气井携砂可视化实验研究

VISUALIZED EXPERIMENTAL STUDY ON SAND-CARRYING GAS WELL

气井出砂是天然气开采过程常见问题，给气井正常生产及各种采气工艺措施开展带来很多影响，轻微出砂可迫使气井停产，大量出砂会导致气井报废。气砂两相流动状态是影响气井出砂与否的关键因素，而砂粒的运动状态与气流速度的大小有着直接的关系。为了保证气井正常生产，防止砂粒沉积井底造成砂卡，在自建高16m，直径40mm有机玻璃管可视化实验架的基础上，通过实验手段采用压缩空气作为介质，模拟气井连续携砂这一物理现象，并测定砂粒悬浮状态下气流的临界流量及井口压力，用经验公式计算出临界速度，与理论临界流速公式计算结果相差不大，说明该实验装置实际可行。从而确定了井口的压力和采气出砂时的气量，为确保合理的防砂方法提供可靠的依据。

Sand flow of gas well is an ordinary problem during the production of natural gas, causing much influence on normal production of gas well and implement of different gas production methods. Slight sanding may give rise to stop production, but sanding in large amount may cause abandoned gas wells. Flow state of gas and sand are key factors affecting the sand flow of gas well, and state of sand grain movement has direct relation with gas flow velocity. In order to ensure normal production of gas well and to prevent sand grains deposits at bottom hole, and on the basis of self-built visualized experimental instrument of lucite tube with height of 16m and diameter of 40mm, this paper takes compressed air as medium to simulate physical phenomenon of continuous sand carrying and measure critical flow and well head pressure of air flow under the condition of sand grains suspending. Critical speed drawn from empirical formula fundamentally coincides with that of theoretical threshold velocity formula, which proves the feasibility of this experimental instrument. Based on the research, well head pressure and gas production when sand flow occurs in gas well can be determined, offering a reliable basis for selection of reasonable sand control program.