水合物法天然气管道输送的实验研究

随着海洋油气开发向深海进军,海底油气混输管线受困于天然气水合物堵塞问题。天然气水合物浆液管道输送技术是保障深水油气田开发的新工艺,而研究天然气水合物浆液的流动特性则是实现上述管输新技术大规模工业应用的重要基础。为此,自行设计了一套模拟海底油气管道天然气水合物生成及其浆体流动的实验装置,分析了模拟海底管道工况下天然气水合物的生成特点,推断出海底管道中天然气水合物生成大致经历乳状物→粒状物→团状物→云状物4个过程;测定了不同工况下天然气水合物生成的诱导时间和生成时间,发现随着反应压力增大,天然气水合物的诱导、生成时间逐渐缩短;比较了温度对天然气水合物生成的影响,发现随着温度升高,天然气水合物的诱导、生成时间均变长;研究了不同工况下的耗气量;初步探讨了海底管道中流动体系下天然气水合物的生成机理。该成果为海底管道以水合物法输送天然气提供了技术依据。

An experimental study on deepwater natural gas transmission based on the hydrate slurry flow technology

With the increasing depth of undersea oil and gas development, more concern has been shown on the issue of gas hydrate blockage in seafloor oil-gas mixed transmission lines. The research of a natural gas hydrate slurry flow will be a guarantee for the further development of deepwater oil and gas fields. And the study on the rheological and flow properties of hydrate slurry is the basis for the industrial employment of submarine pipeline technology. In view of this, we designed and developed a set of experimental devices of simulating the natural gas hydrate formation and slurry flow under submarine pipeline operation conditions. From the simulation, we inferred that the formation of natural gas hydrate in submarine lines would change from the primitive milk form to the later saccharoid, cluster forms, and to the final cloud form. Meanwhile, we measured the induction time and generation time of gas hydrates formed under different working conditions in submarine lines. And we found that with the increase of reaction pressure, the induction time and generation time would be gradually shortened; but with the increase of temperatures, the above mentioned time would become longer. Moreover, we studied the gas consumption under different working conditions, and preliminarily discussed the mechanism of hydrate formation under the flow system in submarine lines. This study lays a foundation for deepwater natural gas transmission lines based upon gas hydrate flow technology.