稠油油藏蒸汽吞吐防砂完井产能评价新方法

在优选防砂完井方式时，当量产能比为目前主要的产能评价指标。但对于稠油蒸汽吞吐而言，产能预测模型缺乏考虑防砂的影响，加上蒸汽的降黏增产作用，使得传统评价方法对吞吐井防砂、注汽的适应性较差。通过提出复合产能比和最终产能比两个新概念，表征了防砂前后蒸汽吞吐井产能的变化，使用最终产能比作为新评价指标的计算结果更直观、更便于应用。为计算最终产能比，建立了防砂完井产能新模型，该模型针对防砂和蒸汽吞吐的特点，根据非等温分布加热半径计算公式和达西定律，考虑了高温蒸汽对原油黏度的影响，引入防砂表皮系数，从而实现了防砂和蒸汽吞吐的耦合。应用结果表明，防砂措施对蒸汽吞吐井产能的影响更加明显，表现为各防砂方式的最终产能比均低于当量产能比。其中，压裂充填防砂具有增产作用，但相较于常规开采井，该方式对蒸汽吞吐井的增产效果有所降低。从油井流入动态的角度进行验证的结果表明，新指标对稠油蒸汽吞吐井的产能评价更具意义，且预测误差在允许范围内。

A new productivity evaluation method of sand control completion for steam stimulation in heavy oil reservoirs

At present, the equivalent productivity ratio is the main productivity evaluation index for selecting the optimal sand control completion method. However, the direct impact of sand control on productivity in heavy oil steam stimulation wells is seldom considered; additionally, the injected steam can reduce oil viscosity and increase well productivity. Thus, conventional methods are less applicable to sand control and steam injection in steam stimulation wells. This paper proposes the composite productivity ratio and final productivity ratio for characterizing the change of productivity before and after sand control in steam stimulation wells; the final production ratio is used as a new productivity evaluation index, making the results more visual, characterized with more applicability. The calculation of the new index depends on the new productivity model under sand control completion. Based on the characteristics of sand control and steam stimulation, as well as the calculation formula of non-isothermal heating radius and Darcy's law, this model achieves the coupling of sand control and steam stimulation by considering the influences of high-temperature steam on crude oil viscosity and introducing sand control skin factor. The application practice shows that the final productivity ratio under each sand control method is lower than the equivalent productivity ratio, indicating that the same sand control measures have a more obvious impact on the productivity of steam stimulation wells. Among those measures, fracturing packing sand control can increase well productivity; this method has less effect on increasing the productivity of steam stimulation wells as compared with the conventional production wells. As verified in terms of well inflow performance, it is indicated that the new index is of great significance for evaluating the productivity of heavy oil steam stimulation wells, and the error in productivity prediction is within the allowable range. Therefore, this new method can provide a more direct reference for selecting the optimal sand control completion method applied to heavy-oil steam stimulation wells.