锤磨热解析处理油基钻井液钻屑的效果评价

锤磨热解析是解决目前页岩气钻井过程中油基钻井液含油钻屑处理难题的新型环保技术,但国内对该技术的研究起步较晚,对其处理性能尚缺乏有效的评价手段和方法。为此,以处理效果、能耗以及处理量为评价指标,建立了含油钻屑锤磨热解析处理性能的评价体系,并在四川盆地长宁—威远国家级页岩气示范区某钻井平台建成了含油钻屑锤磨热解析处理站,开展含油钻屑锤磨热解析试验、建立系统能量平衡方程评价能耗、利用正交试验方法评价处理量,进而形成了一套评价含油钻屑锤磨热解析处理性能的方法。研究结果表明:(1)含油钻屑锤磨热解析处理性能评价体系准则——处理后固相残渣含油率小于1%、回收油含固率小于0.3%,系统热效率大于节能评价值88%、热利用率大于95%,锤磨热解析机单位功率处理量大于4.23×10-3 t/(h·k W);(2)在工作温度310℃、处理时间10 min的优化工况下,处理后的固相残渣含油率为0.88%,回收油含固率为0.28%,处理效果能满足环保标准;(3)锤磨热解析技术的热效率高达93.39%,热利用率高达98.82%,不仅处理含油钻屑效率高,而且节能降耗优势明显;(4)预处理含油钻屑以降低含水率可以显著提高处理量,而预热含油钻屑对于提高处理量的效果则不明显。结论认为,该研究成果为提高含油钻屑锤磨热解析处理性能提供了参考,并且利用回收油重配的油基钻井液能够满足现场钻井的要求,实现了油资源的有效再利用。

Effect evaluation of hammer–milling thermal desorption technology on oil-based drilling fluid cuttings

The oily cuttings of oil based drilling fluid in shale gas drilling can be hardly treated. And hammer–milling thermal desorption is a new environmental protection technology to solve this difficulty. In China, however, the research on this technology began later and there are no effective means and methods to evaluate its performance. In this paper, an evaluation system to evaluate the oily cuttings processing performance of hammer–milling thermal desorption was established with processing effect, energy consumption and processing capacity as evaluation indicators. Then, a hammer–milling thermal desorption station for processing oily cuttings was built up at one drilling platform in Changning–Weiyuan National Shale Gas Demonstration Area, Sichuan Basin. Finally, a hammer–milling thermal desorption test was conducted on oily cuttings, a system energy balance equation was established to evaluate energy consumption and the processing capacity was assessed by means of orthogonal test. Thus, a set of method for evaluating the oily cuttings processing performance of hammer–milling thermal desorption was developed. And the following research results were obtained. First, the evaluation system criterion on the oily cuttings processing performance of hammer–milling thermal desorption is as follows. The oil content of solid residual after processing is less than 1%, the solid content of recovered oil is lower than 0.3%, the thermal efficiency of the system is 88%, higher than the energy saving evaluation index, the thermal utilization is higher than 95% and the unitpower processing capacity of hammer–milling thermal desorption device is higher than 4.23×10－3 t/(h·kW). Second, under the optimum condition of operating temperature of 310? ℃ and processing time of 10 min, the oil content of solid residual after processing is 0.88% and the solid content of recovered oil is 0.28%. And it is indicated that the processing performance meets the environmental protection standards. Third, the thermal efficiency of hammer–milling thermal desorption technology reaches 93.39% and its thermal utilization is up to 98.82%, which means that this technology is not only high in oily cuttings processing efficiency, but also remarkable in energy saving and cost reducing. Fourth, preprocessing oily cuttings to reduce the moisture content of the drill cuttings can improve the processing capacity significantly, while preheating oily cuttings cannot improve it well. It is concluded that the research results can provide reference for improving the oily cuttings processing performance of hammer–milling thermal desorption. Besides, the oil-based drilling fluid that is made of recovered oil satisfies the requirements of on-site drilling, and thus the effective reutilization of oil resources is realized.