防止水合物形成的气井井口温度定量分析

QUANTITATIVE ANALYSIS OF THE GAS-WELL WELLHEAD TEMPERATURE TO PREVENT THE HYDRATE FORMATION

为避免气井地面节流温降形成水合物,发生堵塞超压,危及生产安全,通过分析井口温度变化特征,运用统计热力学模型计算气井地面节流压降点的水合物形成温度,提出采气地面流程水合物形成判定方法。采用气井非稳态传热模型和气井稳态传热模型综合分析井口温度变化类型、变化速度和井口稳定温度大小对水合物形成的影响。以龙王庙组气藏气井为例对防止水合物形成的主要生产参数控制指标进行计算分析,提出水合物形成井口临界温度及对应的水合物形成临界产量参数作为避免水合物形成的主要生产控制指标;在气井开井时,可以通过提高产量,加快井口温度上升速度,缩短水合物生成窗口时间,避免水合物堵塞,为生产管理和地面建设提供参考。

In order to avoid the suhed from the surface throttling hydrate formation, blockage and overpressure to damage the production safety re- temperature drop of the gas wells, through the analysis of the variation characteris- tics of the wellhead temperature, and moreover with the help of the statistical thermodynamic model, the hydrate formation temperatures in the position of the gas-well surface throttling pressure drops were calculated, and further- more the judging method was proposed for the hydrate formation in the surface process of the gas production. The in- fluences of the changed type of the well head temperature, change speed and wellhead stability temperature on the hydrate formation were analyzed comprehensively by using the unsteady and steady states＂ heat transferring models of the gas well. Taking the gas wells in Longwangmiao-Formation gas reservoirs as an example, the controlling inde- xes of the main production parameters were calculated and analyzed to prevent the formation of the hydrates, and moreover the wellhead critical temperature and production parameters were put forward for the formation of the hy- drates, both of the two kinds of data are regarded as the main production controlling indexes for the formation; when the gas wells are opened, the hydrate blockage can be avoided by increasing the production, accelerating the well- head temperature rising speed, shortening the window time of the gas hydrate formation. All the countermeasures have provided the references for the production management and ground construction.