冻土区天然气水合物勘探低温钻井液理论与试验

Theory and Experiments of Low Temperature Drilling Fluid for Natural Gas Hydrate Exploration in Permafrost Area

摘要:

天然气水合物是在特定的低温与高压条件下形成的产物。在天然气水合物勘探工作中，低温钻井液是获得天然气水合物真实样品的重要保证条件之一。低温钻井液应具有低的冰点、良好的抵制能力与良好的流动性。结合天然气水合物勘探工作的特点，在试验的基础上，对比分析了PAM、PHPA、PAC-141、Na-CMC与KHm的分子结构、官能团的种类与数量对钻井液的防塌能力和流动性的影响，得出了几种处理剂的耐低温能力大小的顺序为：PAC-141＜PHPA＜PAM＜Na-CMC＜KHm，为天然气水合物勘探中低温钻井液的配制与使用，奠定了重要的基础。

Abstract:

Natural gas hydrate is formed under the specific conditions of low temperature and high pressure. Low temperature drilling fluid is the key to get high quality samples of natural gas hydrate during exploration work. Acceptable low temperature drilling fluid for natural gas hydrate should be characterized by low freezing point, good inhibitive capacity and flowability. According to the characteristics of natural gas hydrate exploration and based on the laboratory experiments, the comparison and analysis were made on the influence of molecular structure of PAM, PHPA, PAC-141, Na-CMC and KHm; type and number of functional group to the anti-collapse capacity and flowability of drilling fluids. The results indicated that the low temperature tolerance of above mentioned additives could be listed in order from low to high as PAC-141＜PHPA＜PAM＜Na-CMC＜KHm, which would provide important reference for the preparation and application of low temperature drilling fluid in natural gas hydrate exploration.