Patent ID: 11873712
Assignee: CHINA UNIVERSITY OF PETROLEUM—BEIJING
Field: Measurement (Instruments)
Classification: CPC E  G | IPC E  G

Claim 2:
3. An edge and bottom water invasion simulation method, wherein the method comprises:
determining an initial gas pressure according to an actual recovery of natural gas, controlling an inert gas to be injected into a first intermediate container through a gas inlet end of the first intermediate container, and stopping the inert gas from being injected into the first intermediate container when an internal pressure of the first intermediate container reaches the initial gas pressure;
controlling formation water to be injected into the first intermediate container through a liquid inlet end of the first intermediate container, and stopping the formation water from being injected into the first intermediate container when the internal pressure of the first intermediate container reaches an initial formation pressure; and
controlling a liquid outlet end of the first intermediate container to be communicated with an inlet end of a core holder, and adjusting a pressure of a back pressure valve to reduce a pressure at an outlet end of the core holder, so that the formation water in the first intermediate container enters a core saturated with the natural gas in the core holder through the liquid outlet end of the first intermediate container and the inlet end of the core holder sequentially, so as to simulate an actual edge and bottom water invasion;
wherein after the adjusting the pressure of the back pressure valve to reduce the pressure at the outlet end of the core holder, the method further comprises:
controlling the outlet end of the core holder to be disconnected from a recovery device when the outlet end of the core holder is subjected to a first water breakthrough;
setting a corresponding pressure value of a displacement pump to the initial formation pressure, so that a liquid enters a second intermediate container from a liquid inlet end of the second intermediate container to compress an inert gas inside the second intermediate container, so as to make an internal pressure of the second intermediate container reach the initial formation pressure;
when the internal pressure of the second intermediate container reaches the initial formation pressure, controlling the outlet end of the core holder to be communicated with a gas outlet end of the second intermediate container, so that the inert gas in the second intermediate container enters the core holder through the gas outlet end of the second intermediate container and the outlet end of the core holder sequentially, and determining an injection volume of the inert gas entering the core holder according to a liquid injection volume when an internal pressure of the core holder reaches the initial formation pressure;
when the internal pressure of the core holder is the initial formation pressure, controlling the outlet end of the core holder to be communicated with the recovery device, and adjusting the pressure of the back pressure valve to reduce the pressure at the outlet end of the core holder, so that a gas inside the core holder flows from the outlet end into the recovery device; and
when the outlet end of the core holder is subjected to a second water breakthrough, controlling the outlet end of the core holder to be disconnected from the recovery device, and analyzing a gas recovered by the recovery device to determine a recovery volume of the natural gas, and determining a recovery of the natural gas during the second water breakthrough according to the recovery volume of the natural gas and a total volume of the natural gas in a core saturated with the natural gas.