Abstract: Downhole high-temperature in deep and ultra-deep reservoirs has always been a major factor limiting the stable operation of drilling instruments, thereby restricting the exploration and development process of deep petroleum resources. One of the methods for solving the downhole high-temperature problem is to integrate an active cooling device inside the drilling instruments, which can reduce the temperature of the drilling instrument compartment and guarantee the operation of conventional components, thus indirectly improving the overall high-temperature resistance of the instrument system. Further, an active cooling device that can adapt to ultra-high downhole temperature (>200 ℃) was developed based on the principle of reversed Stirling cycle. Then a physical model was established to analyze its cooling performance by numerical simulation, and ground-based test was performed to assess its cooling effect at different simulated formation temperatures. The research results show that the active cooling device can generate a cooling power of 2.26 W in the ultra-high temperature environment of 225 ℃, and maintain the temperature in the simulated local space of the drilling instrument at 100 ℃. The structural size of the designed active cooling device meets the downhole conditions; moreover, the device shows good adaptability to the thermal environment, thus demonstrating a feasible solution. It is expected to significantly enhance the high-temperature resistance performance of conventional drilling instruments.

Key words: drilling instrument, active cooling device, cooling effect, ultra-high temperature environment, downhole air-conditioner

摘要： 深层、超深层带来的井下高温问题一直是制约随钻仪器稳定工作的重要因素,限制了深层油气资源的勘探开发进程,而在随钻仪器中增加主动降温装置,通过降低仪器舱体的温度,保障常规元器件正常工作,以间接提升其抗高温能力,是解决井下高温问题的方法之一。基于逆斯特林循环原理,设计了一种适应井下超高温环境(＞200℃)的主动降温装置,建立了物理模型,通过数值模型分析了制冷性能,并对其处于不同模拟地层温度下的制冷效果进行地面实验。研究结果表明,该主动降温装置在225℃的超高温环境中,产生2.26 W制冷功率,可将模拟随钻仪器局部空间内的温度控制在100℃,所设计的主动降温装置结构尺寸满足下井条件、热环境适应良好、方案可行,预期能有效提升常规随钻仪器抗高温性能。

关键词: 随钻仪器, 主动降温装置, 冷却效果, 超高温环境, 井下空调