Li Jinbu, Liu Lili, Zhu Yuan, Zhao Lian, Chai Xiaolong, Tian Leng
Exploration and Development Research Institute of Petro-China Changqing Oil Field Company Ltd, Xi'an, China.
State Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields, Xi'an, China.
Sci Rep. 2025 Apr 9;15(1):12178. doi: 10.1038/s41598-025-88131-z.
Tight gas is a clean and low-carbon energy with great development potential. However, in the middle and late stages of development of tight gas reservoirs, there are characteristics of low pressure, low production and high water cut. At present, there are few studies on the dynamic supply boundary considering the threshold pressure gradient, reservoir and fracture stress sensitivity and slip effect for the gas-water two-phase model of tight gas reservoirs. In order to improve the assessment of the supply boundary and production capacity features of tight gas wells at low pressure, a new coupling model of gas-water two-phase was established in this paper and the threshold pressure gradient, stress sensitivity and slip effect are taken into account the built model. Subsequently, the steady-state substitution method and the material balance method were used to develop the supply boundary calculation model. Finally, an analysis is done on how the supply boundary is affected by the threshold pressure gradient production, stress sensitivity and production pressure difference. The results demonstrate that, in contrast to the slower propagation observed in the matrix zone, the supply boundary propagates relatively quickly within the fracture modification zone. The threshold pressure gradient and stress-sensitive increase the resistance of gas seepage and delay the propagation of the supply boundary, which reduces the production of gas well. The propagation of the supply boundary accelerates with increasing production pressure difference, but the pressure difference's effect decreases. The production of gas is significantly impacted by the threshold pressure gradient, stress sensitivity and production pressure difference. Efficient production of tight gas reservoirs necessitates minimizing water production and preserving formation pressure.
致密气是一种具有巨大发展潜力的清洁低碳能源。然而，在致密气藏开发的中后期，存在低压、低产、高含水的特点。目前，对于考虑启动压力梯度、储层和裂缝应力敏感性以及滑脱效应的致密气藏气水两相模型的动态供给边界研究较少。为了改进对低压致密气井供给边界和产能特征的评估，本文建立了一种新的气水两相耦合模型，并在建立的模型中考虑了启动压力梯度、应力敏感性和滑脱效应。随后，采用稳态替换法和物质平衡法建立了供给边界计算模型。最后，分析了启动压力梯度、应力敏感性和生产压差对供给边界的影响。结果表明，与基质区中观察到的较慢传播相比，供给边界在裂缝改造区内传播相对较快。启动压力梯度和应力敏感性增加了气体渗流阻力，延迟了供给边界的传播，从而降低了气井产量。供给边界的传播随着生产压差的增加而加速，但压差的影响减小。气产量受启动压力梯度、应力敏感性和生产压差的显著影响。致密气藏的高效生产需要尽量减少产水并保持地层压力。
