Research On Pressure-Sensitive Seepage Of Cracks In Extra Low Permeability Reservoirs And Its Application

This paper mainly studies the pressure sensitive mechanism of ultra-low permeability fractured reservoirs and the optimization of well pattern for such reservoirs.The most important feature in ultra-low permeability fractured reservoirs is the anisotropy of permeability and pressure-sensitive properties.The pressure sensitivity of a reservoir refers to the property of reservoir permeability that changes with pressure as the development progresses.Pressure sensitivity will degrade the physical properties of the reservoir and affect well productivity.The directional nature of the permeability also has a significant impact on the deployment and development of the injection well pattern.In this paper,physics experiments,reservoir engineering analysis and numerical simulation methods are mainly used to study the microscopic seepage law and water drive development law of ultra-low permeability fractured reservoirs.Firstly,similar physical cracks were used to perform physical experiments and the results of physical experiments were analyzed.Then the reservoir engineering method is used to derive the equivalent permeability model of fractured reservoirs and the mathematical model of reservoir seepage.Then,using numerical simulation software,the method of equivalent fracture permeability reservoirs was used to study pressure-sensitive fractured reservoir numerical simulation methods.Numerical simulations were conducted for different fracture directionality and different well network elements.Based on the above methods,the expected research results were obtained,including the new pressure-sensitive equation,the mathematical model of equivalent continuous medium seepage in fractured reservoirs,and the development patterns of different well patterns in fractured reservoirs.The research results show that fractured reservoirs have strong pressure-sensitive properties and can be expressed using the given pressure-sensitive equations.The relationship between the development effect and the angle of cracks in the development of such reservoirs is given,and the rationality of the obtained development method is verified with the actual reservoir.