Research On Dynamic Properties And Stress Wave Attenuation Of Exposed Marine Carbonate Rocks

In order to ascertain the distribution and reserves of marine carbonate rocks in the South,a large number of on-site surveys are required.Seismic exploration is the most common and important method in petroleum exploration.When seismic exploration is carried out,there are dynamic loads such as impact,explosion and vibration on the marine carbonate rock with the impact of borehole charge,explosive source explosion and seismic wave acquisition.Grasping the dynamic mechanical properties of marine carbonate rock is an important data to study its impact rock breaking,blasting mechanism,stress wave propagation law and seismic effect.The dynamic characteristics are the key to understanding the dynamic failure mechanism of rock and the law of stress wave propagation in rock.In this paper,exposed marine carbonate rock is the main study object,and experiment researched measure,theory analyzed and numerical simulation is the method and means.With the help of advanced testing technology and analysis methods,combined with modern mechanical and stress wave theory,we make systematic study on this condition:(1)Experimental study on physical and mechanical properties and parameters of marine carbonate rocks.The physical and mechanical properties and parameters of marine carbonate rock were tested by laboratory equipment.The uniaxial compression stress-strain curve of marine carbonate rock was obtained,and the parameters such as longitudinal wave velocity,elastic modulus,Poisson's ratio and uniaxial compressive strength of marine carbonate rock were obtained.(2)Experimental study on marine carbonate rock under dynamic impact load.The uniaxial dynamic impact compression tests of marine carbonate rocks under different strain rates were carried out by using split Hopkinson pressure bar(SHPB)test system.The variation of peak stress with strain rate and the variation of stress wave spectrum curve with strain rate were studied.(3)Research on dynamic crushing energy consumption characteristics of marine carbonate rocks.Based on the experiment,the particle size analysis of the sample fragments in the uniaxial impact compression test of marine carbonate rock is carried out.By studying the dynamic impact crushing characteristics and crushing energy consumption characteristics of marine carbonate rock,the relationship between the energy dissipation of marine carbonate rock dynamic crushing and the fragmentation size,strain rate and dynamic compressive strength is obtained.(4)Numerical simulation of stress wave propagation in marine carbonate rocks under dynamic loading.Numerical simulation of SHPB test,one-dimensional bar impact test and one-dimensional rock bar explosion test of marine carbonate rock are carried out.The stress process and stress wave propagation law of marine carbonate rock specimen under impact load are obtained,including the variation law of stress wave attenuation with propagation distance,and the variation law of frequency spectrum in the process of stress wave propagation.(5)Numerical simulation of seismic explosive source parameters in marine carbonate formation.In this paper,the numerical simulation of seismic exploration in marine carbonate strata is carried out,and the influence of source parameters including initiation mode,uncoupled medium,charge structure,depth of explosive and charge weight on the generation of explosion stress wave and attenuation of energy and frequency in marine carbonate rock are obtained.By comparing and analyzing the field test data of source excitation well depth and charge quantity in marine carbonate outcropping area,it is found that there is an optimal excitation well depth and charge quantity,which makes the seismic excitation downward transmission energy stronger and the seismic signal-to-noise ratio higher.The research results can provide an important reference for drilling and blasting of seismic exploration in marine carbonate areas.There are 108 pictures,33 tables and 185 references.