To improve the understanding of the transport mechanism in shale gas reservoirs and build a theoretical basic for further researches on productivity evaluation and efficient exploitation, various gas transport mechani...To improve the understanding of the transport mechanism in shale gas reservoirs and build a theoretical basic for further researches on productivity evaluation and efficient exploitation, various gas transport mechanisms within a shale gas reservoir exploited by a horizontal well were thoroughly investigated, which took diffusion, adsorption/desorption and Darcy flow into account. The characteristics of diffusion in nano-scale pores in matrix and desorption on the matrix surface were both considered in the improved differential equations for seepage flow. By integrating the Langmuir isotherm desorption items into the new total dimensionless compression coefficient in matrix, the transport function and seepage flow could be formalized, simplified and consistent with the conventional form of diffusion equation. Furthermore, by utilizing the Laplace change and Sethfest inversion changes, the calculated results were obtained and further discussions indicated that transfer mechanisms were influenced by diffusion, adsorption/desorption. The research shows that when the matrix permeability is closed to magnitude of 10^-9D, the matrix flow only occurs near the surfacial matrix; as to the actual production, the central matrix blocks are barely involved in the production; the closer to the surface of matrix, the lower the pressure is and the more obvious the diffusion effect is; the behavior of adsorption/desorption can increase the matrix flow rate significantly and slow down the pressure of horizontal well obviously.展开更多
随着分布式光纤温度(distributed temperature sensing,DTS)监测精度和分辨率的提升,逐渐成为油气生产管理和动态分析中产出剖面监测的重要技术之一,但其解释技术还处于起步探索阶段。考虑流体渗流过程中焦耳汤普逊效应以及诸多微量热效...随着分布式光纤温度(distributed temperature sensing,DTS)监测精度和分辨率的提升,逐渐成为油气生产管理和动态分析中产出剖面监测的重要技术之一,但其解释技术还处于起步探索阶段。考虑流体渗流过程中焦耳汤普逊效应以及诸多微量热效应,结合质量守恒、动量守恒、能量守恒定律建立低渗多层合采气井温度剖面预测模型。该模型耦合了渗流过程中压力和温度场两部分数学模型,求解模型分析讨论了产量、生产时间和渗透率对产出温度剖面影响,结果表明:产量增加产出剖面温度降低;储层渗透率对产出温度剖面影响最为明显;储层渗透率降低,产出剖面温度增加,且增加幅度是非线性的;随着生产时间增加温度增加,但增加幅度逐渐减小且趋于稳定。最后以南海永乐区一口多层合采探井DTS实际温度测试数据进行了产出剖面解释,结果与实际地质认识具有一致性,验证了理论模型的可靠性。该研究结果促进了DTS监测技术在低渗致密多层合采气藏监测中的推广与应用。展开更多
基金Foundation item： Project（PLN1129）supported by Opening Fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation （Southwest Petroleum University）, China
文摘To improve the understanding of the transport mechanism in shale gas reservoirs and build a theoretical basic for further researches on productivity evaluation and efficient exploitation, various gas transport mechanisms within a shale gas reservoir exploited by a horizontal well were thoroughly investigated, which took diffusion, adsorption/desorption and Darcy flow into account. The characteristics of diffusion in nano-scale pores in matrix and desorption on the matrix surface were both considered in the improved differential equations for seepage flow. By integrating the Langmuir isotherm desorption items into the new total dimensionless compression coefficient in matrix, the transport function and seepage flow could be formalized, simplified and consistent with the conventional form of diffusion equation. Furthermore, by utilizing the Laplace change and Sethfest inversion changes, the calculated results were obtained and further discussions indicated that transfer mechanisms were influenced by diffusion, adsorption/desorption. The research shows that when the matrix permeability is closed to magnitude of 10^-9D, the matrix flow only occurs near the surfacial matrix; as to the actual production, the central matrix blocks are barely involved in the production; the closer to the surface of matrix, the lower the pressure is and the more obvious the diffusion effect is; the behavior of adsorption/desorption can increase the matrix flow rate significantly and slow down the pressure of horizontal well obviously.
文摘随着分布式光纤温度(distributed temperature sensing,DTS)监测精度和分辨率的提升,逐渐成为油气生产管理和动态分析中产出剖面监测的重要技术之一,但其解释技术还处于起步探索阶段。考虑流体渗流过程中焦耳汤普逊效应以及诸多微量热效应,结合质量守恒、动量守恒、能量守恒定律建立低渗多层合采气井温度剖面预测模型。该模型耦合了渗流过程中压力和温度场两部分数学模型,求解模型分析讨论了产量、生产时间和渗透率对产出温度剖面影响,结果表明:产量增加产出剖面温度降低;储层渗透率对产出温度剖面影响最为明显;储层渗透率降低,产出剖面温度增加,且增加幅度是非线性的;随着生产时间增加温度增加,但增加幅度逐渐减小且趋于稳定。最后以南海永乐区一口多层合采探井DTS实际温度测试数据进行了产出剖面解释,结果与实际地质认识具有一致性,验证了理论模型的可靠性。该研究结果促进了DTS监测技术在低渗致密多层合采气藏监测中的推广与应用。
