天然气水合物地层钻井时井内温度特征的分析研究

Analytical research on well temperature characteristic while drilling in frozen formations containing natural gas hydrate

摘要: 根据热交换原理,提出了井内温度规程的数学模型,按照这个模型可以计算出井内任何时间、任何深度的温度。以冷却空气作为冲洗介质为例,给出了冷却空气洗井钻进时井内温度的简化计算公式和代表性关系曲线,按照这些计算公式和关系曲线可以计算出和看出空气洗井时井内任何时间、任何深度的温度。根据计算和研究的结果,指出了为了保证在冻土中进行正常钻井,从外环状空间内返回的冲洗介质的温度不宜高于0℃,并提出了相应的建议。

Abstract: A mathematical model of temperature situations in the well is suggested based heat exchange principle. According to the model temperature of any depth and any time of drilling well can be calculated.Taking cold air as a circulation medium, a simplified calculation formula of the well temperature while drilling the formations with cold air is given. According to the formula temperature of any depth and any time of drilling the well with cold air can be calculated and representative dependence curves are given. Based the results of the calculating and considering, the temperature in annular space outside the drill stem should be no more than Ot,and corresponding suggestions are proposed.