A supercritical gas phase displacement medium-condensate oil and gas equilibrium phase behavior evaluation method

Abstract

The invention introduces a supercritical gas phase displacement medium-condensate oil gas equilibrium phase behavior evaluation method. The method is to inject a supercritical gas-phase displacement medium into the condensate gas, and it is observed that there is a gas-gas two-phase interface during the injection process. On the basis of the experiment, aiming at the interface phenomenon in the process of injection of supercritical gas phase displacement medium into condensate gas, starting from the analysis of phase behavior of binary fluid mixture of gas phase displacement medium, analyzing the contact between supercritical gas phase displacement medium and condensate gas Whether there is a phase change behavior, and establish a condensate oil-gas phase equilibrium model of the supercritical gas phase displacement medium under high temperature conditions with interface phenomena.

Description

technical field [0001] The invention relates to the field of phase behavior evaluation methods, in particular to a gas-gas-liquid three-phase phase behavior evaluation method. Background technique [0002] Aiming at the problems that most oil and gas field developments are facing the need to further enhance the recovery and improve the displacement efficiency, the research and development and application of the technology of injecting gas phase displacement media to drive oil to enhance the recovery have been vigorously carried out internationally. In the field of Tibetan resource exploitation, the effect of improving the recovery rate is obvious. Under the guidance of this idea, experts and scholars in related fields intend to apply gas flooding technology to the field of condensate gas recovery to improve the recovery rate of condensate gas. However, the phase state of gas-phase displacement medium injected into condensate gas reservoirs is completely different from that ...

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Problems solved by technology

Condensate gas reservoirs produce natural gas and condensate oil at the same time. The economic value is high but the development is very complicated. There are phase changes and reverse condensation phenomena of condensate oil and gas. The phase fluctuation caused by improper operation during production will cause great Large condensate oil formation loss, so it is necessary to determine economical, reasonable and effective development methods to enhance recovery

In particular, continental sedimentary reservoirs have the characteristics of low porosity, low permeability, and strong heterogeneity, and formation condensate gas reservoirs are prone to reverse condensation and liquid lock. Under these conditions, the development of condensate gas reservoirs is difficult

In the prior art, the complex phase transition between supercritical gas-phase displacement medium and condensate gas is mainly characterized by gas (V)-liquid (L) two-phase equilibrium. This model is too simple to characterize the displacement by gas-phase displacement medium. Complicated changes of three phases (LVV) in condensate gas reservoirs when the phase state changes with the production temperature, pressure and injection volume of gas phase displacement medium

In particular, the downhole environment of condensate gas reservoirs is mostly a high temperature and high pressure environment, and mining is difficult. It takes a lot of manpower and material resources to organize a mining operation. If the displacement cannot be accurately and effectively evaluated The phase relationship of the phase relationship often delays production, and in severe cases, reverse condensation pollution occurs, and even damages the reservoir

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