Characteristics Of Mesozoic Siliceous Source Rocks And Siliceous Shale In The Nadanhada Terrane

Siliceous rock reservoirs are widely distributed in the world.In the past,siliceous rocks have not been included in the exploration targets.There are T₃-J₁ radiolarian siliceous rocks,clay siliceous rocks and siliceous shale in the eastern Heilongjiang Province,but the previous studies have not been systematically studied in this area.Through field survey sampling and experimental observation,we found good oil and gas display in the fracture and pore of siliceous rocks.This discovery belongs to "new layer,new type and new field".On the basis of field geological survey and rock sample collection in the eastern Heilongjiang,the analysis of siliceous rock cracks by means of organic geochemical analysis,microscopic examination,fluorescence testing,palaeontological identification,whole rock XRD test,inclusions test,argon ion polishing and high resolution scanning electron microscope.The abundance,type and maturity of organic matter in the pores,as well as the mineral composition and brittleness of siliceous rocks,diagenetic characteristics,pore types and pore throat structure,study the organic geochemical characteristics,formation environment,reservoir characteristics and preservation conditions of siliceous rocks.The structural evolution characteristics,sedimentary environment and diagenetic characteristics of the Nadanhada terrane are further elaborated to reveal the hydrocarbon generating potential and the reservoir forming mechanism of siliceous rocks.In this research process,the following main points have been achieved:1.The siliceous rocks in the Sanjiang basin are still at high maturity stage,with liquid hydrocarbon and good hydrocarbon potential.2.From the south to the north and from the west to the East,the dynamic metamorphism and thermal contact metamorphism of the siliceous rocks of the Nadanhada terrane are gradually weakened,the folds and the intrusion of the magma gradually lessen,the abundance of organic matter increases,the maturity of organic matter decreases,and the preservation conditions of oil and gas become better.3.The Sanjiang basin forward depression?Fuyuan area?has high organic abundance,low maturity and good preservation conditions,which is a favorable area for the exploration of T₃-J₁ siliceous rocks.4.The siliceous siliceous rocks and siliceous shale of the Nadanhada terrane are good in brittleness,microcracks and dissolution pores developed,and the overall connectivity of the pores is good.It is easy to form fractured and pore type reservoirs,and has good fracturing conditions.5.The discovery of the light oil in the siliceous rock and siliceous shale have important petroleum geological significance.This discovery is a new layer?T₃-J₁?,a new type?siliceous rock and siliceous shale?and a new area?the Nadanhada terrane?in the northeast of China.