天然气水合物孔底冷冻取样器储冷腔的设计与试验研究

Design and Experimental Research on Cold Storage Chamber of the Freezing Sampler for Gas Hydrates at Hole Bottom

摘要:

孔底冷冻取样是一种有效的钻取天然气水合物岩心的方法，绳索取心式孔底冷冻取样器的制冷能力由可存储冷源干冰和制冷酒精的储冷腔决定。本文就不同内部结构的储冷腔进行了储冷能力和制冷效果的设计与试验研究，计算了储冷腔的保冷层厚度，并设计了分层式、螺旋阶梯式和带孔管式3种储冷腔内部结构；通过对储冷腔保冷能力的试验研究，干冰存储1 h后平均损失率为31.3%，能满足后续制冷酒精的要求；并对不同结构的储冷腔开展试验研究，试验结果表明，带孔管式储冷腔可在短时间内完成对酒精的冷冻，酒精降温幅度达36.3 ℃，可满足水合物冷冻取样的能量要求。

Abstract:

Hole bottom sampling freezing technology is an effective method to get gas hydrate cores, the cooling capacity of wire-line coring hole bottom freezing sampler is determined by the cold storage chamber which can store dry ice and cool down alcohol. In this paper, cold storage chambers with different internal structures were designed, the experimental studies were made on their cold storage capacity and cooling effect. The thickness of the insulation layer was calculated, and 3 types of internal structure for the cold storage chamber were designed. The tests of cold-keeping ability show that the average loss rate of dry ice is 31.3% after being stored for 1h, which can meet the requirements of subsequent alcohol cooling. The tests also show that the storage cold chamber with perforated-pipe can cool alcohol in a short time, and the cooling rate is up to 36.3℃, which can meet the requirements for gas hydrate freezing sampling.