face,using combination of surface and underground,geological-geophysical-geochemistry,using drilling data,logging data,test data,seismic data,study on geological characteristics,lithofacies types and distribution of the igneous rocks of the Permian in western Sichuan.Using multi-method and multi-methods such as outcrop profile measurement,core observation,rock slice identification,geochemical analysis test,water rock action to study the main controlling factors of rock types,reservoir physical properties,diagenesis and reservoir space evolution,and reservoir development of igneous reservoirs,the combination of well and earthquake(seismic attribute extraction,seismic inversion prediction)reveals the distribution characteristics of high-quality reservoirs of the Permian igneous rocks in western Sichuan.The Permian igneous rocks in western Sichuan have experienced the following stages: volcanic stage,hydrothermal stage,epigenetic stage,and buried stage.Different types of diagenesis at different stages.Constructive diagenesis of igneous reservoirs: condensation and shrinkage,dissolution,and structural rupture,destructive diagenesis of igneous reservoirs includes: hydrothermal alteration and filling.The rock types of the Permian igneous rocks in western Sichuan are dominated by overflow facies,followed by volcanic clastic rocks.In the longitudinal direction,the reservoir is mainly developed in the middle and upper part of the spiral,and the rock types are mainly basaltic slag-like lava,porous lava,and pulp lava,etc.Diversified reservoir types of the Permian igneous reservoirs in western Sichuan:intercrystalline pores,intracrystalline pores,dissolved pores,micropores,residual pores,pores,shrinkage pores.Most of the reservoir space of the Permian igneous reservoirs in western Sichuan does not exist alone,and many of them appear in combination.Common intergranular pore-cracks,stomatal-cracks,and dissolvedpores-cracks are common types.The evolution of the reservoir space of the Permian igneous reservoir in western Sichuan has experienced the following stages:the original space is formed after the effluent and condensing ? the hydrothermal filling in the sprinkling period ? the intermittent exposure during the effluent,the secondary pore formation of the tectonic action ? the leaching of the atmospheric water ? the filling of the reservoir during the burial period ? the acidic fluid and leaching during the burial period? late structural damage.The main controlling factors for the formation of the Permian igneous reservoirs in western Sichuan are rock types,lithofacies,and diagenesis(dissolution,ect.).The distribution of the igneous reservoirs in the western Sichuan Basin is controlled by volcanic institutions,the combination of drilling and seismic with positive and inversion studies identified the spill-sag phase and reservoir favorable development areas of Yongsheng,Xindu,Lianshan and Gudian.