Simulation device of condensate gas constant volume depletion in dense porous medium and experiment method

Abstract

The invention discloses a simulation device of condensate gas constant volume depletion in a dense porous medium and an experiment method. The device comprises a constant volume condensate gas reservoir module, a pressure supply module and an oil and gas separation module, wherein in the constant volume condensate gas reservoir module, a core to be tested is placed in a constant volume full diameter kettle, an end cap is provided with an inlet hole, an outlet hole and a pressure monitoring hole, and a first connecting pipe line is connected to the inlet hole and a center of a circle of a bottom surface of the core to be tested; the pressure supply module includes a constant pressure constant speed displacement pump which is connected to one ends of a condensate gas intermediate container and a high pressure separator gas intermediate container, and the other ends of the condensate gas intermediate container and the high pressure separator gas intermediate container are connected to the inlet hole through the first connecting pipe line; and the oil and gas separation module includes a back pressure pump, a back pressure valve, an oil and gas separator and a gas meter which are connected successively, and an inlet end of the back pressure valve is connected to the outlet hole through a second connecting pipe line. The device and the method have advantages that changes of an oil and gas phase in a depletion process of a condensate gas reservoir in fractured tight reservoir can be simulated, and an oil and gas state under a condensate gas reservoir condition can be maximumly restored.

Description

technical field [0001] The invention relates to the technical field of condensate gas reservoir development experiments, and more specifically, to a simulation device and an experimental method for constant-volume depletion of condensate gas in dense porous media. Background technique [0002] Condensate gas reservoirs are the most "delicate" gas reservoirs among all types of oil and gas reservoirs. Once some mistakes occur in the development process, the impact on condensate gas reservoirs is irreversible. At present, theoretical methods and experimental techniques for the study of the phase state of condensate oil and gas systems have been gradually formed and gradually improved. Conventional phase state experiments are mainly carried out through high-temperature and high-pressure PVT kettles for single flash experiments, constant mass expansion experiments, and condensate inversion experiments. Quantitative experiments and constant volume depletion experiments are used to...

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Problems solved by technology

CN1971273A discloses a test method for constant volume depletion of condensate gas reservoir fluid: starting from the dew point pressure, the constant fluid volume is depressurized step by step, the fluid is discharged, the oil and gas production are measured, and the components of the oil and gas are analyzed respectively. The recovery rate of natural gas and condensate oil and the amount of residual formation liquid in the depleted production process are obtained, but this method cannot determine the influence of porous media on the phase change of oil and gas, and only considers the macroscopic phase properties of the fluid, but in the actual condensate gas In the process of reservoir development, the influence of porous media on the fluid phase state cannot be ignored. It can even be said that some phase state parameters obtained through PVT experiments are different from those in actual porous media, which will inevitably affect the condensate. impact on the development of gas reservoirs

[0003] At present, the methods for simulating constant volume depletion of condensate gas in porous media mainly use long core depletion experiments (Sui Shuling. Experimental Research on Condensate Gas Depletion in Porous Media with Low Permeability, 2010, 32(3):97-100) or full-diameter depletion experiments. (Guo Ping. Dynamic Experimental Research on Depletion of Fracture-Cavity Condensate Gas Reservoirs, 2013, 35(2): 67-70), through these two depletion experiments to simulate the depletion development process of condensate gas reservoirs, so as to obtain the required formation However, the scale of the condensate gas reservoir simulated by the long core depletion experiment is small, and the oil drainage area of ​​the core section is small, which belongs to one-dimensional simulation, and the long cores spliced ​​by short cores are mostly placed horizontally and There are differences in the actual development of condensate gas. Although the simulation scale and drainage area of ​​the traditional full-diameter depletion experiment have been increased, like the long core experiment, it is impossible to simulate fractures or fractures due to the confining pressure of the rubber sleeve around the core. Influence on the development effect of condensate gas when it exists

In addition, with the continuous change of the applied confining pressure, the pore volume of the core in the rubber tube will change slightly, which will affect the production of condensate oil and gas, and then affect the accuracy of the experimental results, resulting in the adjustment of the field development plan or There are deviations in the formulation of the plan, which ultimately affects the development effect

[0004] In order to solve the problems of inability to simulate fractures, pore volume changes, and small simulation scales in traditional condensate gas growth core depletion experiments and full-diameter depletion experiments, it is necessary to develop a simulation device for constant volume depletion of condensate gas in dense porous media and experimental methods

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