Effectiveness Evaluation Of Artificial Fracture In Inter-salt Shale Oil Reservoirs

Inter-salt shale oil reservoirs in Qianjiang depression are rare both at home and abroad.Its reserves are abundant,which is of great significance for increasing production in Jianghan oil field.In view of the problems of strong rock plasticity,short effective period of fracture and easy crystallization of salt,the factors affecting the effectiveness of the artificial fractures in inter-salt shale oil reservoirs are studied.First,using a rotating disk instrument to test the dissolution rate of salt rock under the conditions of different temperature,concentration and pressure.Then FCS-842-type conductivity meter physical map is used to test the conductivity of the fracture in the process of salt rock dissolution.Next,under the conditions of different sizes of proppant,different types of proppant and different sand concentrations,the short-term conductivity and long-term conductivity are tested.Finally,using COMSOL software to simulate the distribution of the concentration in the formation.The results show that:(1)the temperature and solution concentration have a great influence on the dissolution rate of salt rock,but the effect of pressure is not obvious;(2)The salt rock dissolution can increase the fracture conductivity,at the same time it maybe cause the collapse of the rock,leading to fracture failure;(3)Using high sand concentration,large diameter proppant,and resin coated ceramic proppant can reduce the embedding of the proppant,and improve the conductivity;(4)The solute migrates with the flow of fluid in the fracture,and the distribution of solute in the rough fracture is not uniform.The study of the distribution of solute lays the foundation for the later study of recrystallization of salt solute.The work in this paper provides scientific basis and regular knowledge for optimizing fracturing design of inter-salt shale oil reservoirs and solving production problems in field.