Study On Rock Brittleness Of Tight Reservoir Based On Acoustic Emission Technique

SRV fracturing is a key technology to develop a tight reservoir,rock brittleness is an important factor on SRV fracturing effect,rock mechanics and mineral content methods are the most common brittleness calculation methods,although widely used,but they are not proposed based on brittleness control mechanism,so it is necessary to propose a new brittleness calculation method.This paper firstly carries out the AE experiment and obtains AE events,AE energy and other AE parameters,the failure process of core is analyzed by acoustic emission parameters.Based on the principle of damage mechanics,the relationship between the rock brittleness and the AE events is established,so we can obtain rock brittleness index,and analyze the relationships between the AE brittleness and rock mechanical brittleness and mineral content brittleness.Finally,the experiment and the fracturing analysis method are used to demonstrate the acoustic emission brittleness.Through the study,it is found that the acoustic emission of rock has a sudden,AE events reflect the number of micro cracks,acoustic emission exists the initial area,violent area,descending area and quiet area.Acoustic emission energy rate and acoustic emission event rate does not necessarily have a good corresponding relationship,it is related to the composition and physical properties of the rock.There is a good correlation between acoustic emission brittleness and rock mechanical brittleness and mineral content brittleness.The change of core permeability before and after three axial compression is great,it has a positive correlation with rock brittleness.In the case of same construction parameters,the larger the size of the SRV zone formed by the higher brittleness is found by the method of fracturing analysis,it demonstrates the acoustic emission brittleness.