压裂凝析气井产能影响因素模拟分析

MODELING ANALYSIS OF PRODUCTIVITY-INFLUENCING FACTORS FOR FRACTURED CONDENSATE WELLS

凝析气藏压裂后产能模拟 ,以往一直使用干气预测模型。由于凝析和反凝析现象的存在 ,干气预测模型不能准确的预测准确的预测凝析气藏开发动态 ,以组分模型、热力学方程为基础 ,首次通过描述平衡气液相组成、物质量及平衡常数与压力、温度关系的物质平衡条件方程组 ;平衡气液相组成、物质量、平衡常数与逸度关系的热力学平衡条件方程组及用于平衡计算的状态方程 ,结合组分模型建立了相应的数学增加 ,天然气和凝析液的产量均增加 ,裂缝越长 ,增产越明显。这与常规气藏、黑油油藏压裂增产相似 ,地层混合物中重烃组分含量越大 ,凝析现象也将更为明显 ,凝析现象对生产的影响将更大。因此 ,凝析气藏压裂增产效果不仅取决与压裂裂缝几何尺寸 。

Productivity simulation of condensate reservoirs after fracturing has been conducted with the dry gas prediction model before. Since there are condensate and retrograde condensate phenomena, the dry gas prediction model can’t predict the production performance of condensate reservoirs accurately. Based on the compositional model and the thermodynamic equation, with the equation group to describe the material equilibrium conditions of gas/liquid components, mole fraction and equilibrium constant related with pressure and temperature; the equation group to describe the thermodynamic equilibrium conditions of gas/liquid components, mole fraction and equilibrium constant related with fugacity; and the state equation to calculate the phase balance, combining with the compositional model, the corresponding mathematical model and numeral calculation model are developed, which can be used to predict the production performance of condensate reservoirs after fracturing. The production of both gas and condensate increases as the length of fractures expands. The longer the fractures are, the more obvious the increase is, which is similar with the fracturing stimulation of conventional gas reservoirs and black oil reservoirs. The bigger the content of heavy hydrocarbon components in the formation mixer is, the more obvious the condensate phenomenon is, and the greater the influence of the condensate phenomenon on production is. Therefore, the results of fracturing stimulation for condensate reservoirs depend on not only the geometry of the fractures but also the composition of the reservoir fluid, the pressure and temperature.