Considering The Complexity Of The Multiphase Fluid Phase Change Of The Condensate Gas Well Production Performance Analysis Method

With more and more natural gas exploited in deep reservoir, some special condensate gas reservoirs with rich gaseous condensate water in abnormally high temperature and pressure are emerging continuously. When the formation under the condition of high temperature, more and more bottom water, edge water and active porous water will coexist with condensate gas in vapor. If we still use conventional phase research ways in such special condensate gas reservoirs exploitation, it will result in some errors in producing method, engineering design and performance analysis. So, in order to use and develop gas condensate reservoirs in reason, improving the production and management level of condensate gas reservoirs, all-round and systemic research in production performance analysis will be necessary. Accordingly, this paper put forward a new method of production performance analysis in gas condensate well which considering complex phase behavior of multi-phase liquid.Based on systemic research, this paper obtained some achievements as bellow:(1) Establishing a gas-liquid-liquid 3-phase equilibrium model, applying Newton-Raphson algorithm, giving the calculated ways of model. It is the theory basic of phase equilibrium in production performance analysis which considering complex phase behavior of multi-phase liquid.(2) Based on time-invariant seepage of gas condensate reservoir, considering condensate gas obey non-Darcy's law as its low viscosity and high velocity, while considering condensate oil and water obey Darcy's law as its low velocity, establishing a formation flow model which considering oil, gas and water 3-phase flow. Giving the calculated ways of model.(3) By the use of formula for flow in vertical pipe, according to GLR, dividing the wellbore performance analysis method into two cases, combing the flash calculation and EOS, amending the compressibility factor, gas-liquid superficial tension, viscosity and so on. Establishing a wellbore performance analysis method and give the calculated ways.(4) Combining the gas-liquid-liquid 3-phase flash calculation model and wellbore liquid continuous withdrawal model, establishing a condensate gas well liquid continuous withdrawal model which considering oil, gas and water 3-phase complex phase behavior. In combine with formation inflow model and wellbore outflow model, drafting system analysis curve, through this curve, we can predict the gas well production performance more directly and allsidedly.(5) Combining the gas-liquid-liquid 3-phase flash calculation model and the definition of wellbore storage, deriving a formula which can calculate the variable wellbore storage considering complex phase behavior of multi-phase liquid.(6) Combining the formation inflow model, wellbore outflow model and wellbore liquid continuous withdrawal model, establishing a new production performance analysis method which considering complex phase behavior of multi-phase liquid. This method improves the accuracy of performance analysis, especially to condensate gas reservoirs with rich gaseous condensate water in abnormally high temperature and pressure. By the use of this method, we can exploit the gas reservoir more reasonably. Applying VB programming language and Access database, designing the corresponded production performance analysis software package.(7) Making sense parameter analysis of gas condensate production performance which considering complex phase behavior of multi-phase liquid, which can optimize the production of condensate gas well.