Abstract Gas condensate reservoir is a special kind of oil and gas system that involves two-phase flow during production, because oil condensation occurs when reservoir pressure drops below the dew point pressure. It is of great importance to develop some well testing models for the gas condensate reservoir, yet there exists no analytical well-testing model for horizontal well in such formations. This paper proposes an analytical model for the production performance analysis of horizontal well in gas condensate reservoir. The three-region model is employed to characterize the flow and production of gas condensate, and the three regions are: region-1 in which oil and gas are both mobile, region-2 in which only gas is mobile whereas the oil cannot flow, and region-3 in which only the gas phase exists. To solve the proposed model, Laplace transformation and Cosine transformation are applied to change the partial differential equations to ordinary differential equations. Then, Stehfest numerical inversion technique is used to convert the solution of the proposed model into real space. Afterwards, the pressure response type curve is obtained and nine flow regimes are identified. Subsequently, sensitivity analysis is carried out to investigate the influence of several factors on production performance. Finally, field application is carried out to validate the accuracy of our model, and it is shown that the model prediction result is in accordance with the real production data. The proposed model provides some insights toward the production behavior of horizontal well in gas condensate reservoir, and can be used to evaluate the horizontal well productivity of the such reservoirs.

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基于三区模型的凝析气藏水平井生产动态分析

摘要 凝析气藏是一种特殊的油气系统，在生产过程中涉及两相流动，因为当储层压力低于露点压力时会发生凝析油。开发一些凝析气藏试井模型具有重要意义，但目前尚无针对此类地层水平井的解析试井模型。本文提出了一种用于凝析气藏水平井生产动态分析的分析模型。采用三区模型来表征凝析气的流动和生产，三个区分别是：1区油气都可流动，2区只有气可动，油不能流动，和区域 3，其中仅存在气相。为了解决所提出的模型，应用拉普拉斯变换和余弦变换将偏微分方程变为常微分方程。然后，使用 Stehfest 数值反演技术将所提出模型的解转换为真实空间。然后，获得压力响应类型曲线并识别九个流态。随后，进行敏感性分析以研究几个因素对生产性能的影响。最后通过现场应用验证了模型的准确性，模型预测结果与实际生产数据相符。所提出的模型为凝析气藏水平井的生产行为提供了一些见解，