聚胺水基钻井液中天然气水合物生成过程实验研究

Experimental Study on Methane Hydrate Formation from Water-based Drilling Fluid

实验采用定容压力搜索法测量了聚胺钻井液在3℃ - 13℃范围内甲烷水合物的三相平衡条件.定容条件下考察了在初始压力分别为8 MPa、10 MPa、12 MPa 条件下聚胺钻井液中甲烷水合物的生成过程.结果表明,聚胺钻井液对甲烷水合物生成的热力学抑制作用并不明显.同时,提高反应的初始压力会显著缩短水合物的生成时间、增加水合物的生成总量、增大反应初期生长速率以及水合物生长的不均匀性.强化聚胺钻井液的传热传质速率并降低钻探时的井下压力有利于抑制钻井液中水合物的生成.

The three phase equilibrium conditions of methane hydrate from water-based drilling fluid were measuredranging from 3oC to 13oC by isochoric pressure-search method. The methane hydrate formation from water-based drillingfluid was carried out under isochoric conditions with an initial pressure of 8 MPa, 10 MPa and 12 MPa respectively.Results showed that the inhibition effect of water-based drilling fluid on methane hydrate was not obviousthermodynamically. Meanwhile, increasing the initial pressure could greatly reduce the hydrate formation time, increasethe production and initial hydrate growth rate and spoil the homogenous hydrate growth in liquid bulk. Strengthening theheat and mass transfer in water-based drilling fluid and lowering the pressure in drilling site would be useful to inhibit thehydrate growth.