高含硫天然气水合物生长特性实验研究

Experimental study on the growth characteristics of high-sulfur gas hydrates

目的解决高含硫气田开发过程中在井筒和管道中形成的天然气水合物造成冰堵的问题。方法在恒温、恒容条件下,采用耐高压哈氏合金釜研究了高含硫天然气水合物宏观生长速率及气田水矿物离子对其的影响情况,同时,采用直接观察法从俯视角度研究了压力、气田水矿物离子及溶液形态对气液界面高含硫天然气水合物生长过程形貌特征、生长特性及延展规律的影响。结果气田水中矿物离子的存在可降低水合物的生长速率,同时改变水合物形貌。在气液界面,水合物从成核点以二维拓展模式向四周生长。升高压力对水合物形貌影响较小,但会提高水合物的生长速率。结论分析认为,矿物离子主要是通过离子化作用来降低水的活性,从而影响水合物的生长过程。研究结果对水合物安全防治和高含硫气田的顺利开发具有理论指导意义。

Objective During the exploitation process of high-sulfur gas reservoirs,natural gas hydrates are easily formed in the wellbore and pipeline,causing ice blockage and affecting normal production.Methods Under the conditions of constant temperature and volume,the effects of the mineralization ions on the growth rate of high-sulfur gas hydrates are experimentally studied in an Hastelloy reactor.The effects of pressure,mineral ions of gas field water and solution morphology on the growth process morphology,growth characteristics and extension pattern of high-sulfur gas hydrate at the gas-liquid interface were also studied by direct top-view observation.Results It is shown that the salts can decrease the growth rate of hydrates and change the morphology of the hydrate crystal.At the gas-liquid interface,the hydrate grows from the nucleation point in a two-dimensional expansion pattern.When elevating the pressure,it has little effects on the morphology of hydrate crystal,but it can increase the growth rate of hydrate.Conclusions The analysis shows that ionization effects of the salts decrease the activities of water and affect the growth process of hydrate.The experimental results of this work have great significance for hydrate prevention and the normal exploitation of high-sulfur gas reservoir.