Application of Material Balance Equations of Multicompartment Gas Reservoirs in YC Gas Reservoir

A compartmented gas reservoir is defined as a reservoir involving two or more distinct blocks in hydraulic communication.A common one is a fault block gas reservoir separated into different fault blocks by partially sealing faults.The fault plane in fault block gas reservoir works as the migration pathway of oil and gas sometimes, which makes the determination of reservoir pressure and dynamic reserves as well as remaining reserves complicated.Hence, in order to accomplish the goal of producing gas fields efficiently, it is necessary to have further study on the determination of reservoir pressure and evaluation methods of dynamic reserves, which can especially lay basis for the establishment of sequent development or adjustment program.This paper establishes the mathematical model of multicompartment gas reservoirs and derives the corresponding material balance equations (MBEs) according to material balance.Then Newton-Raphson iteration scheme is employed to solve these equations.This model can be used not only for history matching, but also for performance prediction.An example is presented to analyze how transmissibility, gas initially in place (GIIP), gas production rate and commissioning time of the nonproducing reservoir affect the P/Z behavior.The practical application of this method proves the method to be applicable.The change in influx and instantaneous flow rate between blocks can be quantitatively expressed by this method as well.Thus, producing degree of the nonproducing reservoir can be determined, which would be helpful to reduce costs and improve economic efficiency.