低渗透气藏压裂水平井产出剖面与裂缝参数反演解释

为解决低渗透气藏水平井投产后产气剖面不清、裂缝贡献未知、裂缝参数难以确定等问题，以耦合的压裂水平井温度剖面预测模型作为正演模型，基于Simulated Annealing（SA）算法建立了分布式温度测试（DTS）数据反演模型，并对反演流程进行了优化，最终形成了一套基于DTS的压裂水平井产出剖面与裂缝参数定量解释方法。通过模拟分析裂缝半长对温度剖面的影响发现，压裂水平井温度剖面呈不规则"锯齿状"，且随裂缝半长的增加，井筒温度剖面整体升高，各级裂缝对应温度降与裂缝流量呈正相关关系。对1口现场实例井的DTS数据进行了反演，基于准确的有效人工裂缝诊断，反演误差函数值达到了5×10^-6，各级裂缝位置处温度误差绝对值小于0.02 K，反演获得的单井产量与井口实测产量误差小于5 m³/d，解释出的各级裂缝流量与拖动式生产测井工具实测值也较为吻合，从而验证了反演解释模型的可靠性。

Inversion and interpretation of production profile and fracture parameters of fractured horizontal wells in low-permeability gas reservoirs

To solve the problems such as unclear gas production profile, unknown contributions of fractures, and difficulty in determining fracture parameters during the exploration of horizontal wells in low-permeability gas reservoirs, this paper establishes an inversion model for distributed temperature sensing (DTS) data based on the Simulated Annealing (SA) algorithm when using the coupled prediction model of temperature profile of fractured horizontal wells as the forward model, optimizes the inversion process, and finally obtains a set of quantitative interpretation methods for the production profile and fracture parameters of fractured horizontal wells based on DTS. Through simulation analysis of the influence of fracture half-length on temperature profile, it is found that the temperature profile of fractured horizontal wells is irregular-sawtooth shaped, and as the fracture half-length increases, the temperature profile of the wellbore increases as a whole, and the corresponding temperature drop of fracture is positively correlated with flow rate. The DTS data of a well have been inverted. Based on the accurate and effective diagnosis of artificial fractures, the value of error function after inversion reaches 5×10^-6, and the absolute value of temperature error at each fracture positions is less than 0.02 K. The error between the single well production obtained by inversion and the measured production rate at the wellhead is less than 5 m³/d, and the interpreted fracture flowrates of all fracturesare also in good agreement with the measured PLT values that verifies the reliability of the inversion interpretation model.