Seismic Prediction Of The Sinian Dengying Formation Reservoir In The Gaoshiti-Moxi Area, Sichuan Basin

Gaoshiti-Moxi Structure is located in the east slope of the Sichuan Baisin Leshan-Longnvsi ancient uplift.The results show that the reservoirs of the Gaoshiti-Moxi Structure are well developed.They have good oil-bearing properties.And they have good exploration potential.Based on 3D seismic data of Gaoshiti-Moxi Structure,this paper combines the data of logging,core,sheet and oil test in the study area.It has done fine structure interpretation of Cambrian Gaotai group bottom,Cambrian bottom,and Sinian Dengying group section three.The structural characteristics and fracture characteristics of the main layer are anal yzed.The characteristics of reservoir geology,logging response and seismic response are analyzed.Based on this,the reservoir thickness is predicted by wave impedance inversion method.Prestack expansion elastic impedance inversion is used to predict the gas condition of Dengying Formation through the petrophysical analysis.The fissure development of Dengying Formation is predicted by prestack subdivision fracture prediction combined with the post-stack coherence analysis.Finally,the reservoirs of Dengying Formation are comprehensively evaluated and predicted combined with the results of structure,reservoir,hydrocarbon study and fracture prediction.Based on this,the locations of the wells are selected.According to the comprehensive study,it is concluded that:1)the trap scale of the main purpose layer Cambrian Gaotai Formation bottom,Cambrian bottom,Sinian Dengying group three sections increases from the surface to the abdomen.lt developes a large scale traps and normal faults.The axis of Moxi latent structure moves northward.There is north-south drop-off in the western region.2)The main reservoir rocks in the study area are algae debris,algae clumps,and algae.There are three kinds of reservoir types:fracture-hole type,fracture-porosity type and cave type.The main reservoir of Dengying group are section four and section two.3)The reservoirs of Dengying Formation are generally developed.These reservoirs are contiguous.And the reservoirs near the drop-off are the most developed reservoirs.4)The gas layer of the upper part of the Dengying Formation section four and section two are both distributed in a sheet form.The area with high gas-bearing probability in the upper part of Dengying Formation section four is mainly distributed along the drop-off of Cambrian bottom from north to south.5)The fissures and holes of Dengying Formation are most developed.The areas with high fissure density in the Dengying Formation section four and section two are mainly concentrated in the middle of the study area.